Design And Research Of Sensors Based On Surface Plasmon Resonance Of Graphene

The miniaturization and high integration of optical devices have become one of the hot trends.How to design,manufacture and utilize optical nanodevices has also become an important research content.Constrained by the diffraction limit,opto-electronic devices have certain difficulties in achieving light regulation at sub-wavelength sizes.The introduction of surface plasmons offers the possibility to solve this problem.Compared with traditional metal materials,the surface plasmons supported by graphene have stronger electric field locality and adjustability.In view of the above reasons,this thesis designed and studied a nanostructure to achieve the regulation of graphene surface plasmons in the nanometer scale.Based on the unique lattice structure and excellent optoelectronic properties of graphene,how to excite graphene surface plasmons is analyzed.The graphene surface plasmon is compared to the conventional metal excited.On this basis,the principle of graphene photoelectric tunability is introduced,and the variation of Fermi level,conductivity,dielectric constant and refractive index of graphene are calculated.The possibility of using metal nanostructures to control the optical properties of graphene is analyzed.A graphene-gold grating composite structure is designed to excite surface plasmons on single layer of graphene,and the finite element method calculation software COMSOL Multiphysics is used to model and calculate.The optical properties of composite structures with and without graphene covering the gold grating are compared,indicating that the combination of graphene and gold grating enhances the mutual coupling of incident light and structure,and stimulates high-quality surface plasmon resonance.Based on the graphene-gold grating structure,the reflection spectrum,electric field distribution and quality factor of the device are analyzed by optimizing the Fermi level,the carrier mobility of graphene and the period,ridge height and width of the gold grating.It is proved that the structure can effectively improve the light absorption efficiency of graphene and have stronger sensing characteristics in a wide spectral range.Through the above research,the feasibility and adjustability of the sensor based on surface plasmon resonance of graphene are proved,which embodies the superior performance of graphene in the field of photoelectric sensing and has an important significance in the field of optics.