Li-impurity effect in optical spectra of KTaO 3 :Er 3+ crystals

The f–f absorption and emission spectra of Er 3+ impurities were observed and identified in KTaO 3 and K 1 – x Li x TaO 3 single crystals. It was shown that Li off-centers related random fields markedly influence intensity, width and position of zero-phonon lines. The detail analysis of the absorption spectra obtained allowed one to determine energies of the Stark sublevels of excited states for Er 3+ dominant centers of noncubic symmetry.