The Effect of Finite Element Mesh Style and Size on Nano-Optic Computational Electromagnetic Simulations*

Finite element method analysis produces highly accurate computational models for electromagnetics, especially the field of plasmonics. However, mesh size can vary across studies, and how it affects simulation accuracy for nanoscale electromagnetic could use further investigation. Larger mesh elements can reduce computation time, and so an understanding of mesh size upon model accuracy is significant. The purpose of our work is to investigate the relationship between mesh element size and deviancy from expected values of optical characteristics of the nanostructures. Specifically, we are trying to define a maximum mesh element size that retains acceptable deviance from expected values. 

Additionally, mesh creation style has some effect on the impact of mesh size on optical enhancement. Two methods of mesh creation have been investigated. One, the “Allmesh” method, used one unified mesh across the entire structure. The second, the “Mesh-Scalar” method, used multiple meshes to simulate different elements of the nanostructure.

Results for plasmonics structures indicate that mesh element sizes beyond 10 nm resulted in severe deviancy in optical enhancement, and that the “mesh-scalar” method was more sensitive to change in element size. Next we will investigate photonic crystals.