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HL: Fachverband Halbleiterphysik

HL 29: Focussed Session: Metasurfaces I

HL 29.6: Hauptvortrag

Mittwoch, 14. März 2018, 17:30–18:00, EW 201

Nonlinear Metasurface Holography — •Thomas Zentgraf — Department of Physics, University of Paderborn, Germany

For efficient nonlinear processes, the engineering of the nonlinear optical properties of media becomes important. A continuous tailoring of the phase of the nonlinear susceptibility would greatly enhance flexibility in the design of nonlinear elements. Here we will discuss a novel nonlinear metamaterial which can exhibit homogeneous linear optical properties but continuously controllable phase of the local effective nonlinear polarizability. For the demonstration, we use plasmonic metasurfaces with various designs for the meta-atom geometry together with circular polarized light states. The controllable nonlinearity phase results from the phase accumulation due to the polarization change along the polarization path on the Poincare sphere (the so-called Pancharatnam-Berry phase) and depends therefore only on the spatial geometry of the metasurface. We will demonstrate the concept of phase engineering for the manipulation of second- and third-harmonic generation from metasurfaces and the restriction with respect to symmetry and geometry of meta-atoms on a few examples.