Controlling the recombination rate of semiconductor active layers via coupling to dispersion-engineered surface plasmons

The coupling between excited electron-hole pairs in semiconductor active layers and surface plasmon polaritons in metallo-dielectric stacks is investigated. These structures can be used to engineer the surface-plasmon dispersion properties so as to introduce tunable singularities in the photonic density of modes, and hence in the recombination rate of nearby active media. A detailed theoretical study of this effect is presented together with the experimental demonstration of geometrically tunable increased recombination in GaN/AlGaN quantum wells via near-UV photoluminescence measurements. If combined with a suitable geometry to efficiently scatter the emitted surface waves into radiation, this approach can be used for light-emission efficiency enhancement at tunable wavelengths. (C) 2008 Optical Society of America