Fig. 4: Impact of the linear-to-circular polarization conversion on the laser filamentation.
Dark field images of the fused silica sample after laser damage filamentation experiments carried out at different laser fluences and polarization states. The laser beam comes from the right side. It is characterized by a pulse duration of 3 ns, flat in time, and a wavelength of 351 nm. The left edge of the images corresponds to the start of the bevel sample, located 1 mm away from the sample exit face. Images correspond to a surface of the sample of 2.5 × 15 mm2. Images show the sample after the filamentation experiment performed at a mean fluence of 5.7 J/cm2 (a, c) and laser (b, d), with a linear (a, c) and circular polarization (b, d). e Number of white pixels in (a, c, d) as a function of the distance from the chamfer (no pixel can be counted in (b)). Green line: circular polarization at 7.0 J/cm2; black line: linear polarization at 5.7 J/cm2; red line: linear polarization at 7.0 J/cm2.
