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Spatially engineered nonlinearity in resonant metasurfaces

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Photonics Research 2023年第2期11卷 252-259页

作者： ANNA FEDOTOVA MOHAMMADREZA YOUNESI MAXIMILIAN WEISSFLOG DENNIS ARSLAN THOMAS PERTSCH ISABELLE STAUDE frank setzpfandt Institute of Solid State Physics Friedrich Schiller University Jena07743 JenaGermany Institute of Applied Physics Abbe Center of PhotonicsFriedrich Schiller University Jena07745 JenaGermany Max Planck School of Photonics 07745 JenaGermany Fraunhofer Institute for Applied Optics and Precision Engineering 07745 JenaGermany

Spatial engineering of the nonlinear susceptibility χ^((2)) in resonant metasurfaces offers a new degree of freedom in the design of the far-field response of second-harmonic generation(SHG). We demonstrate this by applying electric field poling to lithium niobate(LN) thin films, which inverts the spontaneous polarization and thus the sign of χ^((2)). Metasurfaces fabricated in periodically poled LN films reveal the distinct influence of theχ^((2))-patterning on the spatial distribution of the second harmonic. This work is a first step toward far-field engineering of SHG in metasurfaces with electric field poling.

关键词： resonant surfaces harmonic

Near-field launching and mapping unidirectional surface plasmon polaritons using an automated dual-tip scanning near-field optical microscope

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Photonics Research 2022年第11期10卷 2628-2641页

作者： NAJMEH ABBASIRAD ANGELA BARREDA YI-JU CHEN JER-SHING HUANG ISABELLE STAUDE frank setzpfandt THOMAS PERTSCH Institute of Applied Physics Abbe Center of PhotonicsFriedrich Schiller University Jena07745 JenaGermany Institute of Solid State Physics Friedrich Schiller University Jena07743 JenaGermany Research Department of Nanooptics Leibniz Institute of Photonic Technology07745 JenaGermany Fraunhofer-Institute for Applied Optics and Precision Engineering IOF 07745 JenaGermany

The spatial distribution of electromagnetic fields emitted from the aperture tip of a scanning near-field optical microscope(SNOM), which is called the emission pattern, depends on the geometry of the apex and the material composition of the tip’s coating. In previous works, experimental measurements of the emission pattern from the aperture tip were performed mostly in the far field. Moreover, the corresponding theoretical models were also developed based on these far-field measurements. Here, we have used the automated dual-tip SNOM to systematically characterize the emission from the aperture tip in the near field. In this regard, we have considered three different pairs of excitation and detection tips with distinct geometries. The emission patterns of the excitation tips were mapped using detection tips. Unidirectional surface plasmon polaritons(SPPs) at the surface of a gold platelet were launched by an excitation tip and measured in the near field by the detection tip. The experimental results were numerically reproduced by means of the Bethe–Bouwkamp model. This work puts into evidence the applicability of the automated dual-tip SNOM as the only available characterization technique to measure the emission from aperture tips in the near field. The reported asymmetric SPP radiation patterns can find applications in photonic integrated circuits or in biological and chemical sensing.

关键词： optical excitation field

Dielectric metasurfaces for distance measurements and three-dimensional imaging

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Advanced Photonics 2019年第3期1卷 20-28页

作者： Chunqi Jin Mina Afsharnia RenéBerlich Stefan Fasold Chengjun Zou Dennis Arslan Isabelle Staude Thomas Pertsch frank setzpfandt Friedrich Schiller University Jena Institute of Applied PhysicsAbbe Center of PhotonicsJenaGermany Chinese Academy of Sciences Changchun Institute of OpticsFine Mechanics and PhysicsChangchunChina University of the Chinese Academy of Sciences BeijingChina Fraunhofer Institute for Applied Optics and Precision Engineering JenaGermany

Ultrathin metasurfaces have shown the capability to influence all aspects of light propagation.This has made them promising options for replacing conventional bulky imaging optics while adding advantageous optical properties or functionalities.We demonstrate that such metasurfaces can also be applied for single-lens three-dimensional(3-D)imaging based on a specifically engineered point-spread function(PSF).Using Huygens’metasurfaces with high transmission,we design and realize a phase mask that implements a rotating PSF for 3-D imaging.We experimentally characterize the properties of the realized double-helix PSF,finding that it can uniquely encode object distances within a wide range.Furthermore,we experimentally demonstrate wide-field depth retrieval within a 3-D scene,showing the suitability of metasurfaces to realize optics for 3-D imaging,using just a single camera and lens system.

关键词： optics nanophotonics metasurfaces Mie-resonances three-dimensional imaging point-spread function engineering