“…J-O intensity parameters Ω t (t = 2, 4, 6) for Dy 3+ in ZASP glasses were calculated to be 5.74 ×10 −20 cm 2 , 1.47 × 10 −20 cm 2 and 1.12 × 10 −20 cm 2 , respectively, and the rootmean-square deviation between the experimental and calculated oscillator strengths was assessed to be 2.3 × 10 −7 , indicating that the fitting process is reliable. Ω 2 of Dy 3+ in ZASP glasses is close to 5.41 × 10 −20 cm 2 in lead fluorogermanate glasses [64], 5.19 × 10 −20 cm 2 in lead tungsten tellurite glasses [65] and 4.90 × 10 −20 cm 2 in lead borate glasses [66], demonstrating a higher asymmetrical and stronger covalent environment around Dy 3+ in the ZASP glass system. Using these intensity parameters, the spontaneous emission probability (A rad ) and branching ratio (β) were calculated to be 541 s −1 and 64.85 % for the 4 F 9/2 → 6 H 13/2 transition, respectively, while they are 101 s −1 and 12.11 % for the The β for 4 F 9/2 → 6 H 13/2 transition is 64.9 %, revealing that yellow emission is the dominant radiative component of Dy 3+ .…”