Future Research Infrastructures: Challenges and Opportunities, July 8-11, Varenna, Italy C....

Future Research Infrastructures: Challenges and Opportunities, July 8-11, Varenna, Italy

C. Masciovecchio C. Masciovecchio

Free Electron Laser based Multicolor Spectroscopy

Introduction to FERMI Free Electron LaserIntroduction to FERMI Free Electron Laser The Experimental End-StationsThe Experimental End-Stations EIS program (TIMEX & TIMER) EIS program (TIMEX & TIMER) MULTICOLOR SpectroscopyMULTICOLOR Spectroscopy

Elettra - Sincrotrone Trieste, Basovizza, Trieste I-34149


Why Free Electron Lasers ?

Pea

k br

illi

ance

Pea

k br

illi

ance

= p

hoto

ns/

s/m

rad

2/m

m2/0

.1%

bandw

idth

ImagingImaging with high Spatial Resolution (~ ~ ): fixed target imaging, particle injection

imaging,..

DynamicsDynamics: four wave mixing (nanoscale), warm dense matter, extreme condition, ....

ResonantResonant Experiments: XANES (tunability), XMCD (polarization), chemical mapping, ……

Pulse Duration

100 nm

1ns 1ps 10ps 100ps 1fs 10fs 100fs

1μm

10nm

1 nm

1 A

1eV

10eV

100eV

1keV

10keV

Synchrotron radiation

Conventional lasers

LPE FELs

HPE FELs

HHG in gasesPlasma lasers


SASE vs Seeded

x 105

L. H. Yu et al., PRL (2003)

time

Electron bunch

Optical pulse


t < 100 fs

Flux ~ 1013 ph/pulse

E ~ 10 - 500 eV

Total Control Total Control on

Pulse Energy

Time Shape

Polarization

E. Allaria et al., Nat. Phot. (2012); Nat. Phot. (2013)


The Experimental Hall

EISEIS (Elastic & Inelastic Scattering)(Elastic & Inelastic Scattering)

TIMERTIMERTIMERTIMER

TIMEXTIMEXTIMEXTIMEX

DIPROIDIPROI (DIffraction & PROjection Imaging) (DIffraction & PROjection Imaging)

LDMLDM (Low Density Matter)(Low Density Matter)

TeraFERMITeraFERMI (THz beramline)(THz beramline)

MagneDYNMagneDYN (Magnetic Dynamics)(Magnetic Dynamics)

C. Masciovecchio et al., J. Synch. Rad. (2015)

F. Capotondi et al., J. Synch. Rad. (2015)


The Experimental Hall

LDMLDM

DIPROIDIPROI TIMEXTIMEX

TIMERTIMERTIMERTIMER


C. von Korff Schmising, S. Eisebitt et al, submitted

Controlling ultrafast demagnetization ultrafast demagnetization using localized optical excitation

Ultrafast Magnetic DynamicsUltrafast Magnetic Dynamics

DIPROI Highlights

Co/Pt ML


DIPROI Highlights

X-ray holographyholography with customizable referencecustomizable reference

Ideal FTH overcoming restriction due to the reference wave single-shot imaging

Sample

Diffraction

Known reference

Hologram refined Hologram refined with RAAR phase with RAAR phase

retrivial retrivial

Conjugate-gradient algorithm Conjugate-gradient algorithm to recover the image

FTH with an almost unrestricted choice for the referenceunrestricted choice for the reference

Longitudinal Longitudinal coherence coherence matters!! matters!!

A. Martin et al. (2014)


Pump & Probe

Signal

The pump pump pulse produces a change a change in the sample

-stimulate a chemical reaction -non-equilibrium states -extreme thermodynamic conditions-ultrafast demagnetization-coherent excitations-.................. that is monitored is monitored by the probeprobe pulse

-1 0 1 2 3 4 5 6 7 8 9

x 10-12

-0.06

-0.05

-0.04

-0.03

-0.02

-0.01

0

0.01

0.02

0.03

Time (sec)

R

/R

GaAs

Jitter ~Jitter ~ 5 fs5 fs

M. Danailov et al., Opt. Express (2014)

WORLD RECORD !!WORLD RECORD !!


Elastic and Inelastic Scattering (EIS)

ShortShort pulses with very high peak power t ~ 100 fs ; Peak Power ~ 5 GW ; E ~ 100 eV

What happens to the Sample? Sample?

