Dresden 2014 – scientific programme
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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
Tuesday, April 1, 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.