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Structured light in metamaterials IV

10:30 Invited talk : Observation of power controlled discrete vortices in optically induced nonlinear waveguide array

Falko Diebel (1),Daniel Leykam (2),Martin Boguslawski (1),Patrick Rose (1),Cornelia Denz (1),Anton Desyatnikov (2)

(1)Universitat Munster (Germany) , (2)The Australian National University (Australia)

We introduce a circular array of four coupled nonlinear waveguides, optically induced in a photorefractive crystal using an incoherent superposition of nondiffracting Bessel beams. The array supports nonlinear vortex breather modes, in which the vortex charge and orbital angular momentum reverse periodically during propagation, with the period controlled by the optical power. Propagating a discrete vortex beam through the crystal, we experimentally observe charge reversal at low power and the conservation of its charge in the nonlinear regime.
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10:50 Invited talk : Nanoscale Plasmonic Patch Antennas for Control of Optical Processes

Maiken Mikkelsen

Duke University (USA)

Here, we provide an overview of our recent demonstrations and latest progress on controlling radiative processes and nonlinear effects using a large-area plasmonic nanopatch antenna platform. In particular, we demonstrate large enhancements of fluorescence and spontaneous emission rates of dye molecules embedded in plasmonic nanoantennas with sub-10-nm gap sizes and observe nearly five orders of magnitude enhancements in third-harmonic generation efficiency.
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11:10 Invited talk : Ultrathin metasurfaces with ultrahigh cross-polarization manipulation efficiency

Cheng-Wei Qiu, Lei Zhang, Xumin Ding, Fei Qin

National University of Singapore (Singapore)

Metasurfaces operating in the cross-polarization scheme have shown an interesting degree of control over the wavefront of transmitted light. Nevertheless, their inherently low efficiency raises certain concerns in industrial applications. In this work, two types of ultrathin metasurfaces with ultrahigh cross-polarization manipulation efficiency were introduced at visible and microwave ranges, which almost approached the theoretical limit. Also, our designs interestingly show that the conversion efficiency could be as good as that of dielectric metasurfaces.
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