HANDLING OF QUASI-GAUSSIAN BEAMS BY PHASE PLATES - FAR-FIELD SIMULATION

Effects of phase plates on focused laser beams are studied numerically . Gaussian beams are simulated when they pass through several kinds of phase device (random phase plates, phase gratings, etc.). Partially c oherent and aberrated beams are also considered. Their control by phas e devices is analyzed. In particular this work is devoted either to re ducing the intensity transverse modulations on the spot region, which are able to excite filamentation instability in plasmas, or to produci ng such modulations in a controllable way in order to investigate fila mentation accurately.