Research On Electromagnetic Coupling And Acousto-optic Interaction In Artificial Dielectric Structures

The rapid development of information technology proposes a higher requirement to the traditional electronic circuits in the miniature and integration,which has been released by the development of state-of-the-art fabrication technology of micro-and nano-scale structures.Therefore,the research of micro-and nano-scale structures and devices plays an important role in the field of modern information technology.For the optical information technology,localizing optical energy at subwavelength scale with plasmonic shows certain superior performance,but the loss of metallic materials is significant.In contrast,based on artificial dielectric materials,the magnetoelectric coupling properties and acousto-optic coupling may provide novel processing techniques for optical information technology.In this thesis,the magnetoelectric coupling of dielectric micro-structures and the resulting manipulation of electromagnetic scattering,as well as the interaction between electromagnetic wave and mechanical wave in novel waveguides have been studied,benefiting the investigation of novel optical information technology.The main content of this thesis includes:(1)The magnetoelectric coupling and novel scattering properties of the dielectric micro-dimer structure are theoretically analyzed and experimentally verified.Firstly,in the simulation analysis of the dimer of spherical structure,it is found that under the irradiation of a plane wave,this kind of structures exhibits a tunable electromagnetic coupling phenomenon,which can realize the enhancement and suppression of scattering in visible spectrum.It is further found that there is obvious enhancement of one-way forward scattering among a larger frequency range.Finally,in order to verify the correctness of the theoretical analysis,experiments at the microwave frequency band have been conducted with the gauge invariance of Maxwell’s equations,and the results show good agreements to the theoretical ones.(2)A one-dimensional chain-like silicon waveguide with a strong acousto-optic coupling has been designed and studied.It is found that the artificial dielectric micro-structure can not only realize the effective confinement of electromagnetic field,but also realize a strong acousto-optic coupling effect between the optical field and the mechanical field.According to the results of finite element method analysis,optical energy can be confined in the designed chain-like silicon rod waveguide with the quasi-bound state in the continuum(BIC)mode,which spatially overlaps with the mechanical resonance mode of the silicon rods and results in an acousto-optic coupling rate of up to 1.8MHz.Finally,it is shown that the strong acousto-optic coupling in this kind of chain-like waveguide is robust against the size parameters of the silicon rod.The research of electromagnetic scattering characteristics of artificial dielectric dimer microstructures and the acousto-optic coupling characteristics in the chain-like waveguides in this thesis may be helpful for the study of the electromagnetic properties based on the artificial micro-/ nanostructures and the acousto-optic coupling in the micro-/ nano-devices.