A Highly Performed SPR sensor for Urea Detection Using Au-BeO-GaP Based structure

A highly performed “surface plasmon resonance (SPR) sensor” is presented for urea detection employing gold (Au)-beryllium oxide (BeO)-gallium phosphide (GaP)-based structure in this paper. Au is used to excite surface plasmons at prism surface in the proposed structure, whereas BeO is used for high absorption capability. Moreover, gallium phosphide (GaP) is employed as a higher absorption capability carrier and “biomolecular recognition element (BRE)” in order to prevent the external environment. Three different structures are made with above-defined layers in order to shows influence of proposed materials. The performance parameters for the proposed sensor have been analyzed by considering the transfers matrix method and angular interrogation technique at 670nm wavelength. Initially, the performance in terms of minimum reflectance $(\mathrm{R}_{\min})$ is analyzed and found less $\mathrm{R}_{\min}$ of 0.00013, which is always desired using the optimized Au thickness. Additionally, the study computes the performance parameters, such as sensitivity and quality factor (QF), for very small RI variations of the urea samples. The maximum achieved sensitivities and QF are 125.71 °/ RIU and 32.65 RIU−1 for conventional SPR; 145.71°/ RIU and 32.31RIU−1 for BeO-based SPR; 288.57°/ RIU and 33.63RIU−1 for proposed SPR. Finally, the performance proposed work is compared with existed works done by other researchers, demonstrating the proposed SPR amplifies the sensitivity and heightened the QF.