Search

Highlights • A novel oxyfluorogallate glass with good mid-infrared property was provided. • Femtosecond surface damage characteristics of oxyfluorogallate glass are investigated. • Femtosecond nonlinear effect is studied to explain the damage mechanism. • Surface damage thresholds show an evident reduction as pulses number increasing. • No changes on the chemistry structure occur after femtosecond laser ablation. Abstract The femtosecond laser-induced damage characteristics of a novel oxyfluorogallate glass with good mid-infrared property are analyzed in detail and the surface-damage thresholds for single- and multi- pulses ablation are determined and an evident reduction trend is obtained. The nonlinear absorption coefficient measured through the femtosecond laser z-scan method is used to explain the damage mechanism according to the calculation of Keldysh parameter. The ablation characteristics of the oxyfluorogallate glass demonstrated a clear evidence of melting and the ablation rate decreased in the presence of the melting phenomenon. Based on subsequent X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy analyses, the chemistry of the mid-infrared oxyfluorogallate glass appeared to remain constant before and after femtosecond laser ablation. This work provides a reference to manufacture infrared optical devices and is useful in promoting the application of the mid-infrared glass material. [ABSTRACT FROM AUTHOR]

Abstract: We report on the precipitation of Si nanocrystals inside a borosilicate glass by using an 800nm, 250kHz femtosecond laser irradiation, which was confirmed with X-ray diffraction, Raman spectra and transmission electron microscopy analyses. Refractive index profile reveals that the refractive index of the Si nanocrystals precipitated region increased up to 8.7% in comparison with that of the unirradiated area, leading to a large diffraction efficiency of the fabricated dot structure. Furthermore, the third-order optical nonlinearity of the Si nanocrystals precipitated glass is greatly enhanced based on the Z-scan measurement. These results may find applications for the fabrication diffractive optical devices and optical switches. [Copyright &y& Elsevier]