1. TASC-INFM (National Institute for the Physics of Matter), Elettra Synchrotron Light Source, Lilit Beam-line SS14 km 163.5, Area Science Park, 34012 Basovizza, Trieste, Italy
2. Istituto di Elettronica dello Stato Solido, Via Cineto Romano 42, 00156 Rome, Italy
3. X-Ray Microscopy Beamline, European Synchrotron Radiation Facility, BP220, F-38043 Grenoble Cedex, France

Correspondence to: E. Di Fabrizio¹ Correspondence and requests for materials should be addressed to E.D.F. (e-mail: Email: difabriz@sci.area.trieste.it).

Abstract

The development of high brilliance X-ray sources coupled with advances in manufacturing technologies has led to significant improvements in submicrometre probes for spectroscopy, diffraction and imaging applications. The generation of a small beam spot size is commonly based on three principles¹: total reflection (as used in optical elements involving mirrors or capillaries), refraction (such as in refractive lenses²) and diffraction. The latter effect is employed in Bragg–Fresnel or Soret lenses, commonly known as Fresnel zone plate lenses. These lenses currently give the best spatial resolution, but are traditionally limited to rather soft X-rays—at high energies, their use is still limited by their efficiency. Here we report the fabrication of high-efficiency, high-contrast gold and nickel multistep (quaternary) Fresnel zone plates using electron beam lithography. We achieve a maximum efficiency of 55% for the nickel plate at 7 keV. In addition to their high efficiency, the lenses offer the advantages of low background signal and effective reduction of unwanted diffraction orders. We anticipate that these lenses should have a significant impact on techniques such as microscopy³, micro-fluorescence⁴ and micro-diffraction⁵, which require medium resolution (500–100 nm) and high flux at fixed energies.