Resonant Interaction of Photons with a Random Array of Quantum Dots

Abstract

Resonant scattering of photons by a random array of quantum dots is studied theoretically. The quantum dots are approximated by two-level systems with degenerate excited states, which are distributed randomly over sites of a superlattice with concentration C and are coupled with the electromagnetic fields. The simultaneous equations for the photon Green’s functions are solved by a self-consistent field approximation, which bridges the exact solutions in the both limits C→0 and C→1. It is shown that, as C increases and exceeds a critical value, a stop-band appears in the photon density of state. This indicates the changeover of the character of the resonant interaction from the random Rayleigh scattering of photons to the coherent transfer of polaritons. It is predicted that this phenomenon will be observed in the nonlinear dependence on C of the reflectivity of the sample and in the suppression of the light scattering in the direction normal to the incident light beam.