Tunable continuous-wave deep-ultraviolet laser based on Ce:LiCAF

We demonstrate chopped-cw lasing in a Ce:LiCAF oscillator directly generating deep-UV light around 290 nm. The cw output was achieved by asynchronous pumping of a Ce:LiCAF oscillator by a mode-locked frequency quadrupled Nd:YVO₄ laser that generates 23 ps pulses of 266 nm light at a repetition rate of 80 MHz. The pump laser was chopped with 8.3% duty cycle to minimize thermal effects in the frequency quadrupling stage. The maximum output power achieved was 384 mW when pumped with 3.3 W of pulsed 266 nm light, with a slope efficiency of 33%. The laser output was tunable from 286 to 295 nm with the potential to be broadened over the full gain bandwidth of Ce:LiCAF from 280 to 315 nm.