Compact deep ultraviolet frequency-doubled Tb:LiYF4 lasers at 272 nm

摘要

A new laser system has been developed to generate coherent deep ultraviolet (DUV) radiation at 272 nm. The DUV lasers were produced via intra-cavity frequency doubling of the Tb3+:LiYF4 lasers emitting fundamentally at 544 nm. Continuous-wave (cw) and Q-switched operations were performed with a type I phase-matched beta- BaB2O4 nonlinear crystal. The cw operation produces 127 mW of averaged DUV output power. Passive Q-switched operation was realized by using Co2+:MgAl2O4 saturable absorbers. At an initial transmittance (excluding Fresnel reflections) of 99% at 544 nm, stable pulsed output at 272 nm with maximum single-pulse energy of 7.6 mu J and peak power of 6.1 W was obtained. Furthermore, by employing a smaller initial transmittance of 94.7%, we achieved maximum averaged DUV output power of 277 mW. The statistically averaged single-pulse DUV energy and peak power were estimated to be around 100 mu J and 320 W, respectively, which indicates great potential for this DUV laser system toward high energy an d peak power. (C) 2020 Optical Society of America