Highly Sensitive Salinity and Temperature Sensor Using Tamm Resonance

Abstract

In this paper, a Tamm plasmon resonance-based sensor is theoretically studied to calculate the salinity of seawater as well as a temperature sensor based on photonic crystals. The transfer matrix method (TMM) is used to systematically study and analyze the reflected s-polarized electromagnetic waves from the sensing structure. The proposed structure composes of prism/Au/water/\({(\mathrm{S}\mathrm{i}/{\mathrm{S}\mathrm{i}\mathrm{O}}_{2})}^{N}\)/Si. The sensitivity, figure-of-merit, quality factor, and detection limit of the sensors are improved by optimizing the thickness of the seawater layer, incident angle, salinity concentration, and temperature. The proposed salinity sensor records a very high sensitivity of 8.5 × \({10}^{4}\) nm/RIU and quality factor of \(3\times {10}^{3}\), and a very low detection limit of \({10}^{-7}\) nm. Besides, the suggested temperature sensor achieves high sensitivity (from 2.8 to 10.8 nm/°C), high-quality factor of \(3.5\times {10}^{3}\), and a very low detection limit of \({3\times 10}^{-7}\) nm. These results indicate that the proposed sensor is a strong candidate for salinity and temperature measurements.