title: Self-organized periodic structures on Ge-S based chalcogenide glass induced by femtosecond laser irradiation.
abstract: Self-organized periodic structures have been observed on the surface of the ablation craters of Ge-S based chalcogenide glass produced after irradiation by a focused beam of a femtosecond Ti:sapphire laser (1 kHz, 34 fs, 806 nm). Scanning electron microscopy and atomic force microscopy images of irradiated spots show a periodic structure of ripples with a spatial period of 720 nm (close to the wavelength of fs laser pulses) and an alignment parallel to the electric field of light. With an increasing number of pulses, from 5 to 50 pulses, a characteristic evolution of ripples was observed from a random structure to a series of generally aligned peaks-and-valleys self-organized periodic structures. Additionally, at the center of the ablated spot, micro-domains appear where the ripples are still regular but are assembled in a more complex fashion. The experimental observations are interpreted in terms of strong temperature gradients combined with interference of the incident laser irradiation and a scattered surface electromagnetic wave.
authors: Centre d'optique, photonique et laser, Université Laval, Québec, G1V 0A6 Canada. sandra.messaddeq@copl.ulaval.ca
authors: S H
authors: SH
authors: Messaddeq
authors: R
authors: R
authors: Vallée
authors: P
authors: P
authors: Soucy
authors: M
authors: M
authors: Bernier
authors: M
authors: M
authors: El-Amraoui
authors: Y
authors: Y
authors: Messaddeq