Laser Parallel Nanopatterning of Lines and Curves by Micro-particle Lens Arrays

Laser surface nanopattering using near-field enhancement by particle-lens arrays is studied. Experimental and theoretical investigations are made in order to clarify the properties of the nanopatterns produced. The obtained results show that this nanofabrication technique is a flexible method for precise surface nanopatterning. A close-packed monolayer of SiO2 Spheres (r=500 nm) is directly formed onto the substrate surface by its self-assembling, and a 248nm wavelength KrF excimer laser is used to irradiate the samples. A theoretical treatment of the results obtained is made by FDTD (finite difference time domain) simulation and calculations of the near field scattering cross section based on Mie's theory. The effect of the laser fluences and incident angles is studied. By using lower laser fluence than the ablation threshold of the bulk material, arrays of features can be easily produced. For the first time, it was demonstrated that very flexible patterns like straight lines and curves can be generated on the substrates over a large surface area.