This study presents an optimized high-sensitivity Surface Plasmon Resonance (SPR) sensor based on Group-IV materials integrated with a CaF \(_{2}\) prism in the Kretschmann configuration. The research aims to enhance sensor performance by leveraging the high refractive index(RI) and strong plasmonic coupling of Group-IV materials with silver. The proposed structure consists of CaF \(_{2}\) /Ag/Group-IV materials/Analyte and operates at a wavelength of 633 nm. Through systematic optimization, a silicon configuration of seven monolayers (total thickness 2.31nm) yielded the best performance, achieving a maximum sensitivity(S) of 472 \(^\circ \) /RIU, a Figure of Merit (FoM) of 140.89, a Limit of Detection (LoD) of \(0.636 \times 10^{-5}\) , and a Full Width at Half Maximum (FWHM) of \(3.35^\circ \) for a refractive index range of 1.331 to 1.336. Compared to conventional SPR sensors, the proposed design demonstrates superior plasmonic confinement and reduced damping losses, as evidenced by strong field localization at the metal–dielectric interface and a narrower reflectance dip (FWHM = 3.35 \(^\circ \) ), leading to enhanced sensing accuracy. These findings highlight the sensor’s potential for highly precise chemical and biochemical detection.
