Free-running operation of a semi-monolithic LBO-based resonant cavity for high-power continuous-wave second-harmonic generation.

In this paper, we present a novel method, to the best of our knowledge, for achieving high-power second-harmonic generation (SHG) of continuous-wave light. By employing lithium triborate-based resonant cavity with moderate finesse, we propose an approach for generating efficient SHG in the visible and ultraviolet spectral ranges without requiring an active electronic servo loop. As a proof of concept, we demonstrate frequency doubling of a high-power 1064 nm laser to 532 nm. To the best of our knowledge, this is the first implementation of such a cavity featuring a highly reflective coating on one end of this crystal. This quasi-monolithic design enables simultaneous control of phase matching and cavity resonance solely through temperature adjustment of the nonlinear crystal.