A Multi-Kilojoule, Multi-Petawatt Heating Laser for Fast ... · LFEX-Laser A Multi-Kilojoule,...
Transcript of A Multi-Kilojoule, Multi-Petawatt Heating Laser for Fast ... · LFEX-Laser A Multi-Kilojoule,...
LFEX-Laser A Multi-Kilojoule, Multi-Petawatt Heating Laser
for Fast Ignition
J. Kawanaka, N. Morio, S. Matsuo, K. Kawabata, Y. Kawakami, Y. Fujimura, K. Sawai, K. Tsuji, Y. Suzuki, Y. Matsuda, T. Kawasaki, H. Murakami, M. Ishida, H. Kitamura,
H. Matsuo, T. Sakamoto, T. Sezaki, T. Yanagida, S. Tokita, Y. Nakada, K. Tsubakimoto, S. Fujioka, H. Shiraga, T. Jitsuno, and N. Miyanaga,
and Plasma Exp. Group
Institute of Laser Engineering, Osaka University
26th IAEA Fusion Energy Conference - IAEA CN-234 Kyoto, Japan
1. A view of the whole LFEX system
2. Key technologies of LFEX
2-1 Large aperture dielectric grating for kJ, ps
pulses in a pulse compressor
2-2 Deformable Mirror for wavefront compensation
2-3 Novel pulse cleaner for high intensity contrast
3. Summary
Outline
Implosion by
multiple beams
Fast heating by
Intense laser
Ignition and burn
Fast ignition in laser fusion
Gekko XII LFEX
LFEX Spec.
LFEX spec.
Wavelength: 1053 nm (Nd: glass laser)
Pulse energy: 10 kJ
Pulse width: 1-20 ps (FWHM) 10 ps (typical)
Peak Power: 0.5~10PW (10 kJ/1 ps, 5 kJ/0.5 ps for
ultra high-field science)
Pulse shape: trapezoid with <2 ps rise time
Focal spot: 20-30 µm (≥50 % encircled energy)
For >5-keV heating of dense fuel,
ps-Laser 4 beams
10 kJ 1~20 ps
0.5~10 PW
ns-Laser 12 beams 6 kJ (2w)
2.4 kJ (3w) 1~10 ns
0
1
2
3
4
5
1 10 100 1000 10000 100000
PW lasers in the world
Pulse Energy (J)
5 4 3 2 1 0
Pe
ak P
ow
er
(PW
)
1 10 102 103 104 105
Astra-Gemini
IOP CAS
J-KAREN
SIOM
GIST
Ti:sapphire
TX-PW OMEGA-EP
Vulcan Orion Z-Petawatt
(Nova)
Nd:glass
20 fs 1 ps
0
1
2
3
4
5
1 10 100 1000 10000 100000 1000000 10000000
Pe
ak P
ow
er
(PW
)
Pulse Energy (J)
How can we generate PW peak power?
300 fs
Chirp Pulse Amplification (CPA)
Chirped
Main Pulse
AOPF
Osc. Amplifier
Osc. Amplifier Pulse
Strecher Pulse
Compressor
Dt ~ x 103 ~ 105
High electric field of a laser damages optics, which are used in the amp.
PW with kJ
Seed pulse
Block diagram of the LFEX system
Main Amplifier
3-stage OPCPAs
ML Fiber Osc.
Pulse Stretcher
Spatial Light Modulator
4-pass Rod Amp. Double Rod Amps
Image Relay
Compressor Beam Divider
Target Chamber
Main Amplifier
High power shots are available now!!
1) Monochromatic (ns) > 3 kJ / beam
2) Chirped pulse (ns before compression)
~ 3 kJ / beam
3) Compressed pulse (ps) 2 kJ (4 beams)
1 ps(shortest)
2 PW(Maximum)
For >5-keV heating of dense fuel,
LFEX spec.
Wavelength : 1053 nm
Pulse energy : 10 kJ
Pulse width : 1-20 ps
Peak Power : 0.5~10PW
Pulse Intensity : >1020 W/cm2
(on target)
Pulse Contrast : <10-11
Focal spot : 20-30 µm
~ 40 mJ
~ 10 J
~ 10 J/beam
~ 3 kJ/beam
~ 2.5 kJ/beam 1 ps X 4 100 fs, 1 nJ
2.5 ns
Key Technologies
Main Amplifier
3-stage OPCPAs
ML Fiber Osc.
