Spontaneous emission from within a metal-clad cavity mediated by coupled surface plasmon-polaritons

The emission of light from within a sub-wavelength metal-clad cavity is investigated. We find that emitters placed inside such a cavity emit into the coupled surface plasmon-polariton mode supported by this structure. We use grating structures to couple the non-radiative coupled surface plasmon-polariton modes to light and present the results of measurements of photoluminescence from such structures in the form of dispersion curves. We discuss our findings in the context of sub-wavelength cavities as a means to control the emission of light.