Laser-Induced Damage in Optical Materials
Semiannual technical rept. no. 2
HUGHES RESEARCH LABS MALIBU CA
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The report contains the results of damage experiments performed at 0. 694 and 1.06 micrometer using well controlled ruby and NdYAG lasers. Materials studied at 1.06 micrometer are proustite Ag3AsS3 and lithium niobate LiNbO3. Proustite studies have been directed toward improving surface quality by employing different polishing techniques. Little or no improvement has been obtained over previously measured thresholds. Chemical changes in proustite damage sites are evidenced by the use of electron excited x-ray microprobe measurements. Preliminary ion beam polishing experiments were performed on LiNbO3, but no improvement in damage threshold was observed. However, the damage in this material appears to be inclusion limited in the samples studied so far. The temporal and spatial characteristics of laser pulses were studied for transmitted, reflected, and backscattered pulses both above and below surface damage threshold.