Investigation On The Photonic Spin Hall Effect In Anisotropic Media

At present, the spin Hall effect of classical wave packet and quantum particle has drawn extensive attention, especially in high energy physics field. When the photons reflect or refract in different medium boundary surface, the photonic spin Hall effect is the photonic version of the spin Hall effect in electronic systems, in which the spin photons play the role of spin charge, and a refractive index gradient plays the role of the electric potential gradient. The beam and wave packet will split along the direction perpendicular to the refractive index gradient this moment. Based on the wave theory as the foundation, we make a certain exploration on photonic spin Hall effect in anisotropic medium; reveal the qualitative relationship between the transverse displacements of reflected beam and the electromagnetic parameters of anisotropic medium of of between. The main results are as follow:Firstly, we have reviewed the formation and development history of the electronic spin Hall effect and summarized the development and research situation in the various types of electronic spin Hall effect. On this basis, we also introduce the photonic spin Hall effect and give a summary of the progress on the photonic spin Hall effect at home and abroad, including the theory explanation and experimental measurement about the photonic spin Hall effect. On the one hand, the researchers at home and abroad explain and prove the existence of photonic spin Hall effect from a different view; on the other hand, it is well known that the photonic spin Hall effect is a very weak effect, which is difficult to accurately measure with the conventional measurement means. So a lot of research work is contributed to enhance the photonic spin Hall effect, in order to better control the the spin Hall effect. Based on the research purpose, we also summarized the characteristics and classification of anisotropic medium in the last part of the first chapter.Secondly, we have established the reflected light field paraxial beam transmission model and researched specially the transverse displacements induced by the photonic spin Hall effect on reflection at the interface of air-uniaxial crystal. In the study of the photonic spin Hall effect of uniaxial crystal, we have deduced the reflection coefficient of TE and TM wave, and deduced the transverse displacements expression of the photonic spin Hall effect. The transverse displacements near the Brewster angle have been obtained with the theoretical and experimental methods. The theoretical and experimental results show that the huge transverse displacements near the Brewster angle on reflection, which are almost40times than those before reported on refraction in the air-glass interface. At the same time, we also have obtained the amplified factor of transverse displacements by means of theory calculation and experimental measurement in the weak measurement process. The change rule of amplified factor is:the amplified factor firstly decreases with the angle of incidence, reduce to minimum near the Brewster angle, then increases with the angle of incidence. In addition, through the research, we have found that the Brewster angle can be varied by rotating the optical axis of uniaxial crystal. Therefore, there exists a positive and a negative transverse displacement in the same incident angle for the two different optical axis direction. We can switch the directions of spin accumulation by rotating the optical axis of uniaxial crystal.Thirdly, we have studied the spin Hall effect of reflected beam at the interface air-anisotropic metamaterial. Through the research, we find that the transverse displacements of reflected beam are closely linked with the electromagnetic parameters, optical angle and incident angle. By designing the electromagnetic parameters of anisotropic medium, we can obtain different dispersion relations. For p wave and s wave, it can form different dispersion relation combination. As following, we have investigated the three different dispersion relation combinations: ellipsoid-ellipsoid dispersion relation, ellipsoid-hyperboloid dispersion relation and hyperboloid-hyperboloid dispersion relation. We have respectively analyzed the transverse displacements of H polarization component and V polarization component in the three dispersion relation combinations, p wave and s wave reflection coefficient, and initial phase with the angle of incidence. At the same time, we have also simulated the amplified transverse displacements of H polarization component in three kinds of dispersion relations and the field distribution at the three different angles of incidence. The results of the study show that:under the circumstances of the ellipsoid-ellipsoid dispersion relation and ellipsoid-hyperboloid dispersion relation, the transverse displacements of Hpolarization component are far greater than those of V polarization component. The transverse displacements of H polarization component can be modulated in the range of negative to positive, which are the maximum near the Brewster angle. It is found that the Fresnel reflection coefficients are constants and total reflections don’t exist now. In the hyperboloid-hyperboloid dispersion relation combination, we have got the calculation results completely different that the previous two kinds of dispersion relation combination:the transverse displacements of H polarization component and V polarization component change completely consistent with incident angle. It is found that the Fresnel reflection coefficients are not constants and the Brewster angles don’t exist now.Finally, we have studied the transverse displacements of reflected beams induced by photonic spin Hall effect at the interface of air-anisotropic ultrahigh refractive index metamaterial. Through the study, we have found that the photonic spin Hall effect in the anisotropic ultrahigh refractive index metamaterial shows the unique characteristics. We have theoretically simulated the transverse displacements of H polarization component and V polarization component in anisotropic metamaterial with two kinds of ultrahigh refraction index (no=20, ne=1.515and ne=20, no=1.515). The results show that we can modulate the transverse displacements of H polarization component and V polarization component by adjusting the optical angle or the incident angle. Under the same conditions, the transverse displacements of H polarization component are greater than those of V polarization component and the range of transverse displacements of H polarization component are wider. Also, we have also researched that the transverse displacements of H polarization component and V polarization component change with anisotropic parameter. When the anisotropic parameter δ<1, the transverse displacements of H polarization component on reflection are very large and continuous change. In the near future, the metamaterials technology progress will provide a possible way to further control photonic spin Hall effect.The research on photonic spin Hall effect has drawn extensive attention and also made a lot of impressive achievement. With the maturity of electromagnetic material technology, the study of the photonic spin Hall effect integrated into the metamaterial field may be born as a new photonic device and also may produce a new subject-spin photonics in the future. At the same time, the existing research results in electronic spin Hall effect make researchers to further explore the research of photonic spin Hall effect, in order to achieve more convenient, effectively control photons as the same as to control electron and lay a wide basis for the practical application in future.