Abstract

Recent research¹–⁹ has shown that if a binary-phase diffractive optical element (DOE) has features that are on the order of the illuminating wavelength, the performance limits set by scalar-based diffraction theory can be overcome. In fact, diffraction efficiencies in excess of 90% have been predicted for binary gratings that have subwavelength features.^1,4,5 Due primarily to the availability of tools for modeling, the analysis and design of subwavelength DOEs (SWDOEs) has concentrated primarily on gratings.^1-7,10 To overcome this limitation, we have developed numerical routines that use a boundary element method (BEM) to analyze diffraction from finite extent, aperiodic DOEs.¹¹ In this paper we consider diffractive design, in particular, the design of diffractive lenses, subject to the constraints of fabrication.

© 1998 Optical Society of America