Tunable High-Sensitivity Four-Frequency Refractive Index Sensor Based on Graphene Metamaterial

Xu Bao; Shujun Yu; Wenqiang Lu; Zhiqiang Hao; Zao Yi; Shubo Cheng; Bin Tang; Jianguo Zhang; Chaojun Tang; Yougen Yi

doi:10.3390/s24082658

Tunable High-Sensitivity Four-Frequency Refractive Index Sensor Based on Graphene Metamaterial

Sensors (Basel). 2024 Apr 22;24(8):2658. doi: 10.3390/s24082658.

Authors

Xu Bao¹, Shujun Yu², Wenqiang Lu¹, Zhiqiang Hao², Zao Yi^{1

3

4}, Shubo Cheng³, Bin Tang⁵, Jianguo Zhang⁶, Chaojun Tang⁷, Yougen Yi⁸

Affiliations

¹ Joint Laboratory for Extreme Conditions Matter Properties, Key Laboratory of Manufacturing Process Testing Technology of Ministry of Education, State Key Laboratory of Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang 621010, China.
² Key Laboratory of Metallurgical Equipment and Control Technology of the Ministry of Education, Wuhan University of Science and Technology, Wuhan 430074, China.
³ School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou 434023, China.
⁴ School of Chemistry and Chemical Engineering, Jishou University, Jishou 416000, China.
⁵ School of Microelectronics and Control Engineering, Changzhou University, Changzhou 213164, China.
⁶ Department of Physics, Jinzhong University, Jinzhong 030619, China.
⁷ College of Science, Zhejiang University of Technology, Hangzhou 310023, China.
⁸ College of Physics and Electronics, Central South University, Changsha 410083, China.

Abstract

As graphene-related technology advances, the benefits of graphene metamaterials become more apparent. In this study, a surface-isolated exciton-based absorber is built by running relevant simulations on graphene, which can achieve more than 98% perfect absorption at multiple frequencies in the MWIR (MediumWavelength Infra-Red (MWIR) band as compared to the typical absorber. The absorber consists of three layers: the bottom layer is gold, the middle layer is dielectric, and the top layer is patterned with graphene. Tunability was achieved by electrically altering graphene's Fermi energy, hence the position of the absorption peak. The influence of graphene's relaxation time on the sensor is discussed. Due to the symmetry of its structure, different angles of light source incidence have little effect on the absorption rate, leading to polarization insensitivity, especially for TE waves, and this absorber has polarization insensitivity at ultra-wide-angle degrees. The sensor is characterized by its tunability, polarisation insensitivity, and high sensitivity, with a sensitivity of up to 21.60 THz/refractive index unit (RIU). This paper demonstrates the feasibility of the multi-frequency sensor and provides a theoretical basis for the realization of the multi-frequency sensor. This makes it possible to apply it to high-sensitivity sensors.

Keywords: graphene; high sensitivity; multi-frequency sensor; polarization insensitivity; tunability.

Grants and funding

The authors are grateful to the support provided by the National Natural Science Foundation of China (No. 51606158, 11604311, 61705204, 21506257); the funded by the Sichuan Science and Technology Program (No. 2021JDRC0022); the funded by the Natural Science Foundation of Fujian Province (2021J05202); the funded by the Open Fund of the Key Laboratory for Metallurgical Equipment and Control Technology of Ministry of Education in Wuhan University of Science and Technology, China (No. MECOF2022B01); the funded by the Project supported by Guangxi Key Laboratory of Precision Navigation Technology and Application, Guilin University of Electronic Technology (No. DH202321).