Abstract

In this paper, a plasmonic refractive index sensor for sensing applications in the near-infrared region is presented. The sensor is composed of two straight waveguides and two square-shaped cavities to utilize the resonance effect. The waveguides and cavities are created by pattering a silver substrate. The effect of geometrical parameters and refractive index changes on the reflection spectrum and sensitivity of the sensor are investigated. Simulations are performed using the finite-difference time-domain method. Simulation results show that the sensitivity of the device reached 1670nm/RIU. Additionally, the total footprint of the device is 1.5μm². The high sensitivity and ultra-compact size of the sensor make it a good candidate for use in sensing, imaging, medical and industrial applications.

Keywords:FDTD; Refractive index sensor; Resonator; Plasmonic waveguide; Sensitivity