Temperature Tunable Narrow-Band Terahertz Metasurface Absorber Based on InSb Micro-Cylinder Arrays for Enhanced Sensing Application

Fu Chen,Yongzhi Cheng,Hui Luo

doi:10.1109/access.2020.2991331

Abstract

A narrow-band metasurface absorber (MSA) based on InSb micro-cylinder arrays has been proposed and investigated numerically, which could be believed to be applicable for both temperature and refractive index (RI) sensing in terahertz (THz) region. Distinct from previous designs, the proposed narrow-band MSA is only consisted of a sub-wavelength periodic micro-cylinder array based on the InSb material possessing an extremely thermosensitive relative permittivity which varies with the external environment temperature, and a gold ground-plane deposited on a glass substrate. Numerical simulation results indicate that the proposed MSA can achieve an absorbance of 99.9% at 1.8985 THz and the corresponding Q-factor is about 120.9 at room temperature (300 K). It is inferred that the narrow-band perfect absorption of the MSA could be contributed to the surface plasmon polariton (SPP) resonance mode excitation. Furthermore, the absorption property of the designed MSA is found to be highly sensitive to the RI value variations of the surrounding mediums and fluctuations of external environment temperature. Thus, the proposed MSA can be not only operated as a temperature sensor with a sensitivity of 2.13 GHz/K, but also a RI sensor with a sensitivity of 960 GHz/RIU (refractive index unit). Due to its high sensing performance, it can be believed that the narrow-band MSA has great potential applications in chemical, biological or other optoelectronic related areas.

Highlights

Electromagnetic (EM) metamaterial absorber (MMA) is always composed of a periodic array of sub-wavelength resonator structures, which can absorb the light radiation impinged upon it at a particular frequency range [1], [2]
We have proposed a temperature tunable narrow-band metasurface absorber (MSA) based on the thermosensitive semiconductor material InSb with an environment temperature dependent relative permittivity, which could be functioned as the temperature and refractive index (RI) sensor simultaneously in THz region
In order to investigate the physical mechanisms of the observed perfect absorption phenomenon, the relative wave impedance of proposed MSA has been calculated by extracting the simulated reflection coefficient S11 based on the S-parameter retrieved method [44], [45]

Summary

Introduction

Electromagnetic (EM) metamaterial absorber (MMA) is always composed of a periodic array of sub-wavelength resonator structures, which can absorb the light radiation impinged upon it at a particular frequency range [1], [2]. We have proposed a temperature tunable narrow-band MSA based on the thermosensitive semiconductor material InSb with an environment temperature dependent relative permittivity, which could be functioned as the temperature and refractive index (RI) sensor simultaneously in THz region.

Results

Conclusion