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Dichroism metasurface polarizer. (a) Gold helix nanostructure for the circular polarizer. Reprinted with permission from Gansel et al., Science 325(5947), 1513–1515 (2009). Copyright 2009 AAAS.⁷⁴ (b) Circular dichroism in planar chiral nanostructure made of copper strips arises from different conversion efficiencies of circular polarization. Reprinted with permission from Zheludev et al., Phys. Rev. Lett. 97(16), 167401 (2006). Copyright 2006 American Physical Society.⁷⁷ (c) Large chiroptical effects in L-shaped gold nanostructures based on multimode interference. Reprinted with permission from Zhang et al., Phys. Rev. Appl. 7(5), 054003 (2017). Copyright 2017 American Physical Society.⁸⁵ (d) Strong chiral response induced by the spin-dependent destructive and constructive interference in dielectric birefringent metasurface. Reprinted with permission from Kenney et al., Adv. Mater. 28(43), 9567–9572 (2016). Copyright 2016 Author(s), licensed under a Creative Commons Attribution 4.0 License.⁸⁰ (e) Giant circular polarization dichroism induced by the spin-dependent destructive and constructive interference based on planar dielectric metasurface. Reprinted with permission from Zhang et al., Adv. Funct. Mater. 27(47), 1704295 (2017). Copyright 2017 Author(s), licensed under a Creative Commons Attribution 4.0 License.⁸¹ (f) Arbitrary polarization conversion dichroism metasurfaces for surface Poincaré sphere polarizers. Reprinted with permission from Wang et al., Light: Sci. Appl. 10(1), 24 (2021). Copyright 2021 Author(s), licensed under a Creative Commons Attribution 4.0 License.⁸² (g) Metasurface manipulating both DOP and SOP for full solid Poincaré sphere polarizer. Reprinted with permission from Wang et al., Phys. Rev. Lett. 130(12), 123801 (2023). Copyright 2023 American Physical Society.⁸⁴
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Metasurface polarization optics, manipulating polarization using metasurfaces composed of subwavelength anisotropic nanostructure array, has enabled a lot of innovative integrated strategies for versatile and on-demand polarization generation, modulation, and detection. Compared with conventional bulky optical elements for polarization control, met...
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Large-scale quantum networks require dynamic and resource-efficient solutions to reduce system complexity with maintained security and performance to support growing number of users over large distances. Current encoding schemes including time-bin, polarization, and orbital angular momentum, suffer from the lack of reconfigurability and thus scalab...
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... However, they limit the innovation and diversity of the design. To solve these problems, Deng et al. proposed inverse designed Jones matrix metasurface polarizers [30], [31]. Due to the improvement of the computing power and the development of the machine learning technology, the neural networks became able to control the electric fields [32]- [36]. ...
The metasurfaces are able to flexibly control electromagnetic waves. However, their design necessitates strict phase matching, which requires high computational load, and its control method has low flexibility. This paper proposes a novel method for the customization of the electric field of metalens with high degrees of freedom based on an improved Pixel Generative Adversarial Network (I-pixGAN). This I-pixGAN can design the phase distribution of the metalens according to the customized target electric field, and the constructed metalens based on this phase can modulate the target electric field. The results show that the proposed I-pixGAN can arbitrarily control the position of the focus in three-dimensional space, where the focus position is offset within one wavelength. Therefore, it is not need to strictly follow the electric field distribution characteristics, and it can flexibly construct unknown electric field, realizing a highly free electric field customization method in three-dimensional space, providing a new way for electric field operation. This paper promotes the development of electric focusing systems, not only improving focusing accuracy but also enhancing system flexibility and promoting the automation and intelligence of optical and terahertz systems.
... Metasurfaces, composed of arrays of artificially engineered subwavelength meta-atoms, have emerged as a powerful platform for arbitrarily manipulating the amplitude, phase, and polarization of incident electromagnetic (EM) waves, enabling unprecedented control over wavefronts across a wide range of frequencies [1][2][3][4][5][6]. In particular, metasurfaces operating in the microwave and millimeter-wave (mm-Wave) regimes have demonstrated a plethora of remarkable capabilities in EM shielding [7], radar cross section reduction [8], conformal cloaking [9], beam steering [10], and holographic imaging [11], which are critical for a range of applications, such as stealth radomes, satellite communication systems, and 5G technologies, just to name a few. ...
Metasurfaces have shown remarkable capabilities in tailoring the electromagnetic wavefronts at a subwavelength scale. However, existing metasurfaces that operate at a customized frequency still face significant challenges in satisfying the demands of multi-mode surveillance technologies and integrated systems. Here, we propose a concept of multispectral metasurface that can achieve the compatibility of visible, infrared, and millimeter-wave frequency regions, thereby not only expanding the degree of freedom in manipulating electromagnetic fields, but also facilitating the development of modern optoelectronic devices requiring miniaturization and integration. The proposed metasurface consists of two sets of meta-atoms arranged in an interleaved configuration, enabling independent 3-bit phase modulation at two distinct millimeter-wave frequencies. Proof-of-concept experiments demonstrate the implementation of a frequency-selective bifocal metalens and a dual-channel meta-hologram using the proposed design, both of which exhibit high visible transparency and low infrared emissivity simultaneously. This work provides a new paradigm for multispectral-compatible metasurfaces with boosted information capacity for various application scenarios, including optical windows, high-gain lens antennas, and wireless communication systems requiring multi-channel signal processing.
