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O: Fachverband Oberflächenphysik

O 71: Plasmonics and Nanooptics III

O 71.9: Vortrag

Donnerstag, 3. April 2014, 12:30–12:45, GER 38

Near-field nanospectroscopy on perovskite-based superlenses — •Susanne C. Kehr and L.M. Eng — Institut für Angewandte Physik/Photophysik, Technische Universität Dresden, 01061 Dresden

A planar slab with negative permittivity acts as a superlens: it transforms the evanescent fields from the object located on one side of the slab, to form a sub-diffraction-limited image on the opposite side. We study superlenses based on perovskite oxides that show superlensing in the mid-IR. These materials have little material absorption at the wavelengths of interest and, moreover, can be grown epitaxially in high quality, which reduces any losses due to scattering at the interfaces.

We examine multilayer lenses by scattering-type near-field optical microscopy (s-SNOM) in combination with a free-electron laser. This unique setup allows us to address precisely the superlensing resonance, to record the local images created by the lenses, and to measure their spectral response. We found that different perovskites can be combined to form superlenses at different wavelengths that match perfectly theoretical predictions [1]. All of these superlenses form images beyond the diffraction limit. Moreover, we found that the spectral behavior of the lenses reflects a special probe-sample coupling that is mediated by the superlens [2], which might be of interest for functionalized coupling of nanosized objects. Furthermore, the special properties of perovskites such as colossal magnetoresistance, ferroelectricity, and superconductivity may allow for further applications and variations of superlensing.

[1] S.C. Kehr et al., Opt. Mater. Express 1, 1051 (2011).

[2] S.C. Kehr et al., Nat. Commun. 2, 249 (2011).