Pulse Stretcher
Spatial Light Modulator
4-pass Rod Amp. Double Rod Amps
Image Relay
Compressor Beam Divider
Target Chamber
Main Amplifier
High power shots are available now!!
1) Monochromatic (ns) > 3 kJ / beam
2) Chirped pulse (ns before compression)
~ 3 kJ / beam
3) Compressed pulse (ps) 2 kJ (4 beams)
1 ps(shortest)
2 PW(Maximum)
Large-aperture Deformable Mirror
Novel Pulse Cleaner
Large-aperture Dielectric Grating
Key Technologies
Main Amplifier
3-stage OPCPAs
ML Fiber Osc.
Pulse Stretcher
Spatial Light Modulator
4-pass Rod Amp. Double Rod Amps
Image Relay
Compressor Beam Divider
Target Chamber
Main Amplifier
High power shots are available now!!
1) Monochromatic (ns) > 3 kJ / beam
2) Chirped pulse (ns before compression)
~ 3 kJ / beam
3) Compressed pulse (ps) 2 kJ (4 beams)
1 ps(shortest)
2 PW(Maximum)
Large-aperture Deformable Mirror
Novel Pulse Cleaner
Large-aperture Dielectric Grating
Diamond compressor
Main Amplifier
High power shots are available now!!
1) Monochromatic (ns) > 3 kJ / beam
2) Chirped pulse (ns before compression)
~ 3 kJ / beam
3) Compressed pulse (ps) 2 kJ (4 beams)
1 ps(shortest)
2 PW(Maximum)
Gratings 2
Gratings 1
Mirror
Mirror
Mirror
Mirror
~ 1 ps ns
E = 2.5 kJ/beam
Uth ~ 0.2 J/cm2 (Au)
2 J/cm2 (Dielectric)
S = 5000 cm2 1250 cm2
Meter size
Dielectric Gratings Damage threshold Minimum cross section
Pulse energy
All large aperture dielectric gratings are fully installed.
92 cm × 42 cm, 1740 grooves/mm
R
+Z
+X
-Z
-X X
Z 42 cm
1740 grooves/mm
92 cm
The world’s largest dielectric gratings
Difficulties ・ Dielectric coating on large aperture silica glass ・ Extremely precise grooving (0.05ppm)
Grating blank
92 cm 42 cm
Ion Etching
Scanning Exposure (1.3-m stage)
Resist coating
Dielectirc coating
Polishing
Quartz material (Tosoh Co.)
ILE, Osaka Univ.
Japan
U.S.
Ion source
Melting pot
Wavefront Inspection
Cleaning
Wavefront Inspection
PGL, Massachusetts
Okamoto Optics Works (Yokohama)
2m-size Coating machine
Development & manufacturing system of large-aperture, high perfomance dielectric gratins
The Observed Typical Characteristics
+20%
-20%
The pulse energy is limited below 500 J/beam because of optical damage of mirrors. ↓
2 kJ with 4 beams
Am
plif
ied E
ne
rgy (
J)
Input pulse energy after OPCPA (mJ)
0
100
200
300
400
0
500
100 200 300 500 600 700 400
Pulse energy
H1 SSA
ShotNo.2126 ShotNo.2127
Rod Shot Disk Shot
H1 SSA
ShotNo.2126 ShotNo.2127
Rod Shot Disk Shot
Disk
Rod
Pulse width (Single Shot Auto-Collirator)
1 ps
2kJ, 1 ps, 2 PW
LFEX is the highest peak-power laser in kilojoule
Pulse Energy (J)
LFEX 2 PW 2 kJ 1 ps
5 4 3 2 1 0
Pe
ak P
ow
er
(PW
)
1 10 102 103 104 105
Astra-Gemini
IOP CAS
J-KAREN
SIOM
GIST
Ti:sapphire
TX-PW OMEGA-EP
Vulcan Orion Z-Petawatt
(Nova)
Nd:glass
20 fs 1 ps
The world’s highest peak power in kilo-joule
Key Technologies
Main Amplifier
3-stage OPCPAs
ML Fiber Osc.
Pulse Stretcher
Spatial Light Modulator
4-pass Rod Amp. Double Rod Amps
Image Relay
Compressor Beam Divider
Target Chamber
Main Amplifier
High power shots are available now!!
