Properties and Fabrication of Micro Fresnel Zone Plates

Arrays of ~2-mm diam, f/9, diffraction-limited Fresnel zone plates are made and measured. Amplitude zone plates are fabricated by conventional photolithographic techniques, while a specially developed evaporation/etching technique is used for phase zone plates. The point spread function of such zone plates is measured with a rotating cube scanner and found to agree closely with theory over more than one order of magnitude.