Characteristics of the process of filling the upper active level of neodymium in γ -La2S3 semiconductor crystals and La2S3·2Ga2O3 glasses

An analysis was made of the process of filling the ⁴F_3/2 metastable state of Nd³⁺ in two semiconductor materials, crystalline γ -La₂S₃:Nd³⁺ and glassy La₂S₃·2Ga₂O₃:Nd³⁺, as a result of nonresonant Stokes excitation. It was found that the rate of nonradiative transitions from the upper excited states of Nd³⁺ to the metastable state was considerably higher in the glass than in the crystal. Pumping at wavelengths corresponding to the fundamental absorption band resulted in more efficient excitation of the Nd³⁺ ions in the glass than in the crystal. It was concluded that semiconducting glass of the La₂O₃·2Ga₂O₃:Nd³⁺ composition was free of the negative properties which made the optical pumping of the crystal ineffective.