Nonlocal electrodynamics of weakly confined excitons in semiconductor nanostructures

Abstract

The third order nonlinear optical response of semiconductorquantum dots is calculated in the limit of weak exciton confinement. We treat exactly the nonlocal photon–exciton interaction using Green function techniques, without invoking the long wavelength approximation. This procedure provides a unified treatment of systems with arbitrary size compared with the optical wavelength. Geometric confinement gives rise to quantized polariton modes with a finite radiative lifetime. The variation of optical nonlinearities with size, and the role of local field effects are analyzed.