Microscopic theory of light emission from semiconductor quantum dots in microcavities

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Semiconductor microcavities have been successfully used in the past decade to study fundamental light-matter effects. Previous investigations mainly used quantum wells as active material and Bragg mirrors for a one-dimensional cavity. Our goal is to extend these investigations in two directions: i) In quantumwell nanostructures, the intrinsic interaction processes of carriers (especially the Coulomb interaction) dominate also the light-matter interaction. The use of semiconductor quantum dots for the active material allows to modify these interaction processes and the discrete nature of the electronic states is the key for new light-matter interaction effects involving, e.g., single or few photons. ii) A three-dimensional photonic confinement will be necessary to realize the strong-coupling regime with quantum dots. Furthermore, the three-dimensional photon confinement strongly increases the spontaneous emission coupling which enhances quantum effects in the light emission. A microscopic theory will be used to study the emission properties of quantum dots in semiconductor microcavities. Starting from the electronic states of the quantum dots, electronic relaxation processes and their influence on the excitonic properties (in the low-excitation regime) and on the optical gain (under high-excitation conditions) will be studied. Calculations of the three-dimensional mode structure of semiconductor microcavities will be used to determine the altered spontaneous emission properties in the weak-coupling regime. Furthermore, within a quantum mechanical theory of the light-matter interaction, statistical properties of the light-emission will be investigated. For large spontaneous-emission coupling intensity-intensity correlations in the coupled cavity--quantum-dot system will be studied. In the weak excitation-limit quantumoptical effects like the creation of entangled photons for the biexciton-exciton transition will be analyzed in direct collaboration with the experimental investigations of our research group.