Photochromic effect in neodymium-activated YAG crystals

A study was made of the photochromic effect in Y₃Al₅O₁₂:Nd using optical and rf spectroscopic methods. An investigation was made of two types of crystals containing different quantities of Mo³⁺ impurity ions. Two different centers with similar values of the g factors were observed in a crystal with a lower Mo³ impurity concentration. One of the centers interacted with Al³⁺ ions, but the nature of the other center was not identified.