Resonances are usually associated with finite systems—the vibrations of clamped strings in a guitar or the optical modes in a cavity defined by mirrors.In optics,resonances may be induced in infinite continuous media...Resonances are usually associated with finite systems—the vibrations of clamped strings in a guitar or the optical modes in a cavity defined by mirrors.In optics,resonances may be induced in infinite continuous media via periodic modulations of their optical properties.Here we demonstrate that periodic modulations of the permittivity of a featureless thin film can also act as a symmetry-breaking mechanism,allowing the excitation of photonic quasi-bound states in the continuum(qBICs).By interfering two ultrashort laser pulses in the unbounded film,transient resonances can be tailored through different parameters of the pump beams.We show that the system offers resonances tunable in wavelength and quality-factor,and spectrally selective enhancement of third-harmonic generation.Due to a fast decay of the permittivity asymmetry,we observe ultrafast dynamics,enabling time-selective near-field enhancement with picosecond precision.Optically induced permittivity asymmetries may be exploited in on-demand weak to ultrastrong light-matter interaction regimes and light manipulation at dynamically chosen wavelengths in lithography-free metasurfaces.展开更多
The efficiency of nanoscale nonlinear elements in photonic integrated circuits is hindered by the physical limits to the nonlinear optical response of dielectrics,which cannot be engineered as it is a fundamental mate...The efficiency of nanoscale nonlinear elements in photonic integrated circuits is hindered by the physical limits to the nonlinear optical response of dielectrics,which cannot be engineered as it is a fundamental material property.Here,we experimentally demonstrate that ultrafast optical nonlinearities in doped semiconductors can be engineered and can easily exceed those of conventional undoped dielectrics.The electron response of heavily doped semiconductors acquires in fact a hydrodynamic character that introduces nonlocal effects as well as additional nonlinear sources.Our experimental findings are supported by a comprehensive computational analysis based on the hydrodynamic model.In particular,by studying third-harmonic generation from plasmonic nanoantenna arrays made out of heavily n-doped InGaAs with increasing levels of free-carrier density,we discriminate between hydrodynamic and dielectric nonlinearities.Most importantly,we demonstrate that the maximum nonlinear efficiency as well as its spectral location can be engineered by tuning the doping level.Crucially,the maximum efficiency can be increased by almost two orders of magnitude with respect to the classical dielectric nonlinearity.Having employed the common material platform InGaAs/InP that supports integrated waveguides,our findings pave the way for future exploitation of plasmonic nonlinearities in all-semiconductor photonic integrated circuits.展开更多
Twisted optical fibers are a promising platform for manipulating circularly polarized light and orbital angular momentum beams for applications such as nonlinear frequency conversion,optical communication,or chiral se...Twisted optical fibers are a promising platform for manipulating circularly polarized light and orbital angular momentum beams for applications such as nonlinear frequency conversion,optical communication,or chiral sensing.However,integration into chip-scale technology is challenging because twisted fibers are incompatible with planar photonics and the achieved twist rates are limited.Here,we address these challenges by introducing the concept of 3D-nanoprinted on-chip twisted hollow-core light cages.We show theoretically and experimentally that the geometrical twisting of light cages forces the fundamental core mode of a given handedness to couple with selected higher-order core modes,resulting in strong circular dichroism(CD).These chiral resonances result from the angular momentum harmonics of the fundamental mode,allowing us to predict their spectral locations and the occurrence of circular birefringence.Twisted light cages enable very high twist rates and CD,exceeding those of twisted hollow-core fibers by more than two orders of magnitude(twist period,90μm;CD,0.8 dB∕mm).Moreover,the unique cage design provides lateral access to the central core region,enabling future applications in chiral spectroscopy.Therefore,the presented concept opens a path for translating twisted fiber research to on-chip technology,resulting in a new platform for integrated chiral photonics.展开更多
