2nd INTERNATIONAL WORKSHOP ON LASER-MATTER …wlmi10/BookWLMI10_web.pdf · means to the workshop,...

Edited 25 June 2010

2nd INTERNATIONAL WORKSHOP ON LASER-MATTER

INTERACTION 2010

September 13-17, 2010 Porquerolles, France

Book of abstracts

WORKSHOP ON LASER-MATTER INTERACTION 2010

WLMI-2010

Dear Participants

It is a real pleasure to welcome you to this second edition of the Workshop on Laser-Matter Interaction. After Luminy in 2008, we are pleased to see that this meeting is growing in size, becoming international, and attracting new generations of scientists. This second international edition will hopefully broaden the community and strengthen ties between various laboratories with worldwide reputation. The island of Porquerolles was chosen for its beauty but also for the convenient facilities offered by the IGESA housing. We are 63 registered participants and received 65 contributions. Among those, 44 have been selected for oral sessions and 16 for the poster session. The sessions have been organized into three 30 minutes tutorials, forty one 20 minutes talks and sixteen posters. We tried to mostly follow the participants’ wishes, but we were also concerned with keeping a certain coherence between all the topics addressed within each session. Tutorials have been selected in order to emphasize “hot topics”, such as warm dense matter and radiative shocks, ultra-high intensities and particle acceleration, femtosecond laser filamentation and related applications. We willingly leave the beginning of the afternoons free (between 14:00 and 17:00), so that everybody can enjoy the island by walking or riding a bicycle, by contemplating the Mediterranean depths, or even by tasting local wines. We would like to thank the generous organizations that contributed either financially or by other means to the workshop, namely, the CEA-DAM at Bruyères-le-Châtel and several of its departments, the Laser-Plasmas Institute in France, and the Max-Planck Institute in Germany. We hope that you – and your family for some of you – will enjoy this meeting and your stay at Porquerolles.

Organizing committee Luc Bergé CEA France Christophe Rousseaux CEA France Stefan Skupin MPI-PKS Germany

Scientific committee

Patrick Mora France J.C. Saut France D. Skryabin U.K. G. Steinmeyer Germany V. Tikhonchuk France


WLMI-2010

Program

Monday, September 13 19:15 Welcome reception

Tuesday, September 14 08:45-09:00........... Opening, L. Bergé 09:00-10:30 ....... Session Warm Dense Matter & AstroLab Chair: P. Mora 09:00-09:30........... Tutorial: R. P. Drake “Laboratory astrophysics using HERCULES, Omega and NIF” 09:30-09:50 B. Loupias “Laboratory astrophysics using intense lasers“ 09:50-10:10 S. Brygoo “Measurements of the equation of state of hydrogen/helium mixtures under deep

planetary conditions “ 10:10-10:30 T. Vinci “Numerical and experimental study of quasi-isentropic compression by Laser Irradiation “

10:30-11:00 Coffee break

11:00-12:30 ....... Session Femtosecond Filamentation Chair: L. Bergé 11:00-11:30........... Tutorial: O. Kosareva “Polarization rotation due to femtosecond filamentation in an atomic gas” 11:30-11:50 A. Aceves “Modeling UV filamentation“ 11:50-12:10 J. Kasparian “Higher-order Kerr terms allow ionization-free filamentation in gases“ 12:10-12:30 S. V. Chekalin “Interference effects in supercontinuum conical emission upon filamentation of a

femtosecond laser pulse in condensed matter“

12:30 Lunch

17:00-18:40 ....... Session Ultrafast Microprocessing Chair: J. Kasparian 17:00-17:20 F. Courvoisier “Ultrafast laser micro/nano processing of high aspect ratio channels in dielectrics

with Bessel beams“ 17:20-17:40 V. Mezentsev “Single process femtosecond laser microfabrication -- novel technology in modern

photonics: meticulous experiments and serious numerics“ 17:40-18:00 S. Guizard “Femtosecond ablation of dielectrics : time resolved studies of excitation mechanisms“ 18:00-18:20 T. Itina “Ultra-short laser interactions: insights from numerical modeling“ 18:20-18:40 Yu. Geints “Explosive evaporation of large water droplet irradiated by ultrashort laser pulses“

Wednesday, September 15 08:40-10:00 ....... Session Applied Mathematics Chair: E. A. Kuznetsov 08:40-09:00 D. Lannes “Short pulses approximation in dispersive media“ 09:00-09:20 E. Lorin “A nonlinear quantum optics model for laser-gas interaction in some extreme regimes“ 09:20-09:40 E. Dumas “High frequency behaviour of the Maxwell-Bloch model with relaxations: Convergence

to the Schrödinger-Boltzmann system” 09:40-10:00 R. Sentis “On three-wave coupling system and the related simulations of the Brillouin

Backscattering for ICF target”



WLMI-2010

10:30-12:20 ....... Session Ultra-High Intensities Chair: B. Afeyan 10:30-11:00 .......... Tutorial: P. Mora “Plasma expansion into a vacuum and ion acceleration” 11:00-11:20 V. Yu. Bychenkov “Towards improving the quality of laser-produced particle sources“ 11:20-11:40 S. Ter-Avetisyan “Laser-based ion acceleration: new progress and perspectives for application“ 11:40-12:00 A. A. Andreev “Laser ion acceleration in shaped mass-limited targets“ 12:00-12:20 L. Gremillet “Recent results on unstable relativistic electron transport into dense plasmas“

12:30 Lunch

17:00-19:00 ....... Poster Session

Thursday, September 16 09:00-10:20 ....... Session Pulse Compression and Nonlinear Propagation

Chair: O. Kosareva 09:00-09:20 G. Steinmeyer “Single and multiple filamentary self-compression scenarios“ 09:20-09:40 E. Constant “Ionization induced post compression of high energy pulses“ 09:40-10:00 M. Bache “Few-cycle energetic femtosecond pulses in the visible and near-IR by using cascaded

quadratic soliton compression“ 10:00-10:20 V. Tosa “Pulse propagation effects in high order harmonic generation by mid-infrared source“


11:00-12:20 ....... Session Supercontinuum Generation and Frequency Conversion

Chair: G. Steinmeyer 11:00-11:20 W. Krolikowski “Parametric wave mixing in nonlinear disordered media“ 11:20-11:40 A. V. Gorbach “Nonlinear photonics in silicon nano-structures“ 11:40-12:00 J. Herrmann “Generation of high-power supercontinuum and tunable sub-10-fs VUV pulses in

photonic crystal fibers“ 12:00-12:20 M. Taki “Observation of extreme temporal events in CW-pumped supercontinuum“

12:30 Lunch

17:00-18:40 ....... Session Inertial Confinement Fusion Chair: R. P. Drake 17:00-17:20 P. Michel “Analysis and review of laser plasma interactions in experiments on the National Ignition

Facility“ 17:20-17:40 B. Afeyan “Spike Trains of Uneven Duration and Delay: STUD pulses for the control of nonlinear

optical instabilities in laser-matter interactions“ 17:40-18:00 D. Benisti “Nonlinear properties of an electron plasma wave and application to stimulated Raman

scattering“ 18:00-18:20 P. Loiseau “Realistic modelling of laser-plasma interaction in hot plasmas: toward a predictive

tool?“ 18:20-18:40 P. E. Masson-Laborde “Progress in modeling and understanding of parametric instabilities in

laser-plasma-interaction“

19:30 WLMI Conference Dinner


WLMI-2010

Friday, September 17 08:40-10:20 ....... Session X, VUV and THz Sources Chair: V. Yu.

Bychenkov 08:40-09:00 C. Courtois “MeV X-ray source production on Omega EP laser facility “ 09:00-09:20 J. Liu “Fast electrons and high order harmonics generation from ultraintense laser-plasma

interaction“ 09:20-09:40 I. Babushkin “Modeling of THz emission from plasma-generating femtosecond laser pulses with

unidirectional Maxwell equation in plasma spots and in guided geometries“ 09:40-10:00 S. Le Pape “X-ray Thomson scattering of isochorically proton heated Boron Nitride“ 10:00-10:20 F. Dorchies “Time-resolved XANES to probe the structure of Warm Dense Matter“


10:50-12:10 ....... Session Self-focusing and Singular Dynamics Chair: S. Skupin 10:50-11:10 E. A. Kuznetsov “Collapse as a process of pulse shortening“ 11:10-11:30 P. M. Lushnikov “Statistics of strong optical turbulence“ 11:30-11:50 H. Leblond “Few-cycle optical pulse: Collapse and light bullets“ 11:50-12:10 N. Rosanov “Extreme optical pulse compression and frequency transformation “ 12:10-12:30........... Closing, Organizing Committee

12:30 Lunch

15:00 Departure


WLMI-2010

Oral contributions O 1: Laboratory astrophysics using HERCULES, Omega, and NIF ............................... 12 O 2: Laboratory astrophysics using intense lasers ......................................................... 13 O 3: Measurements of the equation of state of hydrogen/helium mixtures under deep

planetary conditions................................................................................................ 14 O 4: Numerical and Experimental Study of Quasi-Isentropic Compression by Laser

Irradiation ............................................................................................................... 15 O 5: Polarization Rotation due to Femtosecond Filamentation in an Atomic Gas .......... 16 O 6: Modeling UV Filamentation .................................................................................... 17 O 7: Higher-order Kerr terms allow ionization-free filamentation in gases ..................... 18 O 8: Interference effects in supercontinuum conical emission upon filamenttation of a

femtosecond laser pulse in condensed matter ....................................................... 19 O 9: Ultrafast laser micro/nano processing of high aspect ratio channels in dielectrics

with Bessel beams.................................................................................................. 20 O 10: Single process femtosecond laser microfabrication — novel technology in modern

photonics: meticulous experiments and serious numerics ...................................... 21 O 11: Femtosecond ablation of dielectrics : time resolved studies of excitation

mechanisms ........................................................................................................... 22 O 12: Ultra-short laser interactions: insights from numerical modeling ............................ 23 O 13: Explosive Evaporation of Large Water Droplet Irradiated by Ultrashort Laser Pulses

............................................................................................................................... 24 O 14: Short pulses approximation in dispersive media .................................................... 25 O 15: A nonlinear quantum optics model for laser-gas interaction in some extreme

regimes ................................................................................................................... 26 O 16: High Frequency Behaviour of the Maxwell-Bloch Model with Relaxations:

Convergence to the Schrödinger-Boltzmann System ............................................. 27 O 17: On three-wave coupling system and the related simulations of the Brillouin

Backscattering for ICF target. ................................................................................. 28 O 18: Plasma expansion into a vacuum and ion acceleration .......................................... 29 O 19: Towards improving the quality of laser-produced particle sources ......................... 30 O 20: Laser-based ion acceleration: new progress and perspectives for application ....... 31 O 21: Laser ion acceleration in shaped mass-limited targets ........................................... 32 O 22: Recent results on unstable relativistic electron transport into dense plasmas ........ 33 O 23: Single and multiple filamentary self-compression scenarios .................................. 34 O 24: Ionization induced post compression of high energy pulses ................................... 35 O 25: Few-cycle energetic femtosecond pulses in the visible and near-IR by using

cascaded quadratic soliton compression ................................................................ 36 O 26: Pulse propagation effects in high order harmonic generation by mid-infrared source

............................................................................................................................... 37 O 27: Parametric wave mixing in nonlinear disordered media ......................................... 38 O 28: Nonlinear photonics in silicon nano-structures ....................................................... 39 O 29: Generation of high-power supercontinuum and tunable sub-10-fs VUV pulses in

photonic crystal fibers ............................................................................................. 40 O 30: Observation of extreme temporal events in CW-pumped supercontinuum ............. 41 O 31: Analysis and review of laser plasma interactions in experiments on the National

Ignition Facility ........................................................................................................ 42 O 32: Spike Trains of Uneven Duration and Delay: STUD pulses for the Control of

Nonlinear Optical Instabilities in Laser-Matter Interactions* ................................... 43 O 33: Nonlinear properties of an electron plasma wave and application to stimulated

Raman scattering ................................................................................................... 44


WLMI-2010

O 34: Realistic modelling of laser-plasma interaction in hot plasmas: toward a predictive tool? ........................................................................................................................ 45

O 35: Progress in modeling and understanding of parametric instabilities in laser-plasma-interaction ............................................................................................................... 46

O 36: MeV X-ray source production on Omega EP laser facility ....................................... 47 O 37: Fast electrons and high order harmonics generation from ultraintense laser-plasma

interaction ............................................................................................................... 48 O 38: Modeling of THz emission from plasma-generating femtosecond laser pulses with

unidirectional Maxwell equation in plasma spots and in guided geometries ........... 49 O 39: X-ray Thomson scattering of isochorically proton heated Boron Nitride .................. 50 O 40: Time-resolved XANES to probe the structure of Warm Dense Matter .................... 51 O 41: Collapse as a process of pulse shortening .............................................................. 52 O 42: Statistics of strong optical turbulence ...................................................................... 53 O 43: Few-cycle optical pulse: Collapse and light bullets ................................................. 54 O 44: Extreme Optical Pulse Compression and Frequency Transformation ..................... 55


WLMI-2010

Posters contributions P 1: Advances in Optical Mixing Techniques for the Effective Control of Parametric

Instabilities in Laser-Produced Plasmas ................................................................. 56 P 2: Nonlinear Bloch equations for laser-quantum dot interactions ............................... 58 P 3: Scaling laws in laboratory astrophysics .................................................................. 59 P 4: Terahertz radiation from gas plasma, generated by linearly polarized femtosecond

pulses ..................................................................................................................... 60 P 5: Terahertz mode dynamics in beta- barium borate crystals ..................................... 61 P 6: Radiating Solitary Waves in Photonic Band Gap .................................................... 62 P 7: Paths towards the generation of monochromatic ion beams .................................. 63 P 8: All-optical steering of light via spatial Bloch oscillations in a gas of three-level atoms

............................................................................................................................... 64 P 9: Theory of Plasmon-Enhanced High-Harmonic Generation in the Vicinity of Metal

Nanoparticles ......................................................................................................... 65 P 10: Self-compression of ultrashort pulses in media with negative third order nonlinearity

............................................................................................................................... 66 P 11: Coupling between Kerr-induced filamentation and stimulated Brillouin scattering in

silica ....................................................................................................................... 67 P 12: Development of laser plasma instabilities during the interaction of two successive ps

pulses at moderate intensity: space- and time-resolved Thomson scattering measurements ........................................................................................................ 68

P 13: Stability of nonlinear Vlasov waves through Fourier-Hermite discretization ........... 69 P 14: Self-Organized Dissipationless Ginzburg-Landau Solitons .................................... 70 P 15: Analytical solutions for generalized nonlinear Schrodinger equation ...................... 71 P 16: Fast Electron Generation and Transport in Laser-Induced Shock Compressed

Plasmas .................................................................................................................. 72


