Cooperative phenomena in yttrium erbium aluminum garnet crystals

An investigation was made of the kinetics of the luminescence due to ⁴I_11/2 → ⁴I_15/2 and ⁴I_13/2 → ⁴I_15/2 transitions in the Er³⁺ ion in yttrium erbium aluminum garnet crystals subjected to strong resonant excitation argon laser radiation (λ = 4880 nm). The efficiency of the cooperative process resulting in nonlinear quenching of the luminescence from the ⁴I_13/2 level and sensitization of the ⁴I_11/2 level was estimated. The influence of this process on the kinetics of lasing as a result of the ⁴I_11/2 → ⁴I_13/2 transition (λ = 2.94 μ) was analyzed.