Mechanism of quantum cutting in Pr3+–Yb3+ codoped oxyfluoride glass ceramics

Quantum cutting of 0.44 μm photon into 1.0 μm and 1.3 μm photons was demonstrated in Pr3+–Yb3+ codoped oxyfluoride glass ceramics by spectroscopic investigation from blue to near-infrared region. The Pr3+–Yb3+ codoped sample showed energy transfer (Pr3+:3P0→1G4)→(Yb3+:2F5/2←2F7/2). Both under 0.44 μm and 0.94 μm excitations, the codoped sample showed Pr3+:1G4→3H4 luminescence at 1.3 μm, as well as Yb3+:2F5/2→2F7/2 luminescence at 1.0 μm. The relative intensity of (Pr3+:1.3 μm/Yb3+:1.0 μm) by 0.44 μm excitation was much higher than that by 0.94 μm excitation. The mechanism of downconversion was proposed as a quantum cutting process by one-step energy transfer (Pr3+:3P0→1G4)→(Yb3+:2F5/2←2F7/2), which results in generation of two near-infrared photons via the Pr3+:1G4→3H5 and Yb3+:2F5/2→2F7/2 transitions.