WLMI-2010

Author Index Aceves A. 17 Aedy C. 47 Afeyan B. 43, 56, 68 Aleksic N. B. 70 Amadou N. 51 Amiranoff F. 68 Andreev A. A. 32 Atherton L. J. 42 Babushkin I. 49 Bache M. 36 Bandrauk A. 26 Batani D. 72 Baton S. D. 68, 72 Bazzoli S. 47 Beg F. N. 72 Béjot P. 18 Benedetti C. 72 Benisti D. 33, 44, 68, 69 Benocci R. 72 Benuzzi-Mounaix A. 15, 50, 51 Bergé L. 34, 49, 66, 67 Bhuyan M. K. 20 Bidégaray-Fesquet B. 58 Boehly T. R. 14 Bond E. 42 Borghesi M. 31 Bouquet S. 13, 59 Bourgade J.-L. 47 Brambrink E. 15, 51, 72 Brée C. 34 Brenner C. M. 31 Brown C. 50 Brygoo S. 14 Bychenkov V. Yu. 30 Calegari F. 37 Callahan D. A. 42 Carpeggiani P. 72 Carroll D. C. 31 Casanova M. 45, 46 Castella F. 27 Cavet C. 13 Celliers P. M. 14 Chawla S. 72 Chekalin S.V. 19 Chelkowski S. 26 Chen Y. 16 Chin S. L. 16 Collins G. W. 14 Compant la Fontaine A. 47

Constant E. 35 Courtois C. 47 Courvoisier F. 20 Coury M. 72 Davis P. F. 50 de Rességuier T. 15 Degert J. 61 Demircan A. 34 Depierreux S. 45, 46 Derrien Th. 23 Descamps D. 35 Dewald E. L. 42 Diaw A. 63 Divol L. 42 Dixit S. N. 42 Dizière A. 13 Doeppner T. 50 Dorchies F. 51, 72 Doria D. 31 Dormidonov A.E. 19 Dover N. 31 Drake R. P. 12 Drew D. 47 Dubrouil A. 35 Dudley J. M. 20 Dumas E. 27 Edwards M. J. 42 Edwards R. 47 Eggert J. 14 Ettoumi W. 18 Fadeev D. A. 60 Falize E. 13, 59 Faucher O. 18 Fedorov N. 22 Fedotova O. 61 Festa F. 51 Fortmann C. 50 Foster P. S. 31 Fourcade Dutin C. 35 Fourment C. 72 Freysz E. 61 Furfaro L. 20 Gaizauskas E. 62 Galimberti M. 72 Gallegos P. 31 Gardner M. 47 Garnier J. 43 Gazave J. 47 Geints Yu. E. 24


WLMI-2010

Gizzi L. A. 72 Glenzer S. H. 42, 50 Golik S. S. 24 Goossens J.-P. 45 Grech M. 63 Green J. S. 31 Gregori G. 50 Gregory C. D. 13 Gremillet L. 33, 44, 63, 68, 69 Grobach A. V. 39 Guizard S. 22 Guyot F. 15 Hall T. 51 Hang C. 64 Heathcote R. 72 Henin S. 18 Herrmann J. 40, 49, 65 Hertz E. 18 Higginson D. P. 72 Hinkel D. E. 42 Hochhaus D. 50 Honrubia J. J. 72 Hueller S. 43, 45, 46 Hulin S. 72 Husakou A. 40, 65 Im S.-J. 40, 65 Itina T. E. 23 Jacquot M. 20 Jafer R. 72 Jarrot L. C. 72 Jeanloz R. 14 Kabanov A. M. 24 Kandidov V.P. 19 Kasparian J. 18 Khasanov O. 61 Kiefer T. 63 Klimentov S. 22 Kline J. L. 42, 68 Koenig M. 13, 15, 51, 72 Köhler C. 49, 66 Kolobov M. 41 Kompanets V.O. 19 Konotop V. V. 64 Kosareva O. G. 16 Köster P. 72 Kovacs K. 37 Kremer D. 54 Kritcher A. L. 50 Krolikowski W. 38 Kudlinski A. 41 Kuramitsu Y. 13 Kuznetsov E. A. 52

Kyrala G. A. 42 Labate L. 72 Labaune Ch. 46 Lacourt P. A. 20 Lancaster K. 72 Landen O. L. 42, 50 Landoas O. 47 Lannes D. 25 Lavorel B. 18 Le Pape S. 50 Leblond H. 54 Lefebvre E. 33, 47, 63 Lévy A. 51 Li R. 48 Lindl J. D. 42 Liu J. 48 Loiseau P. 45, 46, 68 Lorin E. 26 Loriot V. 18 Loubeyre P. 14 Loupias B. 13, 68 Louvergneaux E. 41 Lushnikov P. M. 53 MacGowan B. J. 42 MacKinnon A. J. 72 Makarov V. A. 16 Marceau C. 16 Mardirian M. 43 Mardirian M. M. 56 Marion D. 45 Masson-Laborde P.-E. 45, 46 Mastrosimone D. 47 Mauger S. 67 Mazevet S. 51 Mazevetv S. 15 McKenna P. 31, 72 McPhee A. G. 72 Meezan N. B. 42 Mével E. 35 Mezentsev V. 21 Michaut C. 13, 59 Michel P. 42 Mihalache D. 54 Mikaberidze A. 63 Mironov V. A. 60 Montgomery D. S. 68 Moody J. D. 42 Mora P. 29 Morard G. 15 Morice O. 44 Morita T. 13 Mouskeftaras A. 22


WLMI-2010

Mussot A. 41 Najmudin Z. 31 Nazarov W. 13, 72 Neely D. 31 Negro M. 37 Neumayer P. 50 Nicolaï Ph. 72 Nuter R. 63 Oberlé J. 61 Oshlakov V. K. 24 Palmer C. A. J. 31 Panov N. A. 16 Pasley J. 72 Perez F. 72 Perezhogin I. A. 16 Pesme D. 45, 46 Petit S. 35 Petit Y. 18 Peyrusse O. 51 Philippe F. 68 Pien G. 47 Pikuz S. 13 Povarnitsyn M. E. 23 Prasad R. 31 Quinn K. E. 31 Rabec Le Glohaec M. 72 Ramis R. 72 Ravasio A. 13, 50, 51 Recoules V. 51 Regan C. 72 Rhee Y. 72 Ribeyre X. 13, 72 Richetta M. 72 Romagnani L. 31 Rosanov N. N. 55 Rousseaux C. 43, 45, 68 Rozmus W. 46 Rusetsky G. 61 Sakawa Y. 13 Santos J. J. 72 Savel’ev A. B. 16 Savickas A. 62 Schlenvoigt H.-P. 72 Schneider M. B. 42 Schreiber J. 31 Schurtz G. 72 Sentis R. 28 Serres F. 72 Sgattoni A. 72 Shcheblanov N. S. 23 Siminos E. 44, 69

Simons A. 47 Skarka V. 70 Skopina O.V. 19 Skupin S. 34, 49, 63, 66, 67 Smetanina E.O. 19 Spaulding D. 14 Spindloe C. 72 Stagira S. 37 Staliunas K. 62 Steinmeyer G. 34 Stoeckl C. 47 Streeter M. J. V. 31 Strozzi D. J. 44 Suter L. J. 42 Takabe H. 13 Taki M. 41 Tatarinova L. T. 71 Ter-Avetisyan S. 31 Teychenne D. 45 Thomas C. A. 42 Tikhonchuk V. T. 63 Tosa V. 37 Town R. P. J. 42 Tresca O. 31 Vaisseau X. 72 Vauzour B. 72 Veltcheva M. 72 Vermersch B. 33 Vidal S. 61 Vieillard T. 18 Vinci T. 15 Vladimirova N. 53 Volpe L. 72 Vozzi C. 37 Wang C. 48 Wang T. 16 Wang W. 48 Widmann K. 42 Williams E. A. 42 Wise F. W. 36 Wolf J.-P. 18 Woolsey N. C. 13 Xia C. 48 Xu Z. 48 Yahia V. 72 Yuan S. 16 Zemlyanov A. A. 24 Zeng H. 16 Zepf M. 31 Zhou B. 36


WLMI-2010

O 1: Laboratory astrophysics using HERCULES, Omega, and NIF

R. Paul Drake University of Michigan - USA

Abstract:

This talk will discuss our work in laboratory astrophysics using intense lasers at the University of Michigan. Our focus is on dynamical processes present in astrophysics that can be produced in the laboratory. We have used the HERCULES laser to explore the filamentation of relativistic electron beams in plasmas, a process that represents on step in the ultimate emission of detectable radiation from relativistic jets. We have use the Omega laser very extensively, in two directions Our focus in radiation hydrodynamics has been the study of radiative shock waves, in which radiative energy transfer produces structure in shock waves that differs dramatically from the structure in more-familiar, purely hydrodynamic cases. To do this, we launch a piston of Be plasma at ~ 200 km/s into a shock tube filled with Xe gas at near atmospheric pressure. This produces a shock wave with a Mach number of about 600, in which most of the thermal energy created by the shock transition is converted to radiation. By means of experiments, theory, advances in diagnostics, computer simulations, and uncertainty quantification we are working to better understand the structure of these systems. Looking ahead, we a turning our attention to radiative reverse shocks, one component of the structure that develops naturally in cataclysmic binary stars. Our focus in high-energy-density hydrodynamics is the fundamental instabilities of compressible, accelerating, ionizing systems. We see novel effects in both the Rayleigh-Taylor instability and the Kelvin Helmholtz instability, very likely reflecting complex properties of high-energy-density systems not present in traditional fluids. Issues in understanding observations of supernovae directly motivate our Rayleigh-Taylor experiments. Combining both these thrust areas, we are doing experiments at the National Ignition Facility for radiation-shock-mediated, hydrodynamic-instability experiments. These experiments are relevant to phenomena in red supergiant stars. Many collaborators, to be acknowledged in the talk, have been essential to this work. The work to be discussed is funded by the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas, by the National Laser User Facility Program in NNSA-DS and by the Predictive Sciences Academic Alliances Program in NNSA-ASC. The corresponding grant numbers are DE-FG52-09NA29548, DE-FG52-09NA29034, and DE-FC52-08NA28616.


WLMI-2010

O 2: Laboratory astrophysics using intense lasers

B. Loupias1 & A. Ravasio2

1 CEA-DAM F-91297 Arpajon, FRANCE 2 Laboratoire LULI, Ecole Polytechnique, Palaiseau, FRANCE

E, Falize1, C. D. Gregory2, A. Dizière2, M. Koenig2, C. Michaut3, C. Cavet3,S. Bouquet1, X. Ribeyre4, H. Takabe5, Y. Sakawa5, Y. Kuramitsu5, T. Morita5, N. C. Woolsey6,

W. Nazarov7, S. Pikuz8

3LUTH, Observatoire de Paris, CNRS, Université Paris-Diderot, 92190 Meudon, France 4Centre Lasers Intenses et Applications (CELIA), UMR 5107 Université Bordeaux 1, 351,

cours de la Liberation, 33405 Talence Cedex FRANCE 5Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka, Japan

6Department of Physics, University of York, York, YO10 5DD, UK 7School of Chemistry, University St Andrews, Purdie Blg, St Andrews, United

Kingdom 8Joint Institute for High Temperatures of RAS, Izhorskaya 13/19, Moscow,

Russia

Thanks to the development of high powered facilities in the last two decades, such as high-energy lasers and fast magnetic pinch machines (Z-pinch), we can today reach in laboratory high pressure and high temperature conditions, typical of astrophysical environments. These progresses, strictly connected with inertial controlled fusion research, has allowed the emergence of a new discipline, the laboratory astrophysics. This new class of experimental science, is perfectly complementary to observations, which cannot always give satisfactory responses, due to an insufficient number of data or a too low phenomena evolution. The possibility of performing well-designed laboratory simulations to study astrophysical objects has been demonstrated and can contribute to understand different processes and to validate complex simulations. Here we present a series of experiments performed at LULI laboratory. Especially we will concentrate on our experiments aiming at reproducing astrophysical events by resemblance or similarity. These include plasma jets and radiative shocks. Both studies have a deep impact to validate radiative hydrodynamic processes encountered around young stellar object and supernovae respectively. We will also present a recent experiment designed to simulate accretion process in magnetic with dwarf.


WLMI-2010

O 3: Measurements of the equation of state of hydrogen/helium mixtures under deep planetary conditions S. Brygoo P. Loubeyre J. Eggert P. M. Celliers D. Spaulding T. R. Boehly R. Jeanloz and G. W. Collins


WLMI-2010

O 4: Numerical and Experimental Study of Quasi-Isentropic Compression by Laser Irradiation

Tommaso Vinci (1)*, Michel Koenig (1), Alessandra Benuzzi Mounaix (1), Erik Brambrink

(1), Stephane Mazevet (2), G. Morard (3), F. Guyot (3), T. de Rességuier (4)

(1) LULI, Ecole Polytechnique, Palaiseau, France (2) CEA-DAM, Bruyeres-le-Chatel, France

(3) IMPMC, 140 rue de Lourmel, 75005 Paris, France (4) ENSMA, 1 ave. Clément Ader, 86961 Futuroscope Cedex, France

In this contribution we are presenting recent numerical and experimental studies done in the framework of a large collaboration (ANR SECHEL) aimed at reproducing earth interior condition by laser generated isentropic ramp compressions in both iron and aluminum. These conditions belong to the WDM field of physics (P ~ 1 Mbar and T ~ 1000˚K). We will report the numerical simulations done with a radiative-hydrodynamic code (MULTI); a second step has been done to couple these simulations with molecular dynamics to reproduce microscopic effects in materials. This is a multi-scale approach to simulate matter in these conditions: the ramp of compression wave of a hydrodynamic simulation is injected as ramp in a pure molecular dynamics simulation (using massive parallel STAMP code) to study the dynamics of the atomic structure of materials on strong stress on the same longitudinal and temporal scales of the experiment (some microns and 1 ns). This a key point to have a complete picture of the experiment since the hydrodynamic approach fails to understand the underlying mechanism of phase changes of the material. On the experimental side, we will present the results of recent experiments done at LULI (France) and ILE (Osaka, Japan) using two experimental approaches and we will report diagnostic measurements and connections with numerical simulation. *E-mail address: [email protected]


WLMI-2010

O 5: Polarization Rotation due to Femtosecond Filamentation in an Atomic Gas

O.G. Kosareva1,, N.A. Panov1, V.A. Makarov1, I.A. Perezhogin1, C. Marceau2, Y. Chen2, S. Yuan2, T. Wang2, H. Zeng3, A.B. Savel’ev1, and S.L. Chin2

1International Laser Center & Faculty of Physics, Lomonosov Moscow State University, Moscow, Russia, e-mail: [email protected] 2Centre d’Optique, Photonique et Laser (COPL) and Département de physique, de génie physique et d’optique, Université Laval, Québec, Québec

G1V 0A6, Canada 3State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China

The high intensity inside femtosecond light filaments generated by linearly polarized infrared (800 nm) pulses is sufficient for symmetry breaking in the nonlinear optical response of isotropic gases. In argon, an initially linearly polarized co-propagating probe pulse at 400 nm becomes elliptically polarized or, for the specifically chosen conditions, remains linearly polarized but rotated by a certain angle [1-3].

In this paper we show the variation with distance of the polarization ellipticity in a weak linearly polarized probe beam at 400 nm co-propagating with an 800 nm pump beam, the latter forming a filament in 1 atm argon. The largest rotation angle relative to the initial direction of the probe’s polarization is induced inside the high-intensity filament core. With propagation distance the nonlinearly rotated probe radiation diffracts outward into the beam periphery. The experimentally obtained and simulated fluence signals are compared after an analyzer at the end of the high-intensity filament zone.

