Multiphoton coloration of lead silicate glasses by high-power laser radiation

A study was made of the mechanism of the formation of colour centres by the exposure of lead silicate glasses to high-power laser radiation. The long-wavelength mobility edge (>5.8 eV) of charge carriers in these glasses was located well above the fundamental absorption edge (3.5 eV), so that coloration was observed only when the glass matrix experienced multiphoton ionisation. The newly formed colour centres make the main contribution to the change in the transmission directly during the action of nanosecond laser pulses. An estimate was obtained of the three-photon absorption coefficient of TF10 glass at the wavelength of 527 nm.