Structural color generation: from layered thin films to optical metasurfaces

Nanophotonics, Journal Year: 2023, Volume and Issue: 12(6), P. 1019 - 1081

Published: Feb. 21, 2023

Recent years have witnessed a rapid development in the field of structural coloration, colors generated from interaction nanostructures with light. Compared to conventional color generation based on pigments and dyes, exhibits unique advantages terms spatial resolution, operational stability, environmental friendliness, multiple functionality. Here, we discuss recent coloration layered thin films optical metasurfaces. This review first presents fundamentals science introduces few popular spaces used for evaluation. Then, it elaborates representative physical mechanisms generation, including Fabry-Pérot resonance, photonic crystal guided mode plasmon Mie resonance. Optimization methods efficient structure parameter searching, fabrication techniques large-scale low-cost manufacturing, as well device designs dynamic displaying are discussed subsequently. In end, surveys diverse applications various areas such printing, sensing, advanced photovoltaics.

Language: Английский

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Classical and generalized geometric phase in electromagnetic metasurfaces

Photonics Insights, Journal Year: 2022, Volume and Issue: 1(1), P. R03 - R03

Published: Jan. 1, 2022

The geometric phase concept has profound implications in many branches of physics, from condensed matter physics to quantum systems. Although a long research history, novel theories, devices, and applications are constantly emerging with developments going down the subwavelength scale. Specifically, as one main approaches implement gradient modulation along thin interface, metasurfaces composed spatially rotated artificial structures have been utilized construct various planar meta-devices. In this paper, we first give simple overview development optics. Then, focus on recent advances continuously shaped metasurfaces, geometric–dynamic composite nonlinear high-order linear Pancharatnam–Berry metasurfaces. Finally, conclusions outlooks for future presented.

Language: Английский

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Edge enhanced depth perception with binocular meta-lens

Opto-Electronic Science, Journal Year: 2024, Volume and Issue: 3(9), P. 230033 - 230033

Published: Jan. 1, 2024

The increasing popularity of the metaverse has led to a growing interest and market size in spatial computing from both academia industry. Developing portable accurate imaging depth sensing systems is crucial for advancing next-generation virtual reality devices. This work demonstrates an intelligent, lightweight, compact edge-enhanced perception system that utilizes binocular meta-lens computing. miniaturized comprises meta-lens, 532 nm filter, CMOS sensor. For disparity computation, we propose stereo-matching neural network with novel H-Module. H-Module incorporates attention mechanism into Siamese network. symmetric architecture, cross-pixel interaction cross-view interaction, enables more comprehensive analysis contextual information stereo images. Based on intensity discontinuity, edge enhancement eliminates ill-posed regions image where ambiguous predictions may occur due lack texture. With assistance deep learning, our provides prompt responses less than 0.15 seconds. will significantly contribute 3D scene modeling, machine vision, autonomous driving, robotics development.

Language: Английский

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Toward High‐Efficiency Ultrahigh Numerical Aperture Freeform Metalens: From Vector Diffraction Theory to Topology Optimization

Laser & Photonics Review, Journal Year: 2022, Volume and Issue: 16(10)

Published: Aug. 11, 2022

Abstract Optical metasurface is a 2D array of subwavelength meta‐atoms that arbitrarily manipulates amplitude, polarization, and wavefront incident light, offering great advantages in miniaturization integration. However, the presuppositions hidden conventional unit‐cell‐based design approach, including discrete phase sampling, local periodicity approximation, normal response, imply responses interactions are almost impossible to be accurately modeled, thus impeding effective high‐efficiency ultrahigh numerical aperture (NA) metalens. Here, based on vector diffraction theory plane wave expansion method, theoretical limitation metalens efficiency comprehensively investigated. It identified for high‐NA metalens, focusing limited by capability field, while evanescent attenuation dominates decline ultrahigh‐NA also shown has huge gap from limitation, owing imperfect diffractive impedance mismatch reflections. To fill such gap, freeform topology optimization further demonstrated. Particularly, geometric constraints utilized reduce minimum feature size keeping high efficiency. The results could shed new light understanding find promising applications optical imaging, microscopy, lithography.

Language: Английский

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Physics-data-driven intelligent optimization for large-aperture metalenses

Opto-Electronic Advances, Journal Year: 2023, Volume and Issue: 6(11), P. 230133 - 230133

Published: Jan. 1, 2023

Metalenses have gained significant attention and been widely utilized in optical systems for focusing imaging, owing to their lightweight, high-integration, exceptional-flexibility capabilities. Traditional design methods neglect the coupling effect between adjacent meta-atoms, thus harming practical performance of meta-devices. The existing physical/data-driven optimization algorithms can solve above problems, but bring time costs or require a large number data-sets. Here, we propose physics-data-driven method employing an “intelligent optimizer” that enables us adaptively modify sizes meta-atom according its surrounding ones. implementation such scheme effectively mitigates undesired impact local lattice coupling, proposed network model works well on thousands data-sets with validation loss 3×10⁻³. Based optimizer”, 1-cm-diameter metalens is designed within 3 hours, experimental results show 1-mm-diameter has relative efficiency 93.4% (compared ideal efficiency) Strehl ratio 0.94. Compared previous inverse method, our significantly boosts designing five orders magnitude reduction time. More generally, it may set new paradigm devising large-aperture

