Long-Wave Infrared ZnGeP2 Optical Parametric Oscillator With a Wide Tuning Range by Rotating a Diffraction Grating

We report a ZnGeP
$_{\mathbf {2}}$
optical parametric oscillator (OPO) with a wide tuning range in the long-wave infrared. The OPO was pumped by a Ho: YLF laser with high peak power, and a resonate cavity with a diffraction grating was used. A tunable long-wave laser with the wavelength of 8.45-
$11.37~\mu \text{m}$
was achieved by rotating the grating. Meanwhile, the linewidth was less than 61 nm at the wavelength within the tunable range from
$8.45~\mu \text{m}$
to
$9.15~\mu \text{m}$
. When the wavelength of the idler light was
$8.84~\mu \text{m}$
, the maximum output energy was
$52.80~\mu \text{J}$
, and the peak power was 6.60 kW. The novel tuning method offers an effective way to realize a tunable long-wave source for stand-off gas concentration detection.