A Plasmonic Refractive Index Sensor for Subwavelength-Scale Detection of Multiple Pesticides

This paper unveils a novel refractive index (RI) sensor, characterized by the integration of a T-shaped resonator within a straight metal-insulator-metal (MIM) waveguide. The sensor's design and functionality are rigorously analyzed using finite element method (FEM) simulations, providing a comprehensive numerical assessment of its optical characteristics. It is specifically engineered to identify alterations in refractive index through the observation of shifts in resonant wavelength. These shifts occur as a consequence of light interacting with the plasmonic components of the sensor. The sensor is particularly effective for pesticide analysis, where accurate chemical detection is essential. Through the refinement of its geometric design, the sensor attains an impressive peak sensitivity of 1784 nm/RIU, significantly enhancing its performance in molecular detection. Further numerical assessments demonstrate its effectiveness in identifying various pesticides, underscoring its broad applicability and potential for diverse uses beyond pesticide monitoring.