Near infrared downconversion in Pr3+–Yb3+ codoped oxyfluoride glass ceramics

The loss mechanism in the Pr3+–Yb3+ codoped glass that showed quantum cutting (QC) phenomenon was investigated and we found that the multi-phonon relaxation from Pr3+:1G4 is the major loss to the quantum cutting process. To reduce the loss, Pr3+–Yb3+ codoped glass ceramics containing SrF2 crystals were prepared and quantum yields (QY) of Yb3+ emission by 440 nm excitation were measured. Only glass ceramics with the highest Yb concentration (x = 2.9) showed higher QY than that of the as-made glass. It is considered that in low Yb concentration Pr3+ and Yb3+ ions were divided into different matrix possibly because of different ionic radius between Pr3+ and Yb3+ ions.