Nie Zhongquan, Ding Weiqiang, Li Dongyu, Zhang Xueru, Wang Yuxiao, Song Yinglin
Opt Express. 2015 Jan 26;23(2):690-701. doi: 10.1364/OE.23.000690.
Based on the vector diffraction theory and the inverse Faraday effect, we numerically study the light-induced magnetization near the focus of a 4π high numerical aperture focusing configuration under the illumination of two counter- propagating radially polarized hollow Gaussian vortex beams. The simulated results demonstrate that, by selecting higher-order vortex beam modes (e.g. n=4with n - the beam order) and proper truncation parameter (e.g. β=1.75 with β- the ratio of the pupil radius to the incident beam waist), spherical and sub-wavelength longitudinal magnetization can be generated in the vicinity of focus. Such special magnetization feature is attributed to not only the interaction between optical vortices and the radially polarized beams, but also the completely destructive interference of azimuthal components and the constructive interference of the longitudinal component of the two counter-propagating radially polarized vortex beams. This spherical and sub-wavelength longitudinal magnetization distribution may be of interest for applications in all-optical magnetic recording and confocal and magnetic resonance microscopy.
基于矢量衍射理论和逆法拉第效应，我们对在两个反向传播的径向偏振空心高斯涡旋光束照射下，4π高数值孔径聚焦配置焦点附近的光致磁化进行了数值研究。模拟结果表明，通过选择高阶涡旋光束模式（例如n = 4，其中n为光束阶数）和适当的截断参数（例如β = 1.75，其中β为光瞳半径与入射光束腰斑半径之比），可以在焦点附近产生球形和亚波长纵向磁化。这种特殊的磁化特性不仅归因于光学涡旋与径向偏振光束之间的相互作用，还归因于两个反向传播的径向偏振涡旋光束方位分量的完全相消干涉和纵向分量的相长干涉。这种球形和亚波长纵向磁化分布可能在全光磁记录、共聚焦和磁共振显微镜等应用中具有重要意义。
