The improvement of CLBO surface durability for high-power kHz UV laser operation

Summary form only given. High-power, solid-state UV lasers have been highly demanding for many applications due to its convenient operation procedure. CsLiB/sub 6/O/sub 10/ (CLBO) crystal has been a most effective nonlinear optical (NLO) crystal for fourth and fifth harmonics generation (4w and 5w) of Nd:YAG laser. However, for high rep.-rate, high-power UV output generation, the surface damage at the exit surfaces of CLBO often limit the performance as that occurred in other UV materials (e.g. fused silica). One of the primary mechanisms proposed for the damage is thermo-mechanical damage due to absorption by polishing contaminants in the near-surface (100 nm) region of the crystal. The surface contamination arising from polishing contaminants can not be eliminated in the conventional mechanical polishing process. In the work, we have removed polishing contaminants with ion beam etching and improved the surface durability for high-power kHz UV laser application (266 nm).