Structural and optical properties of 5 mol% ErF3-doped fluoride crystals

The influence of the fluoride host matrix MeF₂ (Me = Ca, Ba) on the structural and optical properties of 5 mol% ErF₃-doped single crystals was investigated. The MeF₂:Er³⁺ crystals were successfully grown using the Stockbarger–Bridgman technique and analyzed through laboratory X-ray diffraction and spectroscopic methods. Structural refinements revealed distinct behavior upon erbium doping: an expansion of the CaF₂ lattice and a contraction of the BaF₂ lattice, correlated with host-specific charge compensation mechanisms and local lattice distortions. Room temperature absorption and photoluminescence spectra recorded under UV excitation (λexc = 255 nm and 378 nm) showed intense visible emissions in the blue, green, and red domains. Judd–Ofelt analysis provided the intensity parameters Ω₂, Ω₄, and Ω₆, and radiative lifetimes were calculated and compared with literature data. The distinct structural responses and luminescent behavior of MeF₂ (Me = Ca, Ba) hosts at high Er concentrations suggest their suitability for applications in solid-state lasers, visible light-emitting devices, and optical amplifiers. These findings contribute to the optimization of Er³⁺-doped fluorides for use in solid-state lasers, optical amplifiers, and visible light-emitting devices.