Research On Multifunctional Amplitude Control Based On Metamaterial

Metamaterials are artificial materials with subwavelength periodic structures.They can realize physical phenomena that cannot be achieved by natural materials,such as negative refraction,optical super-resolution,and electromagnetic stealth.Metamaterials can be used to significantly enhance the interaction of light and matter and are expected to be key components in optoelectronic devices and systems.This paper mainly studied the amplitude regulation of the optical field.Based on graphene plasmons,metamaterial perfect absorbers and graphene metasurface with functions of optical switching,PIT effect and biosensing were designed.It was simulated and analyzed by finite element analysis,and the theoretical fit was carried out by using a Lorentzian coupled oscillation model.In addition,a silicon-based topological photonic insulator metamaterial was designed,simulated and analyzed by using finite difference time domain(FDTD).The main research contents of the paper were as follows:(1)The background and significance of the topic selection of the article were introduced,and the concept characteristics,types,development history and application of metamaterials were briefly outlined.Combined with the terahertz band involved in this work,the absorption characteristics of metamaterials,plasmon induced transparency and sensor.Therefore,in the application of metamaterials,terahertz metamaterials,metamaterial perfect absorbers,surface plasmon sensors,and plasmon-induced transparency metamaterials were briefly introduced.(2)Traditional optical metamaterials were made of noble metals,but these metals have disadvantages such as high ohmic loss,high cost,and difficulty in adjusting their optical properties after device molding.To overcome these inherent drawbacks,researchers have conducted research into noble metal alternatives,such as conducting oxides,nitrides,superconductors,graphene,and other 2D materials.In this paper,the design of metamaterial was mainly based on the excellent optoelectronic properties of twodimensional material graphene.Therefore,this chapter introduces the basic properties of graphene,graphene metamaterials based on graphene plasmons,and introduces simulation methods and several theoretical models for studying the amplitude regulation of metamaterials.In addition,the work of this paper involves topological photonic insulators,so the relevant knowledge required for their simulation was introduced in this chapter.(3)A tunable four-band graphene metamaterial perfect absorber was proposed based on graphene plasmons.The designed structure was simulated by the finite element analysis method,and the results show that the absorber had four absorption peaks with absorptivity higher than 97% in the terahertz and infrared ranges.Dynamically tunable absorption peaks could be achieved by changing the geometric parameters of the periodic array structure or the Fermi level of graphene.Based on the surface plasmon,a coherent perfect absorber was designed.The absorber not only had an absorption peak with an absorption rate higher than95% in the mid infrared band,but also could adjust the absorption rate from 0 to 95% by changing the phase difference between two coherent beams.(4)A graphene metasurface with three functions of optical switching based on graphene surface plasmons,PIT effect and biosensing was designed.By analyzing the transmission spectrum and the electric field distribution at the resonance wavelength,the physical mechanism of the resonance was expounded.The influence of its structural parameters and the Fermi level of graphene on the resonance position were analyzed.The effects,theoretical basis and conditions of graphene metasurfaces for realizing optical switches,biosensors and slow-light functions were discussed in detail.Based on twodimensional material valleytronics and valley Hall effect,a topological photonic metamaterial on silicon substrate was designed.The designed metamaterial could suppress backscattering in transmission,enabling electromagnetic waves with wavelengths of1360nm-1500 nm to achieve topological transmission within the structure.