Low-temperature dynamic properties of photorefractive grating in potassium-strontium-sodium-barium-niobate crystal

The low-temperature dynamic properties of photorefractive gratings in cobal t-doped potassium-strontium-sodium-barium-niobate crystals are reported. At low temperatures, the photorefractive space-charge field undergoes quasipe riodic oscillations if the crystal is preilluminated by one of the writing beams. The write-erase cycle of the index grating becomes shorter if the cr ystal is preilluminated by one of the writing beams, which provides a means for crystal sensitization. The magnitude of the index grating decreases si gnificantly at low temperatures. The temperature dependence of the dark dec ay of the photorefractive grating is measured to complete our study and dem onstrate the multiple shallow levels existing in the crystal. A model of do uble carriers with multiple shallow levels is assumed to explain the experi mental results. (C) 1999 American Institute of Physics. [S0021-8979(99)0081 7-8].