Calculation of spectra and plasmon wave distribution in one-dimensional periodic structure

Abstract

Surface Plasmon Resonance (SPR) is a resonance phenomenon between electromagnetic waves and electrons, which is formed on the interface between metal and dielectric surface. SPR waves can be generated by using a coupler element, such as prisms and gratings. In this study, we analyzed the effect of groove filling in nanograting structures using computation work based on Rigorous Coupled Wave Analysis (RCWA) method. The structure periodicity is 700 nm with a groove depth of around 350 nm. The reflectance spectra calculation by the RCWA method produces the appearance of SPR dip for an empty groove (with air inside the groove) at around 550 nm - 650 nm. The dip wavelength varies on the incident angles from 30 up to 60 degrees. In addition, the shifting of those dips is also predicted from the calculation results when the groove is filled by a medium with a refractive index of 1.5, which can be the basis of its utilization as optical sensing elements.