Spectroscopic properties of heavily Ho³⁺-doped barium yttrium fluoride crystals

The 30 at.% Ho: BaY₂F₈ crystals were grown by the Czochralski method, and their spectroscopic properties are analyzed systematically by standard Judd-Ofelt theory. The Judd-Ofelt intensity parameters are estimated to be Ω₂=6.74× 10^-20cm², Ω₄=1.20× 10^-20 cm², and Ω₆=0.66× 10^-20cm², and the fluorescence branching ratios and radiative lifetimes for a series of excited state manifolds are also determined. The emission cross sections with our measured infrared luminescence spectra, especially important for 4.1 μm, are calculated to be about 4.37× 10^-21 cm². The crystal quality is preliminarily tested through a mid-infrared laser emission experiment.