Dynamic Modulation Based Upon Interactions Between Terahertz Metamaterial Arrays

The superior properties of terahertz wave has attracted a large number of researchers' attention since the invention of high performance terahertz source and detector.Terahertz wave has many advantages such as low photon energy,wide frequency band and strong penetration,which makes it have great application prospects in the fields of medical treatment,imaging,wireless communication and so on.However,due to the weak interaction between terahertz wave and substances in nature,the development of terahertz wave technology was greatly limited.To solve this problem,terahertz metamaterials have come into people's vision.There is a strong interaction between terahertz metamaterials and terahertz wave,and terahertz waves can be modulated by changing the structural design and size of metamaterials.In addition,the interaction between metamaterials and terahertz waves can be greatly affected by changing the coupling between metamaterial arrays,so as to realize the modulation of terahertz waves.In this work,a metamaterial array composed of open resonant ring is designed.A "impurity" resonant unit was introduced into the metamaterial array,which breaks the symmetry of the metamaterial structure and greatly affects the coupling between terahertz metamaterial arrays to realize modulation of terahertz wave.Using CST software,the field distribution of impurity metamaterial array and symmetrical metamaterial array were analyzed in detail to understand the coupling modse in the array and the formation mechanism of high transparent window.Finally,by comparing the different coupling modes between impurity metamaterials and symmetrical metamaterials,vanadium dioxide with reversible metal-insulation phase transition was introduced into the opening of C-type resonant ring in the lower right side of symmetrical metamaterial array.The dynamic regulation of the coupling mode in terahertz metamaterial array was realized by heating up to achieve modulation depth of up to 86%.Silicon semiconductor material is alternatively introduced into the opening of the C-type resonant ring to achieve fast modulation of terahertz wave by using the generation-recombination process of photogenerated carriers.The modulation depth of both devices is more than 80%.This work provides a new idea for the design of terahertz modulator.