INVESTIGATION OF ENERGY STRUCTURE OF LEAD SILICATE-GLASSES BY NONLINEAR ABSORPTION-SPECTROSCOPY TECHNIQUE

Regularities of color center formation in the lead silicate glasses un der photoexcitation have been studied. It is shown for the first time that the long-wave boundary of carrier mobility of vitreous media can be placed considerably higher then the fundamental absorption edge of the material matrix. For this reason the detection of linear formation of color centers in the lend silicate glasses is not possible. Their coloration arises only from the multi-photon matrix ionization and the excitation occurs through virtual states that are located in the fund amental absorption region. The numerical estimates of the three-photon absorption coefficient and the forming color centers cross-section at 527 nm are obtained for the glasses with different content of lead ox ide.