Abstract: Holographic optical storage exhibits recording and reconstructing ability for three-dimensional information based on optical interference and diffraction. It has ultra-high storage density and parallel reading and writing ability, and becomes an important developing direction of information storage. Among various kinds of holographic storage media, azo molecules have attracted much attention due to their advantages such as small molecular size, polarization sensitivity, fast light response, large refractive index changes, and high compatibility with polymer matrix. Herein, we review the applications of azo materials in polarization holographic storage and surface relief gratings in the past 40 years, especially the design and experimental results of high-density multiplexing polarization holographic storage in azo molecule-doped polymer thin films. The feasibility of application of azo-based thin films in photon integrated chip is also analyzed.

Key words: Azo molecules, Polarization holography, Surface relief gratings