Optical nonlinear crystalline dot and line patterning in samarium bismuth borate glasses by YAG laser irradiation

New transparent surface crystallized glasses in the system of Sm₂O₃-Bi₂O₃-B₂O₃ have been successfully fabricated. The second harmonic generation (SHG) from the crystalline phase at the surface layers has been confirmed from Maker fringe measurements. The chemical composition of optical nonlinear crystals in the crystallized glass of 12.5Sm₂O₃ · 30Bi₂O₃ · 57.5B₂O₃ is determined to be Bi_0.7Sm_0.3BO₃. The irradiation of a continuous-wave YAG laser with a wavelength of 1064 nm induces sharp refractive-index changes or crystalline dot formation, depending on Sm₂O₃ content in the glasses and laser irradiation condition. In 10Sm₂O₃ · 30Bi₂O₃ · 60B₂O₃ glass, refractive-index changes (not crystallites) are induced by laser irradiations (power: 1W, time: 1-250 s), and spherical spots with 2-45 μm are formed. In 12.5Sm₂O₃ · 30Bi₂O₃ · 57.5B₂O₃ and 16.5Sm₂O₃ · 26Bi₂O₃ · 57.5B₂O₃ glasses, crystalline dots with diameters of 5-65 μm are formed by laser irradiations (power: 0.5-0.7 W, times: 1-250 s). The lines consisting of refractive-index changes and crystallites are fabricated by scanning laser spots with the speeds of 5-25 μm · s^-1. It is found that the crystalline phase formed by laser irradiation is the same as that precipitated by usual heat treatment in an electric furnace and thus the crystalline dots and lines generate optical second harmonic waves.