A Mid-IR Optical Parametric Oscillator Pumped by an Actively Q-Switched Ho:YAG Ceramic Laser

We demonstrate a mid-IR ZnGeP₂ (ZGP) optical parametric oscillator (OPO) pumped by a dual-end-pumped actively acousto-optic Q-switched Ho:YAG ceramic laser. The maximum average output power of 35 W is obtained at a pulse repetition frequency of 20 kHz from the Ho:YAG ceramic laser. Under the maximum incident pump power of Ho:YAG ceramic laser, the maximum output power of 14 W is obtained from the ZGP OPO, corresponding to the slope efficiency of 49.6% with respect to the incident pump power. The wavelength can be tuned from 3.5 μm to 4.2 μm (signal), corresponding to 5.2–4.1 μm (idler). The beam quality M² is less than 2.3 from the ZGP OPO.