A 6–17 μm tunable and high-pulse-energy far-infrared laser based on a BaGa₄Se₇ optical parametric oscillator

Tunable mid-infrared and far-infrared laser output was demonstrated based on BaGa₄Se₇ crystals and an optical parametric oscillator (OPO). With a 1.06 μm Nd:YAG laser and a double-pass singly resonant OPO cavity, a laser energy output of 2.2 mJ at 10 μm was obtained. By tuning the angle and temperature, a tunable laser output covering the wavelength range from 6 μm to 17 μm was obtained with a tuning precision better than 3 nm. The corresponding optical-to-optical conversion efficiency was 2.8%, and the slope efficiency was 4.4%. The damage effect of the output laser on detectors was also investigated, and point damage to the detector occurred at an output energy of 16.4 μJ. The laser system has the advantages of miniaturization, a wide tuning range, high energy and high tuning resolution. Its broadband laser characteristics make it highly valuable for applications in atmospheric detection, infrared spectroscopy and electro-optical countermeasures.