Development of a Neutral Atom Microscope

University Of Texas At Austin, Austin TX

Investigators

Abstract

Microscopes of various types are widely used in scientific research, medicine, and industry. The ability to see objects that are too small to see with the naked eye is crucial for characterizing materials, for manufacturing, and for forensic science. New capabilities in scientific research and technology are enabled by developing novel new microscopes with enhanced resolution and sensitivity. This project will explore ways to use focused atom beams to probe surfaces with nanometer-scale resolution. This addresses the longstanding goal in atomic physics of making a neutral atom microscope, similar to an electron microscope, but with different chemical sensitivity and less destructive interactions. An improved method to focus atom beams will be implemented using a pulsed magnetic lens. This aberration-corrected lens for atoms will enable the research team to pioneer applications for a neutral-atom microscope. The correction of aberrations is tremendously important for the performance of optical microscopes, and has enabled atomic scale resolution for electron microscopes. A breakthrough in aberration-corrected lenses for atoms will enable advances in atom lithography and the operation of a neutral atom microscope with molecular resolution. Students working on this project will gain training in atomic physics, atom optics, and surface chemistry research methods, and this will help prepare them for careers in universities and high tech industries. The principle of the microscope to be developed in this project is that neutral neon atoms in an excited metastable state are focused to a surface. After the impact of each atom, an electron is emitted which is energy-analyzed, providing a unique fingerprint of the chemical composition of the surface. The image will be acquired by rastering the atoms across the surface. The research team will use a pulsed electromagnetic coil as a lens for magnetic imaging of atoms. This allows for pulsed, high-current wires to exert a brief, strong focusing field on an atomic beam, taking advantage of the high refractive power without subjecting the atoms to fringing fields as they enter and leave the lens. Aberration correction will be achieved by tapering the lens to be narrower towards the front, thereby applying a greater force to the faster atoms. The pulsed lens is well-matched to a pulsed supersonic beam which produces a very bright beam of metastable neon atoms. The team has constructed a working prototype and plans to implement methods of beam brightening and velocity selection. With these improvements, a resolution better than 10 nm is expected. Further developments of the atomic lens will address residual aberrations. In parallel, the group will develop metastable impact electron microscopy using an analyzer system. Combining the two developments will enable demonstration of a neutral atom microscope with nanoscale resolution.