Investigating the transition from high to low spatial frequency periodic nanoripples on TiO2 (0 0 1) oriented surface upon irradiation with UV-femtosecond pulses

• DOI: 10.1016/j.apsusc.2024.159853
• Publication Date: 2024-03-09T03:29:08Z
• Authors: A. Kanaev; G. Perrakis; G.D. Tsibidis; E. Stratakis; A. Englezis; L. Museur

The formation of laser-induced periodic surface structures (LIPSS) on a TiO2 (0 0 1) oriented upon irradiation with UV-fs laser pulses was analyzed. Two systems low spatial frequency LIPSS (LSFL) perpendicular to the direction polarization are observed after N = 5 pulses. One developed edges crater created by first pulse, while other appeared in center and spread towards edges. When greater than 10, two merge. Both LSFL have period approximately 200 nm due coherent superposition waves scattered at inhomogeneities transient metallic surface. However they differ type defects involved excitation process waves. While pronounced localized rim triggered edge spot, central part nucleated shallow high (HSFL), which parallel polarization. A mechanism is proposed explain role HSFL LSFL. Numerical simulations absorbed power density support evolution from as number increased.