Rate and efficiency of spontaneous emission in metal-clad microcavities

In this article, we report experimental results on the control of spontaneo us emission from sources embedded within metal-clad microcavities. The micr ocavity samples consist of an Eu3+ doped emissive monolayer embedded with a planar dielectric slab, bounded by a silver film on each side. We investig ate the effect of both the cavity thickness and the location of the emissiv e monolayer within the cavity on the spontaneous emission rate of the emitt ers, observing both enhancement and inhibition. By varying the thickness of one of the silver films we also investigate the role of the reflectivity o f the mirrors of the cavity on the control of spontaneous emission. In addi tion to the emission rate, results are presented on the spatial distributio n of the emitted radiation. We find good agreement between our experimental results and those predicted by a classical theory over a large range micro cavity structures. This agreement allows us to assess the contribution of t he decay mediated by the electromagnetic modes of the cavity and the intrin sic nonradiative decay to the spontaneous emission rate. We then compare th e ability of metal-clad and hybrid (one metal mirror and one distributed Br agg reflector) microcavity designs to optimize the efficiency of radiative emission. We show that enhancements, due to the increased confinement of th e electromagnetic modes supported by the metal-clad microcavities, can be s ufficient to overcome the loss associated with the absorption in the metal layers. We discuss the implication these results may have for device design . (C) 2001 American Institute of Physics.