In the experiment, a single filament was created by focusing a 1.1 mJ, linearly polarized, 50 fs Ti:sapphire pump pulse into a gas cell filled with argon. The filament was probed by a second pulse (100 fs, ~1 mJ, 400 nm, polarized at an angle between 0°-90° relative to the pump). After the interaction zone, the probe pulse was transmitted through an analyzer. In our propagation model the light field complex amplitude E of both the pump and the probe radiation is represented by two components Ex and Ey in the plane perpendicular to the propagation direction z. For each of the four light field components we take into account diffraction, material dispersion, the group velocity walk-off, self- and cross-action due to Kerr nonlinearity at the frequencies w and 2w, plasma generation and ionization-induced energy loss. The simulated distribution of the probe light field is projected onto an analyzer and then integrated over the time yielding the fluence similar to the experiment.

In conclusion, the largest rotation occurs in the central spot of the probe beam corresponding to the filament core of the pump (Fig.1). With propagation distance, the elliptically polarized and rotated probe radiation diffracts outwards into the beam periphery while the polarization direction in the core relaxes to almost the initial orientation.

References [1] P. Béjot et al Opt. Express 16, 7564 (2008). [2] Y. Chen et al Opt. Lett. 33, 2731 (2008). [3] C. Marceau et al, Opt. Lett. 34, 1417 (2009).

0 25 50 75 100 125 1500

306090

120

0.00

0.05

0.10 pump, 800 nm, 1 mJ

propagation distance z, cm

Pum

p in

tens

ity,

TW/c

m2

probe 400 nm, 1 mJ

Pro

be in

tens

ity,

GW

/cm

2

0

30

6090

120

150

180

210

240270

300

330Ang

le, d

eg.

0

30

6090

120

150

180

210

240270

300

330

simulations experiment polarization

ellipse main axis initial probe

orientation 75o

z = 98 cm

z = 98 cm

z = 33 cm

z = 33 cm

30°

Probe

Pump

Fig.1. The two upper polar coordinate plots show the probe pulse fluence transmitted by the analyzer as a function of the analyzer angle relative to the initial pump orientation 0°. The lower plot shows peak intensity in both the pump (squares) and the probe (triangles) pulses.


WLMI-2010

O 6: Modeling UV Filamentation

A. Aceves


WLMI-2010

O 7: Higher-order Kerr terms allow ionization-free filamentation in gases P. Béjot1,2, W. Ettoumi1, Y. Petit1, J. Kasparian*1, S. Henin1, V. Loriot2, T. Vieillard2,

E. Hertz2, O. Faucher2, B. Lavorel2, and J.-P. Wolf1 (1) Université de Genève, GAP-Biophotonics, 20 rue de l’Ecole de Médecine, 1211 Geneva 4, Switzerland

(2) Laboratoire Interdisciplinaire CARNOT de Bourgogne (ICB), UMR 5209 CNRS-Université de Bourgogne, BP 47870, 21078 Dijon Cedex, France *email [email protected]

Abstract Higher-order nonlinear indices, rather than plasma, provide the main defocusing

contribution to filamentation in gases at 800 nm. Developing generalized Miller formulae, we discuss the generality of this as a function of the laser wavelength.

Filaments are generally considered to stem from a dynamic balance between Kerr focusing and defocusing by the plasma generated at the non-linear focus. While defocusing by the plasma has periodically been challenged, no alternative regularizing mechanism was exhibited up to now in gases. Fifth-order non-linearity has been discussed in this regard, but without knowledge of its magnitude, preventing quantitative analysis.

Based on the recent experimental measurement of the higher-order Kerr indices n4 through n10 in N2, O2 and Ar [1,2], we investigate their influence on laser filamentation by numerical simulations. We show that their values are sufficient to provide the dominant contribution to the defocusing terms in self-channeling. Their implementation in numerical simulations yields the experimentally observed plasma density. Moreover, setting the plasma term to zero in the simulations (Fig. 1) shows that plasma is not required for filamentation. Rather, plasma generation can be considered as a by-product of the self-guiding of laser filaments in gases at 800 nm [2], which in turn affects the white-light generation and the conical emission. The observation that ionization almost does not affect the results of the model provides an opportunity to speed up the numerical simulations and offers new perspectives for analytic studies of filamentation.

Fig. 1 (a) On-axis intensity and (b) Plasma density as a function of the propagation distance for the classical model (considering only n2 term of the Kerr index and the plasma defocusing), the full model, and the full model without plasma.

However, when varying the wavelength, the respective values of the higher-order non-linear indexes and ionization rates vary, so that their respective contributions to defocusing have to be estimated. Such estimation requires the knowledge of the non-linear indices of arbitrary orders at any wavelength. We therefore extend the Miller formulae to arbitrary orders. Based on a perturbative approach, we show that, for any p ≥ 1, the knowledge of the non-linear index of (2p+1)th order n2p(w0) at frequency w0 and of the dispersion curve for the linear refractive index n0 is sufficient to determine n2p(w) at any frequency.

Based on this new relation, we performed numerical simulations of filamentation over the whole spectrum from the ultraviolet to the infrared. We show that the contribution of plasma is weak over the whole visible and near-infrared spectrum, especially for short pulses [4]. On the other hand, in the ultraviolet where ionization rates are higher, as well as for pulses of a few hundreds of femtoseconds or more where the plasma has time to accumulate, the defocusing contribution of the plasma cannot be neglected. Our results renew the vision of filamentation. While the high-intensities at play in the filaments indeed ionize the propagation medium, the plasma is, over most of the spectrum, a by-product rather than a key ingredient of the filamentation process. References [1] V. Loriot, et al., “Measurement of high-order Kerr refractive index of major air components”, Opt. Express 16, 13429 (2009) [2] P. Béjot, et al., “Higher-order Kerr terms allow ionization-free filamentation in air”, Phys. Rev. Lett. 104, 103903 (2010) [3] W. Ettoumi, Y. Petit, J. Kasparian, J.-P. Wolf, “Generalized Miller formulae”, Opt. Express 18, 6613 (2010) [4] W. Ettoumi, et al., “Generality of all-Kerr driven filamentation in air”, in preparation


WLMI-2010

O 8: Interference effects in supercontinuum conical emission upon filamentation of a femtosecond laser pulse in condensed matter

Chekalin S.V.(1), Dormidonov A.E. (2), Kompanets V.O. (1), Smetanina E.O. (2),

Skopina O.V. (2), and Kandidov V.P. (2)

(1)Institute of Spectroscopy of the Russian Academy of Sciences, Troitsk, Moscow Region 142190, Russia

(2)M.V.Lomonosov Moscow State University, Physics Department, Moscow, Leninskii Gory, 119992, Russia

It is shown both experimentally and theoretically that interference effects play the key role in the formation of frequency-angular spectrum of the filament conical emission (CE).

For the first time we investigated experimentally the transformation of the CE frequency-angular spectrum with increasing of the filament length in fused silica and water. The experimental setup consists of a tunable TOPAS parametric amplifier combined with a regenerative Spitfire Ti:sapphire amplifier. Experiments were performed by using femtosecond pulses with different wavelengths, repetition rate was 1 kHz. The original arrangement of our setup enabled slow variation of the filament length inside the sample without changing of the pulse energy. The length, location, and structure of glowing filament were registered by a digital camera with a microscope objective. The broadening of the CE frequency-angular spectrum with increasing of the filament length was registered, the fine structure of the CE colored rings was discovered in angular distribution of CE spectral components in lengthy filament, the splitting of the CE rings into the high-contrast discrete colored rings after refocusing and appearance of the second emitting region was confirmed.

Computer simulation of laser pulse filamentation and supercontinuum generation in water and fused silica was performed. For interpretation of experimental and numerical results we proposed a simple interference model according to which the CE frequency-angular spectrum is the result of the interference of broadband radiation from moving point sources in the filament. The model reproduces the formation of the X-, O-, and Fish-shaped spectrum, which is typical for the pulse filamentation in conditions of normal, anomalous, and zero group-velocity dispersion. We discovered the appearance of fine structure in the conical emission spectrum produced by lengthy filament. We established general laws of conical emission formation based on the concept of white light generation and interference from the moving point sources produced by the filament. It is shown that the conical emission frequency-angular spectrum is produced by interference of coherent radiation from one or several moving point sources in the lengthy filament. The shape of the conical emission spectrum depends on the medium material dispersion, the spectrum structure is determined by length and relative location of filament emitting regions. Analytical expressions for frequency-angular distribution of the spectral intensity I(θ,λ) for pulses with various wavelengths and different regimes of filamentation were obtained. These expressions describe the fine structure of the CE angular spectrum in lengthy filament and the splitting of the CE rings after refocusing in concordance with experiments.

This work was supported by the Russian Foundation for Basic Research (Grant No. 08-02-00517-a) and by the Russian Federal Agency for Science and Innovation (Rosnauka, the state contract 02.740.11.0223).


WLMI-2010

O 9: Ultrafast laser micro/nano processing of high aspect ratio channels in dielectrics with Bessel beams

M.K. Bhuyan, F. Courvoisier*, M. Jacquot, P.A. Lacourt, L. Furfaro and John M. Dudley FEMTO-ST Institute, Department of Optics P.M. Duffieux, UMR CNRS 6174,

Université de Franche-Comté, 25030 Besançon, France * Tel: (+33)3 81 66 64 01, Fax: (+33)3 81 66 64 23, e-mail: [email protected]

Abstract: Femtosecond laser machining is a powerful technique for processing dielectrics down to subwavelength scales. However, controlling in-depth energy deposition is challenging due to nonlinear processes occurring at high intensities. We show that femtosecond Bessel beams allow for a precise control on this parameter and for fabricating high aspect ratio micro and nano-channels. The underlying physical mechanisms will be discussed. Femtosecond laser machining of transparent materials has been applied to a wide range of applications, from waveguide fabrication to the writing of micron and nanometer scale surface and bulk features through material ablation [1]. Femtosecond machining is particularly attractive because of its low cost and its ability to rapidly machine complex geometrical structures in two and three dimensions. Specifically, sub-10 µm channels are essential structures in the development of system-scale lab-on-chip and sub-micron channels are key components for photonic devices and nanofluidic systems. A particular challenge in femtosecond machining therefore concerns the fabrication of such high aspect ratio channels because strong focusing of Gaussian beams typically limits the longitudinal machining region to only 1 µm [2].

Figure 1 Bessel beam position in the sample (top left) and image of a microchannel processed with

1000 shots(bottom left). A schematic representation of the energy flow in the Bessel beam producing the plasma channel is shown on the right side.

In this presentation, we will review our recent work using nondiffracting Bessel beams to overcome many of the difficulties of Gaussian beam femtosecond laser micromachining. Our results show that Bessel beams can be used to generate taper-free channels of around ~2 µm diameter and ~80 µm length in glass in a straightforward setup without the need for any sample translation. We interpret these results in terms of a specific regime of stable filament formation [4], and identify a working window for the practical use of Bessel beams for glass micromachining. Recent results concerning high aspect ratio nanochannels processing will also be presented with important applications to photonic devices fabrication.

References

[1] Gattass, R.R.; Mazur, E. Nat Photonics, 2, 219-225 (2008) [2] Kudryashov, S.I.; Mourou, G.; Joglekar, A.; Herbstman, J.F.; Hunt, A.J. Appl. Phys. Lett. 91, 141111. (2007) [3] Courvoisier, F. et al.. Opt. Lett. 34, 3163-3165 (2009). [4] Bhuyan, M.K. et al. Opt. Express 18, 566-574 (2010)


WLMI-2010

O 10: Single process femtosecond laser microfabrication — novel techno-logy in modern photonics: meticulous experiments and serious numerics

Vladimir Mezentsev

Photonics Research Group Aston University

Birmingham B4 7ET United Kingdom

Recent results are presented on femtosecond (fs) laser microfabrication of key components for integrated optics such as highly curved low-loss waveguides in glasses, depressed cladding waveguides in crystals. Details of microfabrication and characterisation are discussed. Full vectorial Maxwell's simulations are required to get quantitative description of femtosecond electromagnetics of tightly focussed laser beam. First results on such modelling are presented and discussed.


WLMI-2010

O 11: Femtosecond ablation of dielectrics: time resolved studies of excitation mechanisms

Stéphane Guizard1*, Nikita Fedorov1, Alexandros Mouskeftaras1, Sergey Klimentov2,

1Laboratoire des Solides Irradiés, Ecole Polytechnique, 91128 Palaiseau, France. 2General Physics Institute of the Russian Academy of Sciences, Vavilova St 38, 11991 Moscow,

Russia. *e-mail: [email protected] Abstract : In the field of laser ablation of wide band gap materials by ultrashort laser pulses, there has been a long debate regarding the excitation and energy deposition mechanism. This is due to the lack of direct experimental investigations, which have been mostly limited to the measurement of ablation threshold. Indeed, the measurement of this single parameter, besides its technological importance, is clearly insufficient to understand a phenomenon as complex as laser induced breakdown. The complexity arises from the intricate evolution of the laser pulse propagation and the optical properties of the solid, due to the onset of a dense electronic excitation. If we consider only the very first step which is the electronic excitation, it is noteworthy to observe that one can still find advocate of different mechanisms such as tunnel [1], avalanche [2], or multiphoton [3] ionisation. To investigate this problem, we use an original pump-probe interferometry technique [4, 5] which allows to measure the carrier density as a function of time, and to observe the initial relaxation mechanisms. We will show that, using a pair of excitation pulses with well chosen characteristics, it is possible to clearly identify the excitation mechanism at work at intensities when the breakdown threshold is reached. By using this approach on Al2O3 samples, we have obtained original results showing that the breakdown mechanisms is not involving an increase of the density of carrier, as expected from the avalanche model, but rather from an efficient energy deposition mechanism, by linear and non linear absorption of photons by the previously excited carriers. [1] I. N. Zavestovskaya, P. G. Eliseev, O. N. Krokhin, N. A. Men’kova, Apll. Phys. A, 2008, 92, 903. [2] L. Englert, B. Rethfeld, L. Haag, M. Wollenhaupt, C. Sarpe-Tudoran and T. Baumert, Optics Exp. 15, 17855, 2007. [3] V. Temnov, K. Sokolowski-Tinten, P. Zhou, A. El-Khamhawy, and D. Von Der Linde, Phys. Rev. Lett. 97, 2006, 237403. [4] Audebert P., Daguzan Ph., Guizard S., et al. Physical Review Letters 52, p. 1994. [5] Martin Ph., Guizard S., Daguzan Ph., Petite G., D'Oliveira P., Meynadier P. Perdrix M., Phys. Rev. B, 55, 5799, 1997.


WLMI-2010

O 12: Ultra-short laser interactions: insights from numerical modeling

N. S. Shcheblanov1, M. E. Povarnitsyn2, Th. Derrien3, and T. E. Itina1

1Laboratoire Hubert Curien (LaHC), CNRS/Université Jeann Monnet, Bat. F , 18 rue du Professeur Benoît Lauras, Saint Etienne, 42000, France

2Joint Institute for High Temperatures RAS, 13 Bd. 2, Izhorskaya street, Moscow, Russia 3Laboratoire Lasers, Plasmas et Procédés Photonique (LP3) CNRS/Université de la Méditerranée,

Case 917, 163 avenue de Luminy, 13288 Marseille, France

Better understanding of ultra-short laser interactions requires two-temperature modeling of

laser energy absorption and its following relaxation. In particular, two-temperature hydrodynamic

model with a thermodynamically complete equation of state provide insights into the ablation

mechanisms are observed. For metal targets, the major fraction of the ablated material is found to

originate from the metastable liquid region, which is decomposed either thermally or mechanically.

