Spatio-Temporal Chirped Pulse Amplification for Avoiding Spectral
Modifications in Ultra-Short Petawatt Lasers
C. Radier1,2, F. Giambruno1,3, C. Simon-Boisson2, V. Moro2, G. Chériaux1
1 LOA, Chemin de la Hunière, 91761 Palaiseau Cedex, France2 TOSA-DSL, 2 Avenue Gay Lussac, 78995 Elancourt, France
3 ILE, CNRS, Ecole Polytechnique, ENSTA, Institut d’optique, 91761 Palaiseau Cedex, France
Palaiseau - FRANCE
Context (1/2)
http://loa.ensta.fr/ UMR 7639
• Generation of multi-tens of joules energy and several tens of femtoseconds duration pulses leading to petawatt peak power levels
• Extremely high peak power pulses (10 PW) :=> Vulcan laser 300 J / 30 fs (OPCPA) in LBO and KDP => Apollon-10P 150 J / 15 fs (CPA) in Ti:Sa
• Management of the spectral energy distribution in terms of shape and bandwidth during their amplification process :
=> Temporal profile adapted to the high intensity interaction
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Wavelength (nm)
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Context (2/2)
http://loa.ensta.fr/ UMR 7639
• OPCPA configuration in LBO / BBO / KDP :Control of the spectrum (width and shape) by the angles in the non-linear crystal and by the pump (temporal profile and intensity)
• CPA configuration in Ti:Sa :Amplification of temporally chirped pulses
=> Gain narrowing (inhomogeneous spectral gain )
Input : Δλ½ = 85 nm
Pass 6 : Δλ½ = 62 nm
Frantz et Nodvik model : « Gain regime : J0(t) ~ Jsat / 1000 & G = 100 »
Context (2/2)
http://loa.ensta.fr/ UMR 7639
• OPCPA configuration in LBO / BBO / KDP :Control of the spectrum (width and shape) by the angles in the non-linear crystal and by the pump (temporal profile and intensity)
• CPA configuration in Ti:Sa :Amplification of temporally chirped pulses
= Gain shifting (amplification saturation )
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ectr
al in
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Wavelength (nm)
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ectr
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ain
(u
.a.) Input : λc = 794 nm
Pass 6 : λc = 808 nm
Frantz et Nodvik model : « Saturation regime : J0(t) ~ Jsat / G = 1,8 »
Duration (ps)
Existing solutions
http://loa.ensta.fr/ UMR 7639
• Different relevant active and passive solutions to overcome the gain narrowing issue (mJ-level pulses in the 10 fs regime)
Acousto-optic programmable dispersive filter1
Multilayer Gain Narrowing compensators2,3,4
Negatively and Positively Chirped Pulsed Amplification5
• No solution to suppress the spectral shape modifications due to saturation effects at moderate or high level energy (> 1J). 1. F. Verluise et al., “Amplitude and phase control of ultrashort pulses by use of an acousto-optic programmable dispersive filter: pulse compression and shaping”, Opt. Lett. 25, 575–577 (2000). 2. A. Amani Eilanlou et al., “Direct amplification of terawatt sub-10-fs pulses in a CPA system of Ti:sapphire laser,” Opt. Express 16, 13431–13438 (2008).3. H. Takada, et al., “High-repetition-rate 12fs pulse amplification by a Ti:sapphire regenerative amplifier system,” Opt. Lett. 31, 1145–1147 (2006).4. L. Antonucci, et al., “14 fs high temporal quality injector for ultra-high intensity laser,” Opt. Commun. 282, 1374–1379 (2009). 5. M. P. Kalashnikov et al., “Suppression of gain narrowing in multi-TW lasers with negatively and positively chirped pulse amplification,” Appl. Phys. B 81, 1059 (2005).
Spatio-Temporal Chirped Pulse Amplification(STCPA) (1/2)
http://loa.ensta.fr/ UMR 7639
• Principle : Combination of temporal and spatial
dispersion enable amplified spectra to be unaffected by saturation effect.
i.e. spatially spreading spectral components to separately amplify them and thus deleting the gain competition
• Principle : Combination of temporal and spatial
dispersion enable amplified spectra to be unaffected by saturation effect.
Spatio-Temporal Chirped Pulse Amplification(STCPA) (1/2)
http://loa.ensta.fr/ UMR 7639
Oscillator Stretcher Power amplifier Compressor
Classical CPA scheme
Ti:Sa Crystal
Pump Beam
IR Beam
Spatio-Temporal Chirped Pulse Amplification(STCPA) (1/2)
http://loa.ensta.fr/ UMR 7639
• Principle : Combination of temporal and spatial
dispersion enable amplified spectra to be unaffected by saturation effect.
STCPA scheme Spatial spreading Spatial compression
Oscillator Stretcher Power amplifier Compressor
Gain zone shape adaptation
Ti:Sa Crystal
Pump Beam
IR Beam
Spatio-Temporal Chirped Pulse Amplification(STCPA) (2/2)
http://loa.ensta.fr/ UMR 7639
• Advantages : No spectral shifting while preserving energy extraction in saturation regime i.e. saturation effect is equally distributed on all the spectral range instead of only the infrared edge.
