Femtosecond laser ablation of chalcogenide glass: explosive formation of nano-fibres against thermo-capillary growth of micro-spheres

摘要

Formation of nano-fibres ranging from 30 to 300 nm in diameter and exceeding the length of one millimetre was observed during explosive ablation of As_2S_3 glass by femtosecond pulses at high fluence (>5 J cm~(-2)) irradiation of the 800 nm wavelength, 160 fs duration pulses in air. Spheres of up to several microns in diameter were also found to form, competing with nano-fibre formation and significantly deteriorating their morphology. Theoretical analysis of thermo-capillary and heat exchange mechanisms of the fibre formation predicts conditions under which the good nano-fibre morphology can be preserved.