Omnidirectional resonance in a metal-dielectric-metal geometry

We show that a planar metallic microcavity structure can exhibit an omnidirectional resonance, i.e., a resonance for which the resonance wavelength is independent of the incidence angle of light. The structure consists of a metal-dielectric-metal configuration. The omnidirectional resonance occurs when the reflection phase shift cancels the propagation shift. We numerically demonstrate such an omnidirectional resonance in an Ag-SiO2-Ag structure with realistic material parameters. Such omnidirectionally resonant structures are important for all-angle efficiency enhancement in light emitting diodes and photodetectors. (C) 2004 American Institute of Physics.