Spectral, luminescence, and lasing properties of a yttrium scandium gallium garnet crystal activated with chromium and erbium

A study was made of the spectral, luminescence, and lasing properties of an yttrium scandium gallium garnet crystal activated with chromium and erbium. The lifetimes of the Stark sublevels of some of the levels of Er³⁺ were determined and the schemes of these sublevels were constructed. It was established that, in addition to the "forward" energy transfer, there was also the reverse process Er³⁺→Cr³⁺. The mechanism of the interaction and its microscopic constants were determined. The chromium and erbium concentrations could be varied within wide limits without significant deterioration in the conditions for the transfer of energy from Cr³⁺ to the ⁴I_11/2 level of Er³⁺. A study was made of the lasing properties of this crystal (λ_l = 2.80 ± 0.01μ) under free-running and Q-switching conditions.