Computer simulation of key structural parameters for enhanced infrared absorption with Au nano-array

Abstract

Abstract The optical constants of thin films with nanoscale structures, such as metamaterials and nanostructured films used in surface enhanced infrared absorption (SEIRA), are represented by effective medium approximation (EMA). In a representative EMA, the effective permittivity is determined by parameters such as the volume filling factor (F). In a metal square column array modeled on an evaporated film, the effective permittivity is determined by the gap size/particle size ratio (f). However, f is also expressed as a function of F. For this study, we simulated the SEIRA spectrum using a model in which f and F were varied independently to investigate which was the most important parameter in the square column array. The results showed all the simulations performed, results showed that the gap size/particle size ratio (f) is an important parameter for the increase in SEIRA in the square column array. This study has led to new discoveries that support elucidation of the SEIRA enhancement mechanism.