Optical responses from lossy metallic slit arrays under the excitation of a magnetic polariton

This work numerically investigates optical responses (absorptance, reflectance, and transmittance) of lossy metallic slit arrays at the excitation of a magnetic polariton (MP). The studied wavenumber is between 1: 2 x 10(3) and 2: 5 x 10(4) cm(-1) for the spectral regions in which aluminum and tungsten are lossy, which do not coincide. The loss of silver is negligible. Optical response spectra clearly specify the resonance modes, excitation frequency, and impacts from loss, as well as other mechanisms. The inductance and capacitance circuit model predicting MP frequency is not always valid, and the best fitting constant varies with material, slit geometry, angle of incidence, and wavelength. Electromagnetic fields in the near field further illustrate the interplay between the incidence and slit arrays. (C) 2011 Optical Society of America