Raman scattering near metal nanostructures

We study Raman scattering in active media placed in proximity to different types of metal nanostructures, at wavelengths that display either Fabry-Perot or plasmonic resonances, or a combination of both. We use a semiclassical approach to derive equations of motion for Stokes and anti-Stokes fields that arise from quantum fluctuations. Our calculations suggest that local field enhancement yields Stokes and anti-Stokes conversion efficiencies between 5 and 7 orders of magnitudes larger compared to cases without the metal nanostructure. We also show that to first order in the linear susceptibility the local field correction induces a dynamic, intensitydependent frequency detuning that at high intensities tends to quench Raman gain. © 2012 Optical Society of America.