Growth of Fresnoite Single Crystal Tracks Inside Glass Using Femtosecond Laser Beam Followed by Heat Treatment

• Published in: Crystal growth & design 2018-11, Vol.18 (11), p.7183-7190
• Main Authors: Lipatiev, Alexey S, Moiseev, Ivan A, Lotarev, Sergey V, Lipateva, Tatiana O, Presnyakov, Mikhail Yu, Fedotov, Sergey S, Sigaev, Vladimir N
• Format: Article
• Language: English
• ISSN: 1528-7483; 1528-7505
• DOI: 10.1021/acs.cgd.8b01358

We have studied the space-selective microcrystallization of barium titanium silicate glass under the femtosecond laser beam. The glass composition (mol %) was 40BaO·20TiO2·40SiO2 corresponding to the composition of polar fresnoite phase known for its large second-order optical susceptibility. Optical and micro-Raman microscopy confirmed the laser-induced formation of the Ba2TiSi2O8 crystalline tracks and their morphology was investigated by transmission electron microscopy. The possibility of a 20-fold increase in laser scanning speed providing homogeneous crystal track growth using the laser beam with an elliptical cross-section as compared to the conventional Gaussian beam has been shown. It has been demonstrated for the first time that annealing of laser-written crystalline tracks leads to substantial improvement of the quality of tracks structure tending to that of the fresnoite single crystal, which can be an important step in the development of single crystal optical waveguide components for photonics.