Generation of a large compressive strain wave in graphite by ultrashort-pulse laser irradiation

• Published in: Structural dynamics (Melville, N.Y.) Vol. 6; no. 2; p. 024501
• Main Authors: Wang, Xiaocui, Jarnac, A., Ekström, J. C., Bengtsson, Å. U. J., Dorchies, F., Enquist, H., Jurgilaitis, A., Pedersen, M. N., Tu, C.-M., Wulff, M., Larsson, J.
• Format: Journal Article
• Language: English
• Published: United States American Institute of Physics, Inc 01-03-2019; AIP Publishing; American Crystallographic Association; AIP Publishing LLC and ACA
• Subjects: Ablation; Atom and Molecular Physics and Optics; Atom- och molekylfysik och optik; Carbon; Compressive properties; Condensed Matter Physics; Den kondenserade materiens fysik; Diamonds; Experiments; Fysik; Graphite; Internal pressure; Lasers; Natural Sciences; Naturvetenskap; Phase transitions; Physical Sciences; Physics; Simulation; Single crystals; Wave generation; Wave propagation; X-ray diffraction; X-rays; France; Sweden
• ISSN: 2329-7778; 2329-7778
• DOI: 10.1063/1.5089291

We have studied strain wave generation in graphite induced by an intense ultrashort laser pulse. The study was performed in the intensity regime above the ablation threshold of graphite. The aim was to maximize the strain and, thus, also the internal pressure (stress). Laser pulses with a 1 ps temporal duration melt the surface of graphite resulting in a molten material which initially exists at the solid density. As the molten material expands, a compressive strain wave starts propagating into the crystal below the molten layer. The strain pulse was studied with time-resolved X-ray diffraction. At a temporal delay of 100 ps after laser excitation, we observed >10% compressive strain, which corresponds to a pressure of 7.2 GPa. This strain could be reproduced by hydrodynamic simulations, which also provided a temperature map as a function of time and depth.