Anisotropy of nonlinear absorption in a V3+ : YAG crystal

An investigation was made of the polarisation characteristics of the nonlinear absorption of λ = 1.055 μm radiation in a V³⁺ : YAG crystal at the saturation stage. The duration of a pulse propagating in the crystal was considerably less than the lifetime of an excited state of the V³⁺ impurity centres. A comparison of the experimental results with those of a theoretical calculation showed that the best description was provided by a phenomenological model in which resonant absorption in a crystal is attributed to three linear dipoles oriented along the main crystallographic axes of YAG.