Light emission associated with laser damage in silica glass and optical glass

We studied light emission associated with laser-induced surface damage in high purity silica glass and optical glass (barium borosilicate glass, borosilicate glass, and lead silicate glass). A visual flash and sharp sound were observed with the irradiation of KrF excimer light (5.0 eV) focused with a convex lens. On observing silica glass, in which manufacturing methods and conditions differed, there was no difference in the emission spectrum but there were line spectra from the ionization of atmospheric gas in the continuous spectrum. The intensity of the line spectrum was proportional to the square of the laser intensity. On the other hand, in the case of the optical glass, there were line spectra associated with neutral atoms and ions of the (glass) component atoms in the continuous spectrum. The strength of the line spectrum was in direct proportion to the laser intensity. In silica glass and optical glass, the shape of the damage was different. In the case of silica glass and the borosilicate glass, a crack was formed. In barium borosilicate glass and lead silicate glass a groove was formed. These experiments show that the damage mechanism is different depending on the (energy) absorption process.