With a two-dimensional (2D) optical mask at =1083 nm, nanoscale patterns are created for the first time in an atom lithography process using metastable helium atoms. The internal energy of the atoms is used to locally damage a hydrophobic resist layer, which is removed in a wet etching process. Experiments have been performed with several polarizations for the optical mask, resulting in different intensity patterns, and corresponding nanoscale structures. The results for a linear polarized light field show an array of holes with a diameter of 260 nm, in agreement with a computed pattern. With a circularly polarized light field a line pattern is observed with a spacing of /20.5=766 nm. Simulations taking into account many possible experimental imperfections can not explain this pattern.
Petra, S. J. H., Leeuwen, van, K. A. H., Feenstra, L., Hogervorst, W., & Vassen, W. (2004). Atom lithography with two-dimensional optical masks. Applied Physics B: Lasers and Optics, B79(3), 279-283. https://doi.org/10.1007/s00340-004-1569-4