SPECTROSCOPIC PROPERTIES OF LIGA5O8 SINGLE-CRYSTALS DOPED WITH CHROMIUM

Spectroscopic parameters of chromium-doped lithium-gallium spinel crys tals are studied in the temperature range from 77 to 300 K. It is foun d that optical absorption and luminescence of crystals are related to Cr3+ ions located in octahedral positions with the local symmetry C-3v . The energy level diagram of Cr3+ ions calculated using the crystal-f ield theory is in good agreement with experimental data. Room-temperat ure stationary induced absorption spectra of crystals exhibit strong a bsorption in the 400-700-nm region, which was assigned to transitions from the excited metastable E-2 State to the levels located in the 300 00-36500-cm(-1) region. The broadband absorption from the excited meta stable E-2 State causes great losses in the pumping channel, so that l asing of Cr3+ ions in LiGa5O8 crystals at room temperature is unlikely .