In addition, effects of the ultra-short laser excitations on semiconductors and wide band gap

materials require particular attention. In this case, material ionization through multi-photon

excitation and electron-impact ionization should be considered. These processes are modeled by

using a detailed kinetic approach.

Laser-irradiated material response is based on the electron-phonon/ion interactions, which

in turn depend strongly on the energy of the electron sub-system defined by laser parameters and

on the material properties. In this study, based the numerical modeling, we propose the energy-

based analysis of these interactions.

Single, double and multiple shot interactions are simulated with a particular focus on the

control over the transient reflectivity changes and the energy deposition rate. We show that the

history of laser excitations affects not only the ionization process and the final number of the

conduction band electrons, but also determines the rate of the energy deposition into the material.


WLMI-2010

O 13: Explosive Evaporation of Large Water Droplet Irradiated by Ultrashort Laser Pulses

Yu.E. Geints1, S.S. Golik2, A.M. Kabanov1, V.K. Oshlakov1, and A.A. Zemlyanov1

1Zuev Institute of Atmospheric Optics SB RAS, Tomsk, Russia Yu.E.Geints e-mail: [email protected] 2Far Eastern State University, Vladivostok, Russia

Abstract We have investigated for the first time experimentally and theoretically the interaction of

high-intensive femtosecond laser pulses (800 nm, 1 mJ, 50÷800 fs@1 kHz) with large isolated

suspended in air millimetric drops made of distilled water. The experiments have shown that upon

ultrashort light irradiation large optically transparent drops can evaporate and boil-up with bubble

formation and hot steam/liquid fragments release. This boiling-up dynamics demonstrates an

explosive character and in the condition of long-term laser illumination the boiling channel covers

the major part of the droplet diameter. The theoretical analysis shows that the most probable

physical mechanism of drop explosive evaporation is plasma formation due to laser-induced

breakdown (LIB) inside a droplet in areas of laser internal intensity maxima (the “hot spots”).

These spatial zones, in turn, are supported by the focusing effect of spherical air-droplet interface.

The thermalization of dense plasma produced by multiphoton/avalanche ionization of water

molecules in “hot spots” can lead to the significant rise in water temperature (> 1000 K) and

pressure (> 10 kbar) and cause droplet fragmentation.

The explosive evaporation of large water droplet irradiated by a train of 800-nm

femtosecond laser pulses is accompanied by a bright near isotropic droplet emission in the visible.

The brightness of this emission source and its spectral composition also strongly depend on the

initial laser power. At the high intensity of irradiation the emission lines of oxygen and hydrogen

ions produced by LIB of water are clearly distinguishable in the spectrum. Moreover, integrally the

emission spectrum broadens with the increase in laser pulse power. The temporal dynamics and

spectral form of this emission can be attributed to the combined effect of pulse self-phase

modulation in water due to Kerr and plasma optical nonlinearity and blackbody-type emission of

heated liquid with the temperature of approximately thousands absolute degree.


WLMI-2010

O 14: Short pulses approximation in dispersive media

David Lannes Département de Mathématiques et Applications

Ecole Normale Supérieure 45, rue d’Ulm 75005 Paris FRANCE

We derive various approximations for the solutions of nonlinear hyperbolic systems with fastly oscillating initial data. We first provide error estimates for the so-called slowly varying envelope, full dispersion, and Schrodinger approximations in a Wiener algebra; this functional framework allows us to give precise conditions on the validity of these models; we give in particular a rigorous proof of the “practical rule” which serves as a criterion for the use of the slowly varying envelope approximation (SVEA). We also discuss the extension of these models to short pulses and more generally to large spectrum waves, such as chirped pulses. We then derive and justify rigorously a modified Schrödinger equation with improved frequency dispersion. Numerical computations are then presented, which confirm the theoretical predictions.


WLMI-2010

O 15: A nonlinear quantum optics model for laser-gas interaction in some extreme regimes

E. Lorin1,3,_, S. Chelkowski2, and A. Bandrauk2,3


WLMI-2010

O 16: High Frequency Behaviour of the Maxwell-Bloch Model with Relaxations: Convergence to the Schrödinger-Boltzmann System

F. CASTELLA (1) AND E. DUMAS (2)


WLMI-2010

O 17: On three-wave coupling system and the related simulations of the Brillouin Backscattering for ICF target.

Remi Sentis


WLMI-2010

O 18: Plasma expansion into a vacuum and ion acceleration P. Mora

Centre de Physique Théorique, Ecole Polytechnique, CNRS, 91128 Palaiseau, France

Laser created plasma expansion into a vacuum leads to energetic ions which present a

strong interest for various applications such as hadron (proton) therapy, proton imaging, nuclear

physics, ion accelerators, fast ignition, warm dense matter production, etc. In the case of ultra-high

intensity lasers interacting with thin foils, the laser energy is absorbed by suprathermal electrons

which acquire relativistic energies. These electrons invade the foil and cause its expansion, by

progressively transferring their energy to the ions. Similarly thin foils heated by various means

(electrons, protons, X-rays) expands into vacuum. We will present various results concerning

plasma expansion into a vacuum, involving purely kinetic effects, collisional effects,

electromagnetic instabilities, multi-species ions, two temperatures electron distribution function,

etc.


WLMI-2010

O 19: Towards improving the quality of laser-produced particle sources V. Yu. Bychenkov

P. N. Lebedev Physics Institute, Russian Academy of Science, Leninskii Prospect 53, Moscow 119991, Russia

A long-term difficulty — generation of the very broad, thermal-like energy spectrum of the accelerated particles from short laser pulse interaction with plasma has been overcome recently for both electron and ion beams. This step towards monoenergetic particles shows a distinct improvement of energy spectra, opening new possibilities for different applications. Here we report recent progress in the above aspect achieved by Lebedev Physics Institute with theory of laser triggered particle acceleration and multidimensional PIC simulations. Both simulation-theoretical studies and simulation models for interpretation of the recent experimental results will be presented.

Several models and schemes for production of electrons and ions with monoenergetic features are discussed. (a) The collisionless adiabatic expansion into vacuum of spherical and plane plasma targets composed of two-species ions and hot electrons is studied kinetically by theoretically and numerical solving of the equations of motion of plasma particles in the self-consisting electrostatic field. Special attention is paid to optimization of light ions acceleration from two ion species heterogeneous (structured) and homogeneous targets. (b) The performed 3D PIC simulation study demonstrates that protons beam with therapeutic energy and small energy spread can be generated from ultra-thin (with thickness of tens nanometers) mass-limited targets with hydrogenised impurity irradiated by powerful (with intensity of the order of 1022 W/cm2) ultra-short laser pulses. (c) Simulations with a hybrid code that combines kinetic PIC model with field ionization input demonstrate that collimated beams of backward electrons with quasi-monoenergetic feature can be produced by tightly focused millijoule-energy femtosecond laser pulses incident onto a solid-density plasma with about micron scale length. These simulations are in good agreement with the experimental results on production of electron beams from the interaction of relativistically-intense laser pulses with a solid-density SiO2 target. (d) The hybrid code was also used for study of high-energy electron production in a laser wakefield accelerator in a bubble regime. This study indicates enhanced electron trapping initiated by field ionization of target ions. In agreement with experiment, the addition of a higher Z additive has been shown to increase the trapped charge and lower the transverse emittance of the generated electron beam as compared to pure gas at the same electron density. (e) We have demonstrated that dense hydrogen gas jet or hydric aerogels may serve as competitive sources of protons with therapeutic energy and small energy spread. The space-temporal and spectral features of the protons accelerated from such low-dense targets are compared with that from the thin foils.

This work was partly supported by the Russian Foundation for Basic Research.


WLMI-2010

O 20: Laser-based ion acceleration: new progress and perspectives for application

S. Ter-Avetisyan1, R. Prasad1, D. Doria1, K.E. Quinn1, L. Romagnani1, P. Gallegos2, 3,

P.S. Foster1,2, C.M. Brenner2,3, J.S. Green2, M.J.V. Streeter2, D.C. Carroll3, O. Tresca3, N. Dover4, C.A.J. Palmer4, J. Schreiber4, D. Neely2, 3, Z. Najmudin4, P. McKenna3,

M. Zepf1, and M. Borghesi1

1 School of Mathematics and Physics, Queen's University Belfast, Belfast, UK 2CLF, Rutherford Appleton Laboratory, STFC, Oxfordshire, UK

3SUPA Department of Physics, University of Strathclyde, Glasgow, UK 4The Blackett Laboratory, Imperial College, London, UK

Recent advances in laser technology have led to laser systems with high contrast and extreme intensity values, which

have opened up new perspectives in the field of laser–matter interactions. We will discuss recent results obtained in the

high power (300 TW) Astra-GEMINI laser system at the Rutherford Appleton Laboratory (RAL). These development

enabled access to unprecedented intensities (above 1020 W/cm2), an order of magnitude higher than the previously

achieved with ultra-short (~ 50 fs) laser pulses. The interaction of such an intense and high contrast (~ 1010) laser pulses

with matter still has to be explored carefully and the experiments aiming to obtain scaling laws or conversion

efficiencies are essential.

The measurements provided for the first time the opportunity to extend scaling laws for the acceleration process in

the ultra-short regime beyond the 1020 W/cm2 threshold, and to access new ion acceleration regimes. Comprehensive

on-line diagnostics with high resolution led to a full characterization of the ion emission process and accelerated beam

characteristics. The scaling of accelerated proton energies was investigated by varying a number of parameters such as

target thickness (down to 10 nm), target material (C, Al), laser light polarization (circular and linear) and angle of laser

incidence (oblique - 350, and normal). A pronounced increase in the ion energies has been observed for ultra-thin targets

(10 - 100 nm) at normal laser incidence, with peak energies (~ 20 MeV for protons, ~ 240 MeV for C) significantly

higher than previously reported with ultrashort laser pulses. The transition to a “new” regime of ion acceleration, the so-

called Radiation Pressure Acceleration (RPA) regime, was also identified, showing quasi-monoenergetic proton spectra

and a more favorable ion energy scaling with laser intensity. The experiment was carried out in the framework of the

LIBRA project.


WLMI-2010

O 21: Laser ion acceleration in shaped mass-limited targets

A.A.Andreev1,2 1. Max-Born Institute, Berlin, Germany

2. SIC “S. I. Vavilov State Optical Institute”, St. Petersburg, Russia

Ultrahigh intensity (UHI) laser radiation produces fast ions at interaction with solid targets. Most groups use in experiments a thin foils because of the possibility to characterize them well and they can be positioned easily. UHI laser pulses may accelerate ions in thin foils to energies of several MeV per nucleon and highly collimated ion beams may be formed. In order to avoid the slowly moved foil regions it has been proposed to use a small target with radius about laser spot size, so named mass limited target (MLT). Because these MLT are near solid density and with sizes that are comparable to the laser spot size, high laser pulse absorption and strong laser plasma interaction are expected, where the absorbed energy does not lose to its surroundings through rapid conduction processes. Ion acceleration in targets irradiated by UHI laser pulses has been studied here with analytical model and PIC simulations. Simulations were performed for different sizes and shape targets. Energy spectra of fast ions, laser conversion efficiency to fast ions and the divergence of ion beams are compared for various types of targets. When MLT is irradiated by UHI laser pulse, the resulting pellet plasma is strongly accelerated forward. Even after the laser pulse is reflected, the remaining high-intensity region continues to accelerate forward within the rapidly moving plasma bunch. The kinetic energy of the ions in the bunch’s densest region can exceed tens MeV at about solid density. It was shown that a diffracted laser light additionally accelerates electrons at MLT rear and produces short electron bunches, which correlates with light structure. If the laser spot size is bigger than MLT the radial force at vacuum MLT boundary can provide confinement. The regime of a most effective acceleration is realized in the case when laser field is about electrostatic field of ion core of MLT. It is found that maximal energy of ions and its directionality can be significantly enhanced, by choosing of shaped targets. The results of the simulations were compared with the experimental data and have shown a good coexistence.


WLMI-2010

O 22: Recent results on unstable relativistic electron transport into dense plasmas

Laurent Gremillet, Benoît Vermersch, Didier Bénisti, Erik Lefebvre

CEA, DAM, DIF, 91297 Arpajon, France

Understanding the transport of electron beams in dense plasmas is of critical importance in many

physical settings, notably in the context of relativistic laser-plasma interaction. We will report on

recent results on this topic with particular emphasis on the collective effects arising from beam-

plasma instabilities [1].

The first part of our presentation will address the issue of collisional effects on the purely

electrostatic beam-plasma instability. This is a long-standing issue [2] here revisited within the

rigorous framework of the Vlasov-Landau equation. Exact numerical results will be presented as

well as analytical estimates of the maximum growth rate as a function of the system parameters.

The conditions for collisional stabilization will be highlighted, and compared to those obtained

from simplified Krook-like models.

The second part will focus on the space-time dynamics of the unstable transport of laser-driven

electrons by means of particle-in-cell simulations. Within a 1-D geometry, it will be demonstrated

that, although the longitudinal momentum distribution of the fast electrons at the target boundary

may be a quasi-stationary decreasing function of the longitudinal momentum, time-of-flight effects

lead to a time-varying bump-on-tail distribution deep into the target prone to electrostatic beam-

plasma instabilities, a process reminiscent of that extensively investigated in the context of type III

solar radio bursts [3,4]. For commonly considered laser-plasma parameters, the quasilinear

relaxation proves to be fast enough to generate a plateau within a broad region of the hot electron

phase-space. The dynamics of the plateau formation will be investigated in connection with the

excitation of the plasma waves at the beam front, and their subsequent reabsorption by slower

electrons. A self-similar analytical model extending that of Zaitsev et al. [3] will be presented and

compared to the simulations. The consequences of this transient quasilinear relaxation on the hot

electron energy transport will be discussed, as will be the extension of these results to mobile ions

and to a 2-D geometry.

[1] A. Bret, L. Gremillet, D. Bénisti and E. Lefebvre, Phys. Rev. Lett. 100, 205008 (2008).

[2] H. E. Singhaus, Phys. Fluids 7, 1534 (1964).

[3] V. V. Zaitsev et al., Sov. Phys. JETP 18, 147 (1974).

[4] G. R. Foroutan et al., Phys. Plasmas 12, 042905 (2005).


WLMI-2010

O 23: Single and multiple filamentary self-compression scenarios Günter Steinmeyer1,2, Carsten Brée1,3, Ayhan Demircan3, Stefan Skupin4, Luc Bergé5

1Max-Born-Institut (MBI), Max-Born-Straße 2a, 12489 Berlin, Germany e -mail: [email protected] 2Optoelectronics Research Centre (ORC), Tampere University of Technology, 33101 Tampere, Finland

3Weierstraß-Institut für Angewandte Analysis und Stochastik (WIAS), Mohrenstraße 39, 10117 Berlin, Germany, 4Max-Planck-Institut für Physik komplexer Systeme (MPIPKS), Nöthnitzer Straße 38, 01187 Dresden, Germany

5CEA-DAM, DIF, F-91297 Arpajon, France

The combined action of plasma nonlinearity, Kerr nonlinearity, and linear optical effects in a filament can serve to compress mJ laser pulses without any need for external dispersion compensation. Self-compression of 40 fs input pulses has been demonstrated in several laboratories to date, resulting in sub-10 fs output pulses. Numerical simulations [1] have helped in clarifying the underlying mechanisms, which chiefly act in the spatial domain, contrasting other laser pulse compression schemes, in which dispersion and Kerr nonlinearity act together for temporal pulse contraction. Self-compression typically goes through 3 characteristic stages [2]: In a first stage, the beam profile contracts in its leading and trailing edges and expands around the input pulse peak. Eventually, this causes the on-axis temporal profile to split, yielding a pulse shape with two distinct maxima. Subsequently, one of these pulses starts to diffract out into the reservoir, yielding again a single-maximum pulse shape. This split-isolation cycle alone typically provides about threefold compression. The isolated pulse may then undergo further shortening due to nonlinear propagation.

