Pulsed, single-frequency, ring laser with a holographic output coupler.

A unidirectional, passively Q-switched, 2.05-μm Ho:YLF ring laser providing single-frequency, sub-mJ-energy, 100-200-ns-long laser pulses at a kHz rate is reported. The wavelength selection and "coarse" spectral narrowing is performed by utilizing a volume Bragg grating as a resonant, narrowband output coupler operated at a small angle away from normal incidence.

3.4-mum ZGP RISTRA nanosecond optical parametric oscillator pumped by a 2.05-mum Ho:YLF MOPA system.

We report on the first demonstration of ZGP OPO based on Rotated Image Singly-Resonant Twisted RectAngle (RISTRA) cavity. For the OPO signal wave we achieved a near diffraction-limited beam at 3.4 mum with pulse energy of 10 mJ at repetition rate up to 500 Hz.