Laser control of the properties of nanostructures on Ta and Ni under their ablation in liquids

The process of nanostructures (NS) formation on bulk Ta and Ni immersed into liquids is experimentally investigated under its exposure to short laser pulses. Three types of lasers sources have been used, a Nd:YAG laser with pulse duration of 350 ps, an excimer laser at wavelength of 248 nm and pulse duration of 5 ps, and a Ti:sapphire laser with pulse duration of 180 fs. The morphology of NS on Ta and Ni is characterized with either a nanoprofilometer or a Field Emission Scanning Electron Microscope. Average lateral size of nanostructures decreases with the decrease of the laser fluence. The morphology of nanostructures is investigated depending on laser parameters, such as laser pulse duration and laser fluence. Average lateral size of NS varies in the range 40-250 nm for Tantalum and 30-300 nm for Nickel. Possible applications of generated NS are discussed.