The optical properties of glasses irradiated by high-power, 810 nm femtosecond laser have been studied. Laser-induced processes occurred at irradiation well below the threshold for laser-induced damage. The visible absorption spectra of the original and irradiated glass were measured and darkening lines were found in the irradiated region. According to absorption spectra, the absorption of glass was increased greatly after irradiation by femtosecond laser. The absorption of the irradiated glass decreased along with time and reached stabilization in about 90 minutes. The laser-induced darkening in the glass disappeared when the glass was heat-treated under 200 degrees Celsius for a few minutes. It was considered that darkening was induced by color-center formation because of glass matrix photoionization and the consequent trapping of electrons and holes by intrinsic or impurity defect of the glass. This process is expected to become a useful method used to fabricate optical memory with both an ultra-high storage density and an ultra-high recording and readout speed.

Date Published: 7 February 2001
PDF: 4 pages
Proc. SPIE 4085, Fifth International Symposium on Optical Storage (ISOS 2000), (7 February 2001); doi: 10.1117/12.416845

Published in SPIE Proceedings Vol. 4085:
Fifth International Symposium on Optical Storage (ISOS 2000)
Fuxi Gan; Lisong Hou, Editor(s)