Orbital angular momentum(OAM)modes have emerged as a promising solution for enhancing the capacity of optical multiplexing systems,leveraging their theoretically unbounded set of orthogonal spatial modes.However,the g...Orbital angular momentum(OAM)modes have emerged as a promising solution for enhancing the capacity of optical multiplexing systems,leveraging their theoretically unbounded set of orthogonal spatial modes.However,the generation and detection of OAM multiplexing signals are predominantly reliant on bulky optical components within complex optical setups.We introduce a compact solution for OAM information processing using laser-written glass chips,facilitating efficient multiplexing and demultiplexing of multiple OAM information channels.During the multiplexing process,OAM channels are managed via laser-scribed single-mode waveguides within a glass chip,with their modes converted using laser-written holograms on the side wall of the glass chip.The reciprocal process is employed for OAM demultiplexing.Our chips seamlessly interface with commercial optical fibers,ensuring compatibility with existing fiber-optic communication infrastructure.This work not only establishes,to our knowledge,a novel approach for OAM optical multiplexing but also underscores the potential of laser writing technology in advancing photonics and its practical applications in optical communications.展开更多
Strong focusing on diffraction-limited spots is essential for many photonic applications and is particularly relevant for optical trapping;however,all currently used approaches fail to simultaneously provide flexible ...Strong focusing on diffraction-limited spots is essential for many photonic applications and is particularly relevant for optical trapping;however,all currently used approaches fail to simultaneously provide flexible transportation of light,straightforward implementation,compatibility with waveguide circuitry,and strong focusing.Here,we demonstrate the design and 3D nanoprinting of an ultrahigh numerical aperture meta-fibre for highly flexible optical trapping.Taking into account the peculiarities of the fibre environment,we implemented an ultrathin meta-lens on the facet of a modified single-mode optical fibre via direct laser writing,leading to a diffraction-limited focal spot with a recordhigh numerical aperture of up to NA≈0.9.The unique capabilities of this flexible,cost-effective,bio-and fibre-circuitrycompatible meta-fibre device were demonstrated by optically trapping microbeads and bacteria for the first time with only one single-mode fibre in combination with diffractive optics.Our study highlights the relevance of the unexplored but exciting field of meta-fibre optics to a multitude of fields,such as bioanalytics,quantum technology and life sciences.展开更多
Structuring light emission from single-photon emitters(SPEs)in multiple degrees of freedom is of great importance for quantum information processing towards higher dimensions.However,traditional control of emission fr...Structuring light emission from single-photon emitters(SPEs)in multiple degrees of freedom is of great importance for quantum information processing towards higher dimensions.However,traditional control of emission from quantum light sources relies on the use of multiple bulky optical elements or nanostructured resonators with limited functionalities,constraining the potential of multi-dimensional tailoring.Here we introduce the use of an ultrathin polarisation-beam-splitting metalens for the arbitrary structuring of quantum emission at room temperature.Owing to the complete and independent polarisation and phase control at the single meta-atom level,the designed metalens enables simultaneous mapping of quantum emission from ultra-bright defects in hexagonal boron nitride and imprinting of an arbitrary wavefront onto orthogonal polarisation states of the sources.The hybrid quantum metalens enables simultaneous manipulation of multiple degrees of freedom of a quantum light source,including directionality,polarisation,and orbital angular momentum.This could unleash the full potential of solid-state SPEs for their use as high-dimensional quantum sources for advanced quantum photonic applications.展开更多
While total internal reflection(TIR)lays the foundation for many important applications,foremost fibre optics that revolutionised information technologies,it is undesirable in some other applications such as light-emi...While total internal reflection(TIR)lays the foundation for many important applications,foremost fibre optics that revolutionised information technologies,it is undesirable in some other applications such as light-emitting diodes(LEDs),which are a backbone for energy-efficient light sources.In the case of LEDs,TIR prevents photons from escaping the constituent high-index materials.Advances in material science have led to good efficiencies in generating photons from electron–hole pairs,making light extraction the bottleneck of the overall efficiency of LEDs.In recent years,the extraction efficiency has been improved,using nanostructures at the semiconductor/air interface that outcouple trapped photons to the outside continuum.However,the design of geometrical features for light extraction with sizes comparable to or smaller than the optical wavelength always requires sophisticated and timeconsuming fabrication,which causes a gap between lab demonstration and industrial-level applications.Inspired by lightning bugs,we propose and realise a disordered metasurface for light extraction throughout the visible spectrum,achieved with single-step fabrication.By applying such a cost-effective light extraction layer,we improve the external quantum efficiency by a factor of 1.65 for commercialised GaN LEDs,demonstrating a substantial potential for global energy-saving and sustainability.展开更多
