Fig. 1. Schematic of holographic recording and reproduction

Fig. 2. Schematic of angular multiplexed recording and reproduction

Fig. 3. Typical selectivity curve and diffraction efficiency versus the position of the media relative to the reference beam (provided by Amethystum Storage Technology Co., Ltd.). (a) Typical selectivity curve related to spherical wave reference beam; (b) diffraction efficiency from multiplex-recorded holograms as a function of relative position between the media and the reference beam

Fig. 4. Single arm design for off-axis holographic data storage system and the prototype of holographic data storage^[25] (provided by Amethystum Storage Technology Co., Ltd.)

Fig. 5. Improvement methods of M/#. (a) M/# versus the product of the difference between refractive indices of the photosensitive monomer and the matrix and the volume fraction of the monomer for five different resins (the media are all 200 μm thick)^[40]; (b) general depiction of the structural features of a compound DRED^TM[42]; (c) schematic diagram of a grating forming mechanism in a photopolymer doped with nanoparticles^[43]

Fig. 6. Compositional structure. (a) Structure of oxime ester initiator^[76]; (b) structure of X1^[76]; (c) schematic diagram of simultaneously generated photoinitiation and photoinhibition functions by the photoinitibitor composed of KCD and NPG under a visible light exposure^[37]

Fig. 7. BSDF curves and reproduced data page images from two different kinds of media (provided by Amethystum Storage Technology Co., Ltd.). (a) BSDF versus diffraction angle; (b)(c) corners of the reproduced data page images from holograms recorded in two kinds of media, respectively

Fig. 8. Schematic diagram of the formation of a cross-linked network. (a) Diagram showing the working principle of Bayfol^®HX photopolymer film^[83]; (b) schematic illustration of holographic record through two-stage orthogonal thiol-click chemistry^[87]