Highly-sensitive surface plasmon resonance optical sensor for detection applications with equivalent transmission line circuit analysis

A novel and simple optical Surface Plasmon Resonance (SPR) sensor based on the Kretschmann configuration is presented, featuring a silver (Ag)-zinc selenide (ZnSe) layered structure on a fused silica (SiO2) prism. The Transfer Matrix Method (TMM) is employed to numerically evaluate the sensor performance. An equivalent transmission line circuit for the proposed sensor is introduced to simplify the understanding of each layer electromagnetic contributions. The proposed sensor is tested to detect a wide range of refractive indices (RIs), typically from 1.2 to 1.36. The proposed sensor introduces an excellent behavior with a detection sensitivity (S) and a quality factor (QF) of 451 deg/RIU and 173.46 RIU-1, respectively.