[1] Univ Jena, Inst Solid State Phys, D-07743 Jena, Germany
[2] Max Planck Inst Microstruct Phys, D-06120 Halle, Saale, Germany
[3] Inst Photon Technol, D-07745 Jena, Germany
[4] Max Planck Inst Sci Light, D-91058 Erlangen, Germany
[5] Univ Jena, Ctr Electron Microscopy, D-07743 Jena, Germany