High power high energy ultrafast fiber amplifiers Yoann Zaouter1,2 1 CELIA, UMR 5107 CNRS - Université de Bordeaux 1, France 2 Amplitude Systèmes, Pessac, France yzaouter@amplitude-systemes.com

Interests of Yb-doped fibers as amplifier medium Outline of the talk Interests of Yb-doped fibers as amplifier medium How to use the advantages of fibers ? How to handle or avoid disadvantages of fibers? The double-clad yb-doped fiber concept The micro-structured fibers High power / High energy fiber amplifiers Existing systems Perspectives The ANR project LAL / Amplitude Systemes

High power / High energy CPA systemes High average power 131W, 220fs fiber laser system Röser et al., Optics Letters, vol. 30, n°20 (2005) Jena group – Jens Limpert High energy Liao et al. CLEO 2006 Postdeadline CPDB4 Michigan group – Almantas Galvanauskas

High power / High energy CPA systemes High average power 131W, 220fs fiber laser system Röser et al., Optics Letters, vol. 30, n°20 (2005) Jena group – Jens Limpert High energy Liao et al. CLEO 2006 Postdeadline CPDB4 Michigan group – Almantas Galvanauskas

High average power CPA system Femtosecond oscillator Grating stretcher 150 fs pulses 73 MHz FT limited pulses Compressor Fiber amplifier

High average power CPA system Femtosecond oscillator Grating stretcher 250 ps stretched pulses Small size gold gratings Femtosecond oscillator Compressor Fiber amplifier 150 fs, 73 MHz Gold grating-based strectcher

High average power CPA system Femtosecond oscillator 40µm core diameter 17dB/m absorption @ 976nm Reduced non-linearities Femtosecond oscillator Grating stretcher Compressor Fiber amplifiers Laser Diode Laser Diode 150 fs, 73 MHz 40/170 40/170 OI Gold grating-based strectcher F. Röser et al. Optics letters, 30, p2754, 2005

High average power CPA system Femtosecond oscillator Grating stretcher Compressor Fiber amplifiers Laser Diode Laser Diode 150 fs, 73 MHz 40/170 40/170 OI Gold grating-based strectcher F. Röser et al. Optics letters, 30, p2754, 2005

High average power CPA system Femtosecond oscillator Grating stretcher High efficiency transmission gratings Fiber amplifiers Compressor Laser Diode Laser Diode 150 fs, 73 MHz 40/170 40/170 OI Transmission grating compressor Gold grating-based strectcher F. Röser et al. Optics letters, 30, p2754, 2005

High average power CPA system Femtosecond oscillator Grating stretcher Fiber amplifiers Compressor Laser Diode Laser Diode 150 fs, 73 MHz 40/170 40/170 OI Transmission grating compressor Gold grating-based strectcher F. Röser et al. Optics letters, 30, p2754, 2005

High average power CPA system Femtosecond oscillator Grating stretcher Fiber amplifiers Compressor Laser Diode Laser Diode 150 fs, 73 MHz 40/170 40/170 OI Transmission grating compressor Gold grating-based strectcher F. Röser et al. Optics letters, 30, p2754, 2005

High average power CPA system 131 W average power 220 fs duration 1.8µJ per pulse 73 MHz Femtosecond oscillator Grating stretcher Compressor Fiber amplifiers Laser Diode Laser Diode 150 fs, 73 MHz 40/170 40/170 OI Transmission grating compressor Gold grating-based strectcher F. Röser et al. Optics letters, 30, p2754, 2005

High power / High energy CPA systemes High average power 131W, 220fs fiber laser system Röser et al., Optics Letters, vol. 30, n°20 (2005) Jena group – Jens Limpert High energy Liao et al. CLEO 2006 Postdeadline CPDB4 Michigan group – Almantas Galvanauskas

High energy CPA system Amplified seed source Fiber laser + single mode pré amplifier Grating stretcher Compressor Fiber amplifiers LDD PC TEC oscillator

High energy CPA system Grating stretcher Up to 980ps duration Large size gold grating Amplified seed source Compressor Fiber amplifiers LDD PC TEC oscillator

High energy CPA system 2 pre-amplifiers Division of repetition rate and pulse cleanup Amplified seed source Grating stretcher Compressor Fiber amplifiers LDD PC TEC oscillator LDD LDD TEC TEC AOM AOM

High energy CPA system 2 power amplifiers 30µm and 65µm core diameter 13dB/m absorption Amplified seed source Grating stretcher Compressor Fiber amplifiers LDD PC TEC oscillator LDD LDD TEC TEC AOM AOM 975-nm pump 30-um LMA 1-m long 65-um LMA 975-nm pump

