Filamentation-induced bulk modification in fused silica by excimer laser

Filamentary propagation and laser-induced damage have been demonstrated and investigated in fused silica excited by nanosecond deep-ultraviolet laser pulses. Long-range modification channels, up to 10 mm because of the filamentation and defect absorption in the bulk of the solid transparent materials, are observed. Here we investigate ways to control these laser-induced modifications by varying the laser pulse energy and number of exposures. The effects of objective lens focal length and working distance on the filament and modification are also discussed. Furthermore, the laser-induced fluorescence spectra indicate that dense absorbing defects in the damaged regions. Moreover, the mitigation of the induced damage through thermal effects are discussed. (C) 2017 Optical Society of America