Research On Interaction And Application Of Terahertz Metamaterial

The terahertz(THz)wave,which lies between light waves and microwaves in the electromagnetic spectrum,has unique properties that make it useful for many technologies,such as imaging,nondestructive testing and high-speed wireless communication technologies.In order to realize these technologies,the relevant terahertz electronic components are needed to realize the emission,detection,modulation and absorption of THz waves.However,because of the weak interaction between terahertz waves and naturally matter,special materials and structures are usually required to overcome the unfavorable conditions.Metamaterials are one of the effective ways to achieve the strong interaction between terahertz wave and matter.Metamaterial-THz wave interactions are particularly sensitive to the coupling between metamaterial structures in the array.However,in previous studies of terahertz metamaterials,different interactions between THz waves and metamaterials were usually achieved by modulation of the metamaterial own structure and its dielectric environment.To solve this problem,we design a THz metamaterial array with dual-frequency effect using only one type of basic unit structure of metamaterial(C-type wide open resonant ring).And it is studied as follows:(1)It's show that the coupling between terahertz metamaterial arrays can be greatly affected by introducing only‘vacancy defects'from the terahertz metamaterial arrays without changing the structural parameters of the unit.(2)A detailed analysis of the field distribution of the electromagnetically induced transparency effect of defected metamaterials is also presented by using CST electromagnetic simulation.The electromagnetic properties of such“defects”in THz metamaterial arrays will be very useful for THz electronic components.(3)At the same time,in order to obtain strong interaction metamaterials,the effects of some parameters of perfected and defected metamaterials on resonance were studied in detail by CST electromagnetic simulation.For perfected metamaterials,the different orientation of the C-type wide open resonant rings results in the red or blue shift of the absorption peaks.For defected metamaterials,the increase of the distance‘b'between the C-rings in the Y direction will result in a significant blue shift of the low-frequency resonance,and the intensity of the absorption peak will weaken,while the high-frequency resonance has no significant change.The increase of the size of the two arms of the C-type ring leads to the simultaneous red shift of the two peaks.As the width of C-type resonant ring's arms increases,the two peaks will be redshifted and the intensity of absorption peaks will be enhanced.The increase of width?₀at the bottom of the resonant ring will make the double peaks blue shift and the intensity of absorption peaks increase.The field distribution combined with dipole theory and circuit model is used to analyze the red-blue shift phenomenon.(4)Finally,by comparing the different interactions between the defected metamaterial and the perfected metamaterial,this paper proposes to combine the"vacancy defect"metamaterial with vanadium dioxide to prepare a terahertz modulator,which realizes the active modulation of terahertz wave by temperature control.Furthermore,a terahertz modulator is prepared by combining the defect metamaterials with silicon semiconductor materials,which realizes the active and high-speed modulation of terahertz wave by means of optical control.The results of this study have potential applications in terahertz communication.