Continuous-wave anti-Stokes Raman laser based on phase-matched nondegenerate four-wave mixing

We demonstrate phase-matched nondegenerate four-wave mixing (FWM) in a high-finesse optical cavity using a gaseous Raman-active medium pumped by two independent continuous-wave lasers. Efficient upconversion is achieved for pump beams at different wavelengths under phase-matched conditions by optimizing the total dispersion of the hydrogen-filled optical cavity. The independent control of the pump-beam polarizations leads to further enhancement of the upconversion efficiency arising from a larger Raman gain than that in degenerate FWM. This approach offers a promising alternative for a narrow-linewidth tunable light source for highly precise laser spectroscopy.