Luminescence of Pr-doped LiCaAlF6 and LiSrAlF6 crystals

The spectral and kinetic parameters of LiCaAlF6:Pr and LiSrAlF6:Pr single crystals are studied at LHeT and room temperature (RT). Photon cascade emission (PCE), i.e., 1S0→1I6 and 3P0→3Hj, 3Fj transitions after Pr3+ excitation via 4f2→4f 5d absorption results in the conversion of the vacuum ultraviolet photon to two visible photons. The excitation and photoemission spectra as well as decay times have been measured and compared with those for CaF2:Pr and SrF2:Pr crystals. X-ray luminescence was measured to study the emission origin from both 1S0 and 3P0 states of Pr3+. An intense phosphorescence of LiSrAlF6:Pr was observed in the visible range after X-irradiation at RT, contrary to LiCaAlF6:Pr.