Transition from intensity dependent absorption to transparency in Ce:BaTiO3

The intensity dependent absorption and transparency of Ce:BaTiO3 is examined in relation to the two trap model of the photorefractive effect. At wavelengths of both 532 nm and 633 nm, the material exhibits intensity dependent absorption, while at a wavelength of 790 nm, intensity dependent transparency is observed, with a transition between absorption and transparency at approximately 650 nm. Experimental data is matched to the two trap theoretical model with good agreement. Analysis of this match shows that the light excitation cross-section of the shallow traps are the main contributors to the observed intensity dependent transition.