Dynamic light-induced absorption in highly reduced barium titanate

A highly reduced barium titanate crystal was made. Its light-induced absorption spectrum and dynamic light-induced absorption were investigated. By the analysis of the dynamic light-induced absorption, the photo-excitation cross section and the thermal excitation rate of the shallow level were found. The calculation of the photo-excitation cross section of the deep level was also performed. This calculation is based on the assumption that the light-induced absorption spectrum can be described by the superposition of two Lorentz distribution functions. Using the parameters mentioned above, we estimated the concentrations of the deep and shallow levels through the absorption coefficients.