Design and Simulation of Plasmonic Sensor by Changing the Refractive Index and Based on a Resonance System Using Two Rings, Two Cavities and Two Plasmonic Waveguides

Abstract

In this research, we will design and numerically evaluate a plasmonic sensor based on the resonance system along with the metal-insulated metal waveguide (MIM). The structure of this sensor forms a wide range of wavelengths by changing the refractive index. To design the structure of this sensor, we use two cavities, two plasmonic waveguides and two rings with different dimensions. After designing the sensor structure, we examine the resonant wavelengths and refractive index of the resonators. For this purpose, we use the finite difference method of the time domain, because this method directly obtains Maxwell's equations with proper separation in the two domains of time and space and tells us how to properly design the dimensions and coordinates of the sensor structure and get a good result. At the beginning of the simulation, an electromagnetic wave is sent to the sensor structure to analyze the field distribution and the spectral response of the structural parameters. If the field distribution in the structure is the same, the energy loss is reduced and all dimensions must be optimal to reach the maximum field distribution in the structure. The creation of surface plasmon resonance at the boundary of a metal surface and a dielectric material will increase the intensity of the electric field and correct the sensor performance. In this article, we need factors such as tunability in a range of wavelengths, S sensitivity coefficient, figure of merit (FOM), Q quality factor and width at half maximum value (FWHM) to measure the performance of the sensor. By increasing the number of amplifiers, the FWHM of the resonant wavelength can be modulated, and reach a sensitivity of 2713 nm/RIU is realized in the near-infrared region. We also draw all the diagrams of this sensor using MATLAB software.