Extreme hypersensitivity observed from 6H15/2 ↔ 6F11/2 transition of Dy3+ in inorganic noncrystalline solids

Absorption transition from the ground 6H15/2 state to the superimposed (6H9/2, 6F11/2) states, inverse transition of which leads the Dy3+: 1.3 μm luminescence, in noncrystalline Ge–As–S alloys is dramatically modified upon a least compositional adjustment by Ga and CsBr. The change in oscillator strength of the Dy3+: 6H15/2 ↔ 6F11/2 transition in our modified glasses is more sensitive to the local coordination structure of rare-earths compared to other hypersensitive transitions that have been previously observed in solid-state dielectric hosts. Preferential highly symmetric coordination in nearest-neighbouring shell of dysprosium with bromine in [GaS3/2Br]− complexes, which are formed spontaneously during vitrification process of the host materials, is believed to be responsible for the behaviour.