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

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Title: Near-field distribution and propagation of scattering resonances in Vogel spiral arrays of dielectric nanopillars.
Authors: Intonti, F.1 intonti@lens.unifi.it, Caselli, N.1, Lawrence, N.2, Trevino, J.3, Wiersma, D. S.1, Dal Negro, L.2,3 dalnegro@bu.edu
Source: New Journal of Physics. 2013, Vol. 15 Issue 8, p1-12. 12p.
Subjects: Intracranial tumors, Brain tumors, Tumor surgery, Magnetic resonance imaging, Clinical chemistry, Thickness measurement, Near-field microscopy, Tumor treatment
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 1.56μm by dielectric arrays of silicon nitride nanopillars with chiral α1-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. [ABSTRACT FROM AUTHOR]
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Database: Engineering Source
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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 1.56μm by dielectric arrays of silicon nitride nanopillars with chiral α1-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. [ABSTRACT FROM AUTHOR]
ISSN:13672630
DOI:10.1088/1367-2630/15/8/085023