Crater in a sapphire substrate hit with a femtosecond laser pulse, followed by annealing
to develop the step structure.  Steps on the surface are 3 angstrom atomic steps. 
A small chunk was blown out of the center of the crater. 

Image courtesy of S. MacLaren (sample courtesy Fumiya Watanabe, UIUC),
University of Illinois at Urbana-Champaign.