Regensburg 2002 – scientific programme
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O: Oberflächenphysik
O 5: Rastersondentechniken (I)
O 5.6: Talk
Monday, March 11, 2002, 12:30–12:45, H44
Determination of the Effective Optical Aperture by Deconvolution — •Matthias Wellhöfer1,2, Olaf Hollricher2, and Othmar Marti1 — 1Universität Ulm, Abteilung Experimentelle Physik, Albert-Einstein-Allee 11, D-89069 Ulm — 2WITec Wissenschaftliche Instrumente und Technologie GmbH, Hörvelsinger Weg 6, D-89081 Ulm
Resolution in near-field optical microscopy is a point of intensive discussion. The maximum resolution in a near-field image is determined by aperture size, probe-sample distance and the sample itself. But there are also effects due to nonlinear interaction between the electromagnetic (optical) waves and the surface that often make image interpretation very complicate and give rise to so-called topography induced artifacts.
Many problems have their origin in the fact that the size and shape of the used near-field aperture can only be roughly estimated. Up to now, no method exists that is able to determine the real size and form of the effective optical aperture.
Therefore, we show first results of a calibration test sample. The SNOM measurements are performed in transmission geometry, illumination mode. Deconvolution of the obtained optical near-field images with the sample geometry can give an idea of the shape and size of the effective optical aperture.