ultra-broadband optical parametric chirped pulse
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Junji Kawanaka, Hwang Sungln, Koji Tsubakimoto, Kana Fujioka, Yasushi Fujimoto, and Noriaki Miyanaga
Institute of Laser Engineering (ILE), Osaka University
Ultra-Broadband Optical Parametric Chirped Pulse
Amplification with Partially Deuterated KDP Crystal
ILE / Osaka
HEC-DPSSL Lake Tahoe, California 11th September 2012
RAL: Astra Gemini
ILE Texas
Vulcan:10PW (300J, 30fs)
ILE, LFEX (10kJ, 1-10ps)
JAEA
UK
LLNL
OMEGA-EP: (2.6kJ, 10ps)
MPQ: (5J, 5fs)
LLNL:1PW (13J, 13fs) 10Hz
ILE/ENSTA 20PW (300J,15fs)
LLNL: NIF-ARC: (2.4-13kJ, 10ps) EU, ELI: 0.2EW
(3kJ,15fs), 10 beams CEA, PETAL: (3.5kJ, 0.5-5ps)
ILE-CREST: (150mJ, 5fs) 10Hz
RAL: Vulcan PW
10-4!
10-3!
10-2!
10-1!
100!
101!
102!
103!
104!
Out
put e
nerg
y (J
)!
Pulse width (s)!10-15! 10-14! 10-13! 10-12! 10-11! 10-10!
1PW!
1TW!
1GW! 1MW!
1EW!
Gekko EXA
ILE, GEKKO EXA 0.2EW (2kJ,10fs)
OPCPA + Glass Amp.!OPCPA + Ti:Sapphire!All OPCPA!
Design!
Ultra-intense lasers over the world
✓ Sub-EW ✓ Few cycle
☀ Broadband amplification ☀ Temporal and spectral dispersion control
1. Arrayed-Beam Pumped OPA for kilo-joule
2. Partially Deuterated KDP 2-1 Broadband OPA Gain 2-2 Crystal Growth
3. Broadband Dielectric Grating
3-1 Groove Structure and Material
Outline
Arrayed Beam Pumped OPA for kilo-joule
Laser glass slab!46×81×4 cm3!
kJ-pump source based on LFEX-Laser technologies�
Large laser glass
m-size dielectric grating
2 x 2 disk amplifier
Arrayed compressor
Large-aperture OPCPA pumped by arrayed beams
OPCPA preamp.
35cmx35cm
30cm
KDP ω
ω
2ω
Pump Signal
λ = 1053 nm
λ = 527 nm
Nonlinear crystal
Proof-of-principle of OPA with random-phased pump
Pump laser
Nd:YLFoscillator
:
RPP
P1 P2
P3
Vacuum telescope
Telescope
DM PumpSignal, Idler
BBO
WP PL
WPGLP
EXP
AP
(a) 0 (b) ¹ /2 (c) ¹ (d) 3¹ /2 (e) 2 ¹
Phase
Signal
Pump
Idler
ランダム位相多ビーム励起
NFP
FFP
Pump
OPA
FFP
Random-phased pump
Virtually alignment free for beam combination ?
ランダム位相多ビーム励起
0.0
0.2
0.4
0.6
0.8
1.0
1.2
0.0 1.0 2.0 3.0 4.0 Diameter [Fλ]
RPP OPA
2-beam OPA
Before OPA
Nonlinear crystal�
Pump beams�
Signal�
Is 100PW feasible with single beam?!!→ Arrayed pumps in kJ are used.�
Large-aperture, ultra-broadband OPCPA with arrayed pumps
Partially Deuterated KDP (p-DKDP)
Sellmeier eqations of p-DKDP
p-DKDP Sellmeier equations by using KDP and DKDP,
(1) V. V. Lozhkarev, G. I. Freidman, V. N. Ginzburg, E. A. Khazanov, O. V. Palashov, A. M. Sergeev, and I. V. Yakovlev, “Study of broadband optical parameteric chirped pulse amplification in a DKDP crystal pumped by the second harmonic of a Nd:YLF laser,” Laser Phys. Vol. 15, No. 9 p.p. 1319-1333 (2005).
KDP and DKDP Sellmeier equations,
(2) Kevin W. Kirby and Larry G. DeShazer, “Refractive indices of 14 nonlinear crystal isomorphic to KH2PO4, JOSA B vol. 4, No. 7 pp.1072-1078 (1987).
(3) Frits Zernike, Jr., “Refractive indices of Ammonium Dihydrogen Phosphate and
Potassium Dihydrogen Phosphate between 2000 A and 1.5µ”, JOSA vol. 54, No. 10 pp. 1215-1220 (1964).
