Creation and orientation of nano-crystals by femtosecond laser light for controlling optical non-linear response in silica-based glasses

We explore the femtosecond laser-induced modifications (i.e., morphology, crystallization, and nanostructure) in Li
₂
O-Nb
₂
O
₅
-SiO
₂
glass at high-repetition-rate (1030nm, 300fs, 300 kHz) to get insight on the ultrafast laser-matter interaction according to pulse energy and writing configuration. Three-dimensional SHG patterns with controllable angular dependence were achieved. Electron backscatter diffraction indicated that the angular dependence was associated to preferential nanocrystals orientation: crystal polar axes are distributed within a plane perpendicular to the incident laser polarization direction.