Enhancement of Sensitivity with High-Reflective-Index Guided-Wave Nanomaterials for a Long-Range Surface Plasmon...

A guided-wave long-range surface plasmon resonance (GW-LRSPR) sensor was proposed in this investigation. In the proposed sensor, high-refractive-index (RI) dielectric films (i.e., CH₃NH₃PbBr₃ perovskite, silicon) served as the guided-wave (GW) layer, which was combined with the long-range surface plasmon resonance (LRSPR) structure to form the GW-LRSPR sensing structure. The theoretical results based on the transfer matrix method (TMM) demonstrated that the LRSPR signal was enhanced by the additional high#x2212;RI GW layer, which was called the GW-LRSPR signal. The achieved GW-LRSPR signal had a strong ability to perceive the analyte. By optimizing the low- and high-RI dielectrics in the GW-LRSPR sensing structure, we obtained the highest sensitivity (S) of 1340.4 RIU^-1 based on a CH₃NH₃PbBr₃ GW layer, and the corresponding figure of merit (FOM) was 8.16 × 10⁴ RIU^-1 deg^-1. Compared with the conventional LRSPR sensor (S = 688.9 RIU^-1), the sensitivity of this new type of sensor was improved by nearly 94%.