91.1 kW, 5.3 ns compact mid-infrared optical parametric amplification based on PPMgLN

Abstract

We report a compact mid-infrared optical parametric oscillator (OPO) seeded optical parametric amplifier (OPA) based on PPMgLN. The pump for the OPO and OPA is a split 1064 nm electro-optical Q-switched Nd:YAG laser with a pulse width of 11.7 ns and a pulse repetition frequency of 2 kHz. The idler power of 116 mW of the OPO is used for the OPA seed. Under the incident pump power of 7.36 W and the crystal temperature of 30 °C, the idler power of the OPA is 966 mW with a pulse width of 5.3 ns, corresponding to a conversion efficiency of 11.5% and a calculated peak power of 91.1 kW. The central wavelength of the OPA idler is 3731.2 nm with a linewidth of 8.8 nm at 30 °C, and decreased from 3748.8 nm to 3704.0 nm when the crystal is heated from 20 to 45 °C. The beam quality factors of the OPA are 3.4 and 3.7 in the horizontal and vertical directions, respectively.