Multi-step electron beam technology for the fabrication of high performance diffractive optical elements

The method has been successfully applied in the fabrication of several types of diffractive elements, including micro-Fresnel lens arrays, phase sampling filters and diffraction gratings on quartz and GaAs wafers. The diffraction efficiencies of these elements were found to be up to 92%. The lens exhibited diffraction-limited focusing characteristics and an insignificant wave front aberration (rms 0.01λ).