Transient optical response of a spatially dispersive medium

Abstract

An integral representation for the coupled propagating electromagnetic modes in a spatially dispersive medium is presented, which generalizes the Sommerfeld-Brillouin theory. Analysis of this representation predicts the existence of a new exciton precursor in the transient response; numerical estimates are given for exciton polaritons in CdS. Use of this representation also permits an investigation of signal propagation velocities in regions of anomalous absorption near a resonance of the medium. Inclusion of spatial dispersion leads to a predicted order-of-magnitude enhancement of signal velocities compared to that in the local optics case.