Tunable circular dichroism of stretchable chiral metamaterial

Zhou, Lei; Wang, Yueke; Zhou, Jiaxin; Ding, Jian; Su, Zengping; Li, Mingxing; Lu, Mengjia; Shi, Hangyu; Sang, Tian

doi:10.35848/1882-0786/ab8054

Cited by 15 publications

(5 citation statements)

References 32 publications

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“…In contrast to [22], the proposed unit cell with a metal pattern on only one side of the printed circuit board (PCB) is intrinsically achiral. Through numerical and experimental characterization, we show that these nonplanar structures can present large CD values, up to 0.9, which are higher than those presented by conventional intrinsic CMMs, around 0.6 [27], [28], [29], but also by the planar distribution with oblique incidence. This improvement in the CD resides in the interaction between the unit cells, that is, mutual coupling.…”

mentioning

confidence: 88%

High Circular Dichroism in Extrinsic Chiral Metamaterials Based on Sawtooth and Zigzag Arrangements With Experimental Validation

Yamoun,

Fernández,

Aknin

et al. 2024

IEEE Trans. Microwave Theory Techn.

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This study analyzes the extrinsic chirality of metamaterials based on printed circuit board (PCB). Inspired by extrinsic planar metamaterials, two novel 3-D chiral metamaterials (CMMs) have been proposed and analyzed. In these structures, called sawtooth and zigzag arrangements, each unit cell and not the entire metamaterial is tilted with respect to the incident field. In both cases, the same single-layer metallic pattern, that is, a split-ring resonator (SRR), was used. In comparison with the traditional planar extrinsic chiral structures, it is shown, by numerical and experimental characterization, that these new types of arrangements exhibit a larger circular dichroism (CD), approximately 0.90, in the X-band, with a significant wideband response. The analysis of the extrinsic chirality shows that it is originated by the dipole moments excited on the unit cells. With circular polarization, the constructive/destructive interference between these dipoles produces CD. However, owing to the broadside coupling between adjacent unit cells, the proposed nonplanar arrangements provide higher CD values than the planar structure.

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mentioning

confidence: 88%

High Circular Dichroism in Extrinsic Chiral Metamaterials Based on Sawtooth and Zigzag Arrangements With Experimental Validation

Yamoun,

Fernández,

Aknin

et al. 2024

IEEE Trans. Microwave Theory Techn.

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“…However, all these devices typically lack tuning ability because the chiral eigenstates are often determined by structural parameters such as period and height, and optical functions become fixed once the fabrication is completed. Many efforts have been made to achieve dynamic control of CD behavior in which active materials with externally applied electro-voltage, optical fields, temperature, forces or even chemical reactions are employed, such as applying an external voltage to graphene, , liquid crystals, and other meta-atoms, , injecting extra photons to achieve chiral switch based on physical properties and chemical reactions , of materials, adjusting the temperature to trigger the phase transition of the materials or assembling or applying external forces , on a flexible material substrate (like polydimethylsiloxane and hydrogel). However, the performance of these actively tuned devices is often limited to weak chirality and poor regulation ability due to the limited performance of the available active materials.…”

Section: Introductionmentioning

confidence: 99%

Passively Broadband Tunable Dual Circular Dichroism via Bound States in the Continuum in Topological Chiral Metasurface

Wang,

Cheng

et al. 2024

ACS Nano

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Dynamic control for a strong circular dichroism (CD) response is essential in engineering applications such as polarization manipulation, sensing, and imaging. Here, we propose and experimentally demonstrate a broadband tunable dual CD response via bound states in the continuum (BICs) in two-dimensional topologically protected metasurfaces composed of all-dielectric Si chiral grating structures that generate a pair of mixed and degenerated BIC mode and circular dichroic mode (CDM) as an additional degree of freedom in CD manipulation. It is found that a singular CD peak of nearly 100% at 1.6 μm can be achieved by CDM when BIC is hidden under normal incidence, while the CD peak can be split into two in which peak wavelengths can be precisely and linearly tuned over a bandwidth of 180 nm by the incident angle when the BIC mode is excited under oblique incidence. Additionally, dynamic modulation of output polarization states from linear to circular can be arbitrarily achieved at the split CD peaks by controlling the incident angle when asymmetry perturbations on chiral gratings are introduced due to the decoupling of various polarization states at Γ point by BIC to different positions in K space. The proposed chiral grating metasurface exhibits unique angle-sensitive tunable CD spectral characteristics, making it ideal for hyperspectral and spin-selective wavefront shaping, and holds significant promise in various applications such as optical security, angle sensors, chiral lasers, nonlinear filters, and other active chiral optical devices.

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“…In recent years, metamaterials or metasurfaces have attracted increasing attention. [7,8] Researchers have found that they can easily modulate the polarization modes of electromagnetic (EM) waves. [9][10][11][12][13] To date, a series of novel polarization converters have been realized and studied by using metasurface, [14][15][16][17][18][19][20] which greatly promote the development of optoelectronics and optical communication.…”

Section: Introductionmentioning

confidence: 99%

Tunable wide-angle multi-band mid-infrared linear-to-linear polarization converter based on a graphene metasurface*

Zhang

Song

2021

Chinese Phys. B

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We present a high-efficiency tunable wide-angle multi-band reflective linear-to-linear (LTL) polarization converter, which is composed of an array of two L-shaped graphene patches with different sizes. In the mid-infrared region, the proposed converter can transform x-polarized wave into y-polarized wave at four resonant frequencies. The polarization conversion ratios of the four bands reach 94.4%, 92.7%, 99.3%, and 93.1%, respectively. By carefully choosing the geometric parameter, triple-band LTL polarization conversion can also be realized. The three polarization conversion ratios reach 91.50%, 99.20%, and 97.22%, respectively. The influence of incident angle on the performances of the LTL polarization converter is investigated, and it is found that our polarization converter shows the angle insensitivity. Also, the dynamically tunable properties of the proposed polarization converter are numerically studied by changing Fermi energy. All the simulation results are conducted by finite element method.

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Tunable circular dichroism of stretchable chiral metamaterial

Cited by 15 publications

References 32 publications

High Circular Dichroism in Extrinsic Chiral Metamaterials Based on Sawtooth and Zigzag Arrangements With Experimental Validation

High Circular Dichroism in Extrinsic Chiral Metamaterials Based on Sawtooth and Zigzag Arrangements With Experimental Validation

Passively Broadband Tunable Dual Circular Dichroism via Bound States in the Continuum in Topological Chiral Metasurface

Tunable wide-angle multi-band mid-infrared linear-to-linear polarization converter based on a graphene metasurface*

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