231 W dual-end-pumped Ho:YAG MOPA system and its application to a mid-infrared ZGP OPO.

A high-efficiency and high-brightness Ho:YAG master-oscillator power-amplifier (MOPA) system dual-end pumped by Tm:YLF lasers was demonstrated. The maximum output power of 231 W at a wavelength of 2090.7 nm was achieved with pulse repetition frequency of 10 kHz and pulse width of 22.9 ns, corresponding to pulse energy of 23.1 mJ and peak power of ∼1 MW. The extraction efficiency of the amplifier system was more than 60%. The beam quality factor M2 was measured to be ∼1.05. Using the Ho:YAG MOPA system as the pump source, the ZnGeP2 optical parametric oscillator delivered an output power of 110 W, corresponding to slope efficiency of 62%.