Formation of nanostructures induced by capillary-discharge soft X-ray laser on BaF2 surfaces

BaF2 was ablated by a capillary-discharge pumped soft X-ray laser at 46.9 nm focused by a toroidal mirror at a grazing incidence of 83 degrees. The damaged area, induced by both single and multiple laser pulses, was determined to be covered with fringe-like nanostructures with spacings of approximately 400 nm and mastoid nanostructures with diameters of approximately 600nm. In this study, we analyze the morphology of the detected damage patterns and discuss the damage mechanism. Results indicate that the depth of the nanostructures varies with different pulse numbers and laser power densities. (C) 2016 Elsevier B.V. All rights reserved.