Optical bound states in the continuum in periodic structures: mechanisms, effects, and applications

Photonics Insights, Год журнала: 2024, Номер 3(1), С. R01 - R01

Опубликована: Янв. 1, 2024

Язык: Английский

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Phase-change nonlocal metasurfaces for dynamic wave-front manipulation

Physical Review Applied, Год журнала: 2024, Номер 21(4)

Опубликована: Апрель 1, 2024

Recent advances in nonlocal metasurfaces have enabled unprecedented success shaping the wave front of light with spectral selectivity, offering alternative solutions for many emerging nanophotonics applications. The ability to tune both and spatial properties such a class is highly desirable, but dynamic nonvolatile control remains elusive. Here, we demonstrate active narrowband wave-front manipulation by harnessing quasi-bound states continuum (quasi-BICs) phase-change metasurfaces. proof-of-principle made ${\mathrm{Sb}}_{2}{\mathrm{S}}_{3}$ allow nonvolatile, reversible, tunable over switchable response at given wavelength near-infrared regime. design principle mainly builds upon combination geometry phase quasi-BICs tunability meta-atoms tailor resonant wavelengths. By tuning crystallization level through controlling external stimuli, wave-front-shaping functionalities beam steering, one-dimensional, two-dimensional focusing, holographic imaging are achieved exclusively wavelengths, functionally transparent off resonance. This work represents critical advance towards developing an integrated metasurface future augmented virtual reality wearables.

Язык: Английский

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Nonlocal meta-lens with Huygens’ bound states in the continuum

Nature Communications, Год журнала: 2024, Номер 15(1)

Опубликована: Авг. 2, 2024

Abstract Meta-lenses composed of artificial meta-atoms have stimulated substantial interest due to their compact and flexible wavefront shaping capabilities, outperforming bulk optical devices. The operating bandwidth is a critical factor determining the meta-lens’ performance across various wavelengths. that operate in narrowband manner relying on nonlocal effects can effectively reduce disturbance crosstalk from non-resonant wavelengths, making them well-suitable for specialized applications such as nonlinear generation augmented reality/virtual reality display. However, meta-lenses require striking balance between local phase manipulation resonance excitation, which involves trade-offs among factors like quality-factor, efficiency, dimensions, footprint. In this work, we experimentally demonstrate meta-lens featuring Huygens’ bound states continuum (BICs) its near-infrared imaging application. All-dielectric integrated-resonant unit particularly optimized efficiently induce both quasi-BIC generalized Kerker effect, while ensuring rotation-angle robustness generating geometric phase. experimental results show single-layer possesses high quality-factor 104 achieves transmission polarization conversion efficiency 55%, exceeding theoretical limit 25%. wavelength-selective two-dimensional focusing are demonstrated well. This work will pave way efficient meta-devices.

Язык: Английский

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Continuous spectral and coupling-strength encoding with dual-gradient metasurfaces

Nature Nanotechnology, Год журнала: 2024, Номер 19(12), С. 1804 - 1812

Опубликована: Авг. 26, 2024

Abstract To control and enhance light–matter interactions at the nanoscale, two parameters are central: spectral overlap between an optical cavity mode material’s features (for example, excitonic or molecular absorption lines), quality factor of cavity. Controlling both simultaneously would enable investigation systems with complex features, such as multicomponent mixtures heterogeneous solid-state materials. So far, it has been possible only to sample a limited set data points within this two-dimensional parameter space. Here we introduce nanophotonic approach that can continuously encode quality-factor space compact spatial area. We use dual-gradient metasurface design composed array smoothly varying subwavelength nanoresonators, each supporting unique based on symmetry-protected bound states in continuum. This results 27,500 distinct modes density approaching theoretical upper limit for metasurfaces. By applying our platform surface-enhanced spectroscopy, find optimal maximum sensitivity depends amount analyte, enabling effective detection regardless analyte concentration single metasurface. Our provides method analyse complete coupling-strength material applications photocatalysis, chemical sensing entangled photon generation.

Язык: Английский

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Large‐Area, High‐Numerical‐Aperture, Freeform Metasurfaces

Laser & Photonics Review, Год журнала: 2024, Номер 18(6)

Опубликована: Фев. 17, 2024

Abstract Nanophotonic devices are optical platforms capable of unprecedented wavefront control. To push the limits experimental device performance, scalable design methodologies that combine simplicity and fabricability conventional paradigms with extended capabilities freeform optimization required. A novel gradient‐based framework for large‐area metasurfaces is introduced in which nonlocal interactions between simply shaped nanostructures, placed on an irregular lattice, tailored to produce high‐order hybridized modes support customizable large‐angle scattering profiles. Utilizing this approach, multifunctional super‐dispersive metalenses designed experimentally demonstrated. The approach high‐numerical‐aperture radial diffraction limited focusing generation donut‐shaped point spread functions also extended. It anticipated these concepts will have utility super‐resolution microscopy, particle trapping, additive manufacturing, metrology applications require ultra‐high numerical apertures.

