Controlling THz and far-IR waves with chiral and bianisotropic metamaterials

Kenanakis, George; Economou, E. N.; Soukoulis, Costas M.; Kafesaki, Maria

doi:10.1051/epjam/2015019

Cited by 13 publications

(11 citation statements)

References 62 publications

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“…Artificial chirality, in the form of metamaterials, is a much more promising avenue in this regard, since one can engineer chiral metamaterials with high robustness, low loss, arbitrary operation frequency and tailorable properties (e.g. [30], [31], [32], [33]).…”

Section: A Motivation and Definitionmentioning

confidence: 99%

Electromagnetic Chirality, Part 1: The Microscopic Perspective [Electromagnetic Perspectives]

Caloz

Sihvola

2020

IEEE Antennas Propag. Mag.

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This paper is the first part of a two-part paper, with the second part being [1], presenting a bottom-up description of electromagnetic chirality, which occurs in materials composed of particles with structural handedness 1. This part deals with the microscopic perspective of chirality. First, it highlights the three fundamental concepts related to chirality-mirror asymmetry, polarization rotation and magnetodielectric coupling-and points out the nontrivial interdependencies existing between them. Then, it lists a number of assumptions that pertain to the overall document. Next, it argues that metamaterials represent the most promising technology for chiral applications, and discusses their geometrical parameters, dipolar responses and electromagnetic polarizabilities. The following part compares two representative metaparticles that are complementarily related to chirality, namely the planar Omega particle and the twisted Omega, or helix, particle, shows that only the latter is mirrorasymmetric, and hence chiral, deduces from the mirror asymmetry criterion that chirality requires a voluminal geometry, and infers the magnetoelectric properties of the planar Omega and helix particles from their geometry. Finally, it recalls how to convert the microscopic dipole moments and polarizabilies into macroscopic polarization densities and susceptibilities to obtain a medium representation of a (meta)material structure. Upon this basis, the second part of the paper presents a macroscopic perspective of electromagnetic chirality and chiral materials.

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Section: A Motivation and Definitionmentioning

confidence: 99%

Electromagnetic Chirality, Part 1: The Microscopic Perspective [Electromagnetic Perspectives]

Caloz

Sihvola

2020

IEEE Antennas Propag. Mag.

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“…Using the data from Fig. 2, the ellipticity angle was calculated from both numerically and analytically obtained transmission spectra by the next formula 56 :…”

Section: Resultsmentioning

confidence: 99%

Optically tunable terahertz chiral metasurface based on multi-layered graphene

Masyukov

Vozianova

Grebenchukov

et al. 2020

Sci Rep

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Active manipulation of the polarization states at terahertz frequencies is crucially helpful for polarization-sensitive spectroscopy, having significant applications such as non-contact Hall measurements, vibrational circular dichroism measurements and anisotropy imaging. the weakness of polarization manipulation provided by natural materials can be overcomed by chiral metamaterials. Chiral metamaterials have a huge potential to achieve the necessary polarization effects, hence they provide the basis for applications such as ultracompact polarization components. terahertz chiral metamaterials that allow dynamic polarization modulation of terahertz waves are of great practical interest and still challenging. Here, we show that terahertz metasurface based on the four conjugated "petal" resonators integrated with multi-layered graphene (MLG) can enable dynamically tunable chiroptical response using optical pumping. In particular, a change of ellipticity angle of 20° is observed around 0.76 THz under optical pumping by a 980 nm continuous wave (CW) laser. Furthermore, using temporal coupled-mode theory, our study also reveals that the chiroptical response of the proposed multi-layered graphene-based metasurface is strongly dependent on the influence of optical pumping on the loss parameters of resonance modes, leading to actively controllable polarization states of the transmitted terahertz waves. the present work paves the way for the realization of fundamental terahertz components capable for active polarization manipulation.

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“…Following the interpretation of Kenanakis et al . 18 , the displacement fields link the ends of the upper cross arm with the ends of the lower cross arm, forming current loops. This gives rise to a single magnetic dipole moment with a direction lying in the plane of the sample.…”

Section: Numerical Modelling and Discussionmentioning

confidence: 99%

On the origin of pure optical rotation in twisted-cross metamaterials

Barr

Díaz-Rubio

Tremain

et al. 2016

Sci Rep

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We present an experimental and computational study of the response of twisted-cross metamaterials that provide near dispersionless optical rotation across a broad band of frequencies from 19 GHz to 37 GHz. We compare two distinct geometries: firstly, a bilayer structure comprised of arrays of metallic crosses where the crosses in the second layer are twisted about the layer normal; and secondly where the second layer is replaced by the complementary to the original, i.e. an array of cross-shaped holes. Through numerical modelling we determine the origin of rotatory effects in these two structures. In both, pure optical rotation occurs in a frequency band between two transmission minima, where alignment of electric and magnetic dipole moments occurs. In the cross/cross metamaterial, the transmission minima occur at the symmetric and antisymmetric resonances of the coupled crosses. By contrast, in the cross/complementary-cross structure the transmission minima are associated with the dipole and quadrupole modes of the cross, the frequencies of which appear intrinsic to the cross layer alone. Hence the bandwidth of optical rotation is found to be relatively independent of layer separation.

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Controlling THz and far-IR waves with chiral and bianisotropic metamaterials

Cited by 13 publications

References 62 publications

Electromagnetic Chirality, Part 1: The Microscopic Perspective [Electromagnetic Perspectives]

Electromagnetic Chirality, Part 1: The Microscopic Perspective [Electromagnetic Perspectives]

Optically tunable terahertz chiral metasurface based on multi-layered graphene

On the origin of pure optical rotation in twisted-cross metamaterials

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