Size and shape effects in electromagnetic response of quantum dots and quantum dot arrays

Size and shape effects in electromagnetic response of quantum dots (QDs) such as depolarization shift of the exciton resonance and fine structure of the gain band are considered on the basis of a unified concept of light confinement. We show that at sufficiently large oscillator strength of the transition, QD behaves itself as a microcavity and excitation of cavity eigenmodes becomes possible, indicating induced magnetism of QDs. Exciton radiative lifetime in spherical QD has been evaluated. A phenomenological effective medium theory of electromagnetic response properties of regular ensembles of QDs has been elaborated. We propose that the effect of light confinement should be properly addressed to optimize the design of optoelectronic devices involving QDs.