Growth and optical properties of Yb 3 þ and Tb 3 þ codoped BaB2O4 crystals

3 þ ,T b 3 þ :BaB2O4 crystal abstract Optical absorption and luminescence spectra of ytterbium and terbium codoped BaB2O4 (b-BBO and a- BBO) crystals grown in different conditions have been studied. Low-temperature absorption peaks were observed in all samples. Features related to rare earth ions were observed in absorption and luminescence spectra. Absorption and emission in the range 860-1000 nm are caused by 2 F5/22 2 F7/2 transitions in Yb 3 þ ions. Emission peaks at 500, 550, 590 and 630 nm correspond to 5 D4- 7 F6, 7 F5, 7 F4, and 7 F3 transitions of Tb 3 þ ions, respectively. The probable reasons of variations in spectroscopic features related to Yb in BBO host are discussed. It has been shown that the replacement of Ba 2 þ by Yb 3 þ in the lattice of BaB2O4 results in the decrease in the symmetry of oxygen surrounding of Yb 3 þ .