Spin Angular Momentum of Guided Light Induced by Transverse Confinement and Intrinsic Helicity

Abujetas, Diego R.; Sánchez‐Gil, José A.

doi:10.1021/acsphotonics.0c00064

Cited by 42 publications

(28 citation statements)

References 70 publications

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“…On the other hand, for cylindrically symmetric particles, the absence of backscattered light follows from the preservation of EM helicity [14][15][16][17][18]. Conservation of helicity has proven crucial in many applications such as enhanced chiral light-matter interactions [19][20][21][22][23][24][25], or in the spin-orbit interactions of light [26][27][28][29][30][31][32]. In this vein, it has been reported that from a relatively simple far-field measurement of the EM helicity at a right angle, the radiation pattern of the dipolar particle is inferable [33].…”

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confidence: 99%

Kerker Conditions upon Lossless, Absorption, and Optical Gain Regimes

et al. 2020

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The directionality and polarization of light show peculiar properties when the scattering by a dielectric sphere can be described exclusively by electric and magnetic dipolar modes. Particularly, when these modes oscillate in phase with equal amplitude, at the so-called first Kerker condition, the zero optical backscattering condition emerges for nondissipating spheres. However, the role of absorption and optical gain in the first Kerker condition remains unexplored. In this work, we demonstrate that either absorption or optical gain precludes the first Kerker condition and, hence, the absence of backscattered radiation light, regardless of the particle's size, incident wavelength, and incoming polarization. Finally, we derive the necessary prerequisites of the second Kerker condition of the zero forward light scattering, finding that optical gain is a compulsory requirement.

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confidence: 99%

Kerker Conditions upon Lossless, Absorption, and Optical Gain Regimes

et al. 2020

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“…Moreover, by choosing a square cross section, we ensure that the two first guided modes (i.e., the TE and TM modes) appear to be degenerate. Unlike wires with circular cross section, [48][49][50] there is no analytical solution for the propagating modes of square (or, in general, rectangular) dielectric waveguides, so we ought to calculate the corresponding guided modes by means of numerical simulations. This has been performed with the aid of the commercial 3D full-wave solver CST Microwave Studio (Section 6).…”

Section: Optical Chirality Density In All-dielectric Integrated Photomentioning

confidence: 99%

“…In this regard, it should be noted that, apart from the case of plane-wave propagating in free space, studies on optical chirality (and/or helicity [8] ) in integrated platforms are scarce, with the notable exception of cylindrical dielectric waveguides, for which there are analytical solutions. [48][49][50] In this work, we investigate the existence of (enhanced) optical chirality in lithographically defined integrated dielectric waveguides, as well as its potential in chiral applications such as sensing or spectroscopy. In particular we focus on two of the most common guiding structures used in nanophotonics: strip and slot waveguides.…”

Section: Introductionmentioning

confidence: 99%

Toward Chiral Sensing and Spectroscopy Enabled by All‐Dielectric Integrated Photonic Waveguides

Vázquez‐Lozano

Martı́nez

2020

Laser & Photonics Reviews

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Chiral spectroscopy is a powerful technique enabling to identify optically the chirality of matter. So far, most experiments to check the chirality of matter or nanostructures have been performed through arrangements wherein both the optical excitation and detection are realized via circularly polarized light propagating in free space. However, for the sake of miniaturization, it would be desirable to perform chiral spectroscopy in photonic integrated platforms, with the additional benefit of massive parallel detection, low‐cost production, repeatability, and portability. Here it is shown that all‐dielectric photonic waveguides can support chiral modes under proper combination of fundamental eigenmodes. Two mainstream configurations are investigated: a dielectric wire with square cross section and a slotted waveguide. Three different scenarios in which such waveguides could be used for chiral detection are numerically analyzed: waveguides as near‐field probes, evanescent‐induced chiral fields, and chiroptical interaction in void slots. In all the cases, a metallic nanohelix is considered as a chiral probe, though all the approaches can be extended to other kinds of chiral nanostructures as well as matter. These results establish that chiral applications such as sensing and spectroscopy could be realized in standard integrated optics, in particular, with silicon‐based technology.

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“…Specifically, coupling of the light to the resonant modes of the nanostructure 1 , 2 can tailor the light absorption 3 – 5 , reflection 6 , emission 7 – 9 and lasing 10 , 11 , important for both photodetector and source applications. Furthermore, evanescent modal fields in semiconductor NWs have been shown to carry transverse spin angular momentum (SAM) 12 , 13 , therefore it came naturally to extend NW investigation to spin-related phenomena, chirality and circular dichroism (CD) i.e. different interaction with circular polarizations (CP) of opposite handedness.…”

Section: Introductionmentioning

confidence: 99%

Broadband optical spin dependent reflection in self-assembled GaAs-based nanowires asymmetrically hybridized with Au

Petronijevic

Belardini

Leahu

et al. 2021

Sci Rep

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Hybridization of semiconductor nanostructures with asymmetric metallic layers offers new paths to circular polarization control and chiral properties. Here we study, both experimentally and numerically, chiral properties of GaAs-based nanowires (NWs) which have two out of six sidewalls covered by Au. Sparse ensembles of vertical, free-standing NWs were fabricated by means of lithography-free self-assembled technique on Si substrates and subsequently covered by Au using tilted evaporation. We report on optical spin-dependent specular reflection in the 680–1000 nm spectral range when the orientation of the golden layers follows the rule of extrinsic chirality. The analysis shows reflection peaks of the chiral medium whose intensity is dependent on the light handedness. We further propose a novel, time-efficient numerical method that enables a better insight into the far-field intensity and distribution of the scattered light from a sparse NW ensembles. The measurements done on three different samples in various orientations show good agreement with theoretical predictions over a broad wavelength range.

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Spin Angular Momentum of Guided Light Induced by Transverse Confinement and Intrinsic Helicity

Cited by 42 publications

References 70 publications

Kerker Conditions upon Lossless, Absorption, and Optical Gain Regimes

Kerker Conditions upon Lossless, Absorption, and Optical Gain Regimes

Toward Chiral Sensing and Spectroscopy Enabled by All‐Dielectric Integrated Photonic Waveguides

Broadband optical spin dependent reflection in self-assembled GaAs-based nanowires asymmetrically hybridized with Au

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