Fig. 5: Demonstration of 3D optical data storage and information encryption.

a The 3D optical information written in various layers of the glass, the photograph of the transparent glass with the “KUST” information under the daylight (upper photo), and the optical microscope images of “KUST” information observed by using an optical microscope. b The photograph of glass after the “KUST” information erasing. c The 3D optical information rewritten in various layers of the glass, the photograph of the transparent glass with the “pentacle, quadrate, triangle and circle pattern” information under daylight (upper photo) and the optical microscope images of “pentacle, quadrate, triangle and circle” information observed by using optical microscope. d The 3D structure inside the glass from the front view and top view under daylight.