LD end-pumped Q-switched Nd:YVO4/KTA optical parametric oscillator laser at 1.53 μm

A highly efficient high-repetition-rate CW laser diode end-pumped acousto-optically (AO) Q-switched eye-safe intracavity optical parametric oscillator at 1.53 μm was experimentally investigated. The 20 mm long KTA crystal cut for typeⅡ noncritical phase matching was adopted as the nonlinear crystal parametric converter in this experiment. We have achieved the signal average power of 2.6 W under the LD pumping power of 13.7 W and the pulse repetition rate of 60 kHz, corresponding to an optical-to-optical conversion efficiency of 19%. At the highest output power of 2.6 W, the signal pulse duration of 2.9 ns was obtained, corresponding to the single pulse energy of 43.3 μJ and peak power of 15 kW, respectively.