Fig. 1: Single and double self-compression (a) Temporal pulse profile evolution in the single-compression regime. (b) Same in the double compression regime. Inset shows zoomed view of the second split event. (c) Evolution of peak intensity during propagation for single (dashed) and double (solid) compression. Inset shows resulting temporal profiles. (d) Evolution of pulse duration during propagation.

In this contribution, we will show that self-compression can be cascaded in a single gas cell, without the need for intermediate dispersion compensation or recompression, see Fig. 2(b). The cascaded self-compression gives rise to characteristic spatio-spectral energy distributions that can be seen in numerical simulations as well as in experiments. The latter clearly revealed two separated ionized zones. We will further elucidate the appearance of negative distributions to the group delay dispersion from nonlinear optical effects, another characteristic feature frequently observed in self-compression experiments. We believe that this dispersion contributions stem from nonlinear effects inside the windows of the gas cell, similar to those first discussed in [3]. We will provide experimental evidence for an important role of the windows for pulse shaping in self-compression. Additionally, we will discuss some novel ideas for theoretically explaining this effect. Both these results, the double self-compression as well as the dispersion contribution of the windows, widen the scope of applicability of self-compression schemes and add to a deeper understanding of this remarkable laser pulse compression mechanism. [1] S. Skupin, G. Stibenz, L. Bergé, F. Lederer, T. Sokollik, M. Schnürer, N. Zhavoronkov, G. Steinmeyer, Phys. Rev. E 74, 056604 (2006). [2] C. Brée, A. Demircan, S. Skupin, L. Bergé, G. Steinmeyer., Opt. Express 17, 16429 (2009). [3] L. Bergé, S. Skupin, G. Steinmeyer., Phys. Rev. Lett. 101, 213901 (2008).


WLMI-2010

O 24: Ionization induced post compression of high energy pulses

A. Dubrouil, C. Fourcade Dutin, S. Petit, E. Mével, D. Descamps and E. Constant Centre Lasers Intenses et Applications (Université de Bordeaux, CNRS, CEA, UMR5107),

Université Bordeaux1, France ; www.celia.u-bordeaux1.fr [email protected]

High energy ultrashort pulses are a key tools for studying or initiating ultrafast processes. Amplification of very short pulses to achieve high energies leads however to spectral narrowing that pushes their duration above the minimum value imposed by the gain bandwidth. To overcome these limitations, post-compression techniques have been developed to obtain broadband ultrashort pulses that can even be shorter than the minimum pulse duration imposed by the gain media. These techniques require to create new frequencies by a non linear process and rephase all the frequencies to get shorter pulses. Usually the non linear steps is based on self phase modulation (SPM) that can significantly broaden the pulse spectrum. To achieve a uniform beam, SPM can occur in a guided geometry either by using a capillary filled with gas [1] or by using a self guided geometry where the interplay between Kerr effect and ionization leads to self-guiding [2]. In both cases, the gas pressure is usually high and several parameters such as self-focusing and ionization limit the output peak power [3] and thereby the energy of the post compressed pulse to the mJ level [4].

We present here a new optical post-compression scheme [5] where we use Helium ionization as the spectral broadening mechanism. This is suitable for recompression and compatible with using a gas pressure that is low enough not to perturb beam propagation. To ensure spatial beam homogeneity, the beam propagates in hollow capillary filled with few mbar of helium gas designed for high energy ultra-short pulses. The blue-shifted pulses are then compressed with a combination of chirped mirrors and silica plates. We could obtain a significant spectral broadening associated with a chirp that could be compensated. From a conventional Ti:sapphire laser chain providing pulses of 40 fs – 70 mJ, we demonstrate pulses with a total output energy of 13.7mJ (Fig.1) and a duration of 11.4 fs and nice spatial properties. The pulses were characterized both with single shot autocorrelator and with a single shot SHG frequency resolved optical gating (FROG) [6]. The temporal phase of the shortest pulse exhibits a constant value over a large part of the pulse leading to an excellent recompression (figure 2) and the 11.4 fs FWHM duration of the post-compressed pulse is close to the inverse Fourier Transform FWHM of the experimental spectrum (10.4 fs). This new technique is therefore compatible with the post compression of high energy short pulses and allowed us to reach the 10 mJ – 10 fs level. This is very promising to generate high energy isolated attosecond pulses [7] suitable for XUV induced pump-probe experiments with as resolution.

1. M. Nisoli, S. De Silvestri and O. Svelto , Appl. Phys. Lett. 68, 2793 (1996). 2. C. Hauri, W. Kornelis, F. Helbing, A. Henrich, A. Couairon, A. Mysyrowicz, J. Biegert, U. Keller, Appl. Phys. B 79, 673 (2004). 3. M. Nurhuda, A. Suda, K. Midorikawa and K. Nagasaka, J. Opt. Soc. Am. B 20, 2002 (2003). 4. S. Bohman, A. Suda, T. Kanai, S. Yamaguchi and K. Midorikawa, Opt. Lett. 35, 1887 (2010). 5. C. Fourcade-dutin, A. Dubrouil, S. Petit, E. Mével, E. Constant and D. Descamps, Opt. Lett. 35, 253 (2010). 6. R. Trebino and D. J. Kane, J. Opt. Soc. Am. B 11, 2206 (1994). 7. V. V. Strelkov, E. Mével and E. Constant, New J. Phys. 10, 083040 (2008).

Fig. 1. Output energy and duration of the post compressed pulse for several helium pressures.

Fig. 2. SH FROG measurement of our shortest pulses : in (a) experimental and retrieved FROG spectra of the post-compressed pulse with the residual spectral phase, in (b) intensity profile and temporal phase of the post-compressed pulses.

0 1 2 3 4 5 6 7 8 90

5

10

15

20

25

30

Transmitted energy

Out

put e

nerg

y (m

J)

Helium pressure (mbar)

0

5

10

15

20

25

30

35

40

Best values

Pulse duration

FWHM

of p

ulse

dur

atio

n (fs

)

600 650 700 750 800 850 9000,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

1,6

Phase (rad.)Inte

nsity

(u.a

.)

Experimental spectrum Retrieved FROG spectrum

Wavelength (nm)

-4

-2

0

2(a)

Phase

-40 -30 -20 -10 0 10 20 30 400,0

0,5

1,0

1,5

Phase (rad)

FT experimental spectrum Retrieved FROG profile

Inte

nsity

(u.a

.)

Time (fs)

0

2

4

FWHM 11.4 fs

(b) Temporal phase


WLMI-2010

O 25: Few-cycle energetic femtosecond pulses in the visible and near-IR by using cascaded quadratic soliton compression


WLMI-2010

O 26: Pulse propagation effects in high order harmonic generation by mid-infrared source

V. Tosa1, K. Kovacs1, C. Vozzi2, M. Negro2, F. Calegari2, and S. Stagira2

1Natl. Institute for R&D Isotopic and Molecular Technologies, Cluj-Napoca, Romania 2Dipartimento di Fisica & CNR-IFN, Politecnico di Milano, Milano, Italy

The limited photon energy and photon flux currently available is a major drawback of high order harmonic generation (HHG). A recently investigated route to higher photon energy is HHG driven at wavelengths l longer than the 800 nm of the Ti:Sa laser. At constant intensity, longer wavelengths generate more energetic electrons, opening the possibility of producing multi-kilovolt photons of coherent radiation. Macroscopic aspects of HHG cannot be disregarded in any experiment aiming to optimize the HHG yield. Propagation effects, seen as modifications in the spatial, temporal/spectral structure of the laser pulse are stronger for longer wavelengths because the refractive index change is more sensitive to the plasma variation. In this work we analyze the laser field configuration established as a result of 1550 nm wavelength 20 fs pulse propagation in a Xe jet. We calculated the field amplitude and phase of the field using a non-adiabatic three-dimensional model in a focusing geometry of cylindrical symmetry.

The figure illustrates the on-axis intensity for several runs. For each run a gas medium 1.5 mm long at 20 Torr pressure was placed at different relative positions of the jet with respect to the focus. One can observe that for most of the runs, the on-axis propagated field levels-off at an intensity of ~1.5×1014 W/cm2, regardless the initial intensity. This pattern maintains also for different gas pressures, the higher the pressure the lower the established on-axis intensity. The propagated laser field was used to calculate single dipole response in the strong field approximation and finally to integrate the Maxwell equation for the

harmonic field. The results were found in good agreement with experimental spectra measured recently and were used further to reveal the HHG physics behind the data. We will show how the propagation of the mid-infrared pulse in an ionizing medium directly influences the HHG. We will demonstrate that for these driving frequencies even very low ionization levels perturb the laser pulse propagation and determine the way in which HHG process takes place.

-8 -6 -4 -2 0 2 4 6 80.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

On-

axis

inte

nsity

(1014

W/c

m2 )

z (mm)

Initial field Propagated field


WLMI-2010

O 27: Parametric wave mixing in nonlinear disordered media

Wieslaw Krolikowski

Laser Physics Centre, Research School of Physical Sciences and Engineering, Australian National University, Canberra, Australia

Email: [email protected]

There is a natural common perception that coherent optical phenomena are always intimately associated with the ordered perfect medium. This is for instance the case of normal light propagation in crystals where particular ordering of atoms or ions and associated with this ordering spatial symmetry defines particular optical properties including the nonlinear optical response. In fact the lack of this ordering immediately precludes certain optical properties from being observed. Therefore one can intuitively expect the strong sensitivity to the medium ordering in case of nonlinear properties of the medium. However it turns out that this is no always true and actually introducing disorder into otherwise perfect optical system (structure) is in fact beneficial. It turns out that random ferroelectric domain structures formed naturally in ferroelectric crystals which exhibit multi-domain structure with domains having random distribution of size and orientation can be useful in realization of various parametric processes. Such a disordered nonlinear medium is equivalent to an effective QPM system with almost infinite set of reciprocal wave vectors enabling to quasi-phase-match any parametric process, e.g. second harmonic generation or sum-frequency mixing, in a ultra-broad frequency range.

In this talk we present our recent experimental and theoretical results on second and third harmonic generation in such random nonlinear structures formed in as-grown strontium barium niobate crystals as well fabricated structures in lithium niobate. We will consider various types of interaction geometry, discuss spatial and polarizational properties of the emitted harmonic waves and the possible application of this process.


WLMI-2010

O 28: Nonlinear photonics in silicon nano-structures A.V. Gorbach

Centre for Photonics and Photonic Materials, Department of Physics, University of Bath, Bath BA27AY, UK

Recent progress in the fabrication of nano-structures has stimulated active research in sub-wavelength light guidance and manipulation. Silicon-on-insulator waveguides [1] appear to be promising candidates to become basic elements in nano-photonics. The large refractive index of silicon (n~3.5 at telecom wavelength) allows for tight light confinement by the conventional total internal reflection mechanism, giving the simultaneous advantages of controlled dispersion, and manageable losses. Bringing two silicon waveguides together with a separation of few tens of nanometres produces a high intensity peak in the slot area between the waveguides, with the field predominantly polarized perpendicular to the slot interface [2]. Combination of light being tightly focused in a nanometre scale area, and strong ultrafast Kerr nonlinearity of silicon and/or of dielectrics and polymers filling the slot, makes silicon waveguides and their arrangements to be perfect testing ground for various nonlinear effects. Crucially, main approximations of the conventional and well-established scalar Schrödinger-type models are invalidated due to the abrupt and strong variations of both linear and nonlinear material properties on the sub-wavelength scale. Thus one needs to develop adequate theoretical tools.

In this talk I will overview our recent theoretical and experimental research of nonlinear effects in silicon nano-structures. Starting from first principles, we developed the set of theoretical and computational tools to analyze nonlinear guided modes in silicon slot waveguides and their arrays, as well as basic nonlinear effects in these setups, such as frequency mixing, modulational instability, resonant radiation by solitonic modes.

References: [1] For a recent review see e.g. R. M. Osgood et al., Adv. Opt. Photon. 1, 162 (2009). [2] C. Koos et al., Nature Photonics 3, 216 (2009).


WLMI-2010

O 29: Generation of high-power supercontinuum and tunable sub-10-fs VUV pulses in photonic crystal fibers J.Herrmann, S.-J. Im and A. Husakou Max Born Institute, Berlin, Germany

Phone: +493063921278, Fax: +493063921209, e-mail: [email protected] A decade ago, the discovery of soliton-induced supercontinuum generation in photonic crystal fibers (PCFs) [1,2] has led to extensive research and numerous fascinating applications in frequency metrology, coherence tomography, absorption spectroscopy and other fields. Despite the progress in this field, the output peak powers of supercontinua were up to now limited by the low radius and low damage threshold of solid-core PCFs. In the present talk we study kagome-lattice hollow-core PCFs [3] as an alternative and predict the generation of high-energy soliton-induced supercontinua with spectral width of more than two octaves. Besides, we predict the generation of isolated UV/VUV 5-fs pulses without external chirp compensation during this spectral broadening process, tunable from 350 nm to 120 nm by the variation of pressure. Finally we present results on supercontinuum generation in a water-filled PCF. We have simulated the pulse propagation using the Forward Maxwell equation [2] which includes group velocity dispersion to all orders, as well as the Kerr nonlinearity, plasma effects, and higher-order nonlinear effects. The evolution of the output spectrum is presented in Fig. 1(a) for a 50-fs, 100-TW/cm2 input pulse at 800 nm with output energy of 0.07 mJ, which exceeds the results obtained in solid-core PCFs by roughly five orders of magnitude. As can be seen the spectrum contains a bright spectral peak at around 200 nm which corresponds to an isolated VUV pulse with 5 fs duration [Fig. 1(b)]. The spectral position of the pulse can be easily tuned by changing the pressure. Finally, supercontinuum generation in a water-filled PCF is studied. By filling the central hollow core of this fiber with water, bandgaps do not arise and broadband guiding is posible. Using a pump at 1200 nm and few-microjoule pump pulses, the generation of high-coherent supercontinua with two-octave spectral coverage from 410 to 1640 m is predicted. Our simulations indicate a transition from the soliton-induced mechanism to self-phase modulation dominated spectral broadening with increasing pump power. The numerical simulations show good agreement with experimental measurements at the Max Born Institute.

Fig.1 Evolution of spectrum (a) and output spectrum for different pressures (b). In (b) the pressure is 2 atm (red), 1 atm (green) 0.5 atm (blue) and 0.25 atm (black). References

1. J. K. Ranka, R. S. Windeler, and A. J. Stentz, Opt. Lett. 25, 25 (2000). 2. A. Husakou and J. Herrmann, Phys. Rev. Lett. 87, 203901 (2001). 3. F. Couny et al., Science 318, 1118 (2007).

