Photo-induced processes in silicate glasses exposed to IR femtosecond pulses

The optical properties variation in silicate glasses after exposure to high-power femtosecond laser radiation at 0.85 μm have been studied. The laser spectral line broadening leading to the supercontinuum generation in visible and UV spectral regions was observed in all studied glasses. Color center generation and intrinsic luminescence were found in boro- and alkali-silicate glasses. It is believed that these processes result from linear and/or two-photon absorption of the short-wavelength part of this supercontinuum which causes glass matrix ionization. No color center absorption in the visible region was observed in fused silica at irradiances up to the laser damage threshold. It was concluded that there is no significant ionization of fused silica under exposure to IR femtosecond laser pulses with irradiance below laser induced damage threshold. ©2004 Copyright SPIE - The International Society for Optical Engineering