Micro-hole fabrication based on focus-shaped radially polarized beams

Abstract

A micro-hole fabrication scheme based on focus-shaped radially polarized beams is presented. First, a micro-hole fabrication system is demonstrated based on the focus shaping of radially polarized beams, where a high energy ultra-small spot with a long depth of focus can be obtained by focus shaping using the combination of a diffractive optical element (DOE) and a high numerical-aperture objective, and such focused spot is preferred to fabricate the micro-hole with a high ratio of depth and radius. Then, diffractive optical elements (DOEs) are designed to achieve such ultra-small spots with a long depth of focus using the global search algorithm, and the focus-shaped field intensities are calculated based on vector diffraction theory. Finally, a conclusion is drawn from the theoretical analysis and numerical simulation, and focus-shaped radially polarized beams are suitable to fabricate the micro-hole with a high ratio of depth and radius.