Performance and design of an off-resonant continuous-wave Raman laser

Abstract

A steady-state theory that describes the performance of a cw off-resonant Raman laser is presented. The cw Raman laser is constructed in a nonconfocal high-finesse cavity that allows for high Raman gain with low pump powers. Threshold values of the pump laser used to pump the cw Raman laser are predicted to be as low as 1 mW. The maximum photon-conversion efficiency for the cw Raman laser is predicted to be 50%. The theory is compared with experimental results from a cw Raman laser that operates with a pump wavelength of 532 nm and a Stokes-shifted wavelength of 683 nm. A threshold pump power of 2 mW and a maximum photon-conversion efficiency of $34\%\pm 6\%$ was measured. With the mirrors used in the experiment, these values correspond to the predictions from the steady-state cw Raman laser theory. The theoretical model is then used to design cw Raman lasers operate near the maximum conversion efficiency in the 1–4-μm wavelength region.