High-Sensitivity Terahertz Refractive Index Sensor in a Multilayered Structure with Graphene.

Jiao Tang,Jie Jiang,Zhiwei Zheng,Yuanjiang Xiang,Jiao Xu,Xiangliang Jin,Yunyang Ye,Leyong Jiang

doi:10.3390/nano10030500

Jiao Tang, Jie Jiang + Show 6 more

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https://doi.org/10.3390/nano10030500

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Abstract

In this paper, we propose a high-sensitivity optical sensor at terahertz frequencies based on a composite structure containing a one-dimensional photonic crystal (1D PC) coated with a layer of monolayer graphene. Between the 1D PC and the graphene there is a sensing medium. This high-sensitivity phenomenon originates from the excitation of optical resonance between the graphene and the 1D PC. The proposed sensor is highly sensitive to the Fermi energy of graphene, the thickness and refractive index of the sensing medium, and the number of graphene layers. By selecting appropriate parameters, the maximum sensitivity () is obtained. We believe the proposed configuration is promising for fabricating graphene-based biosensor- or gas-sensor devices and other related applications in the terahertz band.

Highlights

An optical sensor, a classical sensor type based on optical principles, can sensitively monitor measured information and convert the information into optical signals or other forms of data according to certain rules [1]
The Fabry–Perot mode can be excited at a certain structural parameter and there is a dip appearing in the reflectance spectrum owing to the excitation of the Fabry–Perot mode
When the sensing medium is coated with graphene, an obvious reflection dip appears at a wavelength of about 300 μm within the band gap

Summary

Introduction

A classical sensor type based on optical principles, can sensitively monitor measured information and convert the information into optical signals or other forms of data according to certain rules [1]. Graphene has started to play an active role in the realization of high-sensitivity optical sensors due to its excellent optoelectronic properties such as SPR support [16], tunability of optical conductivity [17], broadband [18], etc. In this respect, graphene-based SPR sensors [19,20], hybrid graphene/gold plasmonic fiber-optic sensors [21], mid-infrared plasmonic biosensing with graphene [22], and multi-channel graphene sensors [23], and graphene-based Bloch-like surface wave sensors [24] have been proposed. Optical sensors with new materials or novel structures and working mechanisms have become the main direction of research in the optical sensor industry

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