Generation of a 294.2 nm Ultraviolet Beam Through Frequency Doubling in a BaB₂O₄ Crystal

Abstract

We demonstrate a 294.2 nm all-solid-state Q-switched laser, with 241.4 mW average output power, produced by frequency doubling of a 588.4 nm laser. The 588.4 nm laser is obtained by intracavity sum-frequency generation of a 1064 nm laser and a 1319 nm laser. By synchronizing the fundamental lasers and adjusting the focal length of the focusing lens, average output powers of 10.2 W at 588.4 nm and 241.4 mW at 294.2 nm with 297 ns pulse width are obtained at 6 kHz frequency. The 294.2 nm laser beam quality ${\mathrm{M}}_X^2$ = 1.18 and ${\mathrm{M}}_Y^2$ = 1.26 for the X and Y directions, respectively. To the best of our knowledge, this is the highest power of all-solid-state Q-switched laser at 294.2 nm.