Dresden 2014 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 37: Posters: Plasmonics, Electronic Structure and Spin-Orbit Interaction, Semiconductor and Insulator Surfaces, Nanostructures

O 37.7: Poster

Dienstag, 1. April 2014, 18:30–22:00, P2

Superlensing in n-doped GaAs investigated by near-field microscopy — •Markus Fehrenbacher¹, Stephan Winnerl¹, Harald Schneider¹, Jonathan Döring², Susanne Kehr², Lukas M. Eng², Yongheng Huo³, Oliver G. Schmidt³, Kan Yao⁴, Yongmin Liu⁴, and Manfred Helm¹ — ¹Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany — ²TU Dresden, Dresden, Germany — ³Leibniz Institute for Solid State and Materials Research, Dresden, Germany — ⁴Northeastern University, Boston, USA

It has been shown that materials with negative refractive index n, so-called metamaterials, can be exploited as perfect lenses characterized by a point-to-point projection. In the near-field regime where the distance between object and image is much smaller than the applied wavelength, negative permittivity is sufficient to create such super-resolution images. Those superlenses are based on heterostructures of different chemical composition, where the negative permittivity is induced by phonons. In contrast, in our sample this dielectric behavior is due to the electronic response of a doped GaAs layer sandwiched between two intrinsic layers. This is a simple and elegant way of producing a superlens as its resonant frequency can be controlled simply by varying the dopant level. In our experiments we investigate a sample with a charge carrier concentration tuned for superlensing at a 20μm IR wavelength as explored using a free-electron laser.