Spectral Properties of YAP:Yb Laser Crystals with Additional Li + and Hf 4+ Ions

In the present work single crystals of yttrium orthoaluminate (YAlO 3 ) activated with Yb 3+ ions and additional nonisovalent Li + and Hf 4+ impurities were grown. Comparative measurements of spectral characteristics of crystals including those exposed to gamma-ray irradiation were carried out to reveal the functional role of additional impurities. On the basis of the results obtained, the mechanisms of incorporation and charge compensation mechanisms of Li + and Hf 4+ ions in YAlO 3 :Yb are considered and the efficiency of using these impurities is shown to obtain crystals with a low concentration of anion vacancies and associated color centers.