Transient color centers in GGG crystals

Electron pulse induced absorption and their decay kinetics have been investigated in samples of GGG crystals with different starting absorption spectra. It is shown that for all samples there appears a wide transient absorption (TA) band with two maxima in the region 14,000-17,000 cm^-1 and 22,000-26,000 cm^-1. TA decay kinetics measurements in 14,000cm^-1 and 22,000cm^-1 are two-exponential (with half-time order several tens and several hundreds ns). Analyzing the obtained results, we can suppose that low and high energy TA bands are connected with the F⁺ (or O^-) and F transient color centers (TCC) respectively.