Directional Writing Dependence of Birefringence in Multicomponent Silica-based Glasses with Ultrashort Laser Irradiation

We reveal laser-induced high birefringence in multicomponent silica-based glass by means of ultrashort laser irradiation. It is attributed to the residual stress. A systematic study of birefringence variation is carried out according to laser parameters such as pulse energy, writing speed and direction, and laser polarization. Strong writing directional dependence is clearly observed when the writing direction is perpendicular to the laser polarization at the writing speeds of 20 μm/s - 120 μm/s, which was likely due to an asymmetry of the laser beam or an asymmetry of interaction mechanism.