The Sample SideSample Side

Non-equilibrium distribution of electrons

Converge (electron-electron & electron-phonon collisions) to equilibrium (Fermi-like)

The intensity of the FEL pulses will determine the process to which the sample will undergo: simple heating, structural changes, ultrafast melting or ultrafast ablation

TIMERTIMER TIMEXTIMEX

interior of large large planets planets and stars


Pump & Probe FEL Ti

TIMEX TIme-resolved studies of Matter under EXtreme and metastable conditionsF. Bencivenga et al., (2014)


Pump & Probe on Germanium

20 m

Upon the absorption edge (Fermi level) the spectroscopy is sensitive both to the Fermi Fermi function smearing function smearing (red curve) and to the shift of the edge due to the metallizationmetallization of the sample (blue curve)

Probe FEL

Pump 800 nm

E. Giangrisostomi et al., in preparation


Q ( nm -1)

(m

eV)

-4

10-3

10-2

10-1

100

101

102

V= 500 m

/sV = 7000 m/s

BLS

INS

10-3

10-2

10-1

100

101

10210

BL

30/2

1

IXS

IUVSIUVS

BL

10.2

Challenge: Study Collective Excitations in Disordered Systems Disordered Systems in the UnexploredUnexplored -Q region

Determination of the Dynamic Structure Factor: S(Q,)

=

cs ·Q

Q ()

nano-scale atomic-scalemacro-scale

EIS - TIMERTIMER TIME-Resolved spectroscopy of mesoscopic dynamics in condensed matter

Unsolved problems in physicsUnsolved problems in physics


M. Foret et al., PRL 77, 3831 (1996) They are localized above ~ 1 nm-1

P. Benassi et al., PRL 77, 3835 (1996) Existence of propagating excitations at high frequency

F. Sette et al., Science 280, 1550 (1998) They are acoustic-like

G. Ruocco et al., PRL 83, 5583 (1999) Change of sound attenuation mechanism at 0.1-1 nm-1

B. Ruffle´ et al., PRL 90, 095502 (2003) Change is at 1 nm-1

C. Masciovecchio et al., PRL 97, 035501 (2006) Change is at 0.2 nm-1

W. Schirmacher et al., PRL 98, 025501 (2007) Model agrees with Masciovecchio et al.

B. Ruffle´ et al., PRL 100, 015501 (2008) Shirmacher model is not correct

G. Baldi et al., PRL 104, 195501 (2010) Change is at 1 nm-1

PRL 112, 025502 (2014); Nat. Comm. 5, 3939 (2014); PRL 112, 125502 (2014)

The nature of the vibrational dynamics in glassesglasses at the nanoscale is still unclear (V-SiO2)

Why disordered systems at the nanoscale ?

Fundamental to understand the low temperature anomalies in glassesglasses


Eprobe

Esignal

Epump

Epump

Q(,)

FQt

SolutionSolution: Free Electron Laser based Transient Grating Spectroscopy

(

meV

)

-4

10-3

10-2

10-1

10 0

10 1

10 2

V= 500 m/sV= 7000 m/s

BLS

INS

10 -3 10 -2 10 -1 10 0 10 1 10 210

Q ( nm -1)

IXS

IUVSIUVS

European Research CouncilFunded Grant: 1.8 M€

EIS beamline - TIMER


1 10 100-0.8

0.0

0.8

1.6

F(Q

,t) (

a.u.

)

t (ps)-10 -5 0 5 100

800

1600

2400

S(Q

,)

(a.u

.)

(meV)

H2O 2 nm-1

Gaussian-like time profile

The Spectrum

Optical absorption Temperature Grating Time-dependent Density Response

(driven by thermal expansion)

Sound waves regionS(t

)S

(t)

region

Thermalregion

S(t) ( cost – F(Q,t))

Glycerol T=205 KGlycerol T=205 K


DOE: Phase Mask

AL2

APD

Sample

Probe laser beam

Excitation laser beam

AL1

EL

Epr

DM

Eex1

Eex2

1

2=21

M

M

Delay Line

Es (Homodyne)EL+Es (Heterodyne)

Beam stop (Homodyne)Neutral Filter (Heterodyne)

Phase Control (Heterodyne)

Typical Infrared/Visible Set-Up

ChallengeChallenge: Extend and modify the set-up for UV Transient Grating Experiments


@ sample positionVertical

Horizontal

“Original beam”Vertical

Probe

Pump1 Pump2

Horizontal

Beam waist

Focusing mirror

Plane Mirrors“beam splitters”

3rd harmonic (probe)

FEL pulse:1st and 3rd harmonic (λ3 = λ 1/3)

Delay line: 4 ML mirrors (abs 1st, reflect 3rd harm), time delays up to ~ 3 ns

1st harmonic (pump)

2θθB

TIMER Layout

R. Cucini et al et al., NIMA (2011)


M0M1

M2

2θ

ΔtFEL-FEL= ± 0.5 ps at 2θ = constant

M0M1

M2

λopt

Detector (EUV-Vis cross-corr.)

