Preparation and performance study of erbium-doped chloride borosilicate photothermal refractive glass

Large-scale chloride borosilicate photothermal refractive (PTR) glass doped with Er ³⁺ ions was fabricated by a secondary melting technique. Based on the measured absorption spectrum of 2wt% Er ³⁺ doped chloride borosilicate PTR glass and Judd-Ofelt theory, three intensity parameter Ω _t (t=2,4,6), transition probability A, fluorescence branching ratio β and radiative lifetime τ were determined. The absorption and emission cross-section of ⁴ I _13/2 → ⁴ I _15/2 transition were 6.22×10 ^-21 cm ² and 6.84×10 ^-21 cm ² at 1.5μm, respectively. The differential thermal analysis curves were measured before and after ultraviolet irradiation. When the glass is exposed to ultraviolet light, it will promote the formation of crystalline phases during the subsequent heating process. The precipitation of NaF phase was achieved in Er ³⁺ -doped chloride borosilicate PTR glass via a dual-stage thermal treatment at 480°C and 510°C, which paves the way for the future fabrication of diverse active optical components.