Optical mode hybrids in quantum wells, superlattices and slabs

Abstract

The presence of interfaces causes the hybridization of LO and TO modes in non-polar material and of LO, TO and interface polaritons (IP) in polar material. Hybridization arises as a consequence of the necessity to satisfy simultaneously electromagnetic and mechanical boundary conditions. Optical mode analogues of surface Rayleigh waves appear in non-polar slabs, and in polar superlattices the involvement of interface polaritons causes significant dispersion and anisotropy. Results from a continuum theory are shown to describe experimental results reasonably well. Hybridization affects the quantum properties due to the coherent mixing of LO, TO and IP, and this, in turn, affects the interaction with electrons. Estimates of the electron-hybridon scattering rate in GaAs quantum wells are presented.