Optical spectroscopy of heavily Ho3+-doped BaY2F8 crystals

► The ultraviolet, visible, and near IR (0.8-2.4 μm) luminescence spectra of BaY2F8 single crystals heavily doped with Ho3+ ions (10 and 30 mol%) have been investigated at room temperature and 12 K. ► Excitation in the visible region gives rise to very strong emission bands originating from the first 5I7 level and located around 2070 nm. ► The inter-ionic processes are found to shorten the decay times of the levels emitting in the visible region with respect to the corresponding radiative lifetimes.