High power green picosecond laser and high efficiency ultraviolet femtosecond laser through second harmonic generation using K3B6O10Br crystal

Abstract

We demonstrated high power green picosecond (ps) laser and high efficiency ultraviolet (UV) femtosecond (fs) laser through second harmonic generation (SHG) using type I phase-matched K3B6O10Br (KBOB) nonlinear optical crystals. The green ps laser was generated by using a homemade high power 1064 nm ps laser as the pump source. When the pump power was 28.2 W with a repetition rate of 800 kHz, 14.2 W ps green laser was obtained with the maximum optical conversion efficiency of 50.4%. When the pump power was 85.2 W with a repetition rate of 800 kHz, the maximum output power of 41.8 W of ps green laser was achieved with an optical conversion efficiency of 49.1%. During the UV fs laser generation, a 710 nm fs laser with a repetition rate of 1 kHz was used to pump the KBOB crystal. When the pump power of 710 nm laser was 54 mW, the 355 nm UV fs laser was obtained with output power of 18 mW and optical conversion efficiency of 33.3%. The experimental results show that the KBOB crystal is a highly qualified candidate for the application in generating high power ultrafast green and UV lasers.