High-sensitivity SPR refractive index sensor based on dual C-shaped microstructured optical fiber

Abstract

In response to the significant limitations of low sensitivity and constrained figure of merit (FOM) in surface plasmon resonance (SPR) sensors, this study introduces a novel high-sensitivity SPR refractive index (RI) sensor utilizing dual Cshaped microstructured optical fiber for liquid RI detection. Employing finite element method (FEM) simulations, we study theoretically and numerically the impact of structural parameters, including single- and double-side polished and coated C-shaped holes, on SPR mode loss spectra. The results indicate that within the 600-1000 nm near-infrared range, the sensor exhibits outstanding performance for RI detection from 1.33 to 1.42, achieving a peak sensitivity of 13,800 nm/RIU, which translates into a resolution of 7.246×10-6 RIU-1 and an impressive FOM of 630.1 RIU-1 . These findings offer critical theoretical understanding for the development of microstructured fiber‑based sensors and highlight their significant promise in biomedical detection and chemical monitoring.