The realization of lossless metasurfaces with true chirality crucially requires the fabrication of three-dimensional structures,constraining experimental feasibility and hampering practical implementations.Even though...The realization of lossless metasurfaces with true chirality crucially requires the fabrication of three-dimensional structures,constraining experimental feasibility and hampering practical implementations.Even though the threedimensional assembly of metallic nanostructures has been demonstrated previously,the resulting plasmonic resonances suffer from high intrinsic and radiative losses.The concept of photonic bound states in the continuum(BICs)is instrumental for tailoring radiative losses in diverse geometries,especially when implemented using lossless dielectrics,but applications have so far been limited to planar structures.Here,we introduce a novel nanofabrication approach to unlock the height of individual resonators within all-dielectric metasurfaces as an accessible parameter for the efficient control of resonance features and nanophotonic functionalities.In particular,we realize out-of-plane symmetry breaking in quasi-BIC metasurfaces and leverage this design degree of freedom to demonstrate an optical all-dielectric quasi-BIC metasurface with maximum intrinsic chirality that responds selectively to light of a particular circular polarization depending on the structural handedness.Our experimental results not only open a new paradigm for all-dielectric BICs and chiral nanophotonics,but also promise advances in the realization of efficient generation of optical angular momentum,holographic metasurfaces,and parity-time symmetry-broken optical systems.展开更多
Hyperbolic metamaterials with a unique hyperbolic dispersion relation allow propagating waves with infinitely largewavevectors and a high density of states. Researchers from Korea and Singapore provide a comprehensive...Hyperbolic metamaterials with a unique hyperbolic dispersion relation allow propagating waves with infinitely largewavevectors and a high density of states. Researchers from Korea and Singapore provide a comprehensive review ofhyperbolic metamaterials, including artificially structured hyperbolic media and natural hyperbolic materials. Theyexplain key nanophotonic concepts and describe a range of applications for these versatile materials.展开更多
Controlling coherent interaction between optical fields and quantum systems in scalable,integrated platforms is essential for quantum technologies.Miniaturised,warm alkali-vapour cells integrated with on-chip photonic...Controlling coherent interaction between optical fields and quantum systems in scalable,integrated platforms is essential for quantum technologies.Miniaturised,warm alkali-vapour cells integrated with on-chip photonic devices represent an attractive system,in particular for delay or storage of a single-photon quantum state.Hollow-core fibres or planar waveguides are widely used to confine light over long distances enhancing light-matter interaction in atomic-vapour cells.However,they suffer from inefficient filling times,enhanced dephasing for atoms near the surfaces,and limited light-matter overlap.We report here on the observation of modified electromagnetically induced transparency for a non-diffractive beam of light in an on-chip,laterally-accessible hollow-core light cage.Atomic layer deposition of an alumina nanofilm onto the light-cage structure was utilised to precisely tune the high-transmission spectral region of the light-cage mode to the operation wavelength of the atomic transition,while additionally protecting the polymer against the corrosive alkali vapour.The experiments show strong,coherent light-matter coupling over lengths substantially exceeding the Rayleigh range.Additionally,the stable non-degrading performance and extreme versatility of the light cage provide an excellent basis for a manifold of quantum-storage and quantumnonlinear applications,highlighting it as a compelling candidate for all-on-chip,integrable,low-cost,vapour-based photon delay.展开更多
