Effect of surface degradation on optical performance of potassium dihydrogen phosphate optics

摘要: We have measured scatter produced by roughening of bare potassium dihydrogen phosphate (KDP) surfaces and surface degradation (etch pits) that develop beneath a porous solgel coating on KDP after exposure to ambient relative humidity. The etch pits form coated incident light into strongly anisotropic angular distributions characteristic the defect size shape. total integrated (TIS) can be as high 9% for crystal with compared 0.05% as-manufactured crystal. amount TIS correlates area obscured defects optical microscopy.