Ba_(0.77)Ca_(0.23)TiO_3 (BCT): a new photorefractive material to replace BaTiO_3 in applications

摘要

The most popular photorefractive material BaTiO_3 suffers from a crippling defect when applications are considered: its phase transition around room temperature that can destroy its photorefractive characteristics, if not the crystal itself. Some years ago, University of Osnabrueck, proposed and successfully grew Ba_(0.77)Ca_(0.23)TiO_3 an alloy derived from BaTiO_3, in which the phase transition was pushed away towards low temperature. The remaining question was then: does this new material keep the good photorefractive properties that made the success of BaTiO_3? We will present here some theoretical and experimental results that allow us to answer this question and that show that despite some differences in the photorefractive properties between BaTiO_3 and BCT, the new crystal is an extremely promising materials for photorefractive applications, such as phase conjugation or dynamic holographic intracavity laser mode selection.