Design of Ultra-Narrow Band Graphene Refractive Index Sensor

Qianyi Shangguan; Zihao Chen; Hua Yang; Shubo Cheng; Wenxing Yang; Zao Yi; Xianwen Wu; Shifa Wang; Yougen Yi; Pinghui Wu

doi:10.3390/s22176483

Design of Ultra-Narrow Band Graphene Refractive Index Sensor

Sensors (Basel). 2022 Aug 28;22(17):6483. doi: 10.3390/s22176483.

Authors

Qianyi Shangguan¹, Zihao Chen², Hua Yang³, Shubo Cheng¹, Wenxing Yang¹, Zao Yi⁴, Xianwen Wu⁵, Shifa Wang⁶, Yougen Yi⁷, Pinghui Wu⁸

Affiliations

¹ School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou 434023, China.
² State Key Laboratory of Electronic Thin Film and Integrated Devices, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China.
³ State Key Laboratory of Advanced Processing and Recycling of Non-Ferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China.
⁴ Joint Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology, Mianyang 621010, China.
⁵ School of Chemistry and Chemical Engineering, Jishou University, Jishou 416000, China.
⁶ School of Electronic and Information Engineering, Chongqing Three Gorges University, Chongqing 404000, China.
⁷ College of Physics and Electronics, Central South University, Changsha 410083, China.
⁸ Fujian Provincial Key Laboratory for Advanced Micro-Nano Photonics Technology and Devices, Quanzhou Normal University, Quanzhou 362000, China.

Abstract

The paper proposes an ultra-narrow band graphene refractive index sensor, consisting of a patterned graphene layer on the top, a dielectric layer of SiO₂ in the middle, and a bottom Au layer. The absorption sensor achieves the absorption efficiency of 99.41% and 99.22% at 5.664 THz and 8.062 THz, with the absorption bandwidths 0.0171 THz and 0.0152 THz, respectively. Compared with noble metal absorbers, our graphene absorber can achieve tunability by adjusting the Fermi level and relaxation time of the graphene layer with the geometry of the absorber unchanged, which greatly saves the manufacturing cost. The results show that the sensor has the properties of polarization-independence and large-angle insensitivity due to the symmetric structure. In addition, the practical application of testing the content of hemoglobin biomolecules was conducted, the frequency of first resonance mode shows a shift of 0.017 THz, and the second resonance mode has a shift of 0.016 THz, demonstrating the good frequency sensitivity of our sensor. The S (sensitivities) of the sensor were calculated at 875 GHz/RIU and 775 GHz/RIU, and quality factors FOM (Figure of Merit) are 26.51 and 18.90, respectively; and the minimum limit of detection is 0.04. By comparing with previous similar sensors, our sensor has better sensing performance, which can be applied to photon detection in the terahertz band, biochemical sensing, and other fields.

Keywords: graphene; refractive index sensor; terahertz waves; ultra-narrow band.

MeSH terms

Graphite*
Metals
Refraction, Ocular
Refractometry*
Silicon Dioxide

Substances

Metals
Silicon Dioxide
Graphite

Grants and funding

The authors are grateful to the support by National Natural Science Foundation of China (No. 51606158, 11604311, 61705204, 21506257); the Funded by the Scientific Research Fund of Si Chuan Provincial Science and Technology Department (2020YJ0137; 2020YFG0467; 2021JDRC0019); 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 (No. MECOF2020B02); the Funded by the Undergraduate Innovation Fund Project Precision Funding by Southwest University of Science and Technology (No. JZ20-025); the College Students’ innovation and entrepreneurship training program (S202110619073; S202110619069; S202110619100); the Postgraduate Innovation Fund Project by Southwest University of Science and Technology (No. 18ycx034); the Funded by Southwest University of Science and Technology Students Innovation Fund project (No. CX20-031).