Photonic band gaps in metallic microcavities

We investigate the mode structure of optical microcavities made using metallic mirrors. By giving one of the mirrors wavelength scale periodic texture we show that cavity modes, in particular the antisymmetric coupled surface plasmon polariton mode, may be blocked by a photonic band gap. We compare experimental and theoretical results and use them to indicate how changing the type of texturing may be used to control the modes of the microcavity. The relevance of the reported work to microcavity devices such as the light emitting diode is also discussed.