High-efficiency, continuous-wave Raman lasers

A modified steady-state laser theory that describes a continuous wave (cw) off-resonant Raman laser with asymmetric reflectivities for the cavity is p resented. This theory takes into account different mirror reflectivities of the front and back mirrors of the Raman laser cavity for both the pump and the Stokes wavelengths. An off-resonant cw Raman laser pumped at 795 nm in diatomic hydrogen (Hz) is modeled by use of the results of the steady-stat e theory. The predicted threshold for the cw Raman laser is 2.4 mW, and a m aximum Stokes photon conversion efficiency of 83.0% is predicted for a pump power of 9.9 mW. The high Stokes photon conversion efficiency is obtained with mismatched pump-wavelength reflectivities of the front and the back mi rrors of the laser cavity. By a judicious choice of mirror reflectivities, both the backreflected pump power and the transmitted pump power can be min imized, thus making a maximum amount of pump power available for nonlinear Stokes conversion. (C) 1999 Optical Society of America [S0740-3224(99)01405 -8].