114 W long-wave infrared source based on ZnGeP₂ optical parametric amplifier

Abstract

In this paper we present a high power long-wave infrared ZnGeP₂ (ZGP) optical parametric amplifier (OPA) pumped by a 2097-nm Q-switched Ho:YAG laser with pulse repetition frequency of 20 kHz. When the incident Ho pump power was 116.0 W, the maximum average output power of 11.4 W at 8.3 μm was achieved in the ZGP OPA. The optical conversion efficiency from Ho to long-wave infrared was about 9.8%. The ZGP OPA produced 30.4 ns long-wave infrared laser pulse. The beam quality factor (M²) of ZGP OPA was measured to be about 2.9 at the maximum average output power.