Variable shaped electron-beam lithography application to subwavelength and computer generated diffractive optics fabrication

Abstract

Electron-beam lithography for generation of diffractive optical elements topology is examined. The formula for the estimation of exposure data volume for variable shaped electron-beam lithography is presented as a function of diffractive optical element parameters and approximation accuracy. Diffractive optical elements with a subwavelength feature size were manufactured. These elements act as optical elements with an artificial refractive index. A Fresnel zone plate with an artificial phase retardation has been manufactured. Based on the proximity function measured for the actual exposure conditions, the proximity correction has been provided and undistorted structures have been fabricated. Experimental results are presented on computer generated optical elements for industrial applications. A computer generated lens which focuses radiation into a ring has been fabricated. A photomask set was manufactured for a reflecting optical element which focuses a high power CO2 laser beam to two points with parameters required for laser welding.