Single-longitudinal-mode Ho:YLF unidirectional ring laser with single anti-misalignment corner cube retroflector

A single-longitudinal-mode Ho:YLF unidirectional ring laser with single anti-misalignment corner cube retroflector (CCR) for providing the stable local oscillator to 2.05 μm laser lidar was demonstrated in this paper. The single-longitudinal-mode output power of 569 mW at 2051.76 nm was obtained by inserting a half-wave plate and a Faraday rotator to the ring oscillator. The output wavelength was tuned from 2050.94 nm to 2054.18 nm through a 0.3-mm-thick F-P etalon, which close to the free spectrum range of the etalon. In addition, the anti-misalignment characteristic of the unidirectional ring laser was investigated when the single CCR moved along the optical axis and perpendicular to the optical axis. The beam quality factors M2 of the Ho:YLF single-longitudinal-mode laser were 1.05 in the x direction and 1.02 in the y direction, respectively.