Creation of micro-holes on glass surface by femtosecond laser through the ejection of molten material

The interaction of femtosecond laser pulses (800 nm, 150 fs, 1 kHz) with th e surface of fused silica glass was investigated. The morphology and chemic al composition of unirradiated and irradiated glass surfaces and of the mat erial ejected from the surface were examined by secondary ion mass spectros copy (SIMS), scanning electron microscopy (SEM) and X-ray diffraction (XRD) . The experimental results show that (i) femtosecond laser pulses induced d amage on the surface of the glass by the formation of micro-holes. Material was ejected from the glass surface during laser irradiation while the glas s was melted. (ii) the interaction of the laser beam with glass was initial ly fast but decreased rapidly with time and eventually no change was observ ed, (iii) no significant changes in the chemical composition of the irradia ted glass surfaces were observed. The chemical composition of the ejected a nd original material was essentially identical, and (iv) the presence of cr ystalline phase was detected in the ejected material. (C) 2001 Elsevier Sci ence B.V. All rights reserved.