Study of incident angle dependence for dual-band double negative-index material using elliptical nanohole arrays.

This work demonstrates the angular dependence of dual-band negative-index materials implemented by elliptical nanohole arrays (ENAs) consisting of an Al2O3 dielectric layer between two Au films. This article, it is believed for the first time, analyzes the scattering coefficients and displacement current of the ENA at different angles of plane-wave incidence to show that the ENA is double negative (showing both a negative effective permeability μ(eff) and a negative effective permittivity ε(eff) at multiple wavelengths (1095 and 1680 nm) for p polarization over a broad range of incident angles.