We model the surface resonance effects in a 1D-array of corrugations on a metal-dielectric film with a sub-wavelength nanoaperture, following the earlier work by Moreno et al. [1]. We are interested in computing the coupling of the highly-directional light field emerging from the metal nanoaperture to the lowest-order Gaussian mode. We follow the approach by Vasilyev et al. [2], to compute the coupling to the fundamental Gaussian mode.

We have developed an optimization routine to compute the field emission patterns from a metal nanoaperture and transmission coupling to the fundamental Gaussian mode for various geometrical parameters of the metal nanostructure. We optimize for maximum T (power transmittance to the lowest-order mode) and T/L (ratio of transmittance to loss to higher-order modes), assuming zero absorption so that all reflected light can be potentially recycled in metal nanocavity.

This optimization work on the geometrical parameters of the cavity can be useful in fabricating a high Q cavity with desired resonant wavelength for the future construction of a high-efficiency single-photon emitter.