Metal‐Insulator‐Metal Waveguide Plasmonic Sensor System for Refractive Index Sensing Applications

Abstract

Plasmonic sensors are well known for their miniaturized size and high sensitivity. Herein, a numerical analysis of a metal‐insulator‐metal (MIM) waveguide (WG) for refractive index (RI) sensing applications is proposed. The sensing device is composed of a MIM bus WG with a semicircular formation side coupled to a semicircular cavity. This configuration provides a transmission dip with a high extinction ratio as compared to the standard MIM WG side‐coupled to a semicircular cavity. Moreover, the mode converters are also embedded in the sensing system solving the obstacle of light coupling to the MIM plasmonic WG. The sensitivity of the proposed device is ≈941.33 nm RIU ⁻¹, making it a promising candidate to be employed in point‐of‐care (POC) testing. This typically involves the use of portable or handheld diagnostic devices that can quickly analyze samples of blood, urine, or other bodily fluids to diagnose diseases or conditions such as infections, diabetes, or heart disease.