Efficient 213 nm Radiation Fifth Harmonic Generation of a Laser Diode-Pumped Nd∶YVO_4 Laser

A compact and efficient 213 nm deep-ultraviolet all solid state laser based on Q-switched laser diode (LD)-pumped Nd∶YVO_4 laser is presented. In the experiment, KTP crystal (KTiOPO_4) and BBO crystal (beta-BaB_2O_4) are used for the 532 nm second-harmonic generation and the 266 nm fourth-harmonic generation respectively. Subsequent sum-frequency mixing is performed in a second BBO crystal to mix the fourth-harmonic at 266 nm and the residual fundamental at 1064 nm. At 10.3 W of incident pump power, the average power of 3.1 mW at 213 nm with the pulse width of 7.5 ns is obtained.