Nanostructured target fabrication with metal and semiconductor nanoparticles

Abstract

The development of ultra-intense high-energy (≫1 J) short (<1 ps) laser pulses in the last decade has enabled the acceleration of high-energy short-pulse proton beams. A key parameter for enhancing the acceleration regime is the laser-to-target absorption, which heavily depends on the target structure and material. In this work, we present the realization of a nanostructured target with a sub-laser wavelength nano-layer in the front surface as a possible candidate for improving the absorption. The nanostructured film was realized by a simpler and cheaper method than using conventional lithographic techniques: A colloidal solution of metallic or semiconductor nanoparticles (NPs) was produced by laser ablation and, after a heating and sonication process, was spray-dried on the front surface of an aluminum target. The obtained nanostructured film with a thickness of 1 μm appears, at morphological and chemical analysis, uniformly nanostructured and distributed on the target surface without the presence of oxides or external contaminants. Finally, the size of the NPs can be tuned from tens to hundreds of nanometers simply by varying the growth parameters (i.e., irradiation time, fluence, and laser beam energy).

Laser-Plasma Driven Synthesis of Carbon-Based Nanomaterials

“…Progressive aggregation of nanomaterials in the LASiS plume during the laser irradiation is a well-known phenomenon 10 . The observed starting time for the aggregation (30 s) is identical to what observed for metal and semiconducting nanoparticles 20 – 22 , indicating a plume expansion and evolution similar to that observed for the synthesis of nanoparticles 11 , 12 . The main stages in the LASiS exfoliation process can be resumed as follows: the process starts with the absorption of the laser pulse energy by the Graphite target.…”