All-optical vectorial control of multistate magnetization through anisotropy-mediated spin-orbit coupling

Shirong Lin, Zhongquan Nie, Weichao Yan, Yao Liang, Han Lin, Qing Zhao, Baohua Jia
2019 Nanophotonics  
The interplay between light and magnetism is considered as a promising solution to fully steer multidimensional magnetic oscillations/vectors, facilitating the development of all-optical multilevel recording/memory technologies. To date, impressive progress in multistate magnetization instead of a binary level has been witnessed by primarily resorting to double laser beam excitation. Yet, the control mechanisms are limited to specific magnetic medium or intricate optical configuration as well
more » ... iguration as well as overlooking the crystallographic architecture of the media and the polarization-phase linkage of the light fields. Here, we theoretically present a novel all-optical strategy for generating arbitrary multistate magnetization through the inverse Faraday effect. This is achieved by strongly focusing a single vortex-phase configured beam with circular polarization onto the anisotropic magnetic medium. By judiciously tuning the topological charge effect, the optical anisotropic effect, and the anisotropic optomagnetic effect, the light-induced magnetic vector can be flexibly redistributed between its transverse and longitudinal components, thus enabling orientation-unlimited multilevel magnetization control. In this optomagnetic process, we also reveal the role of anisotropy-mediated spin-orbit coupling, another physical mechanism that enables the effective translation of the angular momentum of light fields to the magnetic system. Furthermore, the conceptual paradigm of all-optical multistate magnetization is verified. Our findings show great prospect in multidimensional high-density optomagnetic recording and memory devices and also in high-speed information processing science and technology.
doi:10.1515/nanoph-2019-0198 fatcat:ab4qk4svnfe4vlbhzg7rru6gri