(a)


WLMI-2010

O 30: Observation of extreme temporal events in CW-pumped super-continuum

M. Taki, A. Mussot, A. Kudlinski, M. Kolobov, E. Louvergneaux

Université Lille 1, Laboratoire PhLAM, IRCICA, 59655 Villeneuve d’Ascq Cedex, France *[email protected]

Abstract: We study experimentally and numerically the temporal features of supercontinuum generated with a continuous-wave ytterbium-doped fiber laser. We show that the temporal output of the supercontinuum is characterized by strong and brief power fluctuations, i.e. so-called optical rogue waves. We show that, in the linear regime, modulational instability is one of crucial mechanisms in their formation. We also show how the power of extreme events is further enhanced by higher order dispersion impacting their probability density function. In the nonlinear regime, we demonstrate numerically that these rare and strong events that appear and disappear from nowhere result from solitonic collisions. New developments in this subject will also be discussed.


WLMI-2010

O 31: Analysis and review of laser plasma interactions in experiments on the National Ignition Facility

Pierre Michel*, L. Divol, S.H. Glenzer, E.A. Williams, D.A. Callahan, N.B. Meezan, R.P.J. Town, D.E. Hinkel, J.D. Moody, E. Bond, S.N. Dixit, M.B. Schneider, E.L. Dewald, C.A. Thomas, G.A. Kyrala2, J.L. Kline2, K. Widmann, B.J. MacGowan, M.J. Edwards, O.L.

Landen, L.J. Atherton, J.D. Lindl and L.J. Suter

Lawrence Livermore National Laboratory 2Los Alamos National Laboratory

The National Ignition Facility (NIF), the world's largest laser with 192 beams delivering more than a megajoule of ultraviolet energy on target, became operational in March 2009. The "hohlraum energetics" experimental campaign was conducted from August to December 2009, and demonstrated symmetric implosion of ignition-emulate hohlraums at radiation temperatures suitable for ignition conditions. The first ignition experiments will begin in 2010. Laser plasma interactions (LPI) can be important for ignition experiments. Stimulated scattering of the laser beams in the hohlraums can cause backscatter of the laser light, which can affect the implosion symmetry, reduce the energy coupling and generate hot electrons that can preheat the target. On the other hand, we have also demonstrated that we can control the scattering processes between laser beams crossing at the entrance of the hohlraums, allowing us to tune the implosion symmetry by controlling the energy transfer between the laser beams. All these LPI processes are diagnosed by a large number of diagnostics, analyzing the backscatter light, the hot electrons generation, the implosion symmetry, the hohlraum radiation temperature and the brightness of the laser beams on the hohlraum walls. In this talk, we will review the status of LPI in the 2009 hohlraum energetics experiments. We will present the experimental diagnostics used during the campaign, and the hydrodynamics and LPI modeling tools used for the design and "post-shot analysis" of these experiments. We will present our latest understanding of the hohlraum energetics campaign with respect to LPI, and explain how we leverage our understanding of LPI to optimize the design of the forthcoming ignition experiments on NIF. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. *email: [email protected]


WLMI-2010

O 32: Spike Trains of Uneven Duration and Delay: STUD pulses for the Control of Nonlinear Optical Instabilities in Laser-Matter Interactions*

Bedros Afeyan, Marine Mardirian, Polymath Research;

Josselin Garnier, Universite Paris VI, Stefan Hueller, Ecole Polytechnique,

Christophe Rousseaux, CEA. We will show analytical and numerical results (And sketch out experiments that could test our findings) on a new concept of laser-plasma instability (LPI) control in high energy density laboratory plasmas. This new STUD pulses technique involves breaking up the continuous laser pulse into short spikes whose durations and delays are to be adaptable to the true plasma conditions and not what is guessed at a priori. These spike trains will modulate the laser amplitude at the fastest growing instability growth time scale so as to make the possible growth of that instability be limited to a prescribed number of growth times (4-8 is advised but remains adjustable). By breaking the coherence of the drive, by allowing damping of the daughter waves to occur in between driven sections and by moving the laser hot spots around between “on” spikes, the instabilities can be strongly suppressed. We will show results in the weak and strong plasma wave damping regimes (EPW or IAW), when the gain within a speckle but at the average intensity is less than 1 and up to 4 and compare our results to RPP, SSD and pseudo-STUD pulses where the laser is modulated in time but the speckle patter is kept fixed (as in the RPP case). These results will show that it is possible to use Green lasers for the driver of ICF and IFE with considerable LPI control, which is thoroughly missing in current schemes touted as being LPI free. STUD pulses also allow the control of interactions between large crossing or spatially overlapping laser beams by controlling their overlap in space-time. This has vast consequences both for direct and indirect drive laser fusion as well as shock and fast ignition schemes. We will show theoretical results based on the Geometry of Gaussian Random Fields and the statistical properties of laser hot spots with and without self-focusing, with and without plasma inhomogeneity, with and without multiple crossing laser beams. These theoretical analyses make predictions that could be tested in experiments we will sketch out that require 100 or more psec long pulses which are psec time scale on-off modulated; psec time scale Thomson scattering and backsattering measurement capability; and short pulse OPAs with tunable frequency and wavenumber which can be used to drive background plasma waves to large levels by optical mixing techniques. * Work supported by DOE NNSA Joint HEDLP Program grant and a DOE OFES SBIR Phase I grant.


WLMI-2010

O 33: Nonlinear properties of an electron plasma wave and application to stimulated Raman scattering Didier Benisti, Olivier Morice, Laurent Gremillet, Evangelos Siminos CEA, DAM, DIF F-91297 Arpajon, France and David J. Strozzi


WLMI-2010

O 34: Realistic modelling of laser-plasma interaction in hot plasmas: toward a predictive tool?

P. Loiseau1, M. Casanova1, D. Teychenn´e1, P.-E. Masson-Laborde1, D. Marion1, C. Rousseaux1, S. Depierreux1, J.-P. Goossens2, D. Pesme3 and S. H¨uller3


WLMI-2010

O 35: Progress in modeling and understanding of parametric instabilities in laser-plasma-interaction

P. E. Masson-Laborde1, S. H¨uller2, D. Pesme2, W. Rozmus4,

M. Casanova1, P. Loiseau1, S. Depierreux1 and Ch. Labaune3


WLMI-2010

O 36: MeV X-ray source production on Omega EP laser facility

Cédric Courtois1, Antoine Compant la Fontaine,1 Ray Edwards,2 Olivier Landoas,1 Jean-

Luc Bourgade,1 J. Gazave,1 S. Bazzoli1, Greg Pien,3 Dino Mastrosimone,3 C. Aedy,2 D. Drew2, M. Gardner2, A. Simons2, E. Lefebvre,1 C. Stoeckl3.

1CEA, DAM, DIF, F-91297 Arpajon, France

2AWE Plc., Aldermaston, Reading RG7 4PR, United Kingdom 3Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA

Results of experimental studies performed on Omega EP laser facility on multi-MeV Bremsstrahlung x-ray source created by picosecond laser pulse are presented. Omega EP is a unique laser facility which is able to focus kJ of laser energy in a ps time scale. The interaction of such a high-intensity laser pulse (Il2> 1019 W.cm-2µm2) with a solid target leads to the generation of relativistic multi-MeV electrons that can produce intense high-energy x-ray Bremsstrahlung emission when they propagate in a (high-Z) solid target located behind the interaction area. High-energy (>1 MeV) X-ray photon sources can be interesting for radiography applications, nuclear activation and fission, radiation effects and radiation safety studies. In the first experiment, the short pulse laser (Backlighter) was focused on thin gold foils 20 or 100 µm thick and delivered up to 300 J in 0.6 ps (l=1.053 µm). The second experiment was performed in a higher laser energy regime (1 kJ, 8 ps). The x-ray converter targets consisted of 2 mm thick, 2 mm diameter Ta cylinders coated with 10 µm thick plastic (CHO).

X-ray source properties are characterized using series of diagnostics. The high energy part of the x-ray spectrum is inferred from activation techniques using copper and carbon samples which undergo (g,n) photo-nuclear reactions. X-ray spectrum and angular distribution of the dose are measured with series of filtered dosimeters (image plates, OSL). Source size is inferred from the radiography of an Image Quality Indicator (IQI) and from penumbral images that can be unfolded to reconstruct two-dimensional images of the source with an autocorrelation method.

Results from the first campaign show a larger x-ray source with the thinnest foil (160µm compared to 90 µm inferred from penumbral images) which could be explained by electrons recirculation in the target. The second experiment indicates that the x-ray source temperature and size are approximately 3.5 MeV and below 200 µm respectively which is potentially interesting for MeV radiography with high spatial resolution. Numerical simulations performed with PIC (Calder) and Monte Carlo (MCNP) codes are also presented.


WLMI-2010

O 37: Fast electrons and high order harmonics generation from ultraintense laser-plasma interaction

Jiansheng Liu, Wentao Wang, Changquan Xia,Cheng Wang, Ruxin Li, and Zhizhan Xu

State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, P. R. of China.

Phone: 86-21-69918187, Fax: 86-21-69918021 [email protected]

Abstract

The interaction of ultraintense laser pulses with plasmas can generate fast electrons, monoenergetic electron and ion beams, and intense coherent X-ray sources, which can find important applications such as laser fusion, medical therapy and diagnostics. We have experimentally investigated angular and energy distributions of fast electrons generated from the interaction of ultraintense laser pulses with foil and subwavelength grating targets with various laser parameters [1,2]. A transition of the angular distribution of outgoing fast electrons from the specular reflection direction to the target normal has been observed for p-polarized laser irradiation. By adding a prepulse to generate preplasma, the electron yields at the direction of the reflected laser can be greatly enhanced, and a double-peak angular distribution is observed. In the case of subwavelength grating targets, the fast electron beam emitted along the target surface is enhanced by more than three times in comparison with a planar target. A more collimated electron beam can be obtained by employing a larger f-number focusing system.

Generation of 100-MeV-scale monoenergetic electron beams is demonstrated by using laser wakefield acceleration in high-density gas jets. Beam splitting due to the plasma instability is observed by using backward Raman scattering. In order to obtain electron beams with much higher energy, we generate 3-cm-long and low-density plasma channels by using ablative capillary discharges [3]. Self guiding of a 200-TW laser pulse in the plasma channel has been observed.

Some issues on high-order harmonics emission, intense attosecond pulse and ultrabroad supercontinuum generation from relativistic laser interaction with dense plasmas have also been discussed [4.5]. References 1. Wentao Wang et al., “Angular and energy distribution of fast electrons emitted from a solid surface irradiated by fs

laser pulses in various conditions”, Physics Plasmas, 17,023108 (2010). 2. Guangyue Hu et al., “Collimated hot electron jets generated from subwavelength grating targets irradiated by

intense short-pulse laser”, 17, 033109 (2010). 3. Mingwei Liu et al., “Low density and long plasma channels generated by laser transversely ignited ablative

capillary discharges”, Rev. Sci. Instrum. 81, 036107 (2010). 4. Jiansheng Liu et al., “Nonlinear Thomson backscattering of intense laser pulses by electrons trapped in plasma-

vacuum boundary”, Laser and Particle Beams, 27, 365 (2009). 5. Li Liu et al., “Control of single attosecond pulse generation from the reflection of a synthesized relativistic laser

pulse on a solid surface”, 15, 103107 (2008).


WLMI-2010

O 38: Modeling of THz emission from plasma-generating femtosecond laser pulses with unidirectional Maxwell equation in plasma spots and in guided geometries

I. Babushkin,1 S. Skupin,2, 3 C. Köhler,2 L. Bergé,4 and J. Herrmann5


WLMI-2010

O 39: X-ray Thomson scattering of isochorically proton heated Boron Nitride

S. Le Pape1, P.F. Davis1, 2, P. Neumayer4, A.L. Kritcher1, 2, T. Doeppner1, 5 A. Bennuzzi-Mounaix, 5A. Ravasio, 6,7 C. Brown, D. Hochhaus4, C. Fortmann1, 3, 6 G. Gregori,

O. L. Landen1, and S. H. Glenzer1 1Lawrence Livermore National Laboratory, P.O. Box 808,

Livermore, California 94551, USA 2University of California, Berkeley, CA, USA

3Physics Department, University of California Los Angeles, Box 951547, Los Angeles, California, 90095, USA

4 Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt, Germany 5 Laboratoire pour l’Utilisation des Lasers Intenses, UMR7605, CNRS – CEA - Université Paris VI

- Ecole Polytechnique,, 91128 Palaiseau Cedex, FRANCE 6 Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, UK

7 AWE Plc., Aldermaston, Reading RG7 4PR, United Kingdom

925-422-6201, [email protected]

Abstract. We have measured for the first time the temperature of proton heated Boron Nitride using

X-ray Thomson scattering. The experiment has been performed on the 300J, 10 ps Titan laser at

Lawrence Livermore National Laboratory. The ultra-intense laser beam was split into two beams.

30% of the energy was directed onto a 10µm Aluminum foil to generate a proton beam, and the

remaining 70% was focused onto a 10µm iron foil to generate a k-alpha backlighter at 6.4 keV. The

proton beam isochorically heats a Boron Nitride foil, creating a solid density plasma with a

temperature between 10-20 eV. X-rays are scattered from the heated target onto a curved HOPG

crystal. X ray Thomson scattering in the collective regime provides an accurate measurement of the

temperature from the ratio of up- vs. down-shifted plasmon signals. Temperature has been

measured as a function of time (from 200 to 400 ps after the proton irradiation) and proton flux (by

changing the intensity of the laser on the proton target).

*This work was performed under the auspices of the U.S. Department of Energy by the Lawrence

Livermore National Laboratory, through the Institute for Laser Science and Applications, under

contract DE-AC52-07NA27344. The authors also acknowledge support from Laboratory Directed

Research and Development Grant No. 08-LW-004.


WLMI-2010

O 40: Time-resolved XANES to probe the structure of Warm Dense Matter

F. Dorchies1, A. Benuzzi-Mounaix2, A. Lévy2, A. Ravasio2, F. Festa2,3, N. Amadou2, E. Brambrink2, S. Mazevet3, V. Recoules3, O. Peyrusse1, T. Hall4, M. Koenig2

1 Université de Bordeaux – CNRS – CEA, Centre Lasers Intenses et Applications (CELIA), Talence, F-33405 France 2 Laboratoire pour l’Utilisation des Lasers Intenses, UMR7605, CNRS-CEA-Université Paris VI-Ecole Polytechnique, 91128 Palaiseau, France 3 Département de Physique Théorique et Appliquée, Commissariat a l’Energie Atomique, 91680 Bruyères-le-Châtel, France 4 Physics Department, University of Essex - Colchester, UK

The study of the so-called « Warm Dense Matter » is the subject of active experimental exploration and theoretical analysis, since it is now possible to bring the matter in such a regime using high power laser or X-FEL. Such a regime designs a large part of the density (0.1 to 10 times the solid density) and temperature (0.1 to a few 10 eV) phase diagram, where the properties of the matter is still poorly understood, although of primary importance in a wide range of physical phenomena (geophysics, astrophysics1, inertial confinement for nuclear fusion2, laser machining, …). Here, the physics is at the crossroads of condensed matter and plasma physics. The matter is mostly degenerated (electrons), strongly coupled (ions) and non-ideal, giving rise to a great physical complexity in its simulation.

