A CONIC PRIMITIVE-BASED PATTERN GENERATOR FOR ELECTRON-BEAM LITHOGRAPHY OF DIFFRACTIVE OPTICAL-ELEMENTS

The efficient lithography of diffractive optical elements requires the pattern data to be optimized in terms of size and of the fidelity wit h which it approximates the design. We describe a hardware and softwar e package that provides direct support for curved patterns, rather tha n resorting to an approximation by polygons, and that can be implement ed to enhance existing electron-beam lithography tools. The method emp loyed allows surfaces bounded by conic sections to be approached to th e best possible accuracy, and substantially reduces the pattern file s ize.