Performance of bare and sol-gel-coated DKDP crystal surfaces exposed to multiple 351-nm laser pulses in vacuum and air

摘要: We have investigated the surface degradation of bare and sol-gel coated deuterated potassium dihydrogen phosphate (DKDP) crystals when exposed to 351-nm laser pulses in atmospheric air nitrogen at pressures ranging from down 10{sup -5} Torr vacuum. Optical microscopy, topography, chemical analyses, pumped photoemission maps, photometry results been used characterize these samples. report occurrence two potentially linked phenomena: development increased unacceptable roughening region beam note no for surfaces or exceeding 1 torr. Diamond-turned DKDP show a ubiquitous, low-intensity signature before exposure any fluence. The observed reduction this emission signal as function operating pressure accumulated energy are can be correlated with removal carbon.