Nándor BOKOR^*, Andrew DOMONDON^1,2, and Yoshinori IKETAKI^3,4

Department of Physics, Budapest University of Technology and Economics, Budafoki u. 8, Budapest 1111, Hungary
¹International Christian University, 3-10-2 Osawa, Mitaka, Tokyo 181-8285, Japan
²Committee on Conceptual and Historical Studies of Science, University of Chicago, 1126 East 59th St., Room 205, Chicago, IL 60637, U.S.A.
³PRESTO “Life Phenomena and Measurement Analysis” Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
⁴Olympus Corporation, 2-3 Kuboyama-cho, Hachioji, Tokyo 192-8512, Japan

(Received July 13, 2009; Accepted December 28, 2009)

Efficient techniques to achieve isotropic edge enhancement in optics involve applying a radial Hilbert, Laguerre–Gaussian, or differentiating filter on the object spectrum. We demonstrate a simple setup for isotropic edge-enhancement in soft-X-ray microscopy, using a single Laguerre–Gaussian zone plate (LGZP). Since the LGZP acts as a beam-splitter, diffraction efficiency problems usually associated with X-ray microscopy optics are not present in this system. As numerically demonstrated, the setup can detect optical path differences as small as λ/50 with high contrast.

Key words: X-ray, edge-enhancement, microscopy, phase-contrast, diffractive optical element, Laguerre–Gaussian, Hilbert, gradient

^*Currently a JSPS fellow at Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan. E-mail address: nandor.bokor@weizmann.ac.il