Chiral near-field manipulation in Au-GaAs hybrid hexagonal nanowires

Petronijevic, Emilija; Centini, Marco; Belardini, A.; Leahu, Grigore; Hakkarainen, Teemu; Sibilia, C.

doi:10.1364/oe.25.014148

Cited by 22 publications

(18 citation statements)

References 28 publications

(40 reference statements)

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“…Namely, in the points of the confinement, electric and magnetic field possess components that are parallel and out-of-phase. In [19], we shown that the same NW geometry can lead to the near chiral field manipulation by means of the angle of incidence span. Moreover, the NWs can be easily hybridized by thin layers of Au; PAS was used to characterize the absorption spectra of these samples in [21] and the results were in agreement with numerical results from Sect.…”

Section: Resultsmentioning

confidence: 97%

“…Numerically, the NW waveguide modes have been vastly investigated [13][14][15][16][17]. The properties of the confined fields have also recently lead to some new prospects in spin angular momentum formation [18], and near chiral field manipulation [19,20]. Finally, semiconductor NW hybridization with metallic layers has recently shown effects such as circular dichroism [21].…”

Section: Introductionmentioning

confidence: 99%

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Resonant Absorption in GaAs-Based Nanowires by Means of Photo-Acoustic Spectroscopy

et al. 2018

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Semiconductor nanowires made of high refractive index materials can couple the incoming light to specific waveguide modes that offer resonant absorption enhancement under the bandgap wavelength, essential for light harvesting, lasing and detection applications. Moreover, the non-trivial ellipticity of such modes can offer near field interactions with chiral molecules, governed by near chiral field. These modes are therefore very important to detect. Here, we present the photo-acoustic spectroscopy as a low-cost, reliable, sensitive and scattering-free tool to measure the spectral position and absorption efficiency of these modes. The investigated samples are hexagonal nanowires with GaAs core; the fabrication by means of lithographyfree molecular beam epitaxy provides controllable and uniform dimensions that allow for the excitation of the fundamental resonant mode around 800 nm. We show that the modulation frequency increase leads to the discrimination of the resonant mode absorption from the overall absorption of the substrate. As the experimental data are in great agreement with numerical simulations, the design can be optimized and followed by photo-acoustic characterization for a specific application.

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Section: Resultsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Resonant Absorption in GaAs-Based Nanowires by Means of Photo-Acoustic Spectroscopy

et al. 2018

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“…Furthermore, the enhanced enantioselectivity due to the enhanced near chiral fields was theoretically proposed in [25,26] and observed in the interaction with plasmonic substrates [27,28]. For this purpose, we previously proposed single hybrid GaAs-Au nanowires [29,30], periodic arrays of high refractive index nanowires [31], and arrays of Al nanopyramids [32]. Moreover, chiroptical responses were studied in simple 1D metal grooves [33] and nanohole arrays [34].…”

Section: Introductionmentioning

confidence: 99%

Circular Dichroism in Low-Cost Plasmonics: 2D Arrays of Nanoholes in Silver

et al. 2020

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Arrays of nanoholes in metal are important plasmonic devices, proposed for applications spanning from biosensing to communications. In this work, we show that in such arrays the symmetry can be broken by means of the elliptical shape of the nanoholes, combined with the in-plane tilt of the ellipse axes away from the array symmetry lines. The array then differently interacts with circular polarizations of opposite handedness at normal incidence, i.e., it becomes intrinsically chiral. The measure of this difference is called circular dichroism (CD). The nanosphere lithography combined with tilted silver evaporation was employed as a low-cost fabrication technique. In this paper, we demonstrate intrinsic chirality and CD by measuring the extinction in the near-infrared range. We further employ numerical analysis to visualize the circular polarization coupling with the nanostructure. We find a good agreement between simulations and the experiment, meaning that the optimization can be used to further increase CD.

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“…We further verified, using photoacoustic spectroscopy, that when such GaAs NWs were partially covered in gold they exhibited strong extrinsic chirality due to the breaking of the symmetry induced by the asymmetric metal coating [11,12]. We also numerically investigated nearfield chiral effects in high-refractive-index nanowires with [22] and without [23] an asymmetric plasmonic layer.…”

Section: Methodsmentioning

confidence: 66%

Circular Dichroism in the Second Harmonic Field Evidenced by Asymmetric Au Coated GaAs Nanowires

et al. 2020

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Optical circular dichroism (CD) is an important phenomenon in nanophotonics, that addresses top level applications such as circular polarized photon generation in optics, enantiomeric recognition in biophotonics and so on. Chiral nanostructures can lead to high CD, but the fabrication process usually requires a large effort, and extrinsic chiral samples can be produced by simpler techniques. Glancing angle deposition of gold on GaAs nanowires can (NWs) induces a symmetry breaking that leads to an optical CD response that mimics chiral behavior. The GaAs NWs have been fabricated by a self-catalyzed, bottom-up approach, leading to large surfaces and high-quality samples at a relatively low cost. Here, we investigate the second harmonic generation circular dichroism (SHG-CD) signal on GaAs nanowires partially covered with Au. SHG is a nonlinear process of even order, and thus extremely sensitive to symmetry breaking. Therefore, the visibility of the signal is very high when the fabricated samples present resonances at first and second harmonic frequencies (i.e., 800 and 400 nm, in our case).

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Chiral near-field manipulation in Au-GaAs hybrid hexagonal nanowires

Cited by 22 publications

References 28 publications

Resonant Absorption in GaAs-Based Nanowires by Means of Photo-Acoustic Spectroscopy

Resonant Absorption in GaAs-Based Nanowires by Means of Photo-Acoustic Spectroscopy

Circular Dichroism in Low-Cost Plasmonics: 2D Arrays of Nanoholes in Silver

Circular Dichroism in the Second Harmonic Field Evidenced by Asymmetric Au Coated GaAs Nanowires

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