Three-dimensionally confined modes in micropost microcavities: quality factors and Purcell factors

We present detailed calculations of the mode structure of distributed-Bragg-reflector micropost microcavities. Two methods are used: a first-principles, finite-difference time-domain model, and an approximate, heuristic model based on the separation of variables. We calculate modal quality factors, as well as enhancement of spontaneous emission rates, from single quantum dots in the microcavities. Both ideal and realistic post shapes are considered. The two methods give similar results, and are capable of accurately predicting experimentally measured values.