Highly ordered vertical nickel nanotubes and nanowires on thin substrate for high power lasers experiments

Nanostructured targets showed improved interaction with ultra-intense laser pulses in comparison to planar ones, both in simulations and in experiments. By increasing the surface area, the absorption and conversion efficiency of the laser energy to the accelerated particle energy are enhanced due to volumetric heating, leading to advanced proton acceleration, x-ray emission, ultra high energy density matter creation, and terabar pressures generation. This work is focused on exploring the limits of the electrodeposition methods for fabrication of nanostructured targets suitable for ultra-intense laser experiments at focused intensities as high as \(10^{23} W/cm^2\). The geometrical characteristics of the nanostructures are expanded to meet a wide range of experimental requirements: diameter, length, distance between structures, and substrate thickness. Nickel nanotubes and nanowires on few hundreds nanometer thick substrates were fabricated using porous alumina as template, obtained by aluminium anodization in various electrolytes solutions. The resulted structures revealed diameters and spacing of several hundreds of nanometers, with length varying between 1-10 micrometers, covering homogeneous areas of several \(cm^2\). The influence of temperature on the current density, with two electrolytes mixtures containing oxalic, citric, phosphoric acids used for anodization, is also reported.