Wedge and gap plasmonic resonances in double nanoholes
Date
2015-11-11
Authors
Chen, Yuanyuan
Kotnala, Abhay
Yu, Li
Zhang, Jiasen
Gordon, Reuven
Journal Title
Journal ISSN
Volume Title
Publisher
Optics Express
Abstract
We study the plasmonic resonances of double nanoholes (DNHs) in metal films. These apertures exhibit the usual gap-mode Fabry-Pérot resonances, where the zeroth order resonance is determined by the waveguide cut-off and the first order resonance shows sensitivity to the film thickness. An additional wedge resonance is observed, which is sensitive to the curvature of the cusps in the DNHs, analogous to the wedge modes of single wedges. While the gap mode intensity increases dramatically with decreasing gap-width, the wedge mode intensity saturates since its field enhancement arises from the curvature of the metal film, like cylindrical Sommerfeld waves. Experimental transmission spectra agree well with finite-difference time-domain simulations showing these separate resonances. The controlled design of these resonances is critical for applications including optical tweezers, nonlinear conversion, sensing and spectroscopy.
Description
Keywords
Metal optics, Surface plasmons, Subwavelength structures, nanostructures, Optical properties, Resonance
Citation
Chen, Y., Kotnala, A., Yu, L., Zhang, J. & Gordon, R. (2015). Wedge and gap plasmonic resonances in double nanoholes. Optics Express, 23(23), 30227-30236.