@article{BastianRobelSchmidtetal.2021,
  author    = {Bastian, Philipp U. and Robel, Nathalie and Schmidt, Peter and Schrumpf, Tim and G{\"u}nter, Christina and Roddatis, Vladimir and Kumke, Michael U.},
  title     = {Resonance energy transfer to track the motion of lanthanide ions},
  series = {Biosensors : open access journal},
  volume    = {11},
  journal   = {Biosensors : open access journal},
  number    = {12},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2079-6374},
  doi       = {10.3390/bios11120515},
  pages     = {23},
  year      = {2021},
  abstract  = {The imagination of clearly separated core-shell structures is already outdated by the fact, that the nanoparticle core-shell structures remain in terms of efficiency behind their respective bulk material due to intermixing between core and shell dopant ions. In order to optimize the photoluminescence of core-shell UCNP the intermixing should be as small as possible and therefore, key parameters of this process need to be identified. In the present work the Ln(III) ion migration in the host lattices NaYF4 and NaGdF4 was monitored. These investigations have been performed by laser spectroscopy with help of lanthanide resonance energy transfer (LRET) between Eu(III) as donor and Pr(III) or Nd(III) as acceptor. The LRET is evaluated based on the Forster theory. The findings corroborate the literature and point out the migration of ions in the host lattices. Based on the introduced LRET model, the acceptor concentration in the surrounding of one donor depends clearly on the design of the applied core-shell-shell nanoparticles. In general, thinner intermediate insulating shells lead to higher acceptor concentration, stronger quenching of the Eu(III) donor and subsequently stronger sensitization of the Pr(III) or the Nd(III) acceptors. The choice of the host lattice as well as of the synthesis temperature are parameters to be considered for the intermixing process.},
  language  = {en}
}
@article{RotheZhaoMuelleretal.2021,
  author    = {Rothe, Martin and Zhao, Yuhang and M{\"u}ller, Johannes and Kewes, G{\"u}nter and Koch, Christoph T. and Lu, Yan and Benson, Oliver},
  title     = {Self-assembly of plasmonic nanoantenna-waveguide structures for subdiffractional chiral sensing},
  series = {ACS nano},
  volume    = {15},
  journal   = {ACS nano},
  number    = {1},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1936-0851},
  doi       = {10.1021/acsnano.0c05240},
  pages     = {351 -- 361},
  year      = {2021},
  abstract  = {Spin-momentum locking is a peculiar effect in the near-field of guided optical or plasmonic modes. It can be utilized to map the spinning or handedness of electromagnetic fields onto the propagation direction. This motivates a method to probe the circular dichroism of an illuminated chiral object. In this work, we demonstrate local, subdiffraction limited chiral coupling of light and propagating surface plasmon polaritons in a self-assembled system of a gold nanoantenna and a silver nanowire. A thin silica shell around the nanowire provides precise distance control and also serves as a host for fluorescent molecules, which indicate the direction of plasmon propagation. We characterize our nanoantenna-nanowire systems comprehensively through correlated electron microscopy, energy-dispersive X-ray spectroscopy, dark-field, and fluorescence imaging. Three-dimensional numerical simulations support the experimental findings. Besides our measurement of far-field polarization, we estimate sensing capabilities and derive not only a sensitivity of 1 mdeg for the ellipticity of the light field, but also find 10(3) deg cm(2)/dmol for the circular dichroism of an analyte locally introduced in the hot spot of the antenna-wire system. Thorough modeling of a prototypical design predicts on-chip sensing of chiral analytes. This introduces our system as an ultracompact sensor for chiral response far below the diffraction limit.},
  language  = {en}
}