Laser patterning of oriented LiNbO ₃ crystal particle arrays in NiO‐doped lithium niobium silicate glasses

Abstract The patterning of LiNbO ₃ crystals was carried out at the surface of NiO‐doped 40Li ₂ O‐32Nb ₂ O ₅ ‐28SiO ₂ (LNS) glasses using continuous‐wave Yb:YVO ₄ fiber laser (wavelength: 1080 nm) to gain a deeper understanding of the crystal growth in the laser‐induced crystallization in glasses. It was suggested that in the conventional crystallization in an electric furnace, NiO acts as a nucleation agent in the LNS glass and the addition of NiO suppresses the c ‐axis orientation of LiNbO ₃ at the glass surface. It was found from birefringence image observations that LiNbO ₃ crystals with a dot shape have a radial orientation from the center to the edge parts. Highly c ‐axis oriented LiNbO ₃ crystal particle (diameter: 7‐11 μm) arrays were patterned along the laser scanning direction in laser irradiations (scanning mode: eg, the laser power of 1.60 W and scanning speeds of 7‐10 μm/s) in 3 mol% NiO‐doped LNS glass. It was suggested that the nucleation and crystal growth of LiNbO ₃ crystals are taking place repeatedly (periodically) along the laser scanning direction, consequently providing LiNbO ₃ crystal particle arrays.