聚焦光在单轴晶体中的感应磁化

Magnetization in the Uniaxial Crystal Induced by Highly Focusing Laser Beam

运用矢量衍射理论,分析了高度聚焦的圆偏振激光脉冲在具有逆法拉第效应的单轴晶体中产生的感应磁化分布.详细研究了界面位置不同对磁化分布的影响,比较了小双折射效应的单轴晶体中的磁化分布与均匀介质中的磁化分布.计算结果发现:随着界面向透镜移动,磁化强度的最大值和磁化斑的最小值位置沿着光轴方向移动.在单轴晶体中的磁化强度大于在均匀介质中的磁化强度.但是,在单轴晶体中的磁化斑的大小比在均匀介质中的小.描述单轴晶体各向异性的光磁常量与各向同性的光磁常量的比值愈大,磁化强度愈大,磁化斑愈小.

Based on the vector diffraction theory,magnetization distributions induced by tightly focusing circularly polarized laser pulses were analyzed in the uniaxial crystal with the inverse Faraday effect.The dependence of the magnetization distributions on the position of the interface was studied.The magnetization distributions in the uniaxial crystal with small birefringence effect and in the isotropic medium were compared.Numerical results show that when the interface is closed to the lens,the positions of the maximum magnetization intensity and the minimum magnetization spot shift along the optical axial direction.The magnetization intensity in the uniaxial crystal is bigger than that in the isotropic medium,but the size of the magnetization spot in the uniaxial crystal is smaller than that in the isotropic medium.For larger ratio（defined as a ratio of the anisotropic optic-magneto constant to the isotropic optic-magneto constant in the uniaxial crystal）,magnetization intensity is larger but the magnetization spot is smaller.