Highly Sensitive Salinity and Temperature Sensor Using Tamm Resonance

Abstract In this paper, a Tamm plasmons 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/(Si/SiO2)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 8.5x104 nm/RIU and quality factor of 3x103, and a very low detection limit of 10-7 nm. Besides, the suggested temperature sensor achieves high sensitivity (from 2.8 nm/˚C to 10.8 nm/˚C), high-quality factor of 3.5x103, and a very low detection limit of 3x10-7 nm. These results indicate that the proposed sensor is a strong candidate for salinity and temperature measurements.