Threshold effects for resistance to optical damage and nonvolatile holographic storage properties in In:Mn:Fe:LiNbO_3 crystals

The threshold concentration for In2O3 was found in In:Mn:Fe:LiNbO3 crystals by measurement of the infrared spectra of the crystals. The resistance of the In:Mn:Fe:LiNbO3 crystals to optical damage is characterized by changes in photoinduced birefringence as well as by distortion of the transmitted beam pattern. The resistance increases remarkably when the concentration of In2O3 exceeds its threshold. The resistance to optical damage of a In(3.0 mol. %):Mn:Fe:LiNbO3 crystal is 2 orders of magnitude higher that of a Mn:Fe:LiNbO3 crystal. The dependence of defects on the resistance to optical damage of the In:Mn:Fe:LiNbO3 crystals is discussed in detail. Nonvolatile holographic storage was achieved for all crystals, and the sensitivity of the In(3.0 mol. %):Mn:Fe:LiNbO3 crystal is much higher than that of the others.