Tm3+ doped CaF2 based oxyfluroborosilicate glasses and glass ceramics for visible and NIR lasers

The structural and luminescence properties of Tm³⁺ doped CaF₂ based oxyfluoroborosilicate glasses and glass ceramics were discussed. The critical glass ceramic (BSTm1.0GC2) nature was obtained through different heat treatment processes as 450 °C for 1 h and the concentration of Tm³⁺ ions was optimized as 1.0 mol% for efficient emission. The spectroscopic and laser characteristic parameters were evaluated applying the standard Judd-Ofelt theory. The emission of blue light through ¹D₂ → ³F₄ transition was studied by exciting at 360 nm UV wavelength. Upon 808 nm laser excitation, the glasses and glass ceramics produce 1.46 μm emission through ³H₄ → ³F₄ transition. The effective bandwidth (114.99 nm), stimulated emission cross-section (14.30 × 10⁻²¹ cm²), gain bandwidth (1644.74 × 10⁻²⁸ cm³), figure of merit (10.21 × 10⁻²⁴ cm²s) and the quantum yield (76 %) of ³H₄ → ³F₄ transition made the BSTm1.0GC2 suitable as gain medium for 1.46 μm NIR fiber laser applications.