Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 98: Plasmonics and Nanooptics V
O 98.3: Vortrag
Freitag, 4. April 2014, 11:00–11:15, TRE Ma
Bloch Oscillations in Plasmonic Waveguide Arrays — •Alexander Block1, Christopf Etrich2, Felix Bleckmann1, Thorsten Limböck1, Carsten Rockstuhl2, and Stefan Linden1 — 1Physikalisches Institut, Bonn, Germany — 2Institut für Festkörpertheorie und -optik, Jena, Germany
We present the experimental observation of spatial Bloch oscillations in arrays of dielectric-loaded surface plasmon polariton waveguides. By fabricating strips of PMMA on a gold film via gray-scale electron beam lithography, it is possible to guide surface plasmon polaritons. We study the evanescent coupling of light propagating through arrays of such plasmonic waveguides which is described by coupled mode theory. The equation of motion for the evolution of the light field along the waveguides takes the same form as the crystal electron wavefunction's time evolution in the tight binding model of solid state physics. Therefore, we can visualize quantum mechanical condensed matter phenomena in a coherent, yet classical wave environment by mapping the probability distribution to the surface plasmon intensity distribution in real space which is directly imaged via leakage radiation microscopy. We observed plasmonic Bloch oscillations by fabricating waveguide arrays with linearly increasing effective refractive indices. This gradient mimics the linear potential gradient of a DC electric field as required for Bloch oscillations of crystal electrons. The results clearly show the expected spatial Bloch oscillation of a shape retaining Gaussian beam wave package. These results excellently agree with finite-difference time-domain simulations, which are also presented.