Research On Artificial Kerr-type Medium Based On Metamaterials

With the development of technology, Kerr effect has been applied to many fields such as high-speed photography, light velocity measurement and so on. However, natural Kerr medium has the disadvantage of high driving voltage, high purity, and unstable chemical property, which bring serious influence to the scope of its application. In recent years, metamaterials have been confirmed to provide stronger anisotropy response than natural Kerr medium because of their special electromagnetic properties. Therefore, the Kerr effect based on metamaterials has attracted people’s attention and interest.This paper carries out the research on artificial Kerr medium which is based on metamaterials, with the purpose to explore the mechanism of Kerr effect. Firstly, this paper briefly introduces the research progress of Kerr medium based on metamaterials, propose the significance of the research, and discusses the principle of Kerr effect and metamaterials with negative permittivity and negative permeability. On this basis, two kinds of artificial Kerr medium structures based on metamaterials whose names are Cross type and T type are designed, and the optimal structures are obtained by the method of optimizing the structure parameters. The simulation results show that the phase different will increase from22°to88°gradually, when the cross structure is loaded the capacitance of9×104-16f,1.2×10-15f,1.5×104-15f and2×10-15f; the phase difference will increase from41°to79°gradually, when the T-type structure is loaded the capacitance of0.1pf,0.2pf and0.3pf. Secondly, a metamaterial-based Kerr medium is designed using MEMS process at THz frequency region. Bending unilateral cell structure with electrostatic actuation, the tuning is achieved. The simulation results show that the phase different will increase from22°to88°gradually when the bending angle is4°,6°,9°and12°. Finally, the T type artificial Kerr medium at microwave frequency is processed and tested. The test result show that the phase different will increase from22°to88°gradually, when the loaded capacitance is0.1pf,0.2pf and0.3pf. Test results are consistent with the simulation results, which proves that the metamaterial-based Kerr medium has the feasibility of achieving Kerr effect.The results of this thesis show that:the artificial Kerr medium structures based on metamaterials are similar with Kerr box, which not only can provide stronger anisotropy response than natural Kerr medium, but also make motivating easier. More importantly, the metamaterial-based Kerr medium can approximately realizes tuning with linearity.