2-FACETED MIRROR FOR ACTIVE INTEGRATION OF COHERENT HIGH-POWER LASER-BEAMS

A new integration method suited for spatially coherent high-power lase r beams is demonstrated. The integrator system is based on a mirror wi th two facets, one of which can vibrate under the action of a piezoele ctric translator. After reflection in the faceted mirror, the beam int ensity distribution is modified to obtain greater uniformity. However, because of the coherence of the reflected beamlets, this distribution is affected by an interference pattern. The active integration consis ts of a periodic displacement of the moving facet that causes the inte rference pattern to vibrate, and its contribution to the intensity pro file therefore averages out (fringe visibility within a 5% range). The combination of a faceted mirror and a simple imaging system results i n an intensity profile with good uniformity over large spot sizes. Bot h simulated and experimental results are presented, the latter showing that a final uniformity within a 10% range can be achieved and it is limited mainly by diffraction at the edges of the facets. (C) 1997 Opt ical Society of America