• Conditions :Input pulse has to be collimatedSpatial spreading law has to be inverse of that of spatial compressionPump beam has to be matched to the oblong seeded beam
• Inconvenient :Gain narrowing not avoided in this configuration
Experiment Set Up
http://loa.ensta.fr/ UMR 7639
Ti:Sa Oscillator
Frequency doubledNd:YVO4
3,8 nJ / 80 MHz
3,7 W
Experiment Set Up
http://loa.ensta.fr/ UMR 7639
Öffner triplet Stretcher
Ti:Sa Oscillator
Frequency doubledNd:YVO4
3,8 nJ / 80 MHz250 ps
3,7 W
Experiment Set Up
http://loa.ensta.fr/ UMR 7639
Regenerative Amplifier
Öffner triplet Stretcher
Ti:Sa Oscillator
Frequency doubledNd:YVO4
3,8 nJ / 80 MHz250 psQ-switched
Nd:YLF
3,7 W1,5 mJ1 kHz
7,1 mJ / 1 kHz
Experiment Set Up
http://loa.ensta.fr/ UMR 7639
Regenerative Amplifier
Öffner triplet Stretcher
Ti:Sa Oscillator
Frequency doubledNd:YVO4
3,8 nJ / 80 MHz250 psQ-switched
Nd:YLF
3,7 W500 µJ1 kHz
7,1 mJ / 1 kHz
+ Birefringent Plate
Experiment Set Up
http://loa.ensta.fr/ UMR 7639
Nd:YAG
LaK8 Prisms
Cylindric lenses
Multipass amplifier6 passes
Regenerative Amplifier
Öffner triplet Stretcher
Ti:Sa Oscillator
Frequency doubledNd:YVO4
Output
3,8 nJ / 80 MHz250 psQ-switched
Nd:YLF
180 mJ / 10 Hz
3,7 W500 µJ1 kHz
Pockels Cell
40 µJ10 Hz
Ti:Sa Absorption : 90%
7,1 mJ / 1 kHz
+ Birefringent Plate
Ø = 15 mm
Experiment Set Up
http://loa.ensta.fr/ UMR 7639
40 µJ10 Hz
Nd:YAG
Cylindric lenses
Multipass amplifier6 passes
180 mJ / 10 Hz
Ti:Sa Absorption : 90%
OutputØ = 15 mm
Aspect Ratio of 1,6
IR Beam Before Prisms
Øx,y,FWHM = 1900 µm
IR Beam After Prisms
Øy,FWHM = 1900 µmØx,FWHM = 3000 µm
LaK8 Prisms
Experiment Set Up
http://loa.ensta.fr/ UMR 7639
Nd:YAG
Cylindric lenses
Multipass amplifier6 passes
180 mJ / 10 Hz
40 µJ10 Hz
Ti:Sa Absorption : 90%
Wavelength spreading 19 nm/mm
OutputØ = 15 mm
LaK8 Prisms
IR Beam After Prisms
Øy,FWHM = 1900 µmØx,FWHM = 3000 µm
Experiment Set Up
http://loa.ensta.fr/ UMR 7639
Nd:YAG
Cylindric lenses
Multipass amplifier6 passes
180 mJ / 10 Hz
40 µJ10 Hz
Ti:Sa Absorption : 90%
Output Beam Pump
Øx,y,FWHM = 10 mm
Right Side
Øy,FWHM = 600 µmØx,FWHM = 4000 µm
Left Side
Øy,FWHM = 600 µmØx,FWHM = 4000 µm
OutputØ = 15 mm
LaK8 Prisms
Experiment Set Up
http://loa.ensta.fr/ UMR 7639
Experiment STCPA
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Wavelength (nm)
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Simulation CPA
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Wavelength (nm)
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Nd:YAG
Cylindric lenses
Multipass amplifier6 passes
Output28 mJ~ 1,8 J/cm²
180 mJ / 10 Hz
40 µJ10 Hz
Ti:Sa Absorption : 90%Ø = 15 mm
LaK8 Prisms
1,00E-05
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Duration (fs)
FFT Calculation
Experiment Set Up
http://loa.ensta.fr/ UMR 7639
Far field Near field
Nd:YAG
Cylindric lenses
Multipass amplifier6 passes
Output28 mJ~ 1,8 J/cm²
180 mJ / 10 Hz
40 µJ10 Hz
Ti:Sa Absorption : 90%Ø = 15 mm
LaK8 Prisms
No angular and transverse chirp
Conclusion
http://loa.ensta.fr/ UMR 7639
• First amplification scheme in Ti:Sa using a combination of spatial and temporal chirp
• STCPA concept avoids effects of saturation / enables a control of the amplified spectrum at high energy
• Using appropriate chirp tool : output beam free of angular and transverse chirp
• Fully relevant technique for obtaining very intense and short laser pulses (energy in excess of 10’s of Joules) with good temporal quality
http://loa.ensta.fr/ UMR 7639
Thank you !