Abstract
A type of laser-induced surface relief nanostructure—the nanocrown—on thin metallic films was studied both experimentally and theoretically. The nanocrowns, representing a thin corrugated rim of resolidified melt and resembling well-known impact-induced water-crown splashes, were produced by single diffraction-limited nanosecond laser pulses on thin gold films of variable thickness on low-melting copper and high-melting tungsten substrates, providing different transient melting and adhesion conditions for these films. The proposed model of the nanocrown formation, based on a hydrodynamical (thermocapillary Marangoni) surface instability and described by a Kuramoto-Sivashinsky equation, envisions key steps of the nanocrown appearance and gives qualitative predictions of the acquired nanocrown parameters.
- Received 8 April 2014
- Revised 18 July 2014
DOI:https://doi.org/10.1103/PhysRevE.90.023017
©2014 American Physical Society