Improvement of the Surface Roughness of KDP Single Crystal on Laser Beam Polishing

Abstract

KDP single crystal used for frequency conversion is a brittle material. Therefore, it takes a large cost to processing. In this study, KDP single crystal is polished by scanning a YAG laser beam. The laser beam is scanned along the edge of the crystal surface in a saturated solution. In this report, this process is called as ″Laser Beam Polishing″. In this study, the surface roughness of the KDP single crystal were measured for several conditions related to the laser beam power, scanning speed, focus shifting and temperature of the saturated solution. Furthermore, polishing condition that can improve roughness was examined by performing a wavelength analysis of roughness curve of before and after processing.