Progress on All Solid State Deep-ultraviolet Laser with KBe2BO3F2 Crystal

General review for the progress on all solid state deep ultraviolet (DUV) laser with a KBe2BO3F2 (KBBF) crystal was given in the paper. The frequency-conversion characteristics of KBBF crystal and the comparison between this crystal and other borate nonlinear optical crystals were simply described. A special prism coupling technique (PCT) for DUV laser generation and some excellent experimental results from the application of this crystal were commented. At last, we believe that the output power and conversion efficiency could be greatly increased in the future if the thicker KBBF crystal with good optical quality is grown and the application technique of solid state DUV laser is further developed.