Abstract
To study the dynamics of laser-ablation induced structure formation (LIPPS), silicon was irradiated by (above-threshold) pulse pairs with a variable time-lag between 100fs and a few picoseconds. With increasing pulse-to-pulse delay we find a significant change in ablated-area morphology: the central range of the irradiated spot becomes less and less depressed whereas a surrounding ring structure exhibits increasingly coarser modulation, typical for strong irradiation, where the ripples are characterized by an alternation between elevation above and depression below the unaffected surface level. At the spot center the ablation depth decreases with increasing pulse separation, showing only structures usually observed for weak irradiation. Micro-Raman spectroscopy of the modified areas indicates an unexpectedly high, almost mono-dispersed, abundance of confined nanostructures. The results clearly seem to rule out structure formation by any interference-induced modulated ablation. Instead, they support the model of self-organized structure formation upon the creation of a thermally unstable, “soft” state of the target after laser impact.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
