Tunable terahertz dual-band perfect absorber based on the combined InSb resonator structures for temperature sensing

In this paper, a tunable perfect absorber (PA) based on a combined InSb resonator structure is proposed and investigated numerically in the terahertz (THz) region, which can serve as a dual-band temperature sensor. The unit cell of the proposed PA consists only of the combined InSb ring-disk-shaped resonator structures adhered on a continuous gold film and dielectric substrate. The permittivity of the InSb material is highly dependent on the variation of the external temperature. Numerical simulation results indicate that the proposed PA at a temperature of 290 K can achieve absorbance of 99.4% and 98.7% at 1.598 THz and 1.926 THz, respectively. The two absorption peaks are mainly attributed to the excitation of fundamental dipolar resonance modes caused by the ring-shaped and disk-shaped structures, separately. The absorption properties of the proposed PA can be adjusted by varying the structure parameters. Furthermore, the proposed dual-band PA can function as a temperature sensor with sensitivities of about 8.54 GHz/K and 16.25 GHz/K, respectively. Due to its excellent performance, the proposed dual-band PA could find many potential applications of thermal emitting, sensing, and detecting in the THz regime. (C) 2021 Optical Society of America