Emission linewidth of laser action in random gain media

Abstract

The linewidth of laser emission in random-scattering gain media is found to be broadened as the number of scatterers increases. This broadening is attributed to the reduction of amplification by stimulated emission as a result of the shortened total path length traversed by the backscattered light in a highly scattering medium. In addition, the spectral shift of the emission peak is found to depend on the dye concentration and the pumping power.