Temporal waveform in collinear OPCPA
θpm=36.9143 z
L=17mm
10 GW/cm2
20 W/cm2
DKDP (0.98)�
Δλ = 300 nm @1030nm CR = 1 nm/ps
1050 nm 850 nm 1250 nm
Non-gain-saturation
G = 300�
Seed
Seed
Amplified
Amplified
Gain Narrowing 300nm 110nm
Gaussian in temporal and spatial
Seed
Pump 515 nm
Seed
Pump
θpm=36.9143 @ 1030nm
z L=17mm
Seed
DKDP (0.98)�
CR = 1 nm/ps
Non-saturation condition
Temporal change of beam profile in collinear OPCPA
-100ps (930nm)
0ps (1030nm)
+100ps (1130nm)
x 1
7.5 x
1 15
Amplified
Seed
Pump
θpm=36.9143 θpm=36.9643
θs-p=0 z
L=17mm
Phase Matching
DKDP (0.98)�
CR = 1 nm/ps
Temporal change of beam profile in collinear OPCPA
Non-Phase Matching
x 1 15
x 1 15
x 1 7.5
x 1 15
0.05
-100ps (930nm)
0ps (1030nm)
+100ps (1130nm)
Gain bandwidth at off-phase-matching in collinear OPCPA
Phase Matching for λ0 and λ2ω
Non-Phase Matching for λ0 and λ2ω
Gain Narrowing 300nm 110nm
Gain Narrowing 300nm 50nm
-100ps
0ps +100ps
1 15
x 1
15 x
1 15
x 1
7.5 x
Gpeak = 300
Gpeak = 20
Deuteration dependence of gain bandwidth
10
11
12
13
14
15
16
100
105
110
115
120
125
130
135
140
145
150
0 20 40 60 80 100
FT-li
mite
d pu
lse
wid
th (n
s)�
Gai
n ba
ndw
idrt
h (F
WH
M) (
nm)�
Deuteration (%)�
Wavelength (nm)
Δk
(cm
-1)
145 nm�
10.5 fs �
0
0.02
0.04
0.06
0.08
0.1
0.12
0 20 40 60 80
100 120 140 160 180 200
0 0.1 0.2 0.3 0.4 0.5
Con
vers
ion
effic
ienc
y�
Gai
n ba
ndw
idrt
h (F
WH
M)
(nm
)�
Seed intensity (GW/cm2) �
Gain bandwidth broadening due to gain saturation
Pump beam depletion
Temporal profile (Spectral profile)
110 nm 190 nm 0.0% 10.1%
pDKDP(40%) + Gain Saturation in collinear OPCPA
Pump 10 GW/cm2
Signal 20 W/cm2
Seed
Seed
Amplified
Amplified
Signal 0.4 GW/cm2
Pump 10 GW/cm2
Amplified Signal
210 nm
pDKDP(40%)
DKDP(98%)
440 nm
Con. eff. 18.8%
How about Non-collinear ? pDKDP(40%) + Gain Saturation
Pump 150 GW/cm2 Signal 6 GW/cm2
pDKDP(40%)
465 nm
Seed Amplified
Con. eff. 18.8%
Con. eff. 8.0%
540 nm
Collinear
Non-Collinear
Seed
Amplified
1) N-CL shows a broader gain bandwidth than CL. 2) Need higher pump intensity in N-CL to recover
the reduced gain. 3) Also, need to take much care of the optically
induced damage.
2010 Check the previous parameters in crystal growth Reconstruct the growth system 2011 Trial of crystal growth in cm-size with deuteration between 50% and 80% Storage procedure of the crystal 2012 Refractive index measurement (Sellmeier equations)
Growth Capping:7days Growth:33days (2mm/day)
30mm
50mm
3-litter much mother solution to avoid segregation of dueterium
Crystal growth schedule of p-DKDP
20
30
40
50
60
70
80
90
0 20 40 60 80 100
30℃40℃50℃60℃70℃
溶解度 [g/100gH2O]
重水素化率 [%]
J. Crystal Growth, 53 (1981) 283.
Easier eduction For Tetragonal system
Deuterated ratio of mother solution [%]
Natural temperature decrease without controlDifferent crystallization conditionC. Belouet et al. [7]
Basic Data of p-DKDP Crystal Growth
Dueteration ratio
Sol
ubili
ty (g
/100
H2O
)
Easier eduction For Orthorhombic system
Partially deuterated KDP crystal for broadband OPA
10cm
13% deuterated KDP Pumping Energy: 8.4 kJ Pulse width: 1 ns Beam size: 32 cm Energy fluence: 10 J/cm2
OPCPA output Energy: ~1.2 kJ Pulse width: 0.5 ns
13%! 50%! 60%!
70%! 80%!
Cracks due to unexpected rotator stopping during the growth process.
First production of p-DKDP crystal
Broadband Dielectric Grating
Groove structure
Λ : 0.7 µm (1429 grooves/mm) f : duty cycle (0.1~0.6) tg : groove depth (0.1 µm) θ : incident angle (65-80 degree)
Groove structure
Deflection Efficiency Map with Wavelength and Groove Depth
material:SiO2 f : 0.4 Θ : 73˚
Wavelength (µm)
Gro
ove
dept
h (µ
m)
Δλ = 300 nm @ R > 80%, tg = 0.4
Deflection Efficiency Map with Wavelength and Groove Depth
Material:HfO2 f : 0.4 θ : 65˚
Δλ = 400 nm @ R > 90%, tg = 0.3 Δλ = 500 nm @ R > 80%
Summary
We are starting the challenging basic technology researches for broadband amplification of OPCPA. 1. Arrayed beams pumped OPA for kilo-joule ・Random-phased pump OPA shows virtually alignment free for beam combination.
2. Partially deuterated DKDP ・Numerical calculation shows
(a) Spectral gain bandwidth is reduced under non-gain-saturation (NGS) in collinear OPA.
(b) Amplified beam profile looks axicon under NGS in collinear OPA. Also, gain bandwidth is further reduced.
(c) Non-collinear OPA expands the gain band width. (d) p-DKDP expands the gain bandwidth. (e) Gain saturation expands the gain bandwidth.
・Non-collinear OPA with p-DKDP(40%) under gain-saturation will realize Δλ = 540 nm, Eff. = 8%.
!3. Broadband grating ・FDTD calculation
!Δλ = 500 nm @ >80%, HfO2, tg=0.3, f=0.4, θ=65˚
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