Optical Near Field Study of Ag Nanowires by the Differential Method

Abstract

The optical response of subwavelength silver nanowires arranged periodically on silica has been analyzed numerically by the differential method improved by the S matrix algorithm. Our results improve the capacity of this rigorous method to give a description of various phenomena occurring in near and far field around the periodic grating. This renders pos- sible to determine the positions of plasmon’s resonance according to the choice of materials used and the geometrical properties. We study the behavior of the diffracted light by the nano-structure in both single nanowire case and grating nanowires case. The influence of the exact grating period and the induced modification of the spacer nanowire depend- ence are then discussed. Moreover, we present mappings of the electromagnetic field located at 50 nm above the nanowires