Femtosecond laser induced microstructure and luminescence changes in oxyfluoride tellurite glasses

We report on microstructure modification and local luminescence change in oxyfluoride tellurite glasses induced by a 1030 nm, 500 kHz femtosecond laser. Tellurium nanoparticles are precipitated in the laser-modified region based on X-ray diffraction analysis and transmission electron microscopy observation. Micro-Raman spectra and energy dispersive spectroscopy show that migration of ions (Te4+, Zn2+ and O2-) and coordination state transformation of Te4+ ions occurred after the irradiation. The luminescence property of Er3+-doped glass also changes in the irradiated zone. The mechanisms of above phenomena are interpreted. During the 500 kHz femtosecond laser irradiation, photo-ionization process plays a significant role in the precipitation of Te crystalline phase. The creation of sharp temperature gradient results in modification of element distribution, which leads to the coordination change of Te4+ ions and luminescence change of Er3+ ions. These results are of reference value to fabricate integrated optical waveguide amplifiers and lasers in oxyfluoride tellurite glasses. (C) 2014 Published by Elsevier B.V.