Metastable optical absorption and luminescence in MgO-doped LiNbO/sub 3/ crystals

The purpose of present work is the investigation of the Mg impurity influence on efficiency of colour centres formation in MgO-doped LiNbO/sub 3/ crystals by techniques of pulsed optical spectroscopy with nanosecond time-resolution. Obtained results show that not only cation vacancies and "antisite" defects determine the formation of colour centres in investigated crystals. Increase of MgO concentration diminishes number of cation vacancies, which stabilize holes. Nevertheless increase of MgO concentration to threshold (about 6% of MgO) leads to increase of concentration of holes color centers. Formation of color centers in irradiated LiNbO/sub 3/ crystals takes place not only as a result of capture of charge carriers on deep traps, but also as a result of formation of structure defects by means of decay of electron excitations in proper crystalline lattice.