Using either isochoric heating by ultra-short and energetic pulses or high-energy laser shock

compression, one can bring the matter in such a regime, but in a transient way (10 ps to 100 ps), before hydrodynamic expansion. Taking advantage of an ultra-short (ps) laser-plasma based X-ray source3,4, time-resolved X-ray Absorption Near-Edge Spectroscopy (XANES) can bring a lot of information at macroscopic (temperature and density) and microscopic scales (electronic and ionic structures).

In this context, we have performed several experiments to reach the Warm Dense Matter regime and

study its properties5. Recently, an experiment has been led using the LULI2000 laser facility. An aluminum target has been compressed and heated, through laser-shock compression, up to three times the solid density and ~ 10 eV. Density and temperature have been characterized using optical diagnostics (VISAR and SOP) coupled with hydrodynamic simulations. Al K-edge XANES spectra have been recorded in a various set of thermodynamic conditions, highlighting the respective influence of density and temperature on the K-edge shift and slope. Experimental data are supported by two types of calculations, one based on Quantum Molecular Dynamic6, the other on a dense plasma model7.

1 T. Guillot et al., Science 286 (1999) 72. 2 J. Lindl et al., Phys. Plasmas 11 (2004) 339. 3 M. Harmand et al., Phys. Plasmas 16 (2009) 063301. 4 F. Dorchies et al., Appl. Phys. Lett. 93 (2008) 121113. 5 A. Mancic et al., Phys. Rev. Lett. 104 (2010) 035002. 6 V. Recoules et al., Phys. Rev. B 80 (2009) 064110. 7 O. Peyrusse, J. Phys.: Condens. Matter 20 (2008) 195211.


WLMI-2010

O 41: Collapse as a process of pulse shortening

E.A. Kuznetsov


WLMI-2010

O 42: Statistics of strong optical turbulence

Pavel M. Lushnikov and Natalia Vladimirova Department of Mathematics and Statistics, University of New Mexico, Albuquerque, NM 87131, USA

Phone: +1 505 277 2104

We consider the statistics of light amplitude fluctuations for the propagation of a laser beam subjected to multiple filamentation in an amplified Kerr media, with both linear and nonlinear dissipation. Dissipation arrests the catastrophic collapse of filaments, causingtheir disintegration into almost linear waves. These waves form a nearly-Gaussian random field which seeds new filaments. For small amplitudes the probability density function (PDF) of light amplitude is close to Gaussian, while for large amplitudes the PDF has a long power-like tail which corresponds to strong non-Gaussian fluctuations, i.e. intermittency of strong optical turbulence. This tail is determined by the universal form of near singular filaments and the PDF for the maximum amplitudes of the filaments.


WLMI-2010

O 43: Few-cycle optical pulse: Collapse and light bullets

Hervé Leblond1, David Kremer1, and Dumitru Mihalache2


WLMI-2010

O 44: Extreme Optical Pulse Compression and Frequency Transformation

Nikolay N. Rosanov

Vavilov State Optical Institute Birzhevaya Liniya 12, Saint-Petersburg, 199034 Russia

Phone: +7 812 3281093 Fax: +7 812 3285891 E-mail: [email protected]

The temporal compression of initial femtosecond pulses up to attosecond dissipative solitons is possible on the basis of self-induced transparency in media with nonlinear amplification and absorption [1-3]. Such few-cycle pulses with coherent spectral supercontinuum are promising for a number of applications; on the other hand, their features reveal new peculiarities of extreme nonlinear optics. In the talk, I describe and compare different mechanisms for few-cycle dissipative soliton pulse formation in laser amplifiers with a coherent amplifier and an absorber. Then I present the theoretical consideration and numerical simulation of relativistic light reflection on medium inhomogeneities induced in a nonlinear medium by strong and ultra-short laser pulses or solitons and moving in the medium jointly with the pulses [4, 5].

First, a matrix with active (with pump) and passive (no pump) dopants is considered. Steady-state pulses in such a medium correspond to the condition of self-induced transparency for the passive (absorbing) dopants which have higher concentration. However, for the active dopants the conditions of self-induced transparency are violated: Pulses with energy exceeding a critical value are observed to collapse. I analyze the mechanisms arresting the collapse on the basis of the 1D-wave equation for the full electric field and the Bloch equations for the passive and active dopants, as well as for the matrix. The ultimate limits to the pulse shortening are typically given by the matrix IR- and UV-absorption spectral bands [2]. Second, studied is propagation of strong ultra-short laser pulses in a medium with fast nonlinearity. Laser pulse induces an inhomogeneity of the medium refraction index moving jointly with the pulse, i.e., with relativistic speed. Reflection of an additional light radiation on such a relativistic mirror is accompanied with a giant Doppler frequency shift, and reflection coefficient can exceed 100% under certain conditions [4]. New regimes of reflection arise when inhomogeneous (evanescent) plane waves are involved [5]. In the talk, presented are the development of the theory and results of computer simulation of such the parametric Doppler effect. New regime of field accumulation near the moving strong pulse is studied. In such a way a low-frequency incident radiation is transformed into a high-frequency radiation due to reflection on the counter-propagating strong laser pulse. Similarly, the pulse of incident radiation is substantially compressed. 1. N.V. Vyssotina, N.N. Rosanov, V.E. Semenov. JETP Lett. 83, 337 (2006). 2. N.V. Vyssotina, N.N. Rosanov, V.E. Semenov. Opt. Spectr. 106, 713 (2009). 3. N.N. Rosanov, V.V. Kozlov, S. Wabnitz. Phys. Rev. A 81, 043815 (2010). 4. N.N. Rosanov. JETP Lett. 88, 501 (2008). 5. N.N. Rosanov. Opt. Spectr. 108, 628 (2010).


WLMI-2010

P 1: Advances in Optical Mixing Techniques for the Effective Control of Parametric Instabilities in Laser-Produced Plasmas

Bedros Afeyan,* M. M. Mardirian, Polymath Research Inc., Pleasanton, CA, and

M. Shoucri, IREQ, Quebec, CA

We have made considerable progress in the taming of parametric instabilities in laser-produced

plasmas and HEDLP. One technique uses nonlinear self-sustaining structures in phase space such as

KEEN waves to suppress the nonlinear undamped-trapped particle states of electron plasma waves.

This may be an ideal method of suppressing unwanted SRS plaguing indirect drive experiments at

present. We will describe the origin of these novel objects, namely kinetic electrostatic electron

nonlinear waves and how they nonlocally affect the EPWs at twice or three times their frequency by

a novel 2:1 and 3:1 resonance between phase locked multiple harmonics of the KEEN wave and the

single mode EPW through their self-consistent E field.

Fig. 1 Shows the evolution of a pair of waves, first a KEEN wave and then an EPW. The EPW fails to form a nonlinear state because its trapping dynamics has been disrupted by extra harmonics of the self-consistent overall E field disallowing that precise dance between electrons and the trapping potential. This is a novel means of snuffing out resonant waves nonlocally in phase space by the use of these novel nonlinear nonstationary self-organized asymptotic states.


WLMI-2010

Fig. 2 shows the density response as a function of time of the KEEN + EPW vs EPW + KEEN driven cases in the 2:1 resonance regimes. The density response of KEEN+EPW driven pairs and the same in the opposite order. Note how the EPW never makes it when a in 2:1 resonance KEEN wave is present prior to the formation of the EPW, while it does, with fits and starts, in the opposite order (bottom panels). The dotted lines are the envelopes of the drives showing their relative amplitudes and durations. * [email protected] Work funded by the DOE NNSA SSAA Grants program as well as a grant from the DOE NNSA-OFES Joint HEDLP Program.


WLMI-2010

P 2: Nonlinear Bloch equations for laser-quantum dot interactions

Brigitte Bidégaray-Fesquet


WLMI-2010

P 3: Scaling laws in laboratory astrophysics

Serge Bouquet, Emmanuel Falize CEA-DAM, DIF

91297 Arpajon cedex France

and

Claire Michaut

Laboratoire Univers et Théories (LUTH) Observatoire de Paris-Meudon

92195 Meudon Cedex France

In this communication, a theoretical connection between laboratory astrophysics experiments and astrophysical phenomena (or objects) is presented. For this purpose, scaling laws based on invariance considerations of the equations of the model are derived. A few cases are considered (purely hydrodynamic, radiatively optically thin ...) and the way this approach works is shown in each case. Finally, specific experiments are shown as examples of application of these scaling laws.


WLMI-2010

P 4: Terahertz radiation from gas plasma, generated by linearly polarized femtosecond pulses

D. A. Fadeev, V. A. Mironov

Institute of Applied Physics RAS, Nizhny Novgorod, 603950, Russia * [email protected]

The significant interest to terahertz waves (the last one insufficiently explored electromagnetic band) is concerned with it’s extremely wide applicability to the different areas of researches from utilitarian imaging in biology and security to investigation of complex molecules in chemistry [1,2]. Some of the most promising alternative for terahertz waves generation are laser plasma methods. The common theoretical approach to this problem is divided into three stages: a) research of self-consistent evolution of laser pulse during the breakdown of gas b) investigation of plasma electrons excitation mechanism c) research of self-consistent low frequency plasma oscillation and calculation of far terahertz field.

Recently in our institute new experimental data were obtained. In the common scheme of generation using short focal length (80-400mm) parabolic lens, short laser pulse (50fs, 2.5 mJ) with linear polarization a radiation pattern with pronounced transverse orientation depending on optic polarization was obtained [3]. This effect could not be explained in terms of ponderomotive force like in [4] due to it’s cylindrical symmetry character.

Here we introduce a new model of terahertz waves generation that could describe novel experimental data. The approach is based on Boltzman equation for electron velocity distribution function with instantaneous appearance of electrons due the tunneling ionization of gas molecules by laser field. Considering linearly polarized laser pulse we calculated distribution function of electrons along velocity component corresponding to laser pulse polarization direction, assuming distributions along other two axis to be delta functions. This effect could be effectively described in hydrodynamic model with constant anisotropic pressure (one component in pressure tensor) appearing with laser pulse action and non vanishing after laser pulse passes.

In this work we present all three (a,b,c) stages of analysis. The first is 2D calculation of laser pulse focusing with breakdown of gas. Because of strong dependence of the results of third stage analysis on plasma column parameters we included ionization damping, Kerr, and Raman responses besides refraction of optic pulse on plasma to obtain quantitative data. The second stage is rather analytic. Here we calculate the dependence of anisotropic pressure on laser pulse amplitude. The third stage is full 3D calculation of plasma column dynamics excited by preset laser pulse. Thus the third is quite qualitative. The calculated electric currents are integrated in order to obtain the far terahertz field. The typical radiation pattern obtained from our model is in good qualitative agreement with experimental data.

M. Tonouchi, ”Cutting-edge terahertz technology”, Nature photonics, 1, 97, 2007 K. Reimann, ”Table-top sources of ultrashort THz pulses”, Rep. Prog. Phys., 70, 1597, 2007 R. A. Akmedzanov, I. E. Ilyakov, V. A. Mironov, E. V. Suvorov, D. A. Fadeev and B. V. Shishkin, “Plasma mechanisms of pulsed terahertz radiation generation”, Radiophysics and Quantum Electronics, 52, 7, 482-493, 2009 C. D. Amico, A. Houard, M. Franco, B. Prade, A. Mysyrowicz, ”Conical Forward THz Emission from Femtosecond-Laser-Beam Filamentation in Air”, PRL, 98, 235002, 2007


WLMI-2010

P 5: Terahertz mode dynamics in beta- barium borate crystals

S.Vidal, J.Degert, J.Oberlé, E.Freysz CPMOH, Bordeaux University, 351 course de Liberation, Talence 33400 France

O.Fedotova, G.Rusetsky, O.Khasanov Belarus National Academy of Sciences, Scientific- Practical Material Research Centre,

19 Brovki str., Minsk 220072 Belarus

Nowadays terahertz (THz) time-domain spectroscopy attracts much attention of scientists because of promising applications in fingerprint spectroscopy, environment monitoring, semiconductor and medical imaging and law enforcement. Although many principal technical advances had been witnessed in developing intense THz sources, there is still a strong need to develop more powerful and tunable sources. Beta-barium borate (BBO) crystals have high impact in harmonic frequency generation and even parametric amplifiers for this spectral range. They are transparent and more importantly have large birefringence and strong dispersion in submillimeter-wave range.

In presented work optical properties in THz range of a 200 µm-thick 29° cut BBO crystal were measured at room temperature by means of THz time-domain spectroscopy. A THz wave with a spectrum covering the 0.25 to 3 THz range was generated by optical rectification of a 800 nm fs laser pulse from a Ti:sapphire regenerative amplifier in a 200 µm-thick (110) ZnTe crystal. This wave was focused onto the sample by means of two off-axis paraboloidal mirrors. After transmission through the sample, it was measured via electro-optic sampling in a second 200 µm-thick (110) ZnTe crystal using a weak probe fs laser pulse. The refractive index and the absorption coefficient are determined from comparison of the transmitted THz spectrum with the incident one. In addition to this measurement, to get some insight into the dynamics of the phonon modes interacting with the THz wave during its propagation through the crystal, we have performed wavelet analysis of the THz waveform. THz wave form transmitted by the BBO and the spectrogram deduced from the wavelet analysis are displayed in the figure below.

To the best of our knowledge in the BBO crystal four absorption peaks are observed at about

1.7, 2.1, 2.5 and 2.8 THz. The origin of these terahertz modes is still controversial, presumably connecting them with translational motion of Ba ions or with librations of (B3O6)3- rings. To get insight into the features of the phonon mode interaction among themselves and with the THz pulses in a wide range of parameters including linear and nonlinear regimes we develop the model of two and four coupled nonlinear forced oscillators with quadratic and cubic nonlinearities as well as various kinds of coupling. Methods of nonlinear dynamics including construction of the phase space trajectories, Poincaré section etc. allow us to reveal not only nonlinear resonances, their overlapping and also chaotic oscillations.


WLMI-2010

P 6: Radiating Solitary Waves in Photonic Band Gap

E.Gaizauskas and A.Savickas, K.Staliunas


WLMI-2010

P 7: Paths towards the generation of monochromatic ion beams M. Grech, S. Skupin, T. Kiefer, A. Diaw, A. Mikaberidze, R. Nuter, L. Gremillet, E. Lefebvre, V. T. Tikhonchuk


WLMI-2010

P 8: All-optical steering of light via spatial Bloch oscillations in a gas of three-level atoms

Chao Hang1;2;¤ and V. V. Konotop


WLMI-2010

P 9: Theory of Plasmon-Enhanced High-Harmonic Generation in the Vicinity of Metal Nanoparticles

Anton Husakou, Song-Jin Im, Joachim Herrmann Max Born Institute, Max Born Str. 2a, D-12489 Berlin, Germany

Phone: +49 30 63921248, Fax: +49 30 63921289 [email protected]

Plasmonic field enhancement by metallic nanostructures plays a key role in nanooptics and

has been the subject of extensive theoretical and experimental research. Recently high-order harmonic generation (HHG) by nJ pulses directly from a laser oscillator has been demonstrated [1] by exploiting the local field enhancement near a metallic nanostructure. In this contribution we present the theory of the high-harmonic generation in the vicinity of nanostructures, and apply it for different nanostructure geometries.

