Energy transfer and frequency upconversion in Pr3+-doped ZBLAN glass

The lifetimes of 3P0 and 1D2 levels of Pr3+ were measured in ZBLAN glasses of composition in mol% 53ZrF4–20BaF2–(4 − x)LaF3–3AlF3–20NaF–xPrF3 (x = 0.1, 0.5, 1, and 3) by resonant excitation. Energy transfer observed between Pr3+ ions was analyzed by means of the Inokuti–Hirayama theory. The non-exponential dependence of the 1D2 decay on Pr3+ concentration indicates that dipole–dipole interaction between Pr3+ is the main process. Orange-to-blue upconversion luminescence was observed and described by two-ion energy transfer mechanism. The temporal evolution of upconversion luminescence was characterized by rise and decay times related to the dopant concentration.