WAVE-FRONT CORRECTION OF FEMTOSECOND TERAWATT LASERS BY DEFORMABLE MIRRORS

Wave-front correction and focal spot improvement of femtosecond laser beams have been achieved, for the first time to our knowledge, with a deformable mirror with an on-line single-shot three-wave lateral shear ing interferometer diagnostic. Wave-front distortions of a 100-fs lase r that are due to third-order nonlinear effects have been compensated for. This technique, which permits correction in a straightforward pro cess that requires no feedback loop, is also used on a 10-TW Ti:sapphi re-Nd:phosphate glass laser in the subpicosecond regime. We also demon strate that having a focal spot close to the diffraction limit does no t constitute a good criterion for the quality of the laser in terms of peak intensity. (C) 1998 Optical Society of America OCIS codes: 160.0 160, 320.0320, 320.7080.