Berlin 2008 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 25: Trends in Ion Beam Technology: From the Fundamentals to the Application

DS 25.3: Vortrag

Donnerstag, 28. Februar 2008, 11:45–12:00, H 2013

Fabrication of novel pinholes for digital in-line X-ray holography by FIB and their application — •Ruth Barth¹, Todd Simpson², Silvia Mittler², Michael Grunze¹, and Axel Rosenhahn¹ — ¹Angewandte Physikalische Chemie, Universität Heidelberg — ²Department of Physics and Astronomy, The University of Western Ontario, Canada

One way of adapting the classical Gabor geometry for in-line holography to photons instead of electrons includes a pinhole which provides a diverging photon beam and a detector to record the hologram. As the resolution is determined by the wavelength of the photons and the numerical aperture of the detection system, it is straightforward to increase the photon energy in order to enhance the performance of the technique. Vacuum-ultraviolet (VUV) synchrotron radiation has been successfully utilized for this purpose, and the implementation of digital Gabor microscopy with 14 nm radiation was proven. As the effective numerical aperture is limited by the size of the central Airy maximum, which is in turn inversely depending on the diameter of the pinhole, small apertures with sizes of the order of the wavelength are desired. We show the application of new pinholes produced by Focused Ion Beam milling through thin gold membranes. Due to the high aspect ratio of about 1:5 to 1:10 it is possible to obtain homogeneous illumination of the CCD chip by the central Airy maximum without direct beam contribution. With these new point sources for soft X-ray holography reconstructions with resolution of presently 400 nm are possible.