Study of crystal formation in borate, niobate, and titanate glasses irradiated by femtosecond laser pulses

The generation of nonlinear optical functional crystals in borate, niobate, and titanate glasses that have been irradiated by 800-nm femtosecond laser pulses was investigated by Raman spectroscopy. The effects of the length of irradiation time on the generation of crystals were measured. We show that the structure of the glass network was destroyed during irradiation by the femtosecond laser. (B3O6)3−, (NbO6)7−, and (TiO4)4− anion units as well as β-BaB2O4, LiNbO3, and Ba2TiO4 crystals were formed in the focal area of the irradiation. We suggest that femtosecond laser irradiation can be a useful approach to the fabrication of integrated optical devices.