Angular-asymmetric nonlinear polariton dynamics in semiconductor microcavities

Abstract

Parametric interactions in semiconductor heterostructures in which two exciton quasiparticles mutually scatter are typically weak because they are restricted by energy-momentum conservation. Here, semiconductor microcavities in the strong coupling regime are optically pumped at specific resonant energy and angle of incidence to enormously enhance the parametric interactions. A femtosecond goniometer is devised to allow time-, wavelength- and polarisation-resolved pump-probe spectroscopy. Time-resolved images of the microcavity emission at different angles reveal a highly asymmetric luminescence distribution which switches on as the pump power is increased. Both signal and idler beams can be identified when a probe purse initiates stimulated scattering of polaritons from a reservoir. The images show the rich variety of interactions produced by the coupling of light-matter modes, and the future promise of dispersion engineering