Optical spectra are measured for transparent and colorless TbAlO 3 single crystals grown by the Czochralski method in a reducing atmosphere, although those grown in an inert atmosphere show blackbody color due to broadband absorption of Tb4+ ions. This is a report on strong Tb3+ emission spectrum at room temperature of aluminates and relevant crystals which contain the Tb ion as a stoichiometric agent. All fine structures in absorption and emission spectra can be assigned to the intra-4f transitions of Tb3+ ions. Similar concentration quenching is observed in TbxGd1-xAlO3 system to that in the Nd:YAG crystals
however, the quenching is found to be very small compared with that of the Nd:YAG. An order estimate of the induced emission cross section for the strongest emission line is calculated to be about 6×10-21 cm2. © 1994 American Institute of Physics.