Writing of crystal-dots and lines by YAG laser irradiation and their morphologies in samarium tellurite glasses

A continuous-wave Nd:YAG laser operating at a wavelength of 1064 nm is used to irradiate BaO–Sm2O3–TeO2 glasses under various conditions (laser power: 0.5–0.7 W, irradiation time: 1–60 s), and the formation, behavior and morphology of crystal-dots and lines consisting of the Sm2Te6O15 phase are examined. Crystal-dots with a corn-like shape are formed at the surface of the glasses. The diameters of crystal-dots are 3–45 μm and their lengths (depths) toward the interior of glasses are 50–110 μm. The size of crystal-dots depends on laser power, laser irradiation time and Sm2O3 content. The diameter and length of crystal-dots increase almost linearly with the cube root of laser irradiation time t1/3, suggesting that the growth of crystal-dots in the YAG laser-induced crystallization is controlled by diffusion of constituent ions. Crystal-lines with a width of ∼10 μm are also written by scanning the YAG laser at a speed of 20–30 μm s−1. A model of YAG laser-induced crystallization is proposed.