Design of a High-Resolution Metal–Insulator–Metal Plasmonic Refractive Index Sensor Based on a Ring-Shaped Si Resonator

• DOI: 10.1007/s11468-019-00926-9
• Publication Date: 2019-03-30T21:02:41Z
• Authors: Mohammad Danaie; Ali Shahzadi
• Keywords: 0103 physical sciences; 01 natural sciences

In this paper, a high-resolution refractive index sensor is proposed based on a novel metal–insulator–metal plasmonic topology. The structure is based on a Si nano-ring located inside a circular cavity. It acts as an optical notch filter with a quality factor equal to 269. The proposed filter topology is numerically simulated using the finite difference time domain method. It is shown that the proposed filter can also act as a refractive index sensor with a sensitivity of 636 nm/RIU and a fairly high figure of merit (FoM) equal to 211.3 RIU−1. It is shown that the sensor can easily detect a refractive index change of ± 0.001 for dielectrics whose refractive index is between 1 and 1.2. For the refractive index range of 1.33 to 1.52, the maximum FoM of the sensor is 191 RIU−1. The simplicity of the design and its high resolution are the two main features of the proposed sensor which make it a good candidate for biomedical applications.