Hao Chenglong, Nie Zhongquan, Ye Huapeng, Li Hao, Luo Yang, Feng Rui, Yu Xia, Wen Feng, Zhang Ying, Yu Changyuan, Teng Jinghua, Luk'yanchuk Boris, Qiu Cheng-Wei
Department of Electrical and Computer Engineering, National University of Singapore,4 Engineering Drive 3, Singapore 117583, Singapore.
Singapore Institute of Manufacturing Technology, ASTAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, Kinesis, Singapore 138634, Singapore.
Sci Adv. 2017 Oct 13;3(10):e1701398. doi: 10.1126/sciadv.1701398. eCollection 2017 Oct.
In the era of big data, there exists a growing gap between data generated and storage capacity using two-dimensional (2D) magnetic storage technologies (for example, hard disk drives), because they have reached their performance saturation. 3D volumetric all-optical magnetic holography is emerging rapidly as a promising road map to realizing high-density capacity for its fast magnetization control and subwavelength magnetization volume. However, most of the reported light-induced magnetization confronts the problems of impurely longitudinal magnetization, diffraction-limited spot, and uncontrollable magnetization reversal. To overcome these challenges, we propose a novel 3D light-induced magnetic holography based on the conceptual supercritical design with multibeam combination in the 4π microscopic system. We theoretically demonstrate a 3D deep super-resolved [Formula: see text] purely longitudinal magnetization spot by focusing six coherent circularly polarized beams with two opposing high numerical aperture objectives, which allows 3D magnetic holography with a volumetric storage density of up to 1872 terabit per cubic inches. The number and locations of the super-resolved magnetization spots are controllable, and thus, desired magnetization arrays in 3D volume can be produced with properly designed phase filters. Moreover, flexible magnetization reversals are also demonstrated in multifocal arrays by using different illuminations with opposite light helicity. In addition to data storage, this magnetic holography may find applications in information security, such as identity verification for a credit card with magnetic stripe.
在大数据时代，使用二维（2D）磁存储技术（例如硬盘驱动器）所产生的数据与存储容量之间的差距日益增大，因为它们已达到性能饱和状态。三维体全光磁全息术正迅速兴起，作为实现高密度存储的一条有前景的途径，因为它具有快速的磁化控制和亚波长磁化体积。然而，大多数已报道的光致磁化面临纵向磁化不纯、衍射受限光斑以及磁化反转不可控等问题。为了克服这些挑战，我们提出了一种基于概念性超临界设计的新型三维光致磁全息术，该设计在4π微观系统中采用多光束组合。我们从理论上证明，通过用两个相对的高数值孔径物镜聚焦六束相干圆偏振光束，可以实现一个三维深度超分辨的、纯纵向磁化光斑，这使得三维磁全息术的体存储密度高达每立方英寸1872太比特。超分辨磁化光斑的数量和位置是可控的，因此，通过适当设计相位滤波器，可以在三维体积中产生所需的磁化阵列。此外，通过使用具有相反光螺旋度的不同照明，还在多焦点阵列中展示了灵活的磁化反转。除了数据存储之外，这种磁全息术还可能在信息安全领域找到应用，例如用于磁条信用卡的身份验证。
