Abstract

Recent progress in the understanding of the physics of femtosecond oscillators has made it possible to produce 10-fs pulses. In order for these pulses to be use in high-field physics experiments, they have to be amplified while an extremely good contrast ratio between the peak of the pulse and its wings is maintained. In chirped-pulse amplification most of the energy found in the final pulse wings comes from an imperfect match of the stretcher and compressor group delays. This leads to a residual group delay after compression that has to be canceled in order to get the shortest and cleanest possible pulses. Instead of using a step-by-step approach and trying to compensate for high-order dispersion terms one by one, we used a global approach. We started from a compressor design that can be considered as perfect from a geometrical-optics point of view. In order to be matched, the stretcher must be equivalent to a compressor with a negative effective length. This means that the image of the first grating through the optical components included in the stretcher must be a perfect grating. Since the beam size on the first grating is small, the most important sources of aberration are spherical aberration, on-axis coma and the chromatic aberration. On the basis of an original idea from DiMauro and.

© 1995 Optical Society of America