Polarization dependence of excitonic-polariton propagation in a GaAs quantum-well waveguide

Anisotropic propagation of excitonic polaritons in GaAs single-quantum-well waveguide structures is evidenced by means of time-of-flight measurements. This anisotropy suggests that the depolarization effect of two-dimensional excitons enhances the polariton propagation. The observed optical nonlinearity of the group velocity supports the existence of polaritons and reflects the effect of a polariton-polariton interaction on their propagation.