Design and Analysis of Planar Waveguide-Based SPR Sensor for Formalin Detection Using Ag-Chloride-BP Structure.

Nowadays, Food additives and preservatives have become a hot topic especially formalin, which is a chemical substance used to preserve food. Chronic cancer is caused by swallowing the formalin-contaminated food on a regular basis. As a result, detection of the formalin in food ingredients is a critical need, and this requirement is becoming increasingly important in new terrains. Therefore, a new approach, planar waveguide-based surface plasmon resonance (SPR) sensor is presented in this paper employing silver-chloride materials-black phosphorus structure to detect the formalin. In this study, the optimization of metal thickness and optimal performance of chloride material are analyzed by observing the transmittance power and resonance shift for conventional and chloride-based sensors, respectively. Moreover, the performance parameters, such as sensitivity of 344°/RIU, quality-factor of 166.99RIU-1, detection-accuracy of 3.34 and figure-of-merit of 164.74, are observed for the proposed sensor. Furthermore, the performance comparative study is conducted and found that the proposed sensor highlighted the enhanced the SPR sensor and highlighted the performance of FOM. Finally, the electromagnetic filed distributions of the proposed WG-based SPR sensor are shown using the Opti-FDTD software.