On use of Bessel light beams in nanotechnologies

A method of focusing of Bessel light beams of zero and first orders is proposed for the first time and studied theoretically and experimentally. This method allows to form axially-symmetric light fields with radii of its central bright or dark spots changing linearly with axial coordinate. The minimum possible spot dimensions are on the order of a wavelength. A new optical element for production of converging Bessel beams is proposed. It is suggested to use focused Bessel beams in nanotechnologies for guiding of cold atoms.