Kinetics of luminescence calcium gallate activated by Yb3+, Er3+ ions

Abstract

The paper presents the results of a study of the luminescent properties of calcium gallate activated by trivalent rare earth ions Yb³⁺ and Er³⁺. IR luminescence spectra of samples with a single activator Ca_1‑хYb_xGa₂O₄,Ca_1‑хEr_xGa₂O₄ were studied when excited by radiation sources with a wavelength of 940 and 790 nm, respectively. The dependence of the luminescence intensity of samples on the concentration of rare earth ions is obtained. When the two-activator composition of Ca_1‑х‑yYb_xEr_yGa₂O₄ is excited by a semiconductor laser diode with a wavelength of 940 nm, IR luminescence is registered in the regions of 980-1100 nm and 1450-1670 nm. The radiation in these bands corresponds to electronic transitions in Yb³⁺ and Er³⁺ ions, respectively. For a luminescence band with a maximum at a wavelength of 1540 nm, the excitation spectra were measured, the maximum intensity is at the wavelengths: 930, 941, 970, 980 nm. The dependence of the IR luminescence intensity of a solid solution of Ca_1‑х‑yYb_xEr_yGa₂O₄ on the concentration of Er³⁺ ions was studied. With an increase in the concentration of Er³⁺ ions in the luminescence spectra, there is a redistribution in the intensity of the bands belonging to Yb³⁺ and Er³⁺ ions, which indicates the presence of energy transfer processes between these ions. The kinetics of IR luminescence attenuation was studied for series with one and two activators: Ca_1‑хYb_xGa₂O₄,Ca_1‑хEr_xGa₂O₄, Ca_1‑х‑yYb_xEr_yGa₂O₄. It is established that the luminescence attenuation occurs mainly according to the exponential law, which indicates the predominance of the intracenter luminescence mechanism in the studied structures. Based on the analysis of the excitation and luminescence spectra of experimental samples, conclusions are made about the interaction of Yb³⁺ and Er³⁺ activator ions in the crystal lattice of calcium gallate.