磁光克尔效应中的光子自旋分裂

光子自旋霍尔效应类似于电子系统中的电子自旋霍尔效应, 是在折射率梯度和光子分别扮演的外场和自旋电子的角色下, 由自旋-轨道相互作用而产生的光子自旋分裂现象. 光子自旋霍尔效应为操控光子提供了新的途径, 同时也提供了一种精确测量相关物理效应的方法. 本文研究了磁光克尔效应中光子自旋分裂现象, 建立了磁光克尔旋转与光子自旋霍尔效应之间的定量关系, 并通过弱测量系统观测了磁场作用下铁膜表面的光子自旋分裂位移, 得到相应的磁光旋转角, 验证了我们所推导的理论预测. 本文的研究成果为精确测量磁光克尔系数和磁光克尔旋转角提供了一种新方法.

Photon spin splitting in magneto-optic Kerr effect

Photonic spin Hall effect (PSHE) of light, similar to the spin Hall effect of an electronic system, is the interaction between photon spin-orbit of spin splitting phenomenon in refractive index gradient field. PSHE provides a new way to manipulate photons and accurately measure relevant physical effects. This paper studies the photon spin splitting in the magneto-optic Kerr effect, and establishes the quantitative relationship between the magneto-optical Kerr rotation and the PSHE. We have observed the magneto-optic Kerr effect of the action of an iron film in the magnetic field. After finishing experiments, we firstly analyze the amplified shift of the spin changing with the magnetic intensity in the case of horizontal polarization and vertical polarization incidence. Then, the Kerr rotations changing with the incident angle for different magnetizations are measured separately. Finally, comparing the above two results, we obtain that the accurate magneto-optic Kerr rotation angle is 6.7×10^-5o/μm. If the position sensor based on phase-locked amplifier (20 nm) is used to measure the magneto-optic Kerr rotation angle, its precision can be improved by one or two orders of magnitude. These results prove that the PSHE not only can be used to accurately measure the magneto-optic Kerr effect, but also have great significance in magnetic film research. Especially, in terms of magnetic-optic devices, PSHE can be used to achieve the superior performance of endurance cycling and data retention.