R&D: Fully Controllable 3D Light-Induced Longitudinal Magnetization Using Single Objective Lens

Optics Letters has published an article written by Xiaoqiang Zhang, Hefei Innovation Research Institute, School of Microelectronics, Beihang University, Hefei 230013, China, and Fert Beijing Institute, BDBC, Beihang University, Beijing 100191, China, Guanghao Rui,Advanced Photonics Center, Southeast University, Nanjing, Jiangsu 2100961, China, Yong Xu, Fan Zhang, Yinchang Du, Xiaoyang Lin, Hefei Innovation Research Institute, School of Microelectronics, Beihang University, Hefei 230013, China, and Fert Beijing Institute, BDBC, Beihang University, Beijing 100191, China, Anting Wang, Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei, 230026, China, and Weisheng Zhao, Hefei Innovation Research Institute, School of Microelectronics, Beihang University, Hefei 230013, China, and Fert Beijing Institute, BDBC, Beihang University, Beijing 100191, China.

Abstract: “With features of fast and energy-efficient data writing, all-optical helicity-dependent switching (AO-HDS) has emerged as a competitive technology to satisfy the demand for the next-generation volume data storage. Unfortunately, to switch the magnetizations in different positions of the magnetic-optic film, the laser beam, the objective lens, or the magnetic recording film should be moved, limiting the advantage of AO-HDS in fast data writing. To achieve on-the-fly magnetization switching, the induced magnetization should be fully controllable. In this Letter, by focusing an azimuthally polarized vortex beam (APVB) and introducing an additional phase, a feasible strategy constructing subwavelength light-induced pure longitudinal multi-magnetization spots is proposed. In addition, the position of the multi-magnetization spots can be dynamically controlled. The distributions of the focused APVBs with different orbital angular momentum, and the induced magnetizations are surveyed. We believe that this is a practical and flexible three-dimensional magnetic recording technique with dynamic control of the recording position.“