Polarization Control Characteristics In All-Dielectric Metamaterials

As a kind of material with characteristics not possessed by the existing materials in nature,metamaterials attracts the attention of the researchers.It can regulate the electromagnetic waves and realize the phenomenon of negative refraction and cloaking.Compared with metal metamaterials,all-dielectric metamaterials can effectively overcome the dispersion and loss from metal materials.The nano-resonators made of high-refractive-index dielectric materials can realize negative dielectric constant and negative permeability,can be used for Huygens super-surface,make magnetic reflector and no reflection plate,or design with electromagnetic induction Transparent or Fano resonant characteristics of the metamaterial,can also be achieved through the use of gradient phase design of the direction of electromagnetic waves,phase control.The dielectric metamaterials can also be designed according to the present metal metamaterial structure to realize the artificial material with the same nature,and solve the problem of the loss of the metallic material in the optical device integration and the production difficulty.In this paper,we present a brief introduction of several different metamaterials,design several kinds of all-dielectric metamaterials and simulate the structure using CST Microwave Studio software.The details are as follows:Firstly,we introduce electromagnetic theory of metamaterials and the design theory of all-dielectric metamaterials,including the transmission characteristics of electromagnetic waves,all-dielectric nano Mie resonators,Huygens metasurface and gradient phase metamaterials with polarization conversion properties,and the simulation method of the metamaterial is also described.Secondly,we design an all-dielectric metamaterial with rectangular strip structure,which includes single-layer rectangular bar structure and double-layer rectangular bar structure.It can convert incident y-linearly polarized light into x-polarized light in near infrared frequency band,then by changing the deflection angle of the structure and the thickness of the nanobar structure,the influence factors of the polarization conversion ability of the metamaterials are obtained by observing the simulation results.At the same time,coupling effect appeared in the transmission amplitude of the double-layer all-dielectric metamaterial and the Fano resonance phenomenon was analyzed.Compared with the same structure using metal material,the structure of all-dielectric metamaterial is significantly better than metal materials in the polarization conversion capability.Thirdly,we design a double-layer all-dielectric metamaterial with gradient phase according to the split-ring structure theory.By adding the additional phase to the adjacent unit structure by changing the central angle of the upper half ring,it can transmit the incident linearly y-polarized light partially converted to x-polarized light,and the direction of transmission of light through the metamaterial will be deflected.Finally,we designed an all-dielectric metasurface using Si C according to the rectangular groove structure.The gradient phase can be realized by changing the direction of the rectangular groove.It can make the incident circularly polarized light reflect abnormally through the metasurface and realize the cross-polarization conversion in the reflected light.