Tunable High-Pulse-Energy Mid-Infrared Laser Source Based on Optical Parametric Amplification in ZnGeP_2

摘要

Nonlinear optical conversion of high-energy 1.064 μm pulses from a Q-switched Nd:YAG laser to the mid-infrared is demonstrated. The experimental setup is based on a two-stage master-oscillator/power-amplifier (MOPA) design with a KTiOPO_4 based MOPA in the first stage and a KTiOAsO_4/ZnGeP_2 based MOPA in the second stage. The setup can be tuned to provide output at wavelengths within the transparency range of ZnGeP_2. We obtain more than 8 mJ at 8 μm, and up to 33 mJ in the 3-5 μm wavelength region. The measured beam quality factors are in the range M~2 =2-4 for both wavelength regions.