Monolithically integrated laser Bragg Q-switch and wavelength converter in a PPLN crystal

We-report a periodically poled lithium niobate (PPLN) crystal for both temperature-insensitive laser Q-switching and temperature-tuned wavelength conversion. The PPLN crystal consists of two sections, a 20.3-μm period section functioning as an electro-optic Bragg grating for Q-switching a diode-pumped Nd:YVO₄ laser at 1064 nm and a 31-μm-period section functioning as an optical parametric generator for down converting the generated 1064-nm laser. When driving the PPLN Bragg grating with 170-V voltage pulses, we measured 181 μJ pulse energy at 1064 nm from the Nd:YVO₄ laser pumped by 20.4 W diode power. The 181-μJ pulsed laser was further converted into mid-infrared radiation in the monolithic PPLN crystal with 35% parametric efficiency. The wavelengths were broadly tunable in the range of 1.75-1.88 μm (signal) and 2.7-2.44 μm (idler) via temperature without affecting the performance of the PPLN Bragg Q-switch.