Analysis of resonant properties in surface plasmon polaritons nanocavities

We analyze the resonant properties in surface plasmon polaritons nanocavities and study the resonant transmission spectrum of light through a sub-wavelength metallic nanocavity composed by two pieces of finite silver thin slabs with nanometer configurations of periodic sinusoid profile on their inner boundary, setting by face-to-face arrangement with a separated spacing. The boundary elements method (BEM) is adopted for analyzing the optical behavior of these metallic nanocavities. We investigate the influence of the number of the grating period on the optical resonant behaviors of the nanocavities. The numerical results indicate that the wavelengths of resonant peaks are well agreed with the predicted resonant wavelength. Furthermore, the number of the resonant wavelength from the scattered resonant transmission spectrum increases as the number of the grating period is increased, and the resonant peaks shift to the longer wavelength while the number of the grating period is increased. It is believed that our analysis will provide important information for designing novel cavity that can select the wavelength or realize ultra-minitune optical sources that can be easily integrated in the all-optical communication system.