Structural phase transition and fluorescence lifetime of amorphous chalcogenide alloys doped with rare-earths

Lifetime of excited electronic states inside the 4f configuration of rare-earth elements embedded in covalent chalcogenide glasses turns out to be sensitive to medium-range structural phase transition of the host glasses. We have measured lifetimes of 1.6 μm emission originating from Pr3+: (3F3, 3F4) → 3H4 transition in amorphous Ge–Sb–Se alloys. The longest lifetime is measured at around the mean coordination number of ∼2.67, which arises coincidently from structural changes of the host glasses from two-dimensional layers to three-dimensional networks.