3D Printing of Luminescent Glass with Controlled Distribution of Emission Colors for Multi‐Dimensional Optical Anti‐Counterfeiting

Abstract

The fabrication of multicolor luminescent glass with simultaneous controlling of the distribution of emission colors within a monolithic medium has been a tremendous challenge, which, however, could be attractive for diverse photonic applications from optical storage to information encryption. Here, a space‐selective doping method based on a stereolithographic technique is designed, enabling the control of the doping domain of the active luminescence ions, such as Eu3+, Ce3+, Tb3+, and Pr3+, in 3D‐printed single silica glasses. The printed glass shows intense multicolor luminescence, and the interface between the two doping areas is invisible under natural light. By using this technique, multicolor luminescent glass with pre‐designed emission color distribution is fabricated, which enables facile and nondestructive decryption strategies based on photoluminescence under controlled excitation conditions. Besides, the extending of this strategy by using a femtosecond laser for photopolymerization dramatically improves the printing resolution down to the few‐micron scale, enabling the multi‐dimensional optical storage and encryption in miniaturized glass items. This work not only delineates the potential applications of multicolor luminescent glass for multi‐dimensional anti‐counterfeiting and information storage, but also opens up new avenues for prospective applications in sensing, lasers, and displays based on glasses with spatially engineered optical responses.

Tricolor Upconversion Phosphors of LiYO2:RE3+/Yb3+ (RE = Tm, Ho, Eu) for Metamerism Anti‐Counterfeiting and 3D Volumetric Display

“…Furthermore, new libraries of pure B/G/R UC phosphors are required to boost metamerism, anti‐counterfeiting, and other applications. Efficient B/G/R UC particles stimulated by a powerful NIR laser also can be used to develop 3D optical data storage and solid‐state 3D displays, [ 13,27,42–47 ] which are capable of visualizing real‐time volumetric data in 3D physical space. The “volumetric” concepts were well demonstrated by Downing et al.…”

Trap Depth Engineering from Persistent Luminescence Phosphors Mg2-xZnxSnO4 for Dynamic Optical Information Encryption Application

“…Optical information encryption shows the advantages of low production cost, low energy consumption and long storage life and is of great significance in the fields of information storage, data security, and optical communication. − Persistent luminescence (PersL) phosphors are characterized by their ability to continue emitting from a few seconds to several hours after the removal of an external excitation source. , PersL phosphors have gained popularity owing to its advantages of high storage capacity, low synthesis cost, diverse colors, flexible, and simple implementation, which arouses great attention due to the promising applications in information storage, anticounterfeiting, and so on. − For typical electron-trapping luminescent material, the trap distribution determines the way of writing and reading the optical information, and also determines the storage capacity of the optical information. ,− Therefore, researchers regulated the defects in order to achieve larger storage density, multicolor, multimode, and multidimensional advanced encryption effects. However, achieving rapid and convenient writing, reading, and erasing of dynamic information remains a challenge.…”