Polarization-oriented LiNbO3 nanocrystals by femtosecond laser irradiation in LiO2–Nb2O5–SiO2–B2O3 glasses

This work investigates the role of a B2O3 addition (up to 21 mole %) into a lithium niobium silicate glass matrix, focusing on the orientational dependency of second harmonic generation (SHG), induced after femtosecond laser irradiation. We detected the sharp emission of light at 515 nm, characteristic of SHG, in both static and scanning configurations, using pulse energy, repetition rate, and laser polarization as varying parameters. Among the results to highlight, the SHG signature appears within a few seconds in highly doped B2O3 glass, i.e., one order of magnitude smaller than in B2O3-free glass. Additionally, we found that the orientability of the polar axis of LiNbO3 nanocrystals by writing laser polarization can be obtained in glasses when SiO2 is substituted with B2O3. These preliminary results open the door to the fabrication of crystal / glass based photonic devices with lower laser power deposited and much faster crystallization kinetics.