Surface Characteristics of Polished YAG Laser Crystal

Abstract Compared with ordinary optical glass, it is much more difficult to achieve high‐precision and ultra‐smooth surface processing on laser crystal materials. In order to improve the processing technology of large‐size Y 3 Al 5 O 12 (YAG) laser crystal components, the surface characteristics of polished YAG crystal are studied. First, the surface mechanical properties of polished YAG crystal are investigated by nanoindentation technology, and the machinability of the crystal is basically evaluated. Then, the characteristics of surface flatness, defects, and surface roughness related to processing requirements of crystal components are further studied. The experimental results show that the high flatness, low defect density, and super smoothness of the surface of YAG crystal material can be obtained by optimizing the polishing process, that is, using a three‐step polishing method combining Al 2 O 3 abrasive and the composite tin polishing plate.