θB

Beamstops

FEL2

Si3N4 reference sample

FEL1

-1 0 1 2 3-0,06

-0,04

-0,02

0,00

R /

R

t (ps)

- FEL2

- FEL1

FEL Transient Grating Experiments on V-SiO2

F. Bencivenga et al., NIMA (2010) R. Cucini et al., NIMA (2011) R. Cucini et al., Opt. Lett. (2011) F. Casolari et al., Appl. Phys. (2014)M. Danailov et al. Opt. Express (2014)R. Cucini et al., Opt. Lett. (2014)


M0M1

M2

2θ

2θ

θ kFEL,1

kFEL,2

θB

FEL Transient Grating Experiments on V-SiO2

F. Bencivenga et al., Nature 2015

λoptkopt

CCD

k fout Permanent Grating after 1k-shots

Optical path difference < λFEL

FEL = 27.6 nm


Transient Grating Experiments on V-SiO2

AcousticAcoustic-like excitationsRamanRaman modes due to tetrahedral bending

Hyper - Raman Hyper - Raman modes due to coupled tetrahedral rotations


Time independent local field

Heterodyning with FEL

0 20 40 60 80 100 1200.0

0.5

1.0

1.5

2.0

2.5

3.0

t (ps)

I [a

rb.

units

]

HeterodyningHeterodyning is a signal processing technique invented in 1901 by R. Fessenden

λoptkopt

CCD

k fout


Four Wave Mixing at FEL’s

Transient grating is one of Four Wave Mixing Four Wave Mixing techniques

Coherent Antistokes Raman Scattering (CARSCARS)

Measure the coherence between the two different sites it makes possible to chose where a given excitation is created, as well as where and when it is probed

delocalization of electronic states and charge/energy transfer processes

ω1

ω2ω3 ωout

VB

CB

atom-A

atom-B

Δt

2 k2

1k1

3 k3

4 k4

S. Tanaka & S. Mukamel PRL (2002)

Charge and Energy transfer are fundamental for:•Metal complexes Metal complexes •Organic solar cellsOrganic solar cells•Metal oxides nanoparticlesMetal oxides nanoparticles•Thin heterostructuresThin heterostructures• ……… ………• ……… ………


Multiple pulse configurationsMultiple pulses can be generated by double pulse seedingdouble pulse seeding

Temporal separation Temporal separation between 25-300 and 700-800 fs. Shorter separations Shorter separations are accessible via FEL pulse splitting. Larger separations require the split & delay linesplit & delay line.

time

spectrum

gain bandwidth

Spectral separation 0.4-0.7%(E. Allaria et al., Nat. Comm 2013)

time

spectrum

MOD gain bandwidth RAD1 gain

bandwidth

RAD2 gain bandwidth Spectral separation 2-3%

or much larger if the two radiators are tuned at different harmonics (Sacchi et al., in preparation)

spectrum

time

spectrum

MOD gain bandwidth

Two (almost) temporally superimposed pulses at harmonic wavelengths of the seed. They are correlated in phase that can be controlled with the phase shifter (K. Prince et al., submitted)

Mahieu et al. Opt. Express (2013)


ΘΘpumppump

ΘΘ probeprobe


Pump & Probe on Silicon

P. F. McMillan et al., Nature (2005)

Probe FEL

Pump FEL

E. Principi et al., in preparation


LDM Highlights

Coherent control Coherent control at the attosecond time scale

Signal detected as function of phase on the VMI detector

Interference effect among quantum states using single and multiphoton ionization

Use of first (62.974 eV ) and second harmonic on 2p54s resonance of Ne

Change of the phases among the two harmonics ‘invented’ by Allaria et al.,

Control of the phase among the two pulses!

Intensity = | M1 + M2(ϕ)| = | M1|2 + |M2(ϕ)|2 + 2 Re(M1 M2(ϕ))

K. Prince et al., submitted

C. Chen et al., PRL (1990)


Conclusions


Conclusions

M. Chergui

K. NelsonT. Scopigno

G. KnoppG. Monaco

A. Föhlisch

• Charge transfer dynamics in metal complexes metal complexes • Charge injection and transport in metal oxides nanoparticles metal oxides nanoparticles • Vibrational modes in GlassesGlasses• Charge Density WaveDensity Wave• Quasiparticle diffusion (PolaronsPolarons)• Sound velocity in GrapheneGraphene


Acknowledgments

M. KiskinovaM. Danailov M. ZangrandoL. Giannessi

P. FinettiF. Capotondi A. Battistoni

A. Gessini

F. Bencivenga

M. Manfredda

O. Plekan

M. Di Fraia

E. Pedersoli R. Cucini

M. Coreno E. Giangrisostomi E. Principi K. Prince R. Mincigrucci

R. Richter

F. Parmigiani C. Callegari

Future Research Infrastructures: Challenges and Opportunities, July 8-11, Varenna, Italy C....

Documents

Transcript of Future Research Infrastructures: Challenges and Opportunities, July 8-11, Varenna, Italy C....