Monolithic diamond Raman laser

A monolithic diamond Raman laser is reported. It utilizes a 13-mm radius of curvature lens etched onto the diamond surface and dielectric mirror coatings to form a stable resonator. The performance is compared to that of a monolithic diamond Raman laser operating in a plane–plane cavity. On pumping with a compact $Q$-switched laser at 532 nm (16 μJ pulse energy; 1.5 ns pulse duration; 10 kHz repetition-rate; ${\mathrm{M}}^2<1.5$), laser action was observed at the first, second, and third Stokes wavelengths (573 nm, 620 nm and 676 nm, respectively) in both cases. For the microlens cavity, a conversion efficiency of 84% was achieved from the pump to the total Raman output power, with a slope efficiency of 88%. This compares to a conversion efficiency of 59% and a slope efficiency of 74% for the plane–plane case. Total Raman output powers of 134 and 96 mW were achieved for the microlens and plane–plane cavities, respectively.