Investigations On The Effect Of Topological Insulator Multilayers On Electromagnetic Wave Polarization Properties And Spontaneous Emission Of Nearby Atoms

Topological insulators are new insulators with quantum effects,due to their non-trivial topological properties,they have caused research and discussion in various sectors of society.The inside of the topological insulator has the same energy gap as the ordinary insulator and exhibits an insulating state,however,the surface is a conductive state without energy gap and has time-reversed symmetry,this surface state reflects the non-trivial topological properties of the topological insulator.After breaking the time inversion of the surface state of the topological insulator,the topological magnetoelectric coupling effect is obtained,that is,the electric field induces magnetization and the magnetic field induces polarization,which changes the electromagnetic properties of the topological insulator.Topological magnetoelectric coupling effect of topological insulators can be used in many research works,such as changes in polarization of beams,atomic spontaneous emission,Casmir effect,etc.The polarization of the light vector is the property of the transverse electromagnetic wave,and the different polarization characteristics of the electric field vector determine the polarization state of the beam.The polarization state of the beam can be changed by the reflection of the material,such as the magneto-optical Kerr effect,and can be controlled by using some special materials to obtain the desired polarization.The spontaneous emission of atoms is the important research content in the field of quantum optics,the spontaneous emission is the transition process of atoms from the excited state to the ground state,this process releases a photon,but because its phase and direction are uncertain,how to control spontaneous emission has become a research hotspot.The experimental results of Purcell in 1946 show that the spontaneous emission of atoms is not only related to the characteristics of the atoms themselves,but also depends on the electromagnetic field environment around the atoms,the regulation of spontaneous emission can be realized by adjusting the environment around the atoms,therefore,some special materials are used to fill the atom's environment and thus control the spontaneous emission of the atom.At the same time,the spontaneous emission of atoms can also be controlled by the mutual drying effect between different attenuation channels of atoms.Based on the structure of topological insulator multilayers,this paper studies and analyzes the Kerr polarization conversion effect of topological insulator multilayers and their effects on spontaneous emission and quantum interference of nearby atoms,the specific work is as follows:(1)Firstly,the topological insulators are reviewed.The topological magnetoelectric coupling effects of topological insulators are discussed in detail,and the non-trivial electromagnetic properties are studied.Then use the transfer matrix method to find the reflection coefficient under the structure of topological insulator multilayers.(2)The Kerr polarization conversion effect of topological insulator multilayers is investigated.First indicating the different polarization states of electromagnetic wave,as well as the transition between polarization states.Then,according to the reflection coefficient matrix of the topological insulator multilayers,the polarization states of reflected light at the time of incident of linearly polarized light and elliptically polarized light are studied,and the results are discussed in detail.Complete polarization conversion can be obtained under certain dielectric constant conditions.(3)The spontaneous emission and quantum interference of atoms near the topological insulator multilayers and in a cavity composed of topological insulator multilayers are studied.Firstly,the theory of spontaneous emission of a three-level atom is discussed,by quantizing the electromagnetic field and using the interaction between the atom and the field,the expression of spontaneous emission is derived from the dyadic Green's function.Then,the spontaneous emission and quantum interference are discussed in terms of magnetic direction of the topological insulator surface,dipole direction,material dissipation,atomic position,cavity length,etc.Compared with ordinary materials,topological insulators can effectively suppress the spontaneous emission of atoms and improve quantum interference,while guaranteeing the atomic life.