Metasurface Enabled Multi‐Target and Multi‐Wavelength Diffraction Neural Networks

Laser & Photonics Review, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 3, 2024

Abstract Benefiting from low power consumption and high processing speed, there is a growing interest in diffraction neural networks (DNNs), which are typically showcased with 3D printing devices, leading to large volumes, costs, levels of integration. Metasurfaces can desirably manipulate wavefronts electromagnetic waves, providing compact platform for mimicking DNNs novel functions. Although multi‐wavelength multi‐target recognition provides richer more detailed understanding complex environments, existing architectures primarily trained classify single target at specific wavelength. A metasurface approach proposed design multiplexed that multiple targets spatial sequences across various wavelengths channels. To realize multi‐task processing, the dielectric designed based on phase wavelength multiplexing, integrate different tasks such as operating distinct classifying diverse targets. The efficacy this method exemplified through numerical simulation experimental demonstration recognizing two wavelengths, wavelength, dual wavelengths. This enables DNNs, opening new window develop massively parallel versatile artificial intelligence systems.

Language: Английский

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An Ultrathin, Fast‐Response, Large‐Scale Liquid‐Crystal‐Facilitated Multi‐Functional Reconfigurable Metasurface for Comprehensive Wavefront Modulation

Advanced Materials, Journal Year: 2024, Volume and Issue: 36(26)

Published: April 8, 2024

The rapid advancement of prevailing communication/sensing technologies necessitates cost-effective millimeter-wave arrays equipped with a massive number phase-shifting cells to perform complicated beamforming tasks. Conventional approaches employing semiconductor switch/varactor components or tunable materials encounter obstacles such as quantization loss, high cost, complexity, and limited adaptability for realizing large-scale arrays. Here, low-cost, ultrathin, fast-response, solution relying on metasurface concepts combined together liquid crystal (LC) requiring layer thickness only 5 µm is reported. Rather than immersing resonant structures in LCs, joint material-circuit-based strategy devised, via integrating deep-subwavelength-thick LCs into slow-wave structures, achieve constitutive metacells continuous phase shifting stable reflectivity. An LC-facilitated reconfigurable sub-system containing more 2300 realized its unprecedented comprehensive wavefront manipulation capacity validated through various functions, including beam focusing/steering, vortex beams, holograms, demonstrating milli-second-level function-switching speed. proposed methodology offers paradigm shift modulating electromagnetic waves non-resonating broadband fashion fast-response low-cost properties by exploiting functionalized LC-enabled metasurfaces. Moreover, this extremely agile metasurface-enabled antenna technology will facilitate transformative impact systems empower new possibilities engineering diffractive wave calculation/inference.

Language: Английский

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Electrically Active Terahertz Liquid‐Crystal Metasurface for Polarization Vortex Beam Switching

Laser & Photonics Review, Journal Year: 2024, Volume and Issue: 18(7)

Published: March 12, 2024

Abstract Polarized vortex waves have attracted widespread attention in investigations of light–matter interactions and the augmentation information capacity owing to their distinctive characteristics. Nevertheless, reconfigurable generation vector beams, especially at terahertz (THz) frequencies, remains challenging. In this study, a tunable THz polarization beam generator based on liquid‐crystal metasurface is proposed. A unit cell featuring linear selectivity developed. general methodology for designing metasurfaces generate customized patterns introduced. Furthermore, electrically polarized cylinder beams experimentally demonstrated. The findings study can open up opportunities wireless communication super‐resolution imaging applications.

Language: Английский

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Physics‐Informed Inverse Design of Programmable Metasurfaces

Advanced Science, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 5, 2024

Abstract Emerging reconfigurable metasurfaces offer various possibilities for programmatically manipulating electromagnetic waves across spatial, spectral, and temporal domains, showcasing great potential enhancing terahertz applications. However, they are hindered by limited tunability, particularly evident in relatively small phase tuning over 270°, due to the design constraints with time‐intensive forward methodologies. Here, a multi‐bit programmable metasurface is demonstrated capable of beam steering facilitated developed physics‐informed inverse (PIID) approach. Through integrating modified coupled mode theory (MCMT) into residual neural networks, PIID algorithm not only significantly increases accuracy compared conventional networks but also elucidates intricate physical relations between geometry modes. Without decreasing reflection intensity, method achieves enhanced as large 300°. Additionally, inverse‐designed experimentally validated, which adaptable 1‐bit, 2‐bit, tri‐state coding schemes, yielding deflection angle up 68° broadened coverage. The demonstration provides promising pathway rapidly exploring advanced devices, potentially impact on communication imaging technologies.

Language: Английский

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Meta‐Device for Field‐of‐View Tunability via Adaptive Optical Spatial Differentiation

Advanced Science, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 13, 2025

Optical edge detection is a crucial optical analog computing method in fundamental artificial intelligence, machine vision, and image recognition, owing to its advantages of parallel processing, high speed, low energy consumption. Field-of-view-tunable particularly significant for detecting broader range objects, enhancing both practicality flexibility. In this work, novel approach-adaptive spatial differentiation proposed field-of-view-tunable detection. This improves the ability acquire information facilitates over wider angular range. The adaptive meta-device relies on two core components: dielectric metasurface liquid prism. shown function as highly efficient (≈85%) isotropic differentiator, operating across entire visible spectrum (400 700 nm) within wide-angle object space, expanding up 4.5 times original field view. scheme presents new opportunities efficient, flexible, high-capacity integrated data processing imaging devices. And simultaneously provides architecture next generation wide field-of-view phase contrast microscopy.

