Extraordinary emission from two-dimensional plasmonic-photonic crystals

Abstract

A metallodielectric architecture is employed to readily tailor the spectral properties of a bulk material for application to infrared sources and spectroscopic sensors. We exploit the interaction between surface plasmons at a metal interface with a photonic crystal in silicon to control the spectral response of the surface in reflection, absorption, and emission. The design uses Si-based thermally isolated suspended bridge structures fabricated using conventional photolithography techniques. The tunable narrow spectral response is defined by the symmetry and periodicity of the metallodielectric photonic crystal. Individual subresonances are recognized within this bandwidth. We model their origin through calculations of surface-plasmon modes in the metallic grating overlayer. Periodic arrays of holes in thin metal layers lead to coupled plasmons at the two metal–dielectric interfaces that, in turn, couple to modes in the underlying silicon–air photonic crystal. The model provides crucial physical insight into the interaction between surface plasmons and photonic crystals, with good agreement with the experimental results.