Wave-front control of solid state lasers using an optically addressed light valve in an adaptive optics loop and applications to ultra-intense pulses

High energy intense lasers are difficult to focus close the diffraction limit because of phase-front aberrations induced in the optics and amplifiers. This may be an issue in applications where the pulses need to be focused near the diffraction limit such as in ultra-intense femtosecond laser-matter interactions. We describe here a new technique that we have implemented and which significantly improves the focal spot quality by correcting the wave front even from highly distorted beam. This correction method is based on an adaptive optical technique using an optically addressed light valve (OALV) and an achromatic three wave lateral shearing interferometer (ATWLSI). Results with strongly aberrated beams focused close to the diffraction limit are presented as well as with fluence as high as 100 mJ/cm².