discovered_01_2016

WWW.HZDR.DE 14 15 TITLE // THE HZDR RESEARCH MAGAZINE SENSITIVE: The near-field microscope ‘T-bone’ is based on a home-constructed atomic force microscope (left). It is illuminated by a parabolic mirror (right). Photo: Oliver Killig Ambitious search for impurity atoms near to absolute zero Just how smooth the transition from one research group to another can really be is illustrated by Denny Lang. When he was working on his "Diplom" at TU Dresden, the 27-year- old was supervised by Susanne Kehr; today, he is doing a doctorate at HZDR. "I use the near-field microscope to investigate the spectrum of individual impurity atoms in silicon. If assignment to the respective wavelengths works out, it might be possible to use the impurity atoms to construct quantum computers." A highly-ambitious project because studies of this kind are only viable at low temperatures of under -250 degree Celsius. The group is thus the first in the world to conduct near-field microscopy at such low temperatures. According to Denny Lang, "It’s only near to absolute zero that we can exclude thermic excitement in the material, which would falsify our measurements." In order to expand the potential of near-field microscopy in the future, the researchers at TU Dresden want to go beyond the infrared range. The goal is to use even longer waves in the terahertz range, which will be available at "TELBE", the new terahertz facility at the ELBE Center, from the second half of 2016. This long-wave, low-frequency radiation could excite many materials during microscopy – another aid to discovering yet more about the nano world. PUBLICATIONS: S. Kehr et al.: "A local superlens", in ACS Photonics 2016 (DOI: 10.1021/acsphotonics.5b00365) M. Fehrenbacher et al.: "Plasmonic superlensing in doped GaAs", in Nano Letters 2015 (DOI: 10.1021/nl503996q) CONTACT _Institute of Applied Physics at TU Dresden Dr. Susanne Kehr susanne.kehr@iapp.de _Institute of Ion Beam Physics and Materials Research at HZDR Dr. Stephan Winnerl s.winnerl@hzdr.de www.iapp.de

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