2026/05/26 by G. Arunachalam, Anand Karuppannan, U. Arun Kumar +2 · 1 citation
Engineering · #Plasmonic and Surface Plasmon Research #Optical Polarization and Ellipsometry #Photonic and Optical Devices
paper · doi:10.1142/s0217984926501393
Early identification and precise quantification of low-concentration protein biomarkers such as C-reactive protein (CRP), prostate-specific antigen (PSA), cardiac troponin, and human epidermal growth factor receptor 2 (HER2) are necessary for the screening and early detection and monitoring of cancer, cardiovascular, and inflammatory diseases. Conventional analytical methods like ELISA, Western blotting, and mass spectrometry typically require long assay times and sophisticated instrumentation, which hinder their use in rapid and portable diagnostic applications. In this paper, we describe a high-sensitivity Kretschmann-configuration surface plasmon resonance (SPR) biosensor, with a Cu/WS 2 /Black phosphorus (BP)/Ni multilayered structure formed on top of a BK7 prism, and illuminated with 633[Formula: see text]nm p-polarized light. The use of a copper layer enhances localized SPR and enables strong electromagnetic field confinement at the sensing interface. A thin nickel (Ni) outer layer serves as the sensing interface, enhancing structural stability and modulating the plasmonic response. The WS 2 /BP heterostructure significantly enhances light–matter interaction and strengthens electromagnetic field confinement at the metal–dielectric interface. Numerical optimizations were performed using both the transfer matrix method (TMM) and FEM simulations within COMSOL Multiphysics to evaluate the effect of varying copper layer thicknesses (40–52[Formula: see text]nm) on the performance of the SPR sensor. The optimized SPR sensor exhibits a peak angular sensitivity of 401.5 ∘ /RIU, a figure of merit of 784.178 RIU[Formula: see text], a signal-to-noise ratio (SNR) of 14.648, and a detection limit of approximately 10[Formula: see text] RIU. Additionally, the full width at half maximum (FWHM) of the optimized SPR sensor remains constant at 0.512 ∘ , indicating good resonance sharpness and stability. Furthermore, an ML-based regression framework was developed to estimate the optimal WS 2 layer thickness, demonstrating [Formula: see text] values [Formula: see text]0.991 and mean absolute percentage error (MAPE) [Formula: see text]1.6% across the evaluated layer thicknesses, which makes the design adaptive and scalable. The proposed multilayer SPR sensor architecture has substantial potential for ultrasensitive screening and early detection of cancer, cardiac proteins, and infectious disease markers, as well as integration into portable lab-on-chip systems.