Dielectric optical antennas have emerged as a promising nanophotonic architecture for manipulating the propagation and localization of light.However,the optically induced Mie resonances in an isolated nanoantenna are ...Dielectric optical antennas have emerged as a promising nanophotonic architecture for manipulating the propagation and localization of light.However,the optically induced Mie resonances in an isolated nanoantenna are normally with broad spectra and poor𝑄-factors,limiting their performances in sensing,lasing,and nonlinear optics.Here,we dramatically enhance the𝑄-factors of Mie resonances in silicon(Si)nanoparticles across the optical band by arranging the nanoparticles in a periodic lattice.We select monocrystalline Si with negligible material losses and develop a unique method to fabricate nanoparticle arrays on a quartz substrate.By extinction dispersion measurements and electromagnetic analysis,we can identify three types of collective Mie resonances with𝑄-factors∼500 in the same nanocylinder arrays,including surface lattice resonances,bound states in the continuum,and quasi-guided modes.Our work paves the way for fundamental research in strong light-matter interactions and the design of highly efficient light-emitting metasurfaces.展开更多
The field of high-bandwidth holography has been extensively studied over the past decade.Orbital angular momentum(OAM)holography,which utilizes vortex beams with theoretically unbounded OAM modes as information carrie...The field of high-bandwidth holography has been extensively studied over the past decade.Orbital angular momentum(OAM)holography,which utilizes vortex beams with theoretically unbounded OAM modes as information carriers,showcases the large capacitance of hologram storage.However,OAM holography has been limited to a single wavelength,restricting its potential for full-color holography and displays.In this study,we propose wavelength and OAM multiplexed holography that utilizes the multiple dimensions of light—wavelength and OAM—to provide a multi-color platform that expands the information capacity of holographic storage devices.The proposed wavelength-OAM multiplexed holography is physically realized by a metasurface,the state-of-the-art optical element consisting of an array of artificially engineered nanostructures.Hydrogenated silicon meta-atoms,the constituents of the metasurface,are engineered to possess wavelength selectivity by tailoring the dispersion of polarization conversion.These meta-atoms are used to encode the calculated OAM-preserved phase maps based on our design.The sampling grid of the phase map is rotated by 45°,which effectively suppress higher-order diffraction,providing a great strategy for achieving large field-of-view(FOV)holography.We successfully demonstrate six holographic images that are selectively reconstructed under the illumination of light with specific wavelengths(λ=450,635 nm)and topological charges(l=-2,0,2),without high-order diffraction.Our work suggests that ultrathin meta-holograms can potentially realize ultrahigh-bandwidth full-color holography and holographic video displays with large FOV.展开更多
High refractive index dielectric nanoantennas strongly modify the decay rate via the Purcell effect through the design of radiative channels.Due to their dielectric nature,the field is mainly confined inside the nanos...High refractive index dielectric nanoantennas strongly modify the decay rate via the Purcell effect through the design of radiative channels.Due to their dielectric nature,the field is mainly confined inside the nanostructure and in the gap,which is hard to probe with scanning probe techniques.Here we use single-molecule fluorescence lifetime imaging microscopy(smFLIM)to map the decay rate enhancement in dielectric GaP nanoantenna dimers with a median localization precision of 14 nm.We measure,in the gap of the nanoantenna,decay rates that are almost 30 times larger than on a glass substrate.By comparing experimental results with numerical simulations we show that this large enhancement is essentially radiative,contrary to the case of plasmonic nanoantennas,and therefore has great potential for applications such as quantum optics and biosensing.展开更多
Recent advances in understanding the hot-electron dynamics in plasmonic nanostructures have significantly impacted a variety of plasmonically powered physical,chemical,and even biological processes.New insights into t...Recent advances in understanding the hot-electron dynamics in plasmonic nanostructures have significantly impacted a variety of plasmonically powered physical,chemical,and even biological processes.New insights into their quantum properties and complex relaxation mechanisms enable the efficient generation.展开更多
