Antireflection-assisted all-dielectric terahertz metamaterial polarization converter

Zi, Jianchen; Xu, Quan; Qiu, Wang; Tian, Chunxiu; Li, Yanfeng; Zhang, Xixiang; Han, Jiaguang; Zhang, Weili

doi:10.1063/1.5042784

Cited by 74 publications

(43 citation statements)

References 34 publications

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“…On the other hand, the reflective half‐wave plate element has a Jones matrix described as:

J_{^{1} /_{2}} = (\begin{matrix} 0 & e^{j {normalΦ}_{0}} \\ e^{j {normalΦ}_{0}} & 0 \end{matrix})

with off‐diagonal symmetry to realize the polarization conversion effect. Here, Φ 0 shows the original phase of the half‐wave plate element.…”

Section: Concept and Meta‐atom Designmentioning

confidence: 99%

“…The above results reveal that the challenge to design broadband spin‐decoupled metasurface can be reduced to find broadband half‐wave plates with different original phases. The literatures of metamaterial fields have explored many methods to manipulate the polarization state of EM wave in a broad band, and this may provide possible solutions.…”

Section: Concept and Meta‐atom Designmentioning

confidence: 99%

“…In this work, we propose a digital strategy to realize ultrawideband spin‐decoupled metasurface capable of independently encoding distinct wavefronts into orthogonal spin channels. Through theoretical analysis, we find that the hybrid method integrating both propagation and geometric phases can be simplified to seek different half‐wave plate meta‐atoms with different original phases. By utilizing digital and coding metasurface, a type of metasurface employing discrete phase elements to achieve diverse wave functions, we further get additional degree of freedom that is quite conducive to broadening the bandwidth as well as reducing the complexity of the design process.…”

Section: Introductionmentioning

confidence: 99%

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Ultrawideband Spin‐Decoupled Coding Metasurface for Independent Dual‐Channel Wavefront Tailoring

et al. 2020

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Achieving distinct functionalities for electromagnetic (EM) waves with opposite handedness in a broad frequency range is highly desirable and essential for modern wireless communications and radar stealth. However, available functional meta‐devices still suffer from the issues of locked functionalities or spin‐decoupled properties but with limited bandwidth. Here, a spin‐decoupled coding metasurface is presented for achieving independently spin‐controlled functionalities with high efficiency in an ultrawide frequency band. By synthesizing the Jones matrix, it is predicted that two half‐wave plates with a phase difference of 90° can form a 1‐bit coding metasurface operating for orthogonal spins independently. As proofs of concept, two meta‐devices are implemented by the metasurface in the microwave region. The first meta‐device performs as a spin‐decoupled beam deflector while the second one shows an ability to generate spin‐decoupled multi‐beams carrying desired orbital angular momentums. Both of the designed meta‐devices can operate in the whole band of 7.5–18.5 GHz (with relative bandwidth of 80%), which, to the best knowledge, is so far the broadest bandwidth that can be achieved by spin‐decoupled metasurfaces. This may trigger interest and open opportunities for advanced functional meta‐devices in practical applications, for example, multichannel metasurface antennas, or multifunctional low‐scattering devices in microwave region.

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“…On the other hand, the reflective half‐wave plate element has a Jones matrix described as:

J_{^{1} /_{2}} = (\begin{matrix} 0 & e^{j {normalΦ}_{0}} \\ e^{j {normalΦ}_{0}} & 0 \end{matrix})

with off‐diagonal symmetry to realize the polarization conversion effect. Here, Φ 0 shows the original phase of the half‐wave plate element.…”

Section: Concept and Meta‐atom Designmentioning

confidence: 99%

Section: Concept and Meta‐atom Designmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ultrawideband Spin‐Decoupled Coding Metasurface for Independent Dual‐Channel Wavefront Tailoring

et al. 2020

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“…Subwavelength structures composed of dielectric materials have been engineered for device‐specific applications at the terahertz regime. On one hand, low‐loss dielectric materials with moderate‐to‐high relative permittivity have been engineered into metasurfaces as phasing elements with nonuniform dimensions for wavefront manipulation and dynamic beam control for antennas and lenses or with anisotropic properties for polarization manipulation . On the other hand, lossy dielectric materials with moderately high relative permittivity are engineered to enhance coupling between and field confinement within subwavelength resonant cavity bodies.…”

Section: Dielectric Materials As Resonant Elements and Structuresmentioning

confidence: 99%

“…In this way, the fundamental frequency of resonance and the device efficiency, are dependent on the resonator structure and dielectric material used. As a result, dielectric resonators made of different materials have been designed in different shapes to interact differently to the two orthogonal polarizations of an incident wave for linear to linear polarization rotation, linear to circular, and circular to circular polarization conversion with preserved handedness . Irrespective of the mode of operation (reflective or transmissive) the materials used are designed to exhibit low dissipation and high radiation losses for efficient output or conversion, as discussed earlier.…”

