Self-organized homo-epitaxial growth in nonlinear optical BaAlBO3F2 crystal crossing lines patterned by laser in glass

Abstract

Crystallization processing of glasses is important as a novel technique for the development of new optical materials, and laser-induced crystallization provides a new challenge in science and technology of materials. Nonlinear optical BaAlBO3F2 crystal lines with crossing, bending, and spiral shapes were patterned at the surface of 2NiO–49BaF2–24.5Al2O3–24.5B2O3 (mol%) and 2.9NiO–48.5BaF2–24.3Al2O3–24.3B2O3 (mol%) glasses by laser irradiation (Yb:YVO4 laser with a wavelength of 1080nm) and the orientation state of BaAlBO3F2 crystals was examined from birefringence image observations. The birefringence images indicate that the growth of highly c-axis oriented BaAlBO3F2 crystals follows along the laser scanning direction even if the laser scanning direction changes, and in particular the direction of the c-axis of BaAlBO3F2 crystals changes gradually at the crossing and bending points. The model of “self-organized homo-epitaxial growth” is proposed for the crystal orientation at the crossing and bending points, as a new crystal growth science and engineering beyond the wise providence of nature.