Optically produced cross patterning based on local dislocations inside MgO single crystals

Here, the authors demonstrate a unique technique to form dense dislocations locally inside a single crystal with a rocksalt-type structure using femtosecond laser irradiation for the first time, to our knowledge. Cross-shaped patterns of micrometer size, originating from densely introduced dislocations, are formed around the focal point. The authors controlled three-dimensional propagation of dislocations by adjusting the pulse energy of femtosecond laser and numerical aperture of objective lens.