Extreme optical activity and circular dichroism of chiral metal hole arrays

Gorkunov, M. V.; Ezhov, A. A.; Артемов, В. В.; Rogov, Oleg Y.; Yudin, S. G.

doi:10.1063/1.4880798

Cited by 47 publications

(45 citation statements)

References 21 publications

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“…Moreover, chiroptical responses were studied in simple 1D metal grooves [33] and nanohole arrays [34]. Most of the chiral nanostructure fabrication involves sophisticated, challenging and expensive techniques; however, authors in [35][36][37] showed that complex chiral shapes can be produced in silver films by a conventional single-pass focused ion beam technique.…”

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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Section: Introductionmentioning

confidence: 99%

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

et al. 2020

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“…Eq (15). versus wavelength, of a LCP wave incident on the square lattice of left twisted nanoholes(Fig.…”

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confidence: 98%

Manipulation of polarization and spatial properties of light beams with chiral metafilms

Климов¹,

Zabkov²,

Pavlov³

et al. 2016

Opt. Express

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Two-dimensional lattices of chiral nanoholes in a plasmonic film with lattice constants being slightly larger than light wavelength are proposed for effective control of polarization and spatial properties of light beams. Effective polarization conversion and strong circular dichroism in non-zero diffraction orders in these chiral metafilms are demonstrated by electromagnetic simulations. These interesting effects are found to result from interplay between radiation pattern of single chiral nanohole and diffraction pattern of the planar lattice, and can be manipulated by varying wavelength and polarization of incoming light as well as period of metastructure and refractive indexes of substrate and overlayer. Therefore, this work offers a novel paradigm for developing planar chiral metafilm-based optical devices with controllable polarization state, spatial orientation and intensity of outgoing light.

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“…The absence of mirror symmetry being a common attribute of numerous natural objects and materials, especially those of biological origin, typically gives rise to very moderate optically observable consequences. Artificial chiral electromagnetic materials provide high and even sometimes extreme degrees of optical activity (OA) and circular dichroism (CD) 1 2 3 4 5 6 7 8 that may also appear via spontaneous symmetry breaking 9 and can possess additional functional properties such as strong nonlinearity 10 and tunability by irradiation 11 . Being unattainable with natural materials, these features are highly advantageous for the potential applications that range from electromagnetic signal manipulation 12 to nanoscale chirality diagnostics 13 .…”

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confidence: 99%

Implications of the causality principle for ultra chiral metamaterials

Gorkunov

Дмитриенко

Ezhov

et al. 2015

Sci Rep

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Chiral metamaterials – artificial subwavelength structures with broken mirror symmetry – demonstrate outstanding degree of optical chirality that exhibits sophisticated spectral behavior and can eventually reach extreme values. Based on the fundamental causality principle we show how one can unambiguously relate the metamaterial circular dichroism and optical activity by the generalized Kramers-Kronig relations. Contrary to the conventional relations, the generalized ones provide a unique opportunity of extracting information on material-dependent zeroes of transmission coefficient in the upper half plane of complex frequency. We illustrate the merit of the formulated relations by applying them to the observed ultra chiral optical transmission spectra of subwavelength arrays of chiral holes in silver films. Apart from the possibility of precise verification of experimental data, the relations enable resolving complex eigenfrequencies of metamaterial intrinsic modes and resonances.

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Extreme optical activity and circular dichroism of chiral metal hole arrays

Cited by 47 publications

References 21 publications

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

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

Manipulation of polarization and spatial properties of light beams with chiral metafilms

Implications of the causality principle for ultra chiral metamaterials

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