Infrared to visible up-conversion luminescence of SrF2:Ho particles upon excitation of the 5I7 level of Ho3+ ions
Journal of Luminescence Vol.261: P. 119942 (1-7) · September 2023
M.V. Chernov, S.V. Gushchin, A.M. Kuzmin, S.V. Kuznetsov, A.A. Lyapin, V.Yu Proydakova, P.A. Ryabochkina, V.V. Voronov, P.P. Fedorov
The visible and near-infrared (NIR) up-conversion luminescence (UCL) of a concentration series of fluoride phosphors SrF2:Ho (CHo = 1.3, 3.5, 4.8, 7.4, 8.9, 10.8, 13.0, 13.6 mol.%) upon excitation of the 5I7 level of Ho3+ ions are presented. The dependences of the UCL intensity corresponding to the 5F35I8, 5S2(5F4)→5I8, 5F55I8, 5I45I8, 5F35I6, 5I55I8, 5F55I7, 5I65I8 transitions on the concentration of Ho3+ ions were revealed. The UCL energy yield, color coordinates, and correlated color temperature (CCT) values were estimated. The maximum values of UCL energy yields of 0.03% (380–780 nm) and 0.09% (380–1100 nm) were registered for SrF2:Ho (3.5 mol.%) sample. All studied fluoride phosphors are characterized by a red glow of UCL. This glow corresponds to CCT of 6711–7474 K upon incident power density of 28 W/cm2. The UCL mechanisms of SrF2:Ho phosphors were proposed. The SrF2:Ho phosphors can be used as laser beam viewers of the two-micron radiation of thulium and holmium commercial lasers.