Ulrich Hohenester
 

Ao. Univ. Prof. Dr.

Ulrich Hohenester

Institut für Physik
Karl-Franzens-Universität Graz
Universitätsplatz 5, 8010 Graz
Austria 
[contact details]


I am a theoretical solid-state physicist, interested in semiconductor and metallic nanostructures, and atom chips. I obtained my PhD in Theoretical Physics at Graz university in 1997. I then moved as a Postdoc to the nanoscience group Modena headed by  Elisa Molinari, where I spent the years 1997 - 2000 working on semiconductor quantum dots. In 2001 I joined the Solid State Theory group in Graz headed by Walter Pötz. In the same year I obtained my Habilitation in Theoretical Physics. Currently I am Associate Professor at the Institute of Physics in Graz. Since 2006 I am Associated Editor of the European Physical Journal B.

Short CV

The research of my group is concerned with the theory of nanostructures. These structures consist of several thousands to millions of atoms, and have sizes of a few nanometers in each spatial direction. For such small objects the physical properties can differ appreciably from those of larger pieces of matter.
  •  In semiconductor quantum dots, quantum effects are known to dominate the optical and transport properties. Our group is particularly interested in possible quantum computation and quantum communication applications. We investigate how in these structures quantum coherence can be created and manipulated, and how it decays through interactions with the solid-state environment. 
  • In cooperation with the experimental nanooptics group in Graz, we study the optical properties of metallic nanoparticles. Due to the different length scales, namely nanometers for the metallic nanoparticles and micrometers for the light, the light-matter coupling is in the nearfield regime and becomes drastically enhanced. This allows to tailor the optical properties of light emitters (molecules, collodial quantum dots, etc.) placed in the vicinity of metallic nanoparticles, which might be beneficial for novel biosensor. applications. 
  • A more recent research activity is concerned with atom chips. Here, current flowing through microstructured wires mounted on a solid-state chip produces magnetic fields that allow to trap and manipulate ultracold atoms or Bose Einstein condensates in the vicinity of the chip. Thermal current noise in the metallic wires causes magnetic field fluctuations at the positions of the atoms, and introduces decoherence. We have shown that superconducting atom chips would allow to almost completely suppress such decoherence. Other work has been devoted to optimal quantum control of Bose Einstein condensates in such atom chips.

    unizeit09  See also feature on nanooptics in UNIZEIT (in german, 4 MB).


Detailed research description


Selected recent publications.

  • G. Soavi et al.:
    Exciton-exciton annihilation and biexciton stimulated emission in graphene nanoribbons;
    Nature Communications 7, 11010 (2016).
      (PDF)   Nano Lett.
  • G. Haberfehlner, A. Trügler, F. P. Schmidt, A. Hörl, F. Hofer, U. Hohenester, and G. Kothleitner:
    Correlated 3D nanoscale mapping and simulation of coupled plasmonic nanoparticles;
    Nano Lett. 15, 7726 (2015).
      (PDF)   Nano Lett.
  • F. Schmidt, H. Ditlbacher, U. Hohenester, A. Hohenau, F. Hofer, and J. Krenn:
    Universal Dispersion of Scaling of Surface Plasmon in Flat Nanostructures;
    Nature Communications 8, 3604 (2014).
       (PDF)  Nature
  • A. Hörl, A. Trügler, and U. Hohenester:
    Tomography of particle plasmons for electron energy loss spectroscopy;
    Phys. Rev. Lett.
    101, 076801 (2013).   (PDF)   Phys. Rev.
  • P. Dombi, A. Hörl, P. Rácz, I. Márton, A. Trügler, J. R. Krenn, and U. Hohenester:
    Ultrafast hot-electron emission from plasmonic nanoparticles;
    Nano Letters
    13, 674 (2013). (PDF)  Nano Lett.
  • F. Schmidt, H. Ditlbacher, U. Hohenester, A. Hohenau, F. Hofer, and J. R. Krenn:
    Dark plasmonic breathing modes in silver nanodisks;
    Nano Letters
    12, 5780  (2012). (PDF)  Nano Lett.

Ulrich Hohenester
Institut für Physik, Karl-Franzens Universität Graz, Austria