Sharper images: Focusing soft X-rays with photon sieves

L. Kipp, M. Kalläne, S. Harm, M. Skibowski, R.L. Johnson, R. Berndt, R. Adelung, R. Seemann
IEAP, Kiel University, DE

Keywords: nanoscopy, X-ray focus, photon sieve

Abstract:
Fresnel zone plates consisting of alternating transmissive and opaque circular rings can be used to focus X-rays. Spatial resolutions achievable are of the order of the width of the outermost zone which is limited by the smallest structural size (20 nm - 40 nm) that can be fabricated by lithography today. Here we show that a large number of pinholes distributed appropriately over the Fresnel zones --- a photon sieve --- make it possible to focus soft X-rays to spot sizes smaller than the diameter of the smallest pinhole. In addition, higher orders of diffraction and secondary maxima can be suppressed by several orders of magnitude. In combination with the next generation of synchrotron light sources (Free-Electron Laser) these photon sieves focusing in three dimensions offer new opportunities with sharper images for highest spatial resolution x-ray microscopy and spectroscopy in nanostructure research and life sciences.

NSTI Nanotech 2003 Conference Technical Program Abstract