Two-faceted mirror for active integration of coherent high-power laser beams

摘要

A new integration method suited for spatially coherent high-power laser beams is demonstrated. The integrator system is based on a mirror with two facets, one of which can vibrate under the action of a piezoelectric translator. After reflection in the faceted mirror, the beam intensity distribution is mod-flied to obtain greater uniformity. However, because of the coherence of the reflected beamlets, this distribution is affected by an interference pattern. The active integration consists of a periodic displacement of the moving facet that causes the interference pattern to vibrate, and its contribution to the intensity profile therefore averages out (fringe visibility within a 5% range). The combination of a faceted mirror and a simple imaging system results in an intensity profile with good uniformity over large spot sizes. Both 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. # 1997 Optical Society of America