An efficient all-solid-state doubly resonant sum-frequency continuous-wave ultraviolet laser at 299 nm

We report for the first time coherent ultraviolet radiation at 299 nm by intracavity sum-frequency generation of an 899 nm Nd:YAG laser and a 456 nm frequency doubling Nd:GdVO4 laser. The ultraviolet laser is obtained by using doubly resonant, type-I critical phase matching CsLiB6O10 (CLBO) crystal sum-frequency mixing. With a total diode pump power of 35.6 W (17.2 W pump power for the 899 nm Nd:YAG laser and 18.4 W pump power for the 456 nm Nd:GdVO4 frequency doubling laser), a TEM00 mode ultraviolet laser at 299 nm of 331 mW is obtained. The power stability is better than 3.4% and the laser beam quality M2 factors are 1.22 and 1.17 in the horizontal and vertical dimensions respectively. (letter)