Mutual coherence and conical pattern of sources optimally excited within multilayer optics

We calculate the power density provided by a set of sources that radiate simultaneously and interfere within a multilayer planar microcavity. This power is shown to depend on interaction of currents, that is, on mutual coherence of sources. Numerical calculation is performed for a single-layer and a double-cavity Fabry-Perot filter, including free-space and modal powers. Elimination of modal power carried by guided modes is discussed, as well as optimal excitation of sources by means of multidielectric resonances. The resulting pattern is shown to be conical in free space and controlled by the cavity poles. Experiments are given concerning absorption and scatter lng measurements at each. multidielectric resonance of the cavity. The applications concern light scattering and roughness-induced absorption within multilayers, as well as spontaneous emission in classical microcavities. (C) 1997 Optical Society of America.