... Utilizing this unique functionality, a miniaturized and simplified two-photon polymerization (TPP) system was developed and demonstrated efficient multi-focus parallel processing [13] . Wavelength and polarization information can be independently encoded into each focal point, enabling the development of compact spectrometer [14] and polarization-resolved device [15] . More importantly, metalensbased optical trapping arrays have emerged as a powerful platform for the preparation and manipulation of ultracold atoms [16,17] , enabling multifunctional control in complex quantum information experiments. ...
Multi-foci metalenses with uniform focal arrays attract special attention as they enable a single incident beam to focus on the same focal plane and share the identical numerical apertures. In this work, we demonstrate the scalable manufacturing of polarization-insensitive metalenses with high-uniform focal arrays in the visible. To overcome the limitations inherent in conventional imprint resins characterized by a low refractive index, hybrid meta-atoms are formed using the imprint resin itself, and a thin layer of titanium dioxide (TiO2) is deposited on it via atomic layer deposition (ALD) to increase the effective refractive index, enabling full phase coverage. We propose the gradient-descent-optimization strategy for phase retrieval of multi-foci metalens, which renders our design free from cross-talk and makes it feasible to achieve uniform focal arrays with flexible geometries. Based on this inverse-design scheme, the capability of nanoimprinted metalenses are explored by directly producing various focal arrays, including complex geometries such as square, rhombic lattices, as well as intact and defective rings. We envision this work may pave the way for various fields, including optical trapping, materials science, and quantum optics.
... Metasurfaces, composed of artificial meta-atoms at subwavelength scales, have emerged as a promising platform for controlling the amplitude, phase, and polarization of light [1][2][3]. Leveraging their powerful light-manipulation capabilities, metasurfaces have enabled the development of various polarization devices [4], including polarization imaging [5][6][7], vectorial holography [8][9][10][11], and complex beam generation [12,13]. In polarization multiplexing, due to the fact that the polarization-dependent optical response of metasurfaces can be described by a 2 × 2 Jones matrix, most metasurface-based devices are restricted to orthogonal polarization channels [14][15][16][17][18][19][20][21][22][23]. ...
Orthogonal polarization multiplexing is typically required to avoid crosstalk between channels. However, for practical applications in optical information encryption, orthogonal polarization channels are vulnerable to decoding. Using non-orthogonal polarization channels can enhance information security. Here, we extend the conventional Jones matrix approach to achieve non-orthogonal tri-channel polarization multiplexing metasurfaces for optical encryption via optical holography. Using a supercell configuration with two pairs of α-Si meta-atoms, we experimentally demonstrate metasurface-based multiplexing under three linear polarization channels, including copolarized and non-copolarized channels. This design strategy is further extended to circular and elliptical polarization channels, which exhibits minimum crosstalk. As a proof-of-concept demonstration, we implement two optical encryption applications, i.e., image encryption and character encryption, based on non-orthogonal polarization-multiplexed metasurfaces. For image encryption, encrypted images are generated only in the correct polarization channels. While using seven different statuses of metasurface under various polarization channels, we also present a character encryption scheme. We envision that the non-orthogonal polarization multiplexing metasurface platform will open new possibilities in optical communication, optical encoding, and information security.
... Many recent papers have been devoted to the study of linear polarization conversion with single metasurfaces (see, e.g, Refs. [9]- [13]), as well as multiple metasurfaces with stacking and twisted configurations [14], [15]. Polarization transformations with metasurfaces have been extensively explored by the Federico Capasso group [16]- [18]. ...
Polarization is a fundamental property of light that can be engineered and controlled efficiently with optical metasurfaces. Here, we employ chiral metasurfaces with monoclinic lattice geometry and achiral meta-atoms for resonant engineering of polarization states of light. We demonstrate, both theoretically and experimentally, that a monoclinic metasurface can convert linearly polarized light into elliptically polarized light not only in the linear regime but also in the nonlinear regime with the resonant generation of the third-harmonic field. We reveal that the ellipticity of the fundamental and higher-harmonic fields depends critically on the angle of the input linear polarization, and the effective chiral response of a monoclinic lattice plays a significant role in the polarization conversion.
In recent years, the active control of terahertz waves using artificial microstructures has attracted increasing attention, especially toward the ones that have multiple plasmon-induced transparency (PIT) responses. Here, a homogeneous graphene-metal metasurface, exhibiting tunable dual-PIT in its terahertz (THz) spectral response, is investigated numerically and theoretically. Individual and simultaneous control of the two PIT transmission windows and the two slow-light effects are achieved by reconstructing the Fermi energies of the graphene strips. The modulation behavior can be expounded by the classical coupled three-particle model, which is confirmed by the simulation results. Moreover, the electric field distribution is introduced to analyze the dual-PIT active modulation mechanism. This work provides theoretical guidance for versatile applications in multi-function terahertz switches and slow-light devices.
Photonic quasi-bound states in the continuum (quasi-BICs) provide an excellent platform for strong light–matter interactions in nanophotonics. In this work, we numerically and experimentally demonstrate that the Si nanorod dimer metasurface offers a new paradigm for realizing multiple wavelength-stabilized and quality-factor-tunable quasi-BICs, through a unique symmetry breaking method that does not alter the metasurface volume. A pronounced electromagnetically induced transparency (EIT) effect, exhibiting a group time delay of 6.7 ps, and strong coupling accompanied by characteristic anticrossing Rabi splitting are realized based on the hybridization between a bright mode and the neighboring quasi-BIC within this multiresonant metasurface. Intriguingly, a sharp transparency window, with tunable bandwidth but a stable wavelength, is achieved. All numerical results are validated by experimental demonstration. Our findings provide a recipe for realizing wavelength-stabilized, quality-factor-tunable quasi-BICs and an EIT-like effect. Our results would find utility in slow light, quantum storage, and nonlinear optics.
