Comparison of high repetition rate Q-switched 355nm ultraviolet lasers with EOM and AOM

摘要

Two kinds of Q-switched ultraviolet lasers using an acousto-optic modulator and an electro-optic modulator in the same cavity structure are demonstrated, with type I phase-matched LBO as second harmonic generation crystal and type Ⅱ phase-matched LBO as third harmonic generation crystal. For acousto-optic Q-switched UV laser, a maximum average power of 6.3 W with the shortest pulse width of 12 ns was obtained at the repetition rate of 22 kHz when the pump power reached 52.4 W. The optical conversion efficiency was up to 12%. Then we used a La_2Ga_5SiO_(14) crystal electro-optic modulator to replace the acousto-optic modulator. The 1.29W output power at 355nm wavelength was obtained at the repetition rate of 10 kHz when the pump power was increased to 20.4W, and the UV laser pulse width was as short as 9.6ns.The optical conversion efficiency was up to 6.3%.