Which period ripples will form on the ablated surface:subwavelength or deep-subwavelength

摘要

Nano-texturing of surface by self-organised ablation ripples as well as modifications of internal volume of materials, transparent at the wavelength of laser irradiation, is gaining interest due to simplicity of direct laser writing/printing. With ultra-short laser pulses (T_p < 1 ps) a wider range of structuring morphologies is ac-cessible, namely, sub-wavelength ripples. The surface wave formed on the plasma-dielectric (air or substrate) explains difference of the formed pattern. These corresponding front- and back-side (in respect to the incoming laser beam) modes of laser structuring accounts for the ripple formation inside transparent materials, where a skin-layer plasma is formed. Emerging applications of nano-textured surfaces for bio-medical field are discussed.