Abstract

One objective in high average power laser research is to attain high beam quality in zigzag slab systems. The physical effects that must be controlled in these flashlamp-pumped convectively cooled slabs are thermal gradients, thermoelastic stresses, and material deformations; these effects govern wavefront phase distortions and beam depolarization in the absence of any significant mechanically induced stresses. This presentation describes the thermooptical mechanics of wavefront phase distortions in zigzag slabs. We identify, from both computations and laboratory measurements, the causes of beam phase distortions that are frequently observed in output beams from zigzag slabs. The thermal stress codes TECATE, TOPAZ, and NIKE and the ray tracing code BREW are used to compute isocontours of optical path differences (OPDs). Material deformations are found to dominate phase distortions in the neodymium-doped glass zigzag slabs considered here; alternative strategies and design criteria that can minimize OPDs in these slab systems are discussed. (Poster paper)

© 1986 Optical Society of America