Temperature dependence of two beam coupling, light-induced erasure decay and dark decay in as-grown and reduced BaTiO3 : Rh

Two beam coupling, light-induced erasure decay and dark decay are investiga ted in as-grown and reduced BaTiO3:Rh as a function of temperature. The pho torefractive sensitivity increases with temperature, mainly due to the incr ease of the speed. As deduced from the dark decay measurement, the shallow trap effect decreases while the dark conductivity increases with increasing temperature. These two factors determine how the two beam coupling gain de pends on intensity and the intensity dependence power coefficient with resp onse time varies as temperature increases. For the as-grown sample, the pho torefractive properties are controlled by the competition between deep and shallow levels when the temperature is below 60 degreesC. Above 60 degreesC , large dark conductivity plays a dominant role. For the sample reduced at an atmosphere of 10(-10) atm oxygen partial pressure, the photorefractive p roperties are controlled by the competition between deep and shallow traps from room temperature to 100 degreesC. For the sample reduced at an atmosph ere of 10(-14) atm oxygen partial pressure, the photorefractive properties are mainly dependent on the dark conductivity though it has a high photocon ductivity.