Near-field distribution and propagation of scattering resonances in Vogel spiral arrays of dielectric nanopillars

Year: 2013

Authors: Intonti F., Caselli N., Lawrence N., Trevino J., Wiersma D., Dal Negro L.

Autors Affiliation: LENS, Department of Physics, University of Florence, I-50019 Sesto Fiorentino, Italy; Department of Electrical and Computer Engineering, Photonics Center, Boston University, Boston, MA, United States; Division of Materials Science and Engineering, Boston University, Brookline, MA, United States

Abstract: In this work, we employ scanning near-field optical microscopy, full-vector finite difference time domain numerical simulations and fractional Fourier transformation to investigate the near-field and propagation behavior of the electromagnetic energy scattered at 1.56 mu m by dielectric arrays of silicon nitride nanopillars with chiral alpha(1)-Vogel spiral geometry. In particular, we experimentally study the spatial evolution of scattered radiation and demonstrate near-field coupling between adjacent nanopillars along the parastichies arms. Moreover, by measuring the spatial distribution of the scattered radiation at different heights from the array plane, we demonstrate a characteristic rotation of the scattered field pattern consistent with net transfer of orbital angular momentum in the Fresnel zone, within a few micrometers from the plane of the array. Our experimental results agree with the simulations we performed and may be of interest to nanophotonics applications.

Journal/Review: NEW JOURNAL OF PHYSICS

Volume: 15      Pages from: 085023-1  to: 085023-12

KeyWords: Fractional Fourier Transformations; Near-field distribution; Orbital angular momentum; Propagation behavior; Scanning near-field optical microscopy; Scattered radiations; Scattering resonance; Time domain numerical simulation, Dielectric materials; Electromagnetic waves; Finite difference time domain method; Orbital transfer; Scattering; Silicon nitride; Nanostructures
DOI: 10.1088/1367-2630/15/8/085023

Citations: 3
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