Surface plasmon interactions between the grating with slanted sidewall and a metallic film

Based on the finite difference time domain method, the optical properties and the plasmonic interactions between the grating with slanted sidewall and a thin gold film were investigated theoretically. We compare the similarities and differences of transmission, reflection, and absorption spectra of the composite system and the single grating with slanted sidewall. When the thicknesses of the two films and the slit widths are changed, the resonance peaks show blue-shifts, red-shifts, split, decrease and other physical phenomena. Based on the distributions of electric field component Ex, Ey and the total energy, we explain the physical mechanism of light passing through the grating/film nanosystem. The adiabatic nanofocusing of the system is also discussed.