Frequency-doubling of a high power cesium vapor laser using a PPKTP crystal

447.3 nm blue light generation was demonstrated through direct frequency doubling a continuous-wave Cesium vapor lasers 894.6 nm output using a PPKTP nonlinear crystal. The diode-pumped Cs vapor laser has an output power as large as 10 W with a very narrow emission linewidth less than 10 GHz. The PPKTP crystal is about 30 mm long and has a moderate acceptance wavelength bandwidth. The second harmonic wave generation efficiency achieved is about 4.4 %/W. Power depletion in second harmonic pulses, which relates to the absorption related thermal effects, was observed when using high pump power, long pulse duration, or high repetition rate.