Revealing the physical mechanisms behind large field enhancement in hybrid spoof plasmonic systems

摘要

We compare different spoof localized surface plasmon (LSP) schemes for increasing the field enhancement in the subwavelength regime. Based on the mechanisms of three differently widely used corrugated metallic disk structures, we compare three widely used corrugated disks and propose a nonconcentric spiral-shaped metallic disk structure, which not only maximizes the electromagnetic field confinement but also effectively reduces the radiation loss. The performance can be further improved by adopting a hybrid system consisting of two closely spaced nonconcentric spiral structures. We show that such a dimer of nonconcentric spiral disk produces significant field enhancement compared with the previously discussed structures. Our study provides a perceptive guideline for potential applications, such as plasmonic sensors and antennas, associated with LSPs in the microwave and terahertz frequencies. (c) 2018 Optical Society of America