Effect of rhodium doping on the photorefractive properties of BCT crystals

Abstract We present an experimental investigation of the photorefractive properties of rhodium-doped barium calcium titanate (BCT) crystals of the congruently melting composition Ba0.77Ca0.23TiO3. We have studied the photorefractive properties of several crystals (undoped, rhodium or iron doped). All the crystals are sensitive in the infrared region (λ=850 nm). We have found that a three-level model of photorefraction is necessary to explain the experimental results. This study has put forward the fact that the BCT crystals that we have studied contain a large amount of iron, which damages the good photorefractive properties of the crystal. Indeed, the high intensity needed to saturate the gain ( I sat >1 W / cm 2 ), which is an important drawback for many applications, seems to be due to iron.