Anomalous reflection from metasurfaces with gradient phase distribution below 2π

Ho, You Zhe; Cheng, Bingying; Hsu, Wen Lian; Wang, Chih–Ming; Tsai, Din Ping

doi:10.7567/apex.9.072502

Cited by 14 publications

(5 citation statements)

References 40 publications

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“…[56] Figure 4a indicates that at λ = 532 nm the reflectance is the same for Au 0.2 Ag 0.8 and Au 0.8 Ag 0.2 nanostructures, while the phase they produce is shifted by 165°; this nanostructures pair can therefore serve as meta-atoms for a binary metasurface. [71] This is confirmed in Figure 4b by measurements on alloyed disc arrays with five different stoichiometries (reflectance measurement setup described in Figure S10, Supporting Information). The agreement between these measurements and simulations is good, especially the spectral locations of the reflection dip agree very well.…”

Section: Alloyed Metasurfacessupporting

confidence: 54%

“…The permittivity for Al and SiO 2 originate from the literature 67 , whereas that for Au x Ag 1-x are computed using Rioux's model 56 . Figure 4a indicates that at  = 532 nm the reflectance is the same for Au 0.2 Ag 0.8 and Au 0.8 Ag 0.2 nanostructures, while the phase they produce is shifted by 165°; this nanostructures pair can therefore serve as meta-atoms for a binary metasurface 68 . This is confirmed in Fig.…”

Section: Alloyed Metasurfacesmentioning

confidence: 99%

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A Low‐Temperature Annealing Method for Alloy Nanostructures and Metasurfaces: Unlocking a Novel Degree of Freedom

et al. 2022

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The material and exact shape of a nanostructure determine its optical response, which is especially strong for plasmonic metals. Unfortunately, only a very few plasmonic metals are available, which limits the spectral range where these strong optical effects can be utilized.Alloying different plasmonic metals can overcome this limitation, at the expense of using a high temperature alloying process, which adversely destroys the nanostructure shape. Here, we develop a low temperature alloying process at only 300°C and fabricate Au-Ag nanostructures with a broad diversity of shapes, aspect ratios and stoichiometries. EDX and XPS analyses confirm the homogeneous alloying through the entire sample. Varying the alloy stoichiometry tunes the optical response of the nanostructure and controls spectral features such as Fano resonances. Binary metasurfaces that combine nanostructures with different stoichiometries are fabricated using multiple-step electron beam lithography, and their optical function as hologram or Fresnel zone plate is demonstrated at the visible wavelength of  = 532 nm. This low temperature annealing technique provides a versatile and cost-effective way of fabricating complex Au-Ag nanostructures with arbitrary stoichiometry.

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Section: Alloyed Metasurfacessupporting

confidence: 54%

Section: Alloyed Metasurfacesmentioning

confidence: 99%

A Low‐Temperature Annealing Method for Alloy Nanostructures and Metasurfaces: Unlocking a Novel Degree of Freedom

et al. 2022

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“…State-ofthe-art technologies for communications and sensing require the ultimate miniaturization of optical devices for manipulation of electromagnetic waves [1][2][3][4][5][6][7]. One of the routes to attain deeply subwavelength structures for wave-front engineering is the use of plasmonic materials [8][9][10][11][12][13][14][15][16]. Despite the wide range of applications accessible with plasmonic metasurfaces, they have an inherent drawback, namely, high dissipation loss.…”

Section: Introductionmentioning

confidence: 99%

All-dielectric metamirror for independent and asymmetric wave-front control

et al. 2019

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We report on the design and the numerical and experimental characterization of an all-dielectric reflecting focusing metasurface (metamirror) which does not have a back reflector, but effectively reflects incident waves with the desired reflection phase gradient. The profile of the reflection phase can be tuned independently for both sides of the single-layer subwavelength-thick metamirror by properly selecting dimensions of its dielectric inclusions. Such a feature stems from the bianisotropic omega properties of the inclusions. To demonstrate independent control of the reflection phase, we have designed a metamirror focusing normally incident plane waves at different focal distances being illuminated from the opposite sides. The proposed two-sided metamirror can find applications in antennas, diffraction gratings, and complex holograms. The absence of conducting elements makes it a perfect candidate for optical applications requiring asymmetric wave-front control.

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“…In the second approach, the metasurface is separated from a metal substrate by a dielectric spacer. Such configuration works only in reflection mode, but can have a high efficiency reaching 100% for negligible loss [2][3][4][29][30][31][32][33][34][35][36][37][38][39][40][41].…”

Section: Introductionmentioning

confidence: 99%

Design and simulation of reflect-array metasurfaces in the visible regime

Alrasheed

Fabrizio

2017

Appl. Opt.

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Metasurfaces are new, promising ultrathin materials that can enable many novel optical devices due to their ability to act as a discontinuity interface that introduces an abrupt change in amplitude, phase, and sometimes the polarization of the incident light at the wavelength scale. Therefore they can function as flat optical elements. Here, we investigate the anomalous reflection of light for transverse-magnetic (TM) polarization for normal and oblique incidence in the visible regime. We propose gradient phase gap-surface plasmon metasurfaces that exhibit high conversion efficiency (up to ∼97% of total reflected light) to the anomalous reflection angle for blue, green, and red wavelengths at normal and oblique incidence, and where light polarization is unchanged after the reflection.

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Anomalous reflection from metasurfaces with gradient phase distribution below 2π

Cited by 14 publications

References 40 publications

A Low‐Temperature Annealing Method for Alloy Nanostructures and Metasurfaces: Unlocking a Novel Degree of Freedom

A Low‐Temperature Annealing Method for Alloy Nanostructures and Metasurfaces: Unlocking a Novel Degree of Freedom

All-dielectric metamirror for independent and asymmetric wave-front control

Design and simulation of reflect-array metasurfaces in the visible regime

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