Optical properties of the Ti surface structured by femtosecond laser beam

Abstract

Abstract. Wavelength-scaled periodic ripples formed on the Ti surface under the action of femtosecond laser irradiation have been investigated. The ripples were oriented in parallel to the incident light polarization. After initial formation of ripples, the following laser induced chemical transformation of metallic Ti into dielectric compound was established using the Raman scattering data. Weak Wood's anomaly in the spectra on light diffracted by the structured Ti surface testifies the minor plasmonic activity.

Switching between normal and anomalous Laser Induced Periodic Surface Structures

“…In this case, the small beam diameter preserves coherency of the scattered light within the beam spot, and the scanning introduces positive nonlocal feedback from already created structure to the new area on the surface. It is important to notice, although many papers demonstrated creation of the structure on the same material (for example on Ti) where it is normal (see for example [3]) or anomalous [2,11], there is no any clear theoretical model presented in literature, which can explain the switching mechanism between these two modes. It was noticed already, that the formation of anomalous structure is associated with thermochemical oxidization, while the formation of normal structure is related to ablation [12].…”