Atom Nanoooptics & Nannophotonics -> Atom nanofabrication

There are several approaches to fabrication of nanostructures with sizes of several tens of nanometers; each of them has a number of advantages and drawbacks. In particular, the difficulties in further development of approved methods are well known: (i) conventional photolithography has a diffraction limit, (ii) lithography based on charged particle beams meets problems related to commercial production of structures and a significant role of Coulomb repulsion, (iii) scanning probes have a low output, and (iv) self assembling fabrication is not an universal process. An alternative approach for nanotechnology is atom optics, i.e., optics of material particles (electron and ion optics). It deals with problems of formation and control of ensembles and beams of neutral atoms. The term “atom optics” is similar to the terms “light optics” or “photon optics”. An important direction of atom optics is the development of basic elements, similar to the elements of conventional light optics. Among many applications of atom optics elements, atom lithography is potentially important for micro and nanofabrication of material structures.

Despite a large number of proposed methods for focusing atomic beams, this problem remains experimentally difficult. The main difficulty is the fabrication of the atom–field interaction potential with properties similar to those of the “ideal” lens for atoms. We experimentally implemented for the first time another approach to the problem of focusing and constructing images in atomic optics, which is based on the concept of a pinhole camera; the latter is used both in light optics and in modern experimental physics when it is difficult to form a focusing potential. In an atomic “pinhole camera”, an atomic beam is transmitted through an array of holes in a mask, thus forming, by analogy with optics, a “luminous object” of specified geometry. The atoms transmitted through the holes in the mask, propagating in vacuum over straight-line trajectories, arrive at a thin film located at a distance L from the mask. Each hole of the film serves as a pinhole camera for atoms, forming an image of the “object” on the surface of a substrate, which is located at a small distances l behind the film. In this geometry, a set of object images, decreased approximately by a factor of m = L/l , is formed on the substrate. The atomic “pinhole camera” is an analog of the Feynman’s scalable manufacturing system that could manufacture a smaller scale replica of itself.