INFLUENCE OF THE PURITY OF THE STARTING MATERIALS ON THE RECORDING OFDYNAMIC HOLOGRAMS IN BI12TIO20 CRYSTALS

The parameters of Bi12TiO20 crystals grown with bismuth oxide of diffe rent degrees of purity were measured by a holographic recording techni que in an external ac electric field and were compared with a crystal specially doped with chromium. Various crystal parameters such as the diffusion length of the photoexcited carriers and the Debye screening length were determined. It was found that the absorption spectrum of t he material and the holographic recording efficiency were strongly inf luenced by light chromium doping and by insufficient purity of the sta rting mixture. (C) 1997 American Institute of Physics.