APODIZING OF AN ACHROMATIC LENS BY A GRAY-GLASS NEGATIVE LENS ELEMENT

The apodizing performance of a plano-concave lens made of gray glass w as analyzed numerically. It was found that apodizing performance depen ds solely on the edge transmittance of the lens (a zero center thickne ss is assumed here) for any reasonable ratio of radius of curvature of the concave surface and the lens radius. If a modest increase in the size of the central diffraction peak and light losses introduced by su ch a lens can be accepted, it is possible to reduce energy diffraction into diffraction rings approximately tenfold.