Design of a highly sensitive terahertz temperature and refractive index composite sensor based on an InSb–Ag composite grating

This paper introduces an exceptionally highly sensitive sensor developed using InSb–Ag composite gratings for sensing temperature and refractive index in the terahertz region. The structural parameters of the sensor were optimized to produce two transmission spectra at frequencies of 2.016 THz and 10.428 THz, respectively, under T =290K with transverse magnetically polarized vertical incidence. The simulation results demonstrate that the temperature sensor displays a sensitivity of 25.27 GHz/K and 4.53 GHz/K; the respective refractive index sensor shows a sensitivity of 0.48 THz/RIU and 3.60 THz/RIU. The current paper analyzes the effects of incidence and polarization angles on the performance of the sensors. The findings indicate that polarization significantly correlates with the sensor. Regarding the incidence angle range of 0°–30°, the performance of the sensors is uncorrelated with the angle of incidence. Compared to other temperature and refractive index sensors, the composite grating sensor demonstrates superior sensing performance and holds great potential for developing high-performance dual-function sensors.