NEAR-INFRARED RESPONSE OF PHOTOREFRACTIVE CRYSTALS (K0.5NA0.5)(0.2)(SR0.75BA0.25)(0.9)NB2O6-CU AND LINBO3-FE

Material response relevant to volume holographic storage for photorefr active crystals (K0.5Na0.5)(0.2)(Sr(0.7)5Ba(0.25))(0.9)Nb2O6:Cu (KNSBN :Cu) and LiNbO3Fe was studied in the near-infrared region. The dark de cay time for KNSBN:Cu was measured to be on the order of 10(6) s. The light-induced erasure time at the 1 mW/cm(2) read beam intensity can b e >1000 h for both KNS8N:Cu and LiNbO3:Fe. Read beam diffraction effic iencies of 28.7% for KNSBN:Cu and 50% for LiNbO3:Fe were obtained at 7 06 nm when the refractive index grating was written at 706 nm. The dec ay rate of the refractive index grating with an extraordinary-wave rea d beam is about 3.6 times smaller than that with an ordinary-wave read beam for KNSBN:Cu. The results show that near-infrared light can be u sed to read holograms in the photorefractive volume holographic storag e application. (C) 1996 American Institute of Physics.