Язык: Английский

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Leaky Guided Mode-Induced Large-Angle Nonlocal Metasurfaces

ACS Photonics, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

Metasurfaces that can manipulate light in the spatial domain via local modes are an ultrathin alternative to conventional optical systems. However, achieving large-angle modulation with such metasurfaces presents significant challenges as diminished efficiency. To address this, concept of metagrating has been introduced, facilitating development devices a high numerical aperture or wide field view. Nonlocal metasurfaces, which possess nonlocal and control both temporal domains, encounter even greater difficulties due mode degradation wavelength-period dependency, but effective solution not proposed yet. Here, we devised method for realizing by inducing multiple leaky guided (LGMs) using minimally perturbed meta-atom array conjunction waveguide slab. A system achieves spectral leveraging geometric phase additional grating vector coupling between LGMs is designed, this quality factor diffraction efficiency 2.2 × 103 29%, respectively, at extreme deflection angle 79°. This investigation holds potential applications systems requiring wavelength-selective modulation, augmented reality harmonic generation.

Язык: Английский

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High quality factor metasurfaces for two-dimensional wavefront manipulation

Nature Communications, Год журнала: 2023, Номер 14(1)

Опубликована: Дек. 20, 2023

The strong interaction of light with micro- and nanostructures plays a critical role in optical sensing, nonlinear optics, active devices, quantum optics. However, for wavefront shaping, the required local control over at subwavelength scale limits this interaction, typically leading to low-quality-factor devices. Here, we demonstrate an avenue towards high-quality-factor shaping two spatial dimensions based on all-dielectric higher-order Mie-resonant metasurfaces. We design experimentally realize transmissive band stop filters, beam deflectors high numerical aperture radial lenses measured quality factors range 202-1475 near-infrared wavelengths. excited mode resulting are both local, allowing versatile operation finite apertures oblique illumination. Our results represent improvement factor by nearly orders magnitude previous localized designs, provide approach new class compact

Язык: Английский

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All‐Dielectric High‐Q Dynamically Tunable Transmissive Metasurfaces

Laser & Photonics Review, Год журнала: 2024, Номер 18(6)

Опубликована: Фев. 8, 2024

Abstract Active metasurfaces, which are arrays of actively tunable resonant elements, can dynamically control the wavefront scattered light at a subwavelength scale. To date, most active metasurfaces that enable dynamic shaping operate in reflection. On other hand, operating transmission considerable interest as they readily be integrated with chip‐scale sources, yielding ultra‐compact devices. Here, designs for all‐dielectric low‐loss manipulate transmitted near‐infrared wavelength range reported. The feature an array amorphous silicon (a‐Si) pillars on silica (SiO 2 ) substate, support resonances quality factors (Q‐factors) high 9800. high‐Q resonance dips observed transformed into peaks by positioning a‐Si pillar resonators prescribed distance from crystalline Si substrate. design metasurface geometry realistic interconnect architectures thermo‐optic beam switching times low 7.3 µs is Beam refractive index differences between neighboring elements 0.0026. It shown structures used steering.

Язык: Английский

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Bound States in the Continuum for Hot Electron Generation in Integrated-Resonant Metasurfaces

The Journal of Physical Chemistry C, Год журнала: 2024, Номер 128(18), С. 7661 - 7668

Опубликована: Март 14, 2024

Hydrogen, as a type of sustainable energy, has the potential to facilitate achievement carbon neutrality by replacing fossil fuels. Conventional plasmonic metal nanostructures efficient photocatalysts have been employed generate hot electrons, thus further facilitating hydrogen production. However, such structures only contain single resonance mode, which restricts field enhancement and limits electron generation rate. In this work, we introduce novel integrated-resonant unit (IRU) that combines local nonlocal modes can excite strong interaction between quasi-bound state in continuum (quasi-BIC) regime for enhancing electric field. As result, achieved maximum factor 168.5 at excitation wavelength 734 nm under period P = 750 nm. Correspondingly, rate electrons exceed 6 × 1019 s–1, is 2 orders magnitude greater than structure without IRU property. This research provides strategic framework development enhance efficiency photocatalytic activity, pivotal advancement clean energy realization decarbonized future.

Язык: Английский

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Giant ultrafast dichroism and birefringence with active nonlocal metasurfaces

Light Science & Applications, Год журнала: 2024, Номер 13(1)

Опубликована: Авг. 23, 2024

Abstract Switching of light polarization on the sub-picosecond timescale is a crucial functionality for applications in variety contexts, including telecommunications, biology and chemistry. The ability to control at ultrafast speed would pave way development unprecedented free-space optical links novel techniques probing dynamical processes complex systems, as chiral molecules. Such high switching speeds can only be reached with an all-optical paradigm, i.e., engineering active platforms capable controlling via ultrashort laser pulses. Here we demonstrate giant modulation dichroism birefringence all-dielectric metasurface, achieved low fluences beam. This performance, which leverages many degrees freedom offered by metasurfaces, obtained combining high-quality factor nonlocal resonance third-order nonlinearity dictated photogenerated hot carriers semiconductor band edge.

Язык: Английский

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