Nm Science Enabled by Waveguides
C. Fuhse, C. Ollinger, and T. Salditt
Institut fuer Roentgenphysik, Universitaet Goettingen, 37077 Goettingen, Germany
Two-dimensionally confining x-ray waveguides [1,2] can be used as very small sources providing highly-coherent beams with cross-sectional dimensions of only some tens of nanometers. They can be applied to various kinds of scanning microscopy, or they can serve as point-like sources for lensless projection microscopy. In the latter case, a magnified in-line hologram is recorded, from which an image of the sample can be calculated by a holographic reconstruction.
A well-known problem of in-line holography is that the reconstructed image is severely disturbed by a so-called "twin image". This problem is overcome when two coherently illuminated waveguides are used to record a magnified off-axis hologram. In first proof-of-principle experiments, the phase part of the optical transmission function of a sample was reconstructed with a spatial resolution of about 100 nm. Spatial resolution is limited by the cross-sectional dimensions of the guiding core, which may approach a fundamental limit slightly below 10 nm [3].
References:
[1] F. Pfeiffer, C. David, M. Burghammer, C. Riekel, and
T. Salditt; Science 297 (2002), 230.
[2] A. Jarre, C. Fuhse, C. Ollinger, J. Seeger, R. Tucoulou, and T. Salditt; Phys. Rev. Lett. 94, 074801(2005)
[3] C. Bergemann, H. Keymeulen. and J. F. Van der Veen; Phys. Rev. Lett. 91, 204801 (2003)
