Optical evaluation of multichannel radiative transitions originating from ⁴G_5/2 level of Sm³⁺ in heavy-metal-gallate glasses

Conventional visible and novel infrared (IR) emissions of Sm³⁺ in heavy-metal-gallate glasses (Li₂O-K₂O-BaO-PbO-Bi ₂O₃-Ga₂O₃, LKBPBG for short) with low phonon energy have been observed. Judd-Ofelt parameters ω₂ (3.00 × 10^-20 cm²), ω₄ (5.19 × 10^-20 cm²), and ω₆ (1.69 × 10^-20 cm²) indicate a higher asymmetry and stronger covalent environment in the optical glasses. For the visible fluorescence bands peaked at 564, 601, 648, and 710 nm, the maximum stimulated emission cross-sections (σ_e) were derived to be 1.35 × 10 ^-22, 9.21 × 10^-22, 9.58 × 10^-22, and 3.91 × 10^-22 cm², respectively, the values are larger than those in phosphate, oxyfluoroborate, tellurite, and calibo glasses obviously. The observed 1185 nm IR emission lies in the low-loss window of telecommunication system, and the maximum value of σ_e for this band was obtained to be 6.09 × 10^-23 cm². The characterization of multichannel radiative transitions of Sm³⁺ in LKBPBG glasses is beneficial in exposing its potential applications in visible and IR optoelectronic devices.