Electrodynamics of the phonon-mediated optical Stark effect

The electrodynamics of three-wave polariton-phonon interactions with spatial dispersion is developed and applied to the phonon-mediated optical Stark effect in bulk polar semiconductors.This electrodynamics is formulated within three macroscopic equations, which describe the coupled probe light field, excitonic polarization, and LO phonons of a semiconductor virtually excited by the pump light. We analyze how the incident probe light reflects (transmits) from a boundary of the crystal in the presence of an intense coherent polariton. A Poynting theorem, which clarifies the structure of the total energy flux of the probe wave resonantly coupled to the pump polariton through Raman interaction, is derived. In order to calculate the reflectivity of the probe light from the boundary of a virtually excited crystal, we apply the recently developed wave-vector-space method [B. Chen and D.F. Nelson, Phys. Rev. B 48, 15 372 (1993)]. The transient excitonic spectra of the phonon-mediated Stark effect are analyzed and calculated numerically for bulk CdS. [S0163-1829(98)01727-5].