Section: Lossless Dielectric Materialsmentioning

confidence: 99%

Dielectrics for Terahertz Metasurfaces: Material Selection and Fabrication Techniques

Ako

Upadhyay

Withayachumnankul

et al. 2019

Advanced Optical Materials

106

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on distinctive spectral signatures resulting from vibrational modes of covalent and hydrogen bonds. [8,[13][14][15][16] The focus on this spectrally rich region is attributed to the highly coherent and nonionizing nature of terahertz radiation, wide unallocated frequency bands, distinctive wavelengths, and their penetration through a significant depth of dielectric materials. Terahertz technology is geared toward realizing devices that can efficiently manipulate the phase, amplitude, and polarization of terahertz radiations for the above-mentioned myriad of applications.However, progress in this domain is held back by low terahertz power available from compact sources, high free-space path loss, and limited choice of materials that exhibit less absorption of terahertz waves. [17] Owing to the fact that natural materials demonstrate weak wave-matter interaction at terahertz frequencies, terahertz devices with engineered subwavelength resonant metallic inclusions on dielectric spacers have been realized, to interact strongly with an incident electromagnetic wave.In the past, metamaterials have been a promising route to building terahertz devices. These devices have in essence been engineered as 3D resonating elements that effectively manipulate both permittivity and permeability of an effective medium to couple to free space. The underlining disadvantage of these structures is the difficulty involved in the fabrication of 3D geometrical structures using standard semiconductor fabrication techniques. Standard fabrication techniques are generally amenable to 2D design with extrusion of these structures into thickness (the third, vertical dimension). Moreover, the choice and availability of dielectric materials and metals that provide sufficient interaction while retaining device efficiency has proved challenging. [13,[18][19][20] Recently, effective manipulation of electromagnetic wave has been widely demonstrated with 2D metasurfaces, which were originally employed as building blocks for 3D metamaterials. In these lower-dimension designs, effective manipulation of terahertz waves for various applications is achieved by carefully designing sub-wavelength resonant structures as is evident in published review articles. [21,22] Metasurfaces present high degree of compactness that enhances radiation efficiency. Additionally, the planar form factor of metasurfaces enables Manipulation of terahertz radiation opens new opportunities that underpin application areas in communication, security, material sensing, and characterization. Metasurfaces employed for terahertz manipulation of phase, amplitude, or polarization of terahertz waves have limitations in radiation efficiency which is attributed to losses in the materials constituting the devices. Metallic resonators-based terahertz devices suffer from high ohmic losses, while dielectric substrates and spacers with high relative permittivity and loss tangent also reduce bandwidth and efficiency. To overcome these issues, a proper choice of low loss and low relative permittivi...

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Stereo Metasurfaces for Efficient and Broadband Terahertz Polarization Conversion

Zhang

et al. 2022

Adv Funct Materials

Self Cite

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Efficient and flexible manipulation of terahertz (THz) polarization in a broadband manner using metasurfaces has attracted continuous attention in recent years. Previous studies commonly apply multilayer metallic resonators or bonded dielectric structures as the basic units, which are affected by the spacer loss or bonding difficulty and stability. Here, we propose a new design scheme based on all-metal stereo U-shaped meta-atom working in a reflection configuration. The stereo metasurface functions as an efficient and broadband THz waveplate with tailorable birefringence simply controlled by the sunken depth. Such an intriguing property is experimentally verified by a reflection-type THz half-waveplate. The polarization conversion ratio is higher than 90% with 69% relative bandwidth and over 85° angle tolerance for incidence. Furthermore, an efficient and broadband meta-grating based on Pancharatnam-Berry phase method is also experimentally demonstrated. The proposed strategy enriches the design degrees of freedom of polarization-related metasurfaces and may find broad applications in realizing various functional devices. 11974259, 61875150, 61935015); Tianjin Municipal Fund for Distinguished Young Scholars (grant No. 18JCJQJC45600).

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Antireflection-assisted all-dielectric terahertz metamaterial polarization converter

Abstract: FIG. 4. Simulation and experimental results of sample 6. (a) Transmission, (b) PCR, and (c) phase difference between u and v polarizations.

Cited by 74 publications

References 34 publications

Ultrawideband Spin‐Decoupled Coding Metasurface for Independent Dual‐Channel Wavefront Tailoring

Ultrawideband Spin‐Decoupled Coding Metasurface for Independent Dual‐Channel Wavefront Tailoring

Dielectrics for Terahertz Metasurfaces: Material Selection and Fabrication Techniques

Stereo Metasurfaces for Efficient and Broadband Terahertz Polarization Conversion

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