On the Feasibility of Thallium Bromide in Long-Range Plasmonic Sensing for Enhancement of Performance

This article introduces a new plasmonic sensor utilizing long range surface plasmon resonance (LRSPR), which is constructed from a heterostructure of thallium bromide (TlBr) along with BluePhosphorene and Tungsten diselenide (BlueP/WSe2). Through meticulous analysis, we systematically investigated the optimal sensor configuration which consists of 8 nm thick silver (Ag) metal layer, a 1900 nm thick Magnesium fluoride (MgF2) dielectric buffer laye (DBL), and a 2-nm thick TlBr layer to enhance the capabilities of the sensor. The achieved configuration of he proposed sensor claims exceptional attributes, including narrower full width at half maximum (FWHM =0.01 Deg.), higher detection accuracy [DA =100 (Deg−1)], imaging figure of merit [IFOM =4410500 (Deg. RIU)−1], imaging sensitivity, ( ${S} _{\text {img.}} =44$ 105 RIU−1), and angular figure of merit (FOM $_{\text {ang.}} =5814.38$ RIU−1). It exhibits significantly improved performance by achieving 38.02, 964.89, 25.39, and 61.40-times higher values of DA, IFOM, ${S} _{\text {img.}}$ , and FOMang respectively, as compared to the conventional surface plasmon resonance (CSPR) sensor. Furthermore, the penetration depth (PD) of 989.45 nm of the proposed LRSPR sensor surpasses the PD (210.01 nm) of CSPR sensors, and demonstrates precise and sensitive refractive index (RI) sensing applications in biomedical. Consequently, the proposed sensor offers superior performance over existing LRSPR sensors.