Orientation dependence of optical activity in light scattering by nanoparticle clusters

Najafabadi, Atefeh Fazel; Auguié, Baptiste

doi:10.1039/d1ma00869b

Cited by 5 publications

(1 citation statement)

References 72 publications

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“…We will assume that the filter, composed of randomly oriented helices embedded in a homogeneous medium with the refractive index of either vacuum or water, can be treated as a single homogenized material. The power loss experienced by a circularly polarized beam propagating along this material in the forward direction can be expressed through the rotationally averaged helicity extinction cross sections for the respective polarization , of the helices, σ ext,± . If we consider a slab of this homogenized material with a thickness Δ z , assuming that it is thin enough for the power flux of the incident beam remaining approximately constant, the power per unit area absorbed or scattered by the medium with a helix number density ρ helices can be obtained as with S z being the component of the time averaged Poynting vector along the propagation direction of the beam.…”

Section: Broad-angle Filtermentioning

confidence: 99%

Toward Maximally Electromagnetically Chiral Scatterers at Optical Frequencies

et al. 2022

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Designing objects with predefined optical properties is a task of fundamental importance for nanophotonics, and chirality is a prototypical example of such a property, with applications ranging from photochemistry to nonlinear photonics. A measure of electromagnetic chirality with a well-defined upper bound has recently been proposed. Here, we optimize the shape of silver helices at discrete frequencies ranging from the far-infrared to the optical band. Gaussian process optimization, taking into account also shape derivative information on the helices scattering response, is used to maximize the electromagnetic chirality. We show that the theoretical designs achieve more than 90% of the upper bound of em-chirality for wavelenghts 3 μm or larger, while their performance decreases toward the optical band. We fabricate and characterize helices for operation at 800 nm and identify some of the imperfections that affect the performance. Our work motivates further research both on the theoretical and fabrication sides to unlock potential applications of objects with large electromagnetic chirality at optical frequencies, such as helicity filtering glasses. We show that, at 3 μm, a thin slab of randomly oriented helices can absorb 99% of the light of one helicity while absorbing only 10% of the opposite helicity.

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Section: Broad-angle Filtermentioning

confidence: 99%

Toward Maximally Electromagnetically Chiral Scatterers at Optical Frequencies

et al. 2022

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Correlation Between Orientation of the Stacked π‐Electron Systems and Chiroptical Properties

et al. 2023

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The correlation between the orientation of the two π-electron systems and the chiroptical properties was investigated using two types of optically active X-shaped molecules consisting of planar chiral [2.2]paracyclophanes. The X-shaped molecules exhibited high photoluminescence quantum efficiencies and good circularly polarized luminescence properties with relatively high anisotropy factors of the order of 10 À 3 . It was experimentally and theoretically elucidated that the chiroptical properties of the two molecules were almost identical, regardless of the orientation of the stacked π-electron systems.

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Orientation-averaged light scattering by nanoparticle clusters: Far-field and near-field benchmarks of numerical cubature methods

Atefeh

Auguié

2022

Journal of Quantitative Spectroscopy and Radiative Transfer

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Orientation dependence of optical activity in light scattering by nanoparticle clusters

Abstract: The optical properties of nanoparticle clusters vary with the spatial arrangement of the constituent particles, but also the overall orientation of the cluster with respect to the incident light. This...

Cited by 5 publications

References 72 publications

Toward Maximally Electromagnetically Chiral Scatterers at Optical Frequencies

Toward Maximally Electromagnetically Chiral Scatterers at Optical Frequencies

Correlation Between Orientation of the Stacked π‐Electron Systems and Chiroptical Properties

Orientation-averaged light scattering by nanoparticle clusters: Far-field and near-field benchmarks of numerical cubature methods

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