title: Tunable angle-independent refractive index sensor based on Fano resonance in integrated metal and graphene nanoribbons.
abstract: We propose a novel mechanism to construct a tunable and ultracompact refractive index sensor by using the Fano resonance in metal-graphene hybrid nanostructure. Plasmon modes in graphene nanoribbons and waveguide resonance modes in the slits of metal strip array coexist in this system. Strong interference between the two different modes occurs when they are spectrally overlapped, resulting in a Fano-type asymmetrically spectral lineshape which can be used for detecting the variations of ambient refractive index. The proposed sensor has a relatively high figure of merit (FOM) over 20 and its sensing performance shows a good tolerance to roughness. In addition to the wide range measurement enabled by the electrical tuning of graphene plasmon modes, such ultracompact system also provides an angle-independent operation and therefore, it can efficiently work for the detection of gas, liquid, or solids. Such optical nanostructure may also be applied to diverse fields such as temperature/pressure metering, medical detection, and mechanical precision measurement.
authors.affiliation: Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006, China.
authors.forename: Meiyan
authors.initials: M
authors.lastname: Pan
authors.affiliation: Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006, China.
authors.forename: Zhaoxing
authors.initials: Z
authors.lastname: Liang
authors.affiliation: Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong SAR, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006, China.
authors.forename: Yihang
authors.initials: Y
authors.lastname: Chen