LIGHT-INDUCED CHARGE-TRANSPORT PROPERTIES OF SR0.61BA0.39NB2O6-CE CRYSTALS

Measurements of absorption, photoconductivity, and dark conductivity a nd of light-induced absorption changes in photorefractive Sr0.61Ba0.39 Nb2O6:Ce crystals with Ce concentrations from 0.025 wt% to 1.6 wt% are carried out for different light wavelengths, intensities, and polariz ations. The experimental findings are interpreted alternatively by the two-center or by the three-valence model. The results yield that the concentrations of the deep and of the more shallow photorefractive lev els increase linearly with the Ce concentration and show that for SBN: Ce the two-center model is probably more appropriate. (C) 1996 Optical Society of America