Language: Английский

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Liquid Crystal Metasurface for On‐Demand Terahertz Beam Forming Over 110° Field‐Of‐View

Laser & Photonics Review, Journal Year: 2024, Volume and Issue: 18(9)

Published: April 15, 2024

Abstract The terahertz spectral region, which bridges between electronics and optics, is poised to play an important role in the development of transformative wireless communication imaging systems with unprecedented functionality. Currently, a major challenge technology develop high‐performance beam‐forming devices that can dynamically shape radiation flexible manner. Existing have limited coding bits, field‐of‐view, beam gain. Here, reconfigurable liquid crystal‐integrated metasurface experimentally demonstrated, each unit cell being independently addressable. has 260° continuous phase tuning range crystal layer thickness only 1% free‐space wavelength. wave diffracted from be steered toward wide directions shown, covering record‐large 110° field‐of‐view peak gain 25 dBi. also features low power consumption sub‐second switching time. Furthermore, formation multiple beams direction ratio adjustable on demand. proposed possesses compelling prospects for future applications.

Language: Английский

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Directional Phase and Polarization Manipulation Using Janus Metasurfaces

Advanced Science, Journal Year: 2024, Volume and Issue: 11(38)

Published: Aug. 9, 2024

Abstract Janus metasurfaces, exemplifying two‐faced 2D metamaterials, have shown unprecedented capabilities in asymmetrically manipulating the wavefront of electromagnetic waves both forward and backward propagating directions, enabling novel applications asymmetric information processing, security, signal multiplexing. However, current metasurfaces only allow for directional phase manipulation, hindering their broader application potential. Here, study proposes a versatile metasurface platform that can directionally control polarization terahertz by integrating functionalities half‐wave plates, quarter‐wave metallic gratings within cascaded structure. As proof‐of‐principle, experimentally demonstrates capable independent simultaneous over polarization, showcasing propagation direction‐encoded focusing conversion. Moreover, focused points are utilized with distinct states advanced direction‐ polarization‐sensitive detection imaging. This unique strategy direction‐dependent versatility opens new avenues designing ultra‐compact devices significant implications imaging, encryption, data storage.

Language: Английский

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A Smart Millimeter-Wave Base Station for 6G Application Based on Programmable Metasurface

National Science Review, Journal Year: 2025, Volume and Issue: 12(4)

Published: Jan. 16, 2025

The evolution of programmable metasurfaces has yielded many exciting electromagnetic (EM) phenomena and applications in both communities physical information sciences. Programmable metasurfaces, also known as reconfigurable intelligent surfaces or reflecting wireless communications, have played important roles enhancing signal coverage transmission quality, building an artificially controlled communication environment. However, most the realistic implementations are designed sub-6G band with a small array scale 1-bit phase control ability, making performance improvement not marvelous compared traditional solutions. Here, we propose large-scale 2-bit millimeter-wave metasurface to build integrated smart base station framework for 6G communications. meta-array is composed 30 × meta-elements, each two embedded positive-intrinsic-negative (PIN) diodes. A dish-cone antenna serve feeding source. board autonomously switch working states all 1800 PIN diodes based on field-programmable gate array, enabling individual adjustment EM responses meta-elements array. Through deliberate arrangement distribution surface, can undergo reconfiguration achieve desired functionalities. We take core assist validate its good communications indoor scenario. Subsequently, four-stream scenario using four arrays demonstrate multi-user transmissions different positions. This work provides great potential aid development novel stations, offering valuable insights advancing next-generation mobile

Language: Английский

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Tristate Switching of Terahertz Metasurfaces Enabled by Transferable VO₂

Laser & Photonics Review, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 22, 2025

Abstract Achieving dynamic switching among absorption (A), reflection (R), and transmission (T) states is not only essential for advancing the understanding of light‐metasurface interactions but also holds significant potential practical applications, such as selective electromagnetic shielding smart windows. However, at terahertz higher frequencies, implementing active elements in multilayer configurations presents challenges that are straightforward those encountered microwave range. In this work, it demonstrated tristate ART tuning can be realized a single‐layer, free‐standing metasurface by between dual dipolar mode (electric dipole magnetic dipole) single dipole). By transferring flexible vanadium dioxide (VO 2 ) thin film onto dielectric Huygens’ metasurface, modulation achieved, transitioning from near‐unity state to near‐perfect state, finally high‐reflection with up 0.65 during insulator‐to‐metal transition induced heating phase‐change material. The results may lead new approaches designing reconfigurable metasurfaces based on materials wavefront control applications.

Language: Английский

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Reconfigurable Manipulation of Sound with a Multimaterial 3D Printed Origami Metasurface

Advanced Materials Technologies, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 22, 2025

Abstract The challenge in reconfigurable manipulation of sound waves using metasurfaces lies achieving precise control over acoustic behavior while developing efficient and practical tuning methods for structural configurations. However, most studies on rely cumbersome time‐consuming systems. These approaches often struggle with fabrication techniques, as conventional face limitations such restricted material choices, challenges complex geometries, difficulties incorporating flexible components. This paper proposes a novel approach metasurface inspired by the Kresling origami, designed programmable at an operating frequency 2000 Hz. origami unit cell is fabricated multimaterial three‐dimensional (3D) printing technology, allowing simultaneous two materials different mechanical properties, thus creating bistable origami‐based structure. Through optimization, equilibrium states achieve reflection phase difference π through application small axial force, F , or torque, T . Various configurations metasurface, generated from combinations these equilibria, enable distinct reflective behaviors switchable functionalities. principle this work simplifies shaping straightforward mechanism, eliminating need systems adjustments.

Language: Английский

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