Plasmonic modes in a conductor-corrugated gap-dielectric system at telecommunication wavelength

¹ State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences - Shanghai 200050, China
² University of Chinese Academy of Sciences - Beijing 100049, China
³ Department of Illuminating Engineering and Light Sources, School of Information Science and Engineering, Fudan University - Shanghai 200433, China
⁴ Engineering Research Center of Advanced Lighting Technology (Ministry of Education) - Shanghai 200433, China

^(a) waylee@mail.sim.cn
^(b) jiangxunya@fudan.edu.cn

Received: 4 February 2016
Accepted: 14 April 2016

Abstract

We propose a conductor-corrugated gap-dielectric structure to realize broadband plasmonic modes at telecommunication wavelength. The structure consists of a corrugated low-index dielectric gap layer sandwiched by high-index dielectric and conductor layers. The electric field of the plasmonic modes is primarily concentrated in the corrugated gap, which not only reduces the metal absorption resulting in long propagation length but also causes good field confinement. It is proved that periodic modulation introduced into the gap can significantly increase the cutoff gap thickness of the structure. The effective medium theory and numerical simulation demonstrate that the cutoff gap thickness can be further increased by decreasing the filling factor of the low-index dielectric in the corrugated gap. Meanwhile, the scattering effects induced by the periodic modulation are also investigated. The results not only provide a new understanding of the surface plasmonic modes but also benefit the designing of compact devices.