Intensities of f-f transitions in pr³⁺ and dy³⁺ in glasses in the near-ir spectral range

The absorption spectra of Pr³⁺ and Dy³⁺ ions in three glass matrices (SiO₂-P₂O₅-GeO₂, Al₂O₁-B₂O₁-SiO₂, and LiB₃O₅) are thoroughly studied in the near-IR spectral range (4600-14 300 cm^-1). The temperature dependences of the intensity, the width, and the location of the absorption bands observed are investigated for the first time. It is shown that the f-f transitions in the studied glasses are allowed by static odd distortions in the environment of the rare-earth ions and these distortions decrease with an increase in temperature. A comparative analysis of the absorption band parameters and their temperature behavior in different materials makes it possible to determine the differences in magnitudes, symmetries, and dispersions of the distortions in the nearest environment of rare-earth ions in different glasses.