Investigation of the Extinction Spectra of a Plasmonic Noble-Metal Hollow Nanocube

Abstract

In this work, a hollow cubic nanostructure based on noble metals of silver and gold is studied. The extinction spectra of the plasmonic hollow cube are numerically calculated via the finite-difference time-domain method. A two-peak feature is witnessed in the extinction spectra, and the electric fields at the two resonance wavelengths are computed, indicating two different electromagnetic modes. The resonance wavelengths, the full widths at half maximum, and the peak intensities are also determined from the extinction spectra. In the calculations, the structural parameters of the hollow nanocube are systematically varied, including the cubic size, the thickness of the metallic wall, the geometric ratio of the cube, and the dielectric constants of the inner and outer surrounding media. With changing the structural parameters, the trends revealed in the simulated extinction spectra highlight a great tunability in the plasmonic resonances. Based on the results shown in this work, it is suggested that the proposed metallic hollow nanocube be implemented in designs of plasmonic devices.