Apodization of generalized axicons to produce uniform axial line images

Abstract

The effects of apodization of a generalized holographic axicon that produces a uniform axial line intensity distribution are considered. It is shown, both by simulations and experimentally, that the apodization considerably improves the image line quality within the extended focal region, especially near the image end points. A simple method of implementing the apodization by a binary-amplitude encoding of the generalized axicon is assessed in detail. Fabrication of the axicon by photoreduction and experimental results on the intensity variations of the line image, which are in substantial agreement with the theoretical considerations, are presented and analysed. On apodization the axial intensity becomes nearly uniform, while transversely the line image retains its high definition.