Language: Английский

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Chiral detection of biomolecules based on reinforcement learning

Opto-Electronic Science, Journal Year: 2023, Volume and Issue: 2(1), P. 220019 - 220019

Published: Jan. 1, 2023

Chirality plays an important role in biological processes, and enantiomers often possess similar physical properties different physiologic functions. In recent years, chiral detection of become a popular topic. Plasmonic metasurfaces enhance weak inherent effects biomolecules, so they are used detection. Artificial intelligence algorithm makes lot contribution to many aspects nanophotonics. Here, we propose nanostructure design method based on reinforcement learning devise nanostructures distinguish enantiomers. The finds out the metallic with sharp peak circular dichroism spectra emphasizes frequency shifts caused by nearfield interaction biomolecules. Our work inspires universal efficient machine-learning methods for nanophotonic design.

Language: Английский

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Direct field-to-pattern monolithic design of holographic metasurface via residual encoder-decoder convolutional neural network

Opto-Electronic Advances, Journal Year: 2023, Volume and Issue: 6(8), P. 220148 - 220148

Published: Jan. 1, 2023

Complex-amplitude holographic metasurfaces (CAHMs) with the flexibility in modulating phase and amplitude profiles have been used to manipulate propagation of wavefront an unprecedented level, leading higher image-reconstruction quality compared their natural counterparts. However, prevailing design methods CAHMs are based on Huygens-Fresnel theory, meta-atom optimization, numerical simulation experimental verification, which results a consumption computing resources. Here, we applied residual encoder-decoder convolutional neural network directly map electric field distributions input images for monolithic metasurface design. A pretrained is firstly trained by calculated diffraction subsequently migrated as transfer learning framework simulated images. The training show that normalized mean pixel error about 3% dataset. As prototypes fabricated, measured. reconstructed reverse-engineered exhibits high similarity target field, demonstrates effectiveness our Encouragingly, this work provides field-to-pattern method CAHMs, paves new route direct reconstruction metasurfaces.

Language: Английский

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A newcomer’s guide to deep learning for inverse design in nano-photonics

Nanophotonics, Journal Year: 2023, Volume and Issue: 12(24), P. 4387 - 4414

Published: Nov. 28, 2023

Nanophotonic devices manipulate light at sub-wavelength scales, enabling tasks such as concentration, routing, and filtering. Designing these to achieve precise light-matter interactions using structural parameters materials is a challenging task. Traditionally, solving this problem has relied on computationally expensive, iterative methods. In recent years, deep learning techniques have emerged promising tools for tackling the inverse design of nanophotonic devices. While several review articles provided an overview progress in rapidly evolving field, there need comprehensive tutorial that specifically targets newcomers without prior experience learning. Our goal address gap provide practical guidance applying individual scientific problems. We introduce fundamental concepts critically discuss potential benefits it offers various problems nanophotonics. present suggested workflow detailed, guidelines help navigate challenges they may encounter. By following our guide, can avoid frustrating roadblocks commonly experienced when venturing into first time. second part, we explore different direct learning-based design, evaluate their respective advantages limitations. To enhance understanding facilitate implementation, supplement manuscript with detailed Python notebook examples, illustrating each step discussed processes. primarily focuses researchers (nano-)photonics, also relevant those working other research domains. aim providing solid starting point empower leverage pursuits.

Language: Английский

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Multiscale Optical Field Manipulation via Planar Digital Optics

ACS Photonics, Journal Year: 2023, Volume and Issue: 10(7), P. 2116 - 2127

Published: Jan. 23, 2023

Replacing curved and bulky optical elements with thin lightweight counterparts is a persistent pursuit of the society. Metasurfaces, as two-dimensional artificial metamaterials, have attracted much attention because their exceptional ability to manipulate electromagnetic waves such amplitude, phase, polarization, propagation direction, so on. With great advances in planar digital optics vector field manipulation via metasurfaces, multiscale from subwavelength meta-atoms (tens nanometers) large-scale devices (hundreds millimeters) highly desired practical applications, which may replace conventional superior performance decreased weight or even create completely new functionalities. Here, we give perspective on based optics. Particular emphasis given multifunctional manipulation, intelligent design, mass fabrication, well potential applications laser systems, diffractive sails, integrated optics, etc.

Language: Английский

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Polarization-Insensitive Metasurface Cloak for Dynamic Illusions with an Electromagnetic Transparent Window

ACS Applied Materials & Interfaces, Journal Year: 2023, Volume and Issue: 15(13), P. 16953 - 16962

Published: March 3, 2023

Artificial camouflage has garnered long-standing interest in both academia and industry. The metasurface-based cloak attracted much attention due to the powerful capability of manipulating electromagnetic wave, convenient multifunctional integration design, easy fabrication. However, existing cloaks tend be passive single function monopolarization, which cannot meet requirement applications ever-changing environments. So far, it is still challenging realize a reconfigurable full-polarization metasurface with integration. Herein, we proposed an innovative cloak, can simultaneously dynamic illusion effects at lower frequencies (e.g., 4.35 GHz) specific microwave transparency higher X band) for communication outside environment. These functionalities are demonstrated by numerical simulations experimental measurements. simulation measurement results agree well each other, indicating that our generate various illusions full polarizations as polarization-insensitive transparent window signal transmission enable between cloaked device It believed design offer tactics address stealth problem

Language: Английский

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