Absorption, emission and absorption saturation of Cr4+ ions in calcium aluminate glass

Absorption, luminescence and absorption saturation of Cr ions in a calcium aluminate glass are studied. In the absorption spectrum, the absorption bands of Cr3+, Cr4+ and Cr6+ ions are revealed. The emission spectrum presents luminescence of Cr3+ ions centered at 0.82 mu m and that of Cr4+ ions at 1.3 mu m. The luminescence signal demonstrates short decay times of 120 +/- 10 ns and 300 +/- 20 ns for Cr3+ and Cr4+ ions, respectively. Absorption saturation measurements allowed an estimate of the ground-state absorption cross-sections for Cr-4 divided by ions at 1.06 mu m of 0.7 x 10(-18) cm(2) and at 0.69 mu m of 1.5 x 10(-18) cm(2). (c) 2005 Elsevier B.V. All rights reserved.