Study of absorption spectra of Er3+ in KTaO3 crystals

The first results of the study of optical absorption spectra of KTaO 3 : Er 3+ crystals are presented. In the 350–660-nm region, lines are observed deriving from intraconfigurational electronic transitions from the 4 I 15/2 ground state to levels of the 4 F 9/2 , 4 S 3/2 , 2 H 11/2 , 4 F 7/2 , 4 F 5/2 ( 4 F 3/2 ), 2 G 9/2 , and 4 G 11/2 excited states of the Er 3+ ions. A comprehensive study of transitions to the 4 F 9/2 , 4 S 3/2 , 2 H 11/2 , and 4 F 7/2 levels at 77 K is carried out. The number of lines observed for the above transitions fits the theoretically possible number for ƒ-ƒ electronic transitions in Er 3+ ions in the cubic crystal field. In the case of a differently charged substituted ion, this situation occurs only under nonlocal impurity charge compensation. The energies of the excited state levels for the transitions under study are determined.