Design study for transmission improvement of resonant surface plasmons using dielectric diffraction gratings

A transmission-type surface plasmon resonance configuration with dielectric gratings regularly patterned on a silver film was investigated with the aim of enhancing the diffraction efficiency of radiative surface plasmons. The theoretical work was conducted using rigorous coupled-wave analysis in terms of first order diffraction efficiency and conversion efficiency (CE). The results show that pyramid gratings can produce a higher transmittance compared with other grating profiles. Design optimization of the pyramid grating at a wide range of grating thicknesses and periods resulted in a maximum transmittance that was larger than 77% and a peak CE of about 85%. This study demonstrates the potential of using transmitted surface plasmon waves in various optical devices, such as optical biosensors, optical imaging systems, and polarization filters.