Excited-state dynamics and enhanced near-IR emission in Nd³⁺-structurally activated aluminophosphate glass containing silver and tin

The excited state dynamics and near-infrared (IR) luminescent properties of Nd³⁺-doped melt-quenched aluminophosphate glass containing silver and tin have been investigated under pulsed-laser and steady-state excitation at 266 nm. A comparative emission dynamics assessment was carried out concerning Ag and Sn dopants in the glass matrix with and without neodymium. The data indicates an effective non-radiative energy transfer from single Ag⁺ ions and Sn centers as donors to neodymium activator ions which ultimately populates the ⁴F_3/2 emitting state in Nd³⁺. As a result, the near-IR (1.06 μm) emission from the ⁴F_3/2 metastable state in Nd³⁺ is enhanced about an order of magnitude relative to a purely Nd-doped reference. In addition, the ⁴F_3/2 excited state lifetime becomes significantly longer in the presence of silver and tin. A comparative ³¹P nuclear magnetic resonance spectroscopy study suggests glass depolymerization upon neodymium doping. It is proposed that a structural alteration might be linked to the established non-radiative energy transfer.