Formation of Periodic Surface Structure by Double-pulsed Femtosecond Laser Irradiation

Abstract

Periodic surface structures formed by femtosecond laser (τ=120fs, λ=800nm, Repetition=1kHz) irradiation improve surface properties of solid materials significantly. This does not necessarily means, however, that microscopic uniformity of individual structure is high. In our experiment, it was found that double-pulsed irradiation of femtosecond laser (pulse separation time Δτ=50∼100ps) can control periodicity, linearity and surface roughness of periodic structures precisely.