A switchable split ring resonator nanoantenna design with organic material composite as a refractive index sensor

Abstract

The intent of this paper is to design of a nanoantenna with Fano response, by using a split ring resonator (SRR) element as a refractive index sensor in the range of 2 – 4μm for the infrared spectrum. A few organic material particles are implanted inside of the gaps which are made by the gold layers so that using organic materials conduce to the switchable characteristic in this nanoantenna. The gaps play a fundamental role to control the electric field and create hot spots at the center of the proposed nanoantenna. The primary antenna shows Fano response at 2450 nm and 3100 nm and the parasitic elements are added to this primary nanoantenna. The parasitic elements are important to control the electric fields in hot spots and change the shape of Fano response in the second nanoantenna. The extinction cross-section (ECS) and the electric field of the antenna are compared for both “On” and “Off” modes of the switches. It shows the organic material particles’ conductivity can be noticed to design a switchable nanoantenna thereby it is suitable to be exploited as an optical sensor. The sensitivity of both suggested structures is obtained from frequency shift and ECS change with a maximum value of 420 nm/RIU and 4.93×105 nm2/RIU.