Besides the electric field enhancement, the HHG in the vicinity of the nanostructures is modified due to two facts: first, the strongly inhomogeneous plasmon-enhanced electric field suggests that its spatial dependence should be taken into account in the description of the electron motion; and second, one can assume that electrons which have reached the metal surface are be absorbed and do not contribute to the HHG signal. We have developed a modification of the Lewenstein formalism to describe both these phenomena. In Fig. 1(a), the high-harmonic spectra are shown for weak (red curves and points), moderate (green) and strong (blue) inhomogeneity with the parameters given in the caption. One can see that for the increased inhomogeneity, even harmonics are generated as well as odd ones due to broken inverse symmetry. Additionally, the cutoff is extended and becomes less pronounced for stronger inhomogeneity. The influence of electrons being absorbed by metal surface (not shown) is similar.

Figure 1. The influence of field inhomogeneity on the HHG (a) and the spatial distribution of the harmonic cutoff in the vicinity of the metal

nanocone (b). In (a), we consider the generation of both odd (solid curves) and even (dots) harmonics for inhomogeneous field E(t,x) = exE(t)(1+x/dinh) with dinh = 1000 nm (red curves and points), dinh = 20 nm (green curves and points), and dinh = 5 nm (blue curves and points) in argon by monochromatic radiation at 830 nm with the intensity of 200 TW/cm2. In (b), we consider a silver nanocone with curvature radius of the tip of 5 nm surrounded by argon and illuminated by cw radiation of 0.3 TW/cm2 at 830 nm.

In Fig. 1(b) we show the distribution of the harmonic cutoff in the vicinity of a silver

nanocone with the curvature radius of 5 nm. The significant enhancement of the electric field (up to 103 for the intensity) led to high harmonic generation of the order up to 120 for the low incident intensity of only 0.3 TW/cm2 which can be obtained directly from the laser oscillator with MHz repetition rate. The influence of the field inhomogeneity and the metal surface is significant in this case: without considering them, the harmonic orders of only up to 45 are predicted. To corroborate the validity of our modeling, we have also calculated the harmonic threshold (not shown) for the bowtie antenna for the input intensity of 0.5 TW/cm2. We have found a harmonic cutoff at 36 nm (Nharm = 23), which is in agreement with the experimental findings [1] (Nharm = 17).

References

1. S. Kim, J. Jin, Y.-J. Kim, I.-Y. Park, Y. Kim, and S.-W. Kim, ”High-harmonic generation by resonant plasmon field enhancement,” Nature 453, 757-760 (2008). 2. M. Lewenstein et al., ”Theory of high-harmonic generation by low-frequency laser fields,” Phys. Rev. A 49, 2117-2132 (1994).

(b)


WLMI-2010

P 10: Self-compression of ultrashort pulses in media with negative third order nonlinearity

Christian Köhler,1 Luc Bergé,2 and Stefan Skupin1, 3


WLMI-2010

P 11: Coupling between Kerr-induced filamentation and stimulated Brillouin scattering in silica

S. Mauger , _ L. Bergé,1 and S. Skupin2


WLMI-2010

P 12: Development of laser plasma instabilities during the interaction of two successive ps pulses at moderate intensity: space- and time-resolved

Thomson scattering measurements

C. Rousseaux1, S.D. Baton2, D. Bénisti1, L. Gremillet1, P. Loiseau, B. Loupias1, F. Philippe1, F. Amiranoff2

1Commissariat à l'Energie Atomique, DAM, DIF, F-91297 Arpajon, France

2LULI, UMR 7605, CNRS-CEA-Ecole Polytechnique-Université Paris VI, Ecole Polytechnique, 91128 Palaiseau, France

in collaboration with J.L. Kline3, D.S. Montgomery3, B.B. Afeyan4 3P-24, Physics Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA

4Polymath Research Inc., 827 Bonde Court, Pleasanton, CA 94566, USA

The development and saturation mechanisms of the electron plasma waves (EPW) and ion

acoustic waves (IAW) respectively driven by stimulated Raman (SRS) and Brillouin (SBS) backscattering are experimentally investigated using the LULI 100-TW laser facility. In this experiment, the laser parametric instabilities (LPI) are excited by two successive 1w, 1.5 ps laser pulses, separated by 3 or 6 ps. The pulses are fired at f/17 into a pre-ionized He plasma (ne ~ 5-7x1019 cm-3). Our objective is to investigate the potential coupling between the instabilities driven by the two pulses as a function of the system parameters, to be compared with the single, monospeckle interaction [1].

The shots are analyzed through two simultaneously operated, time-resolved (t = 300 fs), Thomson-scattering diagnostics. The first one measures the driven IAW and EPW spectra along the laser pump direction (z axis). The second one provides space-resolved measurements of the spectra along the direction perpendicular to the pump direction simultaneously at two or three z locations.

The time delay between the two pulses, the initial gas pressure and the intensity of the first pulse have been varied. Due to the moderate fixed intensity (Imax = 2x1016 W/cm2) of the second pulse, the detected IAWs may not necessarily result from SBS. Second pulse–driven recovery of SRS is observed at low electron density with 3 ps time delay or with 6 ps time delay at higher electron density. As SRS saturates, the EPW spectra exhibit a surprisingly large radial extension around the interaction volume, together with a significant frequency downshift of the EPWs which is found to decrease with the radial distance [2] [3]. The potential implications of the experimental measurements will be briefly discussed. [1] C. Rousseaux et al., Phys. Rev. Lett. 97, 015001 (2006). [2] C. Rousseaux et al., Phys. Rev. Lett. 102, 185003 (2009). [3] C. Rousseaux et al., Anomalous 2008.


WLMI-2010

P 13: Stability of nonlinear Vlasov waves through Fourier-Hermite discretization

Evangelos SIMINOS, Didier BENISTI and Laurent GREMILLET

CEA, DAM, DIF, 91297 Arpajon, France Using an expansion in Fourier-Hermite basis we compute stability of nonlinear Vlasov waves for two problems of relevance to stimulated Raman scattering. We calculate the growth rate of perturbations of BGK equilibria with multiple phase space depressions (holes) that undergo a hole-fusion route to saturation, resembling the vortex fussion observed in SRS simulations. We also present preliminary results concerning subharmonic perturbations of large amplitude electrostatic plasma waves.


WLMI-2010

P 14: Self-Organized Dissipationless Ginzburg-Landau Solitons

V. Skarka1 and N. B. Aleksic2 1Laboratoire POMA, UMR 6136 CNRS, University of Angers, 2, Boulevard Lavoisier,

49045 Angers, France 2Institute of Physics, Pregrevica 118

Belgrade, Serbia e-mail: [email protected]

The diffraction and dispersion of an optical pulse need to be compensated by saturating nonlinearity, in order to be completely confined in space and time forming so-called “light bullet”. In a real experiment, light bullet cannot propagate without losses. We demonstrated that only cross compensation between saturating nonlinearity excess, loss, and gain maintains such self-organized structure in stable dynamic equilibrium, on the stable brunch of bifurcation diagram. We developed the dissipative variational method in order to find steady state solutions of complex cubic-quintic Ginzburg-Landau equation that describe well dissipative solitonic structures of one, two, and three dimensions. A stability criterion is established rendering a large domain of dissipative parameters [4]. Analytically obtained symmetric steady state solutions of Ginzburg-Landau equation are stable in this domain. If these approximate solutions are taken as input for numerical simulations of full Ginzburg-Landau equation, their evolution will always lead to stable dissipative solitons in dynamic equilibrium. A localized light pulse becomes a dissipationless soliton whenever the loss is compensated by the gain and simultaneously the light dispersion is balanced by the medium nonlinearity. It is worthwhile to stress that even very asymmetric input pulses far from stable spherically symmetric steady states, for the same dissipative parameters from our domain, always self-organize into solitons. Analytically obtained stable steady states are in the domain of attraction of the exact solution. As a consequence, bullets are very robust resisting to the successive increase of amplitude during evolution. Variety of different solitons can appear for various parameters. The opportunity to treat analytically and numerically asymmetrical input pulses propagating toward necessarily stable and robust dissipationless light bullets opens possibilities for diverse practical applications including experiments. References [1] G. Nicolis and I. Prigogine, Self-Organization in Nonequilibrium Systems, (John Wiley and Sons, New York, 1977). [2] V. Skarka, V.I. Berezhiani, and R. Miklaszewski, Phys. Rev. E 56, 1080 (1997). [3] V. Skarka, and N.B. Aleksic, Phys. Rev. Lett. 96, 013903 (2006). [4] N.B. Aleksic, V. Skarka, D. V. Timotijevic, and D. Gauthier, Phys. Rev. A 75, 061802(R) (2007).


WLMI-2010

P 15: Analytical solutions for generalized nonlinear Schrodinger equation

Larisa L. Tatarinova

Theoretical Physics, University of Fribourg, Chemin du Musee 3, 1700 Fribourg, Switzerland.

[email protected]

New approximate analytical solutions for the nonlinear Schrodinger equation in (1+1) and (1+2) dimensions are presented. The solutions are obtained on the basis of an extension of an approach formulated in Ref. [1]. Various particular forms of the nonlinear refractive index and the initial intensity distribution are studied. Expressions for determining the nonlinear self-focusing position for each situation under consideration are obtained. Comparison with the Marburger formula and results of numerical simulations of Ref. [2] are presented.

References

[1]. L. L. Tatarinova, M. E. Garcia, Phys. Rev. A 78 (2008) 021806(R) (1-4). [2]. L. Berge, C. Gouedard, J. Schjodt-Eriksen, H. Ward, Physica D 176 (2003) 181- 221


WLMI-2010

P 16: Fast Electron Generation and Transport in Laser-Induced Shock Compressed Plasmas

B. Vauzour1, J. J. Santos1, D. Batani2, S. D. Baton3, M. Koenig3, Ph. Nicolaï1, F. Perez3, F. N. Beg4, C. Benedetti5, R. Benocci2, E. Brambrink3, P. Carpeggiani2, S. Chawla4, M. Coury6, F. Dorchies1, C. Fourment1, M. Galimberti8, L. A. Gizzi9, R. Heathcote8, D. P.

Higginson4, J. J. Honrubia7, S. Hulin1, R. Jafer2, L. C. Jarrot4, L. Labate9, K. Lancaster8, P. Köster9, A. J. MacKinnon10, P. McKenna6, A. G. McPhee10, W. Nazarov11, J. Pasley12, R.

Ramis7, Y. Rhee13, M. Rabec Le Glohaec3, C. Regan1, X. Ribeyre1, M. Richetta14, F. Serres3, H.-P. Schlenvoigt3, G. Schurtz1, A. Sgattoni5, C. Spindloe8, X. Vaisseau1, M.

Veltcheva2, L. Volpe2, V. Yahia3

1 CELIA, Université de Bordeaux-CEA-CNRS, Talence, France, 2 Dipartimento di Fisica, Università di Milano-Bicocca, Milano, Italy 3 LULI, Ecole Polytechnique-CNRS-CEA-UPMC, Palaiseau, France

4 University of California, San Diego, La Jolla, USA 5 Dipartimento di Fisica, Università di Bologna, Italy

6 SUPA, Department of Physics, University of Strathclyde, Glasgow, UK 7 ETSI Aeronauticos, Universidad Politécnica de Madrid, Madrid, Spain

8 Central Laser Facility, Rutherford Appleton Laboratory, Didcot, UK

9 Intense Laser Irradiation Laboratory at INO, CNR, Pisa, Italy

10 Lawrence Livermore National Laboratory, Livermore, USA 11 University of St. Andrews, Fife, UK

12 Department of Physics, University of York, UK 13 KAERI, Republic of Korea

15 Dipartimento di Ingegneria Meccanica, Università di Roma Tor Vergata, Italy

The fast ignition [1] scheme which is an alternative option to the standard Inertial Confinement Fusion (ICF) is based on deep understanding of the fast electron propagation from their generation near the critical density (nc) to the high compressed DT core (~300nc). Although not yet be able to reproduce fusion plasma conditions it is however possible, by varying the compression geometries, to study the fast electrons transport in different kinds of plasmas (classic, coupled and/or degenerated) representative (with lower temperature and density levels) either of the corona or the core of fusion targets. In this context we report on experimental results and their interpretation of the fast electrons transport in compressed plasmas, created by laser-induced shock propagation in both planar and cylindrical geometry. The experiments were respectively performed at PICO2000 (LULI, France) and VULCAN TAW (RAL, UK) laser facilities. The obtained plasmas densities and temperatures ranged from 2 to 11g/cc and 4 to 120eV depending on the initial density of the target and the compression geometry. The planar geometry ensures wide plasma homogeneity around the propagation axis and the surfacic mass seen by the electrons is constant during the compression. Thus changes in the electrons range are mainly governed by collective stopping power mechanism which can be an important source of energy loss for the electrons. An increased stopping power is identified in compressed compared to solid Al. The cylindrical geometry allows reaching higher compression factors and electron collimation depends on density and temperature gradients inside the target. By imaging Ka fluorescence of electron tracers we observed for the first time a fast electron jet propagating inside a compressed target. The fraction of hot electrons crossing the 200µm target length is found to be decreasing for an increasing compression [2]. Experimental results are compared to hydrodynamic simulations for the compression study as well as PIC and hybrid simulations for the electronic transport. This work constitutes a part of the experimental validation program within the Inertial Fusion Energy European project HiPER. [1] Tabak M. et al., Phys. Plasmas (1994) [2]Perez F. et al., PPCF (2009)


WLMI-2010

Notes


WLMI-2010

Poster


WLMI-2010

Program:

Tuesday 14th Wednesday 15th Thursday 16th Friday 17th 8:45

Opening WDM & AstroLab

Chair: P. Mora R. P. Drake B. Loupias S. Brygoo T. Vinci

8:40 Applied Math.

Chair: E. A. Kuznetsov D. Lannes E. Lorin E. Dumas R. Sentis

9:00 Pulse compression

Chair: O. Kosareva G. Steinmeyer E. Constant M. Bache V. Tosa

8:40 X, VUV, THz

Chair: V. Yu. Bychenkov C. Courtois J. Liu I. Babushkin S. Le Pape F. Dorchies

break break break break 10:30

Femto. Filaments Chair: L. Bergé

O. Kosareva A. Aceves J. Kasparian S. V. Chekalin

10:30 UHI

Chair: B. Afeyan P. Mora V. Yu. Bychenkov S. Ter-Avetisyan A. A. Andreev L. Gremillet

11:00 Supercontinuum

Chair: G. Steinmeyer W. Krolikowski A. V. Gorbach J. Herrmann M. Taki

10:50 Self-focusing

Chair: S. Skupin E. A. Kuznetsov P. M. Lushnikov H. Leblond N. Rosanov Closing

12:30 lunch

12:30 lunch

12:30 lunch

12:30 lunch

17:00 Ultrafast Micropr. Chair: J. Kasparian

F. Courvoisier V. Mezentsev S. Guizard T. Itina Yu. Geints

17:00 Poster Session

17:00 ICF

Chair: R. P. Drake P. Miche B. Afeyan D. Benisti P. Loiseau P. E. Masson-Laborde

19:00 Dinner

19:00 Dinner

19:30 Conference Dinner

2nd INTERNATIONAL WORKSHOP ON LASER-MATTER …wlmi10/BookWLMI10_web.pdf · means to the workshop,...

Documents

Transcript of 2nd INTERNATIONAL WORKSHOP ON LASER-MATTER …wlmi10/BookWLMI10_web.pdf · means to the workshop,...