Abstract

Degradation of sol-gel coated KDP surfaces has been observed in crystals used on the OMEGA laser system .in 40-50% relative humidity environments. The defect characteristic is an etch pit which develops under the sol-gel coating and produces a significant Joss in the crystal due to scatter. Both diamond-turned and polished KDP surfaces show evidence of defect growth after sol-gel coating and exposure to ambient conditions; however, there is no relationship between defect growth and exposure to laser radiation. The defect size, orientation, and density is uniform across a diamond-turned surface, and the growth rate is accelerated with exposure to higher relative humidity.

© 2002 Optical Society of America