Ellipsoid Defect in Trapezoidal-Shaped Cavities Coupled to Multi-resonance Plasmonic Metal-Insulator-Metal Waveguide Toward Ultrasensitive Temperature Sensor

A multi-resonance plasmonic temperature and refractive index (RI) sensor is developed based on a metal-insulator-metal (MIM) waveguide with two trapezoidal-shaped cavities and an elliptical island inside. Different dielectrics including ethanol, chloroform, carbon disulfide, glycerin, and polydimethylsiloxane (PDMS) have been utilized for the temperature investigation in the range of - 50 to 70 degrees C. Results revealed the maximum temperature sensitivity (TS) of 1.058 nm/degrees C and the maximum temperature figure of merit (FoM) (FoM(T)) of 0.0141 1/degrees C which correspond to the carbon disulfide and PDMS in the first resonance (FR), respectively. The RI-sensitivity (RIS) of this sensor at the first and second resonance (SR) is 1328.57 nm per RI unit (RIU) and 735.71 nm/RIU as well as its FoM which is 36 1/RIU and 31.31 1/RIU, respectively. This paper confirms the high capabilities for measuring the temperature and RI in a wide spectral range of wavelengths (600 to 3000 nm), and multi-resonance sensing. This reveals significant potential in optical and photonic circuit applications such as different quantities detection, including hemoglobin and cancer.

Automated summary

A multi-resonance plasmonic sensor based on a metal-insulator-metal (MIM) waveguide is developed for temperature and refractive index (RI) detection. Different dielectrics are utilized for temperature investigation, and the sensor exhibits high temperature sensitivity and RI sensitivity, indicating its potential applications in optical and photonic circuits.