Spectral characteristics of chromium-activated yttrium aluminum garnet in the R-line range

The results are given of an investigation of the luminescence and absorption spectra in the region of th stimulated transitions involving the ground and excited states in Y₃Al₅O₁₂:Cr³⁺ crystals. The dependence of the threshold population of the metastable level on the spectral losses at the emission frequency was studied. It was found that the stimulated emission from Cr³⁺ ions in Y₃Al₅O₁₂ crystals was possible only at low temperatures.