Adaptive pulse compression for transform-limited 15-fs high-energy pulse generation

We demonstrate the use of a deformable-mirror pulse shaper, combined with a n evolutionary optimization algorithm, to correct high-order residual phase aberrations in a 1-mJ, 1-kHz, 15-fs laser amplifier. Frequency-resolved op tical gating measurements reveal that the output pulse duration of 15.2 fs is within our measurement error of the theoretical transform limit. This te chnique significantly reduces the pulse duration and the temporal prepulse energy of the pulse while increasing the peak intensity by 26%. It is demon strated, for what is believed to be the first time, that the problem of ped estals in laser amplifiers can he addressed by spectral-domain correction. (C) 2000 Optical Society of America. OCIS codes: 140.7090, 140.3590, 320.55 40, 320.5520.