Photonic crystal nanostructure as a photodetector for NaCl solution monitoring: theoretical approach

In this research, we have a theoretical simple and highly sensitive sodium chloride (NaCl) sensor based on the excitation of Tamm plasmon resonance through a one-dimensional photonic crystal structure. The configuration of the proposed design was, [prism/gold (Au)/water cavity/silicon (Si)/calcium fluoride (CaF2)(10)/glass substrate]. The estimations are mainly investigated based on both the optical properties of the constituent materials and the transfer matrix method as well. The suggested sensor is designed for monitoring the salinity of water by detecting the concentration of NaCl solution through near-infrared (IR) wavelengths. The reflectance numerical analysis showed the Tamm plasmon resonance. As the water cavity is filled with NaCl of concentrations ranging from 0 g l(-1) to 60 g l(-1), Tamm resonance is shifted towards longer wavelengths. Furthermore, the suggested sensor provides a relatively high performance compared to its photonic crystal counterparts and photonic crystal fiber designs. Meanwhile, the sensitivity and detection limit of the suggested sensor could reach the values of 24 700 nm per RIU (0.576 nm (g l)(-1)) and 0.217 g l(-1), respectively. Therefore, the suggested design could be of interest as a promising platform for sensing and monitoring NaCl concentrations and water salinity as well.

Automated summary

In this research, a simple and highly sensitive sodium chloride (NaCl) sensor based on Tamm plasmon resonance was proposed. The sensor was designed to monitor water salinity by detecting the concentration of NaCl solution using near-infrared (IR) wavelengths. Numerical analysis showed Tamm plasmon resonance and as the concentration of NaCl increased, the resonance shifted towards longer wavelengths. The suggested sensor exhibited higher performance compared to other photonic crystal designs, with a sensitivity of 24,700 nm per RIU and a detection limit of 0.217 g l(-1).