Cooperative Quantum Cutting in Er³⁺/Yb³⁺ Codoped Oxyfluoride Glass Ceramics

Oxyfluoride glass ceramics doped with Er³⁺/Yb³⁺ was synthesized. Rare earth ions are doped into fluoride nanocrystals according to x-ray diffractive patterns. The enhanced red emission of Er³⁺/Yb³⁺ in the fluoride nanocrystals, excited by xenon lamp at 449 nm, is investigated and analyzed by cooperative quantum cutting mode. The cross relaxation appears from ⁴F_5/2 →⁴F_9/2 to ⁴I_15/2 →⁴I_13/2 because of the nearer distance of rare earth ions and the larger absorption section of ⁴I_15/2 →⁴I_13/2 in the quantum cutting. It results in two emissions of ⁴F_9/2 →⁴I_15/2 and ⁴I_13/2 →⁴I_15/2. This implies that a 449 nm photon could dissolve into two photons with wavelength 665 nm and 1530 nm. This could be an effective way to obtain 1530 nm emission for optical communication.