Research On Super-sensitive Chemical Potential Sensors Based On Graphene Hyperbolic Metamaterials

Metamaterials are artificial media composed of periodic subwavelength structures.Their unique and peculiar electromagnetic properties are widely used to control the propagation of light.In 2003 and 2006,metamaterials?or called left-handed materials?are selected as the annual"top ten subjects progress"by Science in the United States.In recent years,the research focus of metamaterials has gradually shifted to active and adjustable metamaterials.The hyperbolic metamaterials?HMMs?are one kind of very unusual and highly anisotropic novel metamaterials,which attract extensive attention of scholars at home and abroad.In addition,as a special two-dimensional material,graphene not only has excellent photoelectric properties,but also has sensitive adjustability,which has an important application potential in the construction of hyperbolic metamaterials.In this paper,the research method of theoretical analysis and numerical simulation is used.Combined with the anisotropic properties of hyperbolic materials and the tunable properties of graphene,the graphene dielectric periodic stacking hyperbolic metamaterials are constructed,and a highly sensitive chemical potential sensor is designed.The main research work is as follows:1.The tunable dispersion characteristics of graphene dielectric periodic metamaterials are studied.Starting from the conductivity formula of graphene,the dispersion relation of graphene metamaterials is studied by using the equivalent medium approximation method.It is found that the dispersion relation of graphene metamaterials has the form of quadratic curve,in which the vertical component?_?of the equivalent permittivity of graphene metamaterials is always positive,but the parallel component?_//can switch between positive and negative with the change of graphene chemical potential.For example,when?_c<0.425e V,?_//>0,the dispersion relation is elliptical;when?_c>0.425e V,?_//<0,the dispersion relation is hyperbolic.On this basis,the transmission characteristics of electromagnetic wave are further studied by using equal frequency line analysis and finite-difference time-domain method.2.A high sensitive chemical potential sensor is designed based on the approximate linear characteristic of the transmission curve.The transmission properties of graphene medium super material with triangle shape are studied.The terahertz electromagnetic wave in the air is incident from the inclined side,and it is emitted from the right angle side through the super material structure.The dependence of its transmission with the change of chemical potential is calculated by numerical simulation.The graphene medium super sensitive chemical potential sensor is designed.These results have great application value in optical integrated circuits.