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O: Fachverband Oberflächenphysik

O 71: Plasmonics and Nanooptics III

O 71.6: Vortrag

Donnerstag, 3. April 2014, 11:45–12:00, GER 38

k-space resolved nano-imaging with an adiabatic nanofocusing SNOM — •Simon F. Becker, Martin Esmann, Jens H. Brauer, Petra Groß, Ralf Vogelgesang, and Christoph Lienau — Carl von Ossietzky Universität, 26111 Oldenburg, Germany

Adiabatic nanofocusing of surface plasmon polaritons (SPP) propagating on metallic tapers promises to largely reduce unwanted background contributions in apertureless scanning near-field optical microscopy (SNOM) [1,2]. SPP wavepackets launched on a grating-coupler come to a complete halt at the taper apex for an ideal cone-shaped waveguide. Hence, a single point-dipole like light source is formed which bears great potential for nano-imaging and spectroscopy applications.

Recently, we have developed and implemented a k-space imaging technique to characterize this nano-scale light-source and to separate contributions from different taper eigenmodes [3]. Only the lowest, rotationally symmetric eigenmode is expected to contribute to near-fields at the taper apex. Here, using Stokes polarimetry k-space imaging, we isolate the emission from this lowest eigenmode and demonstrate its radial polarization. This allows us to implement a new adaptive optics scheme (based on [4]) to optimize the emission of this fundamental mode. For the first time, we apply k-space resolved polarimetry to nano-imaging of metallic nanostructures and investigate the near-field coupling between probe and sample.

[1] M.I. Stockman, PRL 93, 137404 (2004); [2] S. Schmidt et al., ACS Nano 6, 6040 (2012); [3] M. Esmann et al., BJ Nano 4, 603 (2013); [4] S. Schmidt et al., Opt. Express 21, 26564 (2013).