Spectroscopic properties of the gamma irradiated ErF₃-DOPED BaF₂ crystals

The spectroscopic properties of the gamma irradiated BaF2:Er3+ crystals were studied. BaF2:0.2 mol% ErF3 crystal was grown using the vertical Bridgman method. The Judd-Ofelt intensity parameters, Omega(t) (t = 2,4,6) for f-f transitions of Er3+ ions were determined from optical absorption spectra recorded before and after gamma irradiation at various doses. The influence of gamma irradiation dose on the Judd-Ofelt parameters and on the radiative transition probability, on the branching ration and on the radiative lifetime was also investigated. The predicted radiative lifetimes were compared with those measured and with those reported by other authors. Apart from the green and red emissions, arising under excitation at 378 nm, a new UV emission band around 321 nm was observed under excitation at 290 nm. This emission was not reported before. Using the FuchtbauerLadenburg method, the emission cross section and optical gain parameter of the red and green emission band were calculated.