Crater in a sapphire substrate hit with a femtosecond laser pulse,
followed by annealing
to develop the step structure. 20µm scan. Steps on the
3Å atomic steps.
A small chunk was blown out of the center of the crater. Imaged with a MFP-3D AFM.
Image courtesy of S. MacLaren (sample courtesy Fumiya Watanabe, UIUC),
University of Illinois at Urbana-Champaign.