Analytic theory for lasers based on stimulated polariton scattering

We present a model for predicting the development of Stokes and terahertz (THz) fields undergoing stimulated polariton scattering. The model is valid for finite beams, avoiding the most limiting assumption of the leading model to date; our model makes significantly different predictions for the narrow pump beams and low-gain systems now commonly being studied. The model accounts for the build-up of the THz field across finite pump beams as well as naturally extending that propagation away from the pumped region, a key requirement for understanding the effectiveness of real experimental geometries.