1) Monochromatic (ns) > 3 kJ / beam
2) Chirped pulse (ns before compression)
~ 3 kJ / beam
3) Compressed pulse (ps) 2 kJ (4 beams)
1 ps(shortest)
2 PW(Maximum) Pulse compressor with large aperture dielectric gratings
Deformable Mirror
Pulse Cleaner
Wavefront compensation with Deformable Mirror
Main Amplifier
High power shots are available now!!
1) Monochromatic (ns) > 3 kJ / beam
2) Chirped pulse (ns before compression)
~ 3 kJ / beam
3) Compressed pulse (ps) 2 kJ (4 beams)
1 ps(shortest)
2 PW(Maximum)
Normal Mirror
Distorted Wavefront
Defomable Mirror (DFM)
Distorted Wavefront
DFM Mirror
Wavefront Compensation!!
Major cause of
phase aberration
0.54µm rms
FFP
Wavefront w/o DFM
Shack-Hartmann
Active pre-compensation with large-aperture DFM
Main Amplifier Image Relay
DFM75 DFM125
H1H-FFP
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Energ
y I
n A
pert
ure
(%
)
1514131211109876543210
Diffraction Limitt (2.44Fλ)
H1_ROD H1_DA
Rod
DA
46% @ 5Fl
FFP
Shack-Hartmann
Wavefront
FFP
w. DFM
0.11µm rms
High focusability 5% @5Fl 35% @5Fl
Key Technologies
Main Amplifier
3-stage OPCPAs
ML Fiber Osc.
Pulse Stretcher
Spatial Light Modulator
4-pass Rod Amp. Double Rod Amps
Image Relay
Compressor Beam Divider
Target Chamber
Main Amplifier
High power shots are available now!!
1) Monochromatic (ns) > 3 kJ / beam
2) Chirped pulse (ns before compression)
~ 3 kJ / beam
3) Compressed pulse (ps) 2 kJ (4 beams)
1 ps(shortest)
2 PW(Maximum) Pulse compressor with large aperture dielectric gratings
Deformable Mirror
Pulse cleaner
Main Pulse
AOPF (Amplified Optical
Parametric
Fluorescence)
Pulse intensity contrast
Pulse Intensity (on target) : >1020 W/cm2
Laser intensity to generate plasma : ~109 W/cm2
Required Intensity Contrast : <10-11
Pre-Plasma Production
Imain
IAOPF Intensity Contrast = Imain
IAOPF
Target
SA (Cr4+:YAG)
Pulse Compression
CPA
General
Main Pulse
AOPF
Chirped Main Pulse
AOPF
Residual AOPF
Compressed
Main Pulse
Pre-Plasma Production
Saturable absorber as pulse cleaner
Cr4+:YAGTransmission
GratingTransmission
Grating
Main Pulse
AOPF
Lens
Original Spectrally Resolved Pulse Cleaner
4-f non-dispersive optical layout
f f f f
Saturable Absorber
(Cr4+:YAG) Transmission
Grating Transmission
Grating
Lens Lens
Chirped
Main Pulse AOPF
2~3 ns
~20 ps
AOPF is reduced
-300 -200 -100 0 100
1 10-1
10-2
10-3
10-4
10-5
10-6
10-7
10-8
10-9
10-10
10-11
Time (ps)
Inte
nsity (
arb
. u
nit)
w/o SA
with SA
10 ps
50 ps
170 ps
Pulse intensity contrast after OPCPA
1 x 10-10 Third autocorrelator Mesurement Limit
High contrast is successfully achieved for plasma experiments.
Key technologies
・ Large aperture dielectric gratings has been developed for kJ, ps pulse
compressor.
・ Large aperture deformable mirrors has been successfully pre-compensated
the wavefront distortion to improve focusability.
・ Our original pulse cleaner improved the intensity contrast.
As a result,
The world’s highest peak-power laser in kilojoule, LFEX has been
successfully demonstrated.
1. Pulse energy : < 500J / beam (due to mirror damage after compression)
2. Pulse duration: 1~2ps (observed with single-shot auto-correlator)
3. Peak Power : ~ 2 PW
4. Pulse contrast : <10-10 (@ -170ps by using our new pulse cleaners)
In future,
Pulse energy will be increased for fast ignition demonstration by improving filling factor and so on,.
