Beyond lock-in analysis for volumetric imaging in apertureless scanning near-field optical microscopy.
Conventional apertureless scanning near-field optical microscopy uses lock-in demodulation techniques to filter higher harmonics from the periodically modulated optical signal. On the one hand, this signal notoriously may contain contaminating mechanical contributions; on the other, it reduces the available data to one number per pixel. Realizing that the vertically oscillating near-field probe actually traverses a whole volume above the sample surface, we discuss a model to extend the data analysis in an attempt to better extract the optical information and to recover its three-dimensional spatial distribution.
Vogelgesang
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Max Planck Institut für Festkörperforschung, 70569 Stuttgart, Germany. r.vogelgesang@fkf.mpg.de
Esteban
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Kern
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