Extraordinary transmission through metallic grating with subwavelength slits for s-polarization illumination

摘要

Based on the rigorous coupled-wave analysis algorithm, we have systematically analysed the effect of the geometrical parameters of a dielectric film coated metallic grating with subwavelength slits on extraordinary optical trans-mission for s-polarization illumination. Results show that the dielectric film which sustains a waveguide electromagnetic mode on the top of the metallic lamellar grating can strongly enhance the transmittance, the positions of the transmission peaks are mainly deter-mined by the period of the metallic grating, the thickness and refractive index of the dielectric film. This structure shows potential applications in excellent polarizers or polarization-isotropic devices at infrared spectral range by appropriately choosing the geometrical parameters.