Steady-state Raman gain in visible and near-infrared waveband of SrWO₄ and BaWO₄ crystals

The steady-state stimulated Raman scattering (SRS) gain with different excitation wavelengths ranging from 400 to 1100 nm of tungstate crystals, SrWO₄ and BaWO₄, is systematically researched. As excitation frequency is close to electronic transition frequency, molecular polarizability is not a constant, which has to be taken into account in our work. The experiment and theory agree well with each other and show that SRS gain is not only proportional to Stokes light frequency, but is also inversely proportional to biquadratic excitation frequency.