Theoretical Assessment on Shape-Dependent Optical Properties of Gold Nanostructures

Abstract

In the current work, detailed investigations on shape-dependent optical properties of gold nanostructures are carried out using the finite element method. The key objective of the work was to explore the optical response of differently shaped gold nanostructures. Five differently shaped gold nanostructures i.e. nanopyramid, nanocylinder, nanocone, nanosphere, and nanocube were considered to study the optical properties including skin depth, relative permittivity, refractive index, absorption cross-section, and extinction cross-section. The optical properties of gold appeared to depend on the shapes of nanostructures. The nanostructures with sharp apexes exhibit more skin depth in contrary to those having smooth surfaces. The surface Plasmon resonance (SPR) for the nanostructures was found maximum at 540 nm throughout the calculated range of wavelengths and the intensity of all the curves depends on the shape of the nanostructure.