Sub-100 nm structures by neutral atom lithography

Instead of using a solid mask to pattern a light beam (optical lithography) we used a mask made of light to pattern a beam of neutral atoms (atom lith ography). By making use of two special features of the atom-light interacti on we wrote structures with periods below lambda/2. In the first approach w e inverted the focussing potentials by switching the detuning of the light field during the deposition. The second method uses the fact that atoms wit h a magnetic substructure in the electronic ground state are strongly sensi tive to the polarization of the light field. Both techniques produce sub-10 0 nm chromium structures in one and two dimensions on silicon substrates.