Trapped mode contribution to spontaneous emission in a planar Fabry-Perot microcavity

Summary form only given. We present the results of a full quantum treatment of the contribution of trapped modes to the total spontaneous emission rate. For the case of a high Q Fabry Perot microcavity of the simple type treated by Dutra and Knight, we find that for both normal and parallel orientations of the atomic dipole matrix element, the trapped mode contribution is negligible for all atomic positions in the microcavity, so that almost all the energy radiated goes into the traveling modes.