Directional Plasmonic Excitation by Helical Nanotips; Maccaferri, Nicolò ; et alin Nanomaterials (2021), 11(5), 1333 The phenomenon of coupling between light and surface plasmon polaritons requires specific momentum matching conditions. In the case of a single scattering object on a metallic surface, such as a ... [more ▼] The phenomenon of coupling between light and surface plasmon polaritons requires specific momentum matching conditions. In the case of a single scattering object on a metallic surface, such as a nanoparticle or a nanohole, the coupling between a broadband effect, i.e., scattering, and a discrete one, such as surface plasmon excitation, leads to Fano-like resonance lineshapes. The necessary phase matching requirements can be used to engineer the light–plasmon coupling and to achieve a directional plasmonic excitation. Here, we investigate this effect by using a chiral nanotip to excite surface plasmons with a strong spin-dependent azimuthal variation. This effect can be described by a Fano-like interference with a complex coupling factor that can be modified thanks to a symmetry breaking of the nanostructure. [less ▲] Detailed reference viewed: 126 (0 UL) Particle trapping and beaming using a 3D nanotip excited with a plasmonic vortex; Maccaferri, Nicolò ; et alin Optics Letters (2020), 45(4), 823-826 Recent advances in nanotechnology have prompted the need for tools to accurately and non-invasively manipulate individual nano-objects. Among the possible strategies, optical forces have been widely used ... [more ▼] Recent advances in nanotechnology have prompted the need for tools to accurately and non-invasively manipulate individual nano-objects. Among the possible strategies, optical forces have been widely used to enable nano-optical tweezers capable of trapping or moving a specimen with unprecedented accuracy. Here, we propose an architecture consisting of a nanotip excited with a plasmonic vortex enabling effective dynamic control of nanoparticles in three dimensions. The structure illuminated by a beam with angular momentum can generate an optical field which can be used to manipulate single dielectric nanoparticles. We demonstrate that it’s possible to stably trap or push the particle from specific points, thus enabling a new platform for nanoparticle manipulation. [less ▲] Detailed reference viewed: 182 (6 UL) Helical light emission from plasmonic vortices via magnetic tapered tipMaccaferri, Nicolò ; ; in Journal of Physics. Conference Series (2018), 961 We investigate an architecture where a plasmonic vortex excited in a gold surface propagates on an adiabatically tapered magnetic tip and detaches to the far-field while carrying a well-defined optical ... [more ▼] We investigate an architecture where a plasmonic vortex excited in a gold surface propagates on an adiabatically tapered magnetic tip and detaches to the far-field while carrying a well-defined optical angular momentum. We analyze the out-coming light and show that, despite generally high losses of flat magnetic surface, our 3D structure exhibits high energy throughput. Moreover, we show that once a magneto-optical activity is activated inside the magnetic tip a modulation of the total power transmittance is possible. [less ▲] Detailed reference viewed: 191 (1 UL)![]() Magnetoplasmonic control of plasmonic vorticesMaccaferri, Nicolò ; ; et alin Applied Physics Letters (2017), 111(20), 201104 We theoretically investigate the generation of far-field propagating optical beams with a desired orbital angular momentum by using an archetypical magnetoplasmonic tip surrounded by a gold spiral slit ... [more ▼] We theoretically investigate the generation of far-field propagating optical beams with a desired orbital angular momentum by using an archetypical magnetoplasmonic tip surrounded by a gold spiral slit. The use of a magnetic material can lead to important implications once magneto-optical activity is activated through the application of an external magnetic field. The physical model and the numerical study presented here introduce the concept of magnetically tunable plasmonic vortex lens, namely a magnetoplasmonic vortex lens, which ensures a tunable selectivity in the polarization state of the generated nanostructured beam. The presented system provides a promising platform for a localized excitation of plasmonic vortices followed by their beaming in the far-field with an active modulation of both light's transmission and helicity. Published by AIP Publishing. [less ▲] Detailed reference viewed: 356 (5 UL) |
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