Improved Surface Plasmonic Wave Propagation of a Prism Coupler through Optimal Grating Structure Design

Abstract

In a prism coupler, a surface plasmonic wave excitation mechanism, the propagating efficiency can be enhanced by employing the grating structure on the thin metal film portion. This study suggests a systematic design approach for the grating structure design using numerical optimization techniques such as the parameter and topology optimization method. The wave propagation model was solved by the finite element analysis, and the design process has been proceeded by the gradient based optimal design method. It is found that the plasmonic wave propagation efficiency is improved by adopting the irregular grating structure obtained from the suggested process.