Summary
0
1
2
3
4
5
1 10 100 1000 10000 100000 1000000 10000000
Pe
ak P
ow
er
(PW
)
Pulse Energy (J)
Stretcher and Compressor
300 fs
Chirped
Main Pulse
AOPF
Lens Lens Grating Grating
Grating
Grating Grating
Compressor
Stretcher
Mirror fs ~ ps ns
fs ~ ps ns
Large aperture grating with high optical strength is necessary to kJ pulse energy.
Output from amplifier
2x2
1x4
2x2
Beam transport
Pulse compressor
Focusin Optic
Sensor - 3
Sensor - 1
GXII Target Chamber
105cm×85cm
・途中大幅設計変更
・LLNLとの共同研究
連携企業:三菱電機通信機製作所
Pulse compressor and focusing optics
Interaction
chamber
SM1
SM2
M2
M7
M7
M6
M4
M3
M9
M-10
M1
Grating 2
Grating 1
Monitor 1
Monitor 3 Off axis
parabola mirror
M5
SiO2 HfO2 SiO2 HfO2
0.575 µm
with
PC
&
PM
w/o
PC
&
PM
@ -2.8 ns
100 μm/div
@ -140 ps @ +1.6 ns @ -2.0 ns
100 μm/div 100 μm/div 100 μm/div
@ -1.3 ns
27
Irradiation to metal target with high energy pulses
S. Fujioka, Y. Arikawa, S. Kojima et al., Physics of Plasmas, 23, 0565308 (2016).
No pre-plasma at 140ps before the main pulse
2013
before
cool REB
2014
after
cool REB
Arikawa et al.,
28
Electron temperature in plasma
w/o pulse cleaners
Reducing electron tempearture
w pulse cleaners
1018
1019
1020
1021
10
100
Experiments
Weak focusing,
High contrast
tL= 1.5 ps
tL= 3 ps
tL= 6 ps
Tight focusing,
Low contrast
tL= 1 ps
M
axim
um
Pro
ton
En
erg
y [
Me
V]
Laser Intensity [Wcm-2]
50Adiabatic model
with 3D effect
for tL = 1 ps
29
Low-contrast pulse Small focal spot VULCAN-PW, 400J, 1ps, Nat. Phys. 3, 58 (2007)
The results were well scaled by TNSA model involving adiabatic cooling and 3D effect that weaken the ion energy.
Scaling of proton energy with PW laser Our experimental results are higher than the prediction of TNSA model.
Proton energy increases with the pulse duration on a fixed intensity.
High-contrast pulse Large focal spot LFEX (present)
Target : Al, 5 mmt
Y. Arikawa, A. Morace, A. Yogo, X. Vaisseau, Y. Abe, S. Kojima, S. Sakata, H. Lee, T. Hosoda, K. Law, K. Matsuo, T. Gawa, S. Tosaki, Y. Fujimoto, T. Jitsuno, Y. Hironaka, K. Mima, M. Murakami, N. Miyanaga, H. Nagatomo, M. Nakai, Y. Nakata, K. Nishihara, H. Nishimura, T. Norimatsu, T. Sano, Y. Sakawa, K. Shigemori, K. Tsubakimoto, H. Shiraga, H. Azechi Institute of Laser Engineering, Osaka University, Japan A. Sunahara Institute for Laser Technology, Japan T. Johzaki Hiroshima University, Japan K. Kondo Tokyo Inst. Tech., Japan A. Iwamoto, T. Ozaki, T. Watanabe, H. Sakagami National Institute for Fusion Science, Japan T. Shirato, N. Ohnishi Tohoku Univ., Japan H. Sawada, Y. Sentoku University of Nevada, Reno, USA Z. Zhang Institute of Physics, China J. Santos, M. Bailly-Grandvaux, D. Batani, R. Bouillaud, P. Forestier-Colleoni, S. Hulin, Ph. Nicolaï, V. Tikhonchuk CELIA, Univ. Bordeaux, France L. Giuffrida ELI-Beamline Project, Institute of Physics, Czech Republic J.L. Dubois, J. Gazave, D. Raffestin and J. Ribolzi. CEA, France M. Chevrot, S. Dorard, E. Loyez, J.R. Marques, F. Serres LULI, Ecole Polytechnique, France J. Honrubia Universidad Politécnica de Madrid, Spain 3
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