New Rare-Earth-Based Hybrid Glass for Fine-Tuning of the Magneto-Optical Faraday Rotation

Rare-earth-doped glasses have great potential in magneto-optical applications due to their high transparency and Verdet constant. However, their synthesis not only requires a high-temperature treatment over 1000 °C, but also involves the use of many expensive heavy rare-earth elements, which significantly increases the manufacturing cost. In this work, a desolvation method is used to synthesize a hybrid glass using a cost-effective Ce element. The use of ethanol as a solvent not only lowers the synthesis temperature down to 90 °C, but also avoids the hydrolysis of the Ce precursor. The Ce-based glass exhibits a light transmittance of up to 80% with an effective magnetic moment of 1.9 μB and a Verdet constant of -33 rad/(T·m) at 405 nm, which is comparable to that of conventional heavy flint glass. Importantly, the synthesis method is demonstrated as a general approach for the whole family of rare-earth elements, generating a rich library of magneto-optical materials. This facile approach enables the tuning of the plus-minus sign of the Verdet constant by Ce and Gd ions, which enables fine-tuning of the Faraday rotation from clockwise to anticlockwise. In a proof-of-concept experiment, an encryption and decryption system is showcased as a tool to convert electronic signals into optical codes, demonstrating the potential of this new type of material in the field of information security.