Generation of 0.6 J pulses of 16 fs duration through high-repetition rate amplification of self phase modulated pulses

International audienceWe have generated optical pulses of 16fs duration in the submicrojoule range and at a repetition rate of 11 kHz. This was obtained by amplifying self-phase modulated pulses at the output of a fiber, using a couple of dyes to achieve gain covering a large spectrum around 620 n

Efficient aberrations pre-compensation and wavefront correction with a deformable mirror in the middle of a petawatt-class CPA laser system

AbstractIn this paper, we describe the experimental validation of the technique of correction of wavefront aberration in the middle of the laser amplifying chain. This technique allows the correction of the aberrations from the first part of the laser system, and the pre-compensation of the aberrations built in the second part. This approach will allow an effective aberration management in the laser chain, to protect the optical surfaces and optimize performances, and is the only possible approach for multi-petawatt laser system from the technical and economical point of view. This approach is now possible after the introduction of new deformable mirrors with lower static aberrations and higher dynamic than the standard devices

Ultra-short high-intensity laser pulse generation and amplification

International audienceSince the beginning of the 1990s the generation of high-intensity laser pulses has known an unprecedented evolution thanks to the conjunction of the possibility of the chirped pulse technique and the availability of spectrally broad-band laser media. Lasers capable of producing multi-terawatt pulses can now be built on few optical tables in a small laboratory. We review the generation and the amplification of ultra-short pulses by the chirped pulse amplification technique

Modélisation des processus liés à l'amplification et à la propagation d'impulsions étirées dans des chaînes laser de très haute densité

PALAISEAU-Polytechnique (914772301) / SudocSudocFranceF

Off-axis aberration compensation of focusing with spherical mirrors using deformable mirrors

International audienceWe studied the possibility of focusing an ultra-intense laser beam with a spherical mirror instead of a parabolic mirror. To correct the induced wavefront aberrations, we used a deformable mirror in a closed-loop configuration with a Shack–Hartmann Wavefront Sensor (SHWS). We demonstrate in this paper that we were able to correct the aberrations induced by spherical mirrors down to an f-number equal to 3.3

Adaptive wavefront correction on a 100-TW/10-Hz chirped pulse amplification laser and effect of residual wavefront on beam propagation

International audienceWe demonstrate the wavefront correction of a 100-TW (25 fs, 2.5 J) high repetition rate Ti:sapphire laser. A 36-actuator bimorph deformable mirror was used under vacuum and the adaptive optic system is working at 10 Hz in a closed-loop configuration with a Shack–Hartmann wavefront sensor. We also numerically studied the effects of the deformable mirror actuators on laser beam free propagation to determine the ideal position of the deformable mirror in the laser chain. Our ability to focus the beam was improved to near-diffraction-limited quality and intensity as high as 1.4 × 10^20 W/cm^2 was reached with a 500-mm focal length off-axis parabolic mirror

Design and characterization of a near-diffraction-limited femtosecond 100-TW 10-Hz high-intensity laser system

International audienceWe present the design and characterization of a femtosecond high-intensity laser system emitting a near-diffraction-limited beam. This system was dimensioned in order to reach intensities in excess of 10^20 W/cm^2 at a high repetition rate for ultrahigh-field physics experiments. We describe the improvements that were added to a conventional chirp pulse amplification configuration in order to decrease the deleterious effects of gain narrowing, gain shifting, thermal focusing in the amplifier stages, and spatial degradation due to multipass amplification processes

Temporal control of amplified femtosecond pulses with a deformable mirror in a stretcher

International audienceWe correct the spectral phases of amplified femtosecond pulses by using a deformable mirror in the stretcher. After the correction the peak intensity is multiplied by 1.5 as a consequence of increasing the contrast by 100× . The spectral phase interferometry for direct electric field reconstruction is used to characterize the pulse temporally

Experimental evidence of 25-fs laser pulse distortion in singlet beam expanders

International audienceWe report the measurement of spatiotemporal distortions of an ultrashort pulse in singlet beam expanders. With a simple second-order autocorrelator the temporal broadening of the pulse from 23 to 40 fs, due to propagation time difference (PTD), is determined. The delay due to PTD between different parts of the beam is also measured. This effect was theoretically studied for the first time by Bor [J. Mod. Opt. 35, 1907 (1988)]. These experimental results are in good agreement with the calculations of a dedicated three-dimensional ray-tracing program developed to simulate the spatial and temporal transformation of femtosecond pulses in optical systems