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.