Tb-doped X–B–Al (X = Li/Na/K/Sb) magneto-optical glass: Performance optimization and information encryption applications

Magneto-optical (MO) glass, which has been garnering increasing interest for its light rotation capability, often faces challenges related to valence variations, resulting in suboptimal MO performance. The composition of the glass matrix and the specifics of the melting process are crucial in determining the glass network structure and cation valence state distribution. This has led to the exploration to enhance network connectivity and introduce more Tb³⁺ ions to boost the MO performance. In this study, alkali metal oxides (Li₂O/Na₂O/K₂O) were introduced to modify the glass network structure and lower melting characteristics accordingly. Particularly noteworthy is the advantage offered by K₂O that lowers free electron density and melting temperature. Through meticulous control of the alkali metal oxide content and the melting temperature, a groundbreaking Verdet constant of 113.87 rad/(T m) at 650 nm for the 40T5K glass was accomplished. Furthermore, the MO glasses have been successfully applied in the encryption and decryption of one-dimensional text and two-dimensional images, thereby exhibiting the utility of this innovative material in information security applications.