Laser-Scanning Direction Effect in Femtosecond Laser-Assisted Etching

In this study we examined how the laser-scanning direction during the inscription of modified lines affects to the etching rate along the lines in the femtosecond laser-assisted etching. An isotropic material (silica) was used as the sample. Circular polarization was used for inscribing modified lines, in order to avoid a direction effect arising from polarization. Scanning direction dependence was observed in the etching rate along the modified lines. The relation between the occurrence of a scanning direction effect and the other inscribing parameters (pitch and pulse energy) was examined.