Transmission and diffraction through metallic nanoslit

The extraordinary optical transmission (EOT) and diffraction through nanoslit composed of two finite-width metallic films with periodic or aperiodic sub-wavelength corrugation were studied. The transmitted spectra were calculated and compared, and the numerical results showed that two transmission peaks exist for the periodic corrugation, while for aperiodic one the transmission peaks are split into seven, corresponding to their different periods and couplings. Further investigation indicated that resonant wavelength of Surface Plasmon Polaritons (SPPs) determined by the nanoslit can be distinguished. It is expected that this investigation will provide useful information for further designing various nano-scaled optical filters and wavelength division multiplexer (WDM) in the next all optical network (AON).