Spectroscopic Properties of TmF(3)-Doped CaF(2) Crystals.

In this study, we report the growth and comprehensive spectroscopic analysis of TmF(3)-doped CaF(2) crystals, grown using the vertical Bridgman method. The optical absorption and photoluminescence properties of both trivalent (Tm(3+)) and divalent (Tm(2+)) thulium ions were investigated. Optical absorption spectra in the UV-VIS-NIR range reveal characteristic transitions of Tm(3+) ions, as well as weaker absorption bands corresponding to Tm(2+) ions. The Judd-Ofelt (JO) formalism was applied to determine the intensity parameters Ω(2), Ω(4), and Ω(6), which were used to calculate radiative transition probabilities, branching ratios, and radiative lifetimes for the Tm(3+) ions. The emission spectra showed concentration-dependent quenching effects, with significant emissions observed for the concentration of 0.1 mol% TmF(3) under excitation at 260 nm and 353 nm for Tm(3)(+) ions and at 305 nm for Tm(2+) ions. A new UV emission associated with divalent Thulium is reported. The results indicate that higher TmF(3) concentrations lead to increased non-radiative energy transfer, which reduces luminescence efficiency. These findings contribute to the understanding of the optical behavior of Tm-doped fluoride crystals, with implications for their application in laser technologies and radiation dosimetry.