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 μm and that of Cr4+ ions at 1.3 μm. 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 Cr4+ ions at 1.06 μm of 0.7 × 10−18 cm2 and at 0.69 μm of 1.5 × 10−18 cm2.