Self-focusing and rear surface damage in a fused silica window at 1064 nm and 355 nm

Rear surface damage is known to occur preferentially to front surface damage on silica lenses and windows transmitting 1ω or 3ω light of a Nd:Yag or Nd:glass laser. Lab-scale Experiments were performed to assess the contribution of self-focusing to the measurement of damage statistics. The occurrence of filamentation in the bulk and the statistics of rear surface damage were studied at 1064 nm and 355 nm, for a pulse length around 3 ns. The measurements were performed on synthetic fused silica samples, 4 to 5 cm thick. The laser beam had dimensions around 0.6 mm at the sample. The results are interpreted with the help of the calculations made by J. H. Marburger et al. They are also compared with other experimental results.