Ultra-high-sensitive sensor based on a metal–insulator–metal waveguide coupled with cross cavity

Abstract

In this paper, a high-sensitive plasmonic sensor based on metal–insulator–metal waveguide coupled with the interesting metal nanoracetrack defects in a cross cavity is proposed and investigated. The sensing characteristics of the proposed design are analyzed by the means of finite difference time domain method which is embedded in the commercial simulator R-Soft. The positions of transmission peaks can be easily manipulated by adjusting both the radius and the distance between the centers of the two racetrack defects in the cavity. The achieved results exhibit a linear relationship between the material’s refractive indices and theirs corresponding wavelengths of resonance, whereas the obtained maximum linear sensitivity is 3410 nm/RIU which corresponds to a sensing resolution as precise as $$2.93 \times 10^{-6}$$ RIU. The proposed sensor has great impact on different technologies advancement as it can be implemented in high performance nanosensors and bio-sensing devices.