High energy CPA system Gold grating based compressor 60% efficiency Amplified seed source Grating stretcher Fiber amplifiers Compressor LDD PC TEC oscillator LDD LDD TEC TEC AOM AOM 975-nm pump 30-um LMA 1-m long 65-um LMA 975-nm pump

High energy CPA system PC Amplified seed source Grating stretcher Compressor Fiber amplifiers LDD PC TEC oscillator LDD LDD TEC TEC AOM AOM 975-nm pump 30-um LMA 1-m long 65-um LMA 975-nm pump

High energy CPA system High energy CPA system Amplified seed source Grating stretcher 980ps stretched pulses Up to 1.5mJ energy Expected energy limitations: Bulk damage at 6.6mJ Self focusing at >5mJ Saturation fluence at 1.4mJ Compressor Fiber amplifiers 20µJ seed

Amplified pulse intensity autocorrelation High energy CPA system High energy CPA system Amplified 800-µJ 980-ps stretched Recompressed 500-µJ 520-fs Amplified seed source Grating stretcher Compressor Fiber amplifiers Amplified pulse intensity autocorrelation Amplified pulse spectrum

Record performances but … High energy CPA system High energy CPA system Amplified 800-µJ 980-ps stretched Recompressed 500-µJ 520-fs Amplified seed source Grating stretcher Compressor Fiber amplifiers Record performances but … Power amplifiers are highly multimode Experiment is believed to be unstable and super-sensitive to misalignments Solution not likely to be used in commercial products

Interests of Yb-doped fibers as amplifier medium Outline of the talk Interests of Yb-doped fibers as amplifier medium How to use the advantages of fibers ? How to handle or avoid disadvantages of fibers? The double-clad yb-doped fiber concept The micro-structured fibers High power / High energy fiber amplifiers Existing systems Perspectives The ANR project LAL / Amplitude Systemes

ANR LAL / Amplitude Systemes Context of the project Seed source for a laser/e- Compton scattering high finess cavity Intense polarized positron source

ANR LAL / Amplitude Systemes Context of the project Seed source for a laser/e- Compton scattering high finess cavity Intense polarized positron source Next generation linearly polarized positron/electron colliders Scenarios beyond the standard model : supersymetry, terascale generation, extra-dimensions, dark matter, superstring…

ANR LAL / Amplitude Systemes Femtosecond oscillator 200 fs pulses 40 to 70 MHz FT limited pulses Synchro locked : Servo motor Piezo actuator Grating stretcher Compressor Fiber amplifier

ANR LAL / Amplitude Systemes Femtosecond oscillator Grating stretcher 250 ps stretched pulses Standard high efficiency transmission gratings Femtosecond oscillator Compressor Fiber amplifier

ANR LAL / Amplitude Systemes Femtosecond oscillator PM-LMA fiber ampli. High pump absorption Polarized output beam High gain Femtosecond oscillator Grating stretcher Compressor Fiber amplifiers Laser Diode PM - LMA fiber

ANR LAL / Amplitude Systemes Femtosecond oscillator PM-LMA fiber ampli. High pump absorption Polarized output beam PCF-Fiber amplifier High launch power >800W pump power Reduced non-linearities Femtosecond oscillator Grating stretcher Compressor Fiber amplifiers Laser Diode PM - LMA fiber PCF fiber OI High power Laser Diode > 300W average power Linearly polarized beam

ANR LAL / Amplitude Systemes Femtosecond oscillator Specially designed high efficiency transmission gratings >200W final output power ~1ps duration 40-70 MHz Synchro-locked Femtosecond oscillator Grating stretcher Fiber amplifiers Compressor Laser Diode PM - LMA fiber PCF fiber OI High power Laser Diode

ANR LAL / Amplitude Systemes Injection in a super high finess FB-cavity Gain ~ 104 – 105 Small interaction region Multi-MW pulses stacked Non-planar geometry Circular polarization Polarized positrons source Femtosecond oscillator Grating stretcher Laser system designed by Amplitude Systemes Compressor Fiber amplifiers Laser input e- beam

ANR LAL / Amplitude Systemes FPGA control Laser intensity Laser frequency Laser phase Cavity parameters Cavity locking Etc… Femtosecond oscillator Grating stretcher Laser system designed by Amplitude Systemes Compressor Fiber amplifiers 1 2 3 4 FPGA-based controle 5 Laser input e- beam

Presented the best performances to date Conclusion Presented the best performances to date High power fibre-CPA High energy fibre-CPA Design of the project submitted to ANR Very high power 1-ps amplifier with a synchro-locked laser seed Non-planar FP-cavity FPGA global control of the experiment Installation at KEK / ATF Production of polarized positrons

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