Spectroscopic characterisation of Er-doped LuVO4 single crystals

Abstract

The LuVO4:Er single crystals were grown by the Czochralski technique. The crystal-field split energy levels of Er3+ ion were derived experimentally employing absorption and emission spectra measured at T=10 K. The Judd–Ofelt phenomenological method was used to estimate intensity parameters, radiative lifetimes and branching ratios of luminescence. The excited state dynamics of the LuVO4:Er systems was investigated and experimental lifetimes of emitting levels were measured. The emission cross section of the 4I13/2→4I15/2 transition in the infrared was calculated by the Fuchtbauer–Ladenburg method. The gain cross section, estimated for several inverse-population parameters, allowed us to evaluate a potential laser activity of the LuVO4:Er system at 1.6 μm. Also, the potential range of the optical pumping was assessed based on absorption spectra achieved at the room temperature. The optical losses related to the green up-converted emission, encountered under the 978 nm excitation between 300 and 670 K were indicated and discussed. Spectroscopic peculiarities of the Er3+-doped LuVO4 crystal were discussed in relation to optical properties of the YVO4:Er and GdVO4:Er crystals. Taking into account the high quantum efficiency of the 4I13/2 level, and satisfactory absorption and emission features, the LuVO4:Er crystal can be considered as a promising active material for laser operation near 1.6 μm.