Two-dimensional(2D)semiconductors possess strongly bound excitons,opening novel opportunities for engineering light-matter interaction at the nanoscale.However,their in-plane confinement leads to large non-radiative e...Two-dimensional(2D)semiconductors possess strongly bound excitons,opening novel opportunities for engineering light-matter interaction at the nanoscale.However,their in-plane confinement leads to large non-radiative exciton–exciton annihilation(EEA)processes,setting a fundamental limit for their photonic applications.In this work,we demonstrate suppression of EEA via enhancement of light-matter interaction in hybrid 2D semiconductor-dielectric nanophotonic platforms,by coupling excitons in WS2 monolayers with optical Mie resonances in dielectric nanoantennas.The hybrid system reaches an intermediate light-matter coupling regime,with photoluminescence enhancement factors up to 102.Probing the exciton ultrafast dynamics reveal suppressed EEA for coupled excitons,even under high exciton densities>10^(12)cm^(−2).We extract EEA coefficients in the order of 10^(−3),compared to 10^(−2)for uncoupled monolayers,as well as a Purcell factor of 4.5.Our results highlight engineering the photonic environment as a route to achieve higher quantum efficiencies,for low-power hybrid devices,and larger exciton densities,towards strongly correlated excitonic phases in 2D semiconductors.展开更多
文摘Resonances are usually associated with finite systems—the vibrations of clamped strings in a guitar or the optical modes in a cavity defined by mirrors.In optics,resonances may be induced in infinite continuous media via periodic modulations of their optical properties.Here we demonstrate that periodic modulations of the permittivity of a featureless thin film can also act as a symmetry-breaking mechanism,allowing the excitation of photonic quasi-bound states in the continuum(qBICs).By interfering two ultrashort laser pulses in the unbounded film,transient resonances can be tailored through different parameters of the pump beams.We show that the system offers resonances tunable in wavelength and quality-factor,and spectrally selective enhancement of third-harmonic generation.Due to a fast decay of the permittivity asymmetry,we observe ultrafast dynamics,enabling time-selective near-field enhancement with picosecond precision.Optically induced permittivity asymmetries may be exploited in on-demand weak to ultrastrong light-matter interaction regimes and light manipulation at dynamically chosen wavelengths in lithography-free metasurfaces.
文摘The efficiency of nanoscale nonlinear elements in photonic integrated circuits is hindered by the physical limits to the nonlinear optical response of dielectrics,which cannot be engineered as it is a fundamental material property.Here,we experimentally demonstrate that ultrafast optical nonlinearities in doped semiconductors can be engineered and can easily exceed those of conventional undoped dielectrics.The electron response of heavily doped semiconductors acquires in fact a hydrodynamic character that introduces nonlocal effects as well as additional nonlinear sources.Our experimental findings are supported by a comprehensive computational analysis based on the hydrodynamic model.In particular,by studying third-harmonic generation from plasmonic nanoantenna arrays made out of heavily n-doped InGaAs with increasing levels of free-carrier density,we discriminate between hydrodynamic and dielectric nonlinearities.Most importantly,we demonstrate that the maximum nonlinear efficiency as well as its spectral location can be engineered by tuning the doping level.Crucially,the maximum efficiency can be increased by almost two orders of magnitude with respect to the classical dielectric nonlinearity.Having employed the common material platform InGaAs/InP that supports integrated waveguides,our findings pave the way for future exploitation of plasmonic nonlinearities in all-semiconductor photonic integrated circuits.
基金financial support from the German Research Foundation via Grant Nos.MA 4699/2-1,MA 4699/9-1,SCHM2655/11-1,SCHM2655/15-1,SCHM2655/8-1,SCHM2655/22-1,and WE 5815/5-1 and via project number 512648189。
文摘Twisted optical fibers are a promising platform for manipulating circularly polarized light and orbital angular momentum beams for applications such as nonlinear frequency conversion,optical communication,or chiral sensing.However,integration into chip-scale technology is challenging because twisted fibers are incompatible with planar photonics and the achieved twist rates are limited.Here,we address these challenges by introducing the concept of 3D-nanoprinted on-chip twisted hollow-core light cages.We show theoretically and experimentally that the geometrical twisting of light cages forces the fundamental core mode of a given handedness to couple with selected higher-order core modes,resulting in strong circular dichroism(CD).These chiral resonances result from the angular momentum harmonics of the fundamental mode,allowing us to predict their spectral locations and the occurrence of circular birefringence.Twisted light cages enable very high twist rates and CD,exceeding those of twisted hollow-core fibers by more than two orders of magnitude(twist period,90μm;CD,0.8 dB∕mm).Moreover,the unique cage design provides lateral access to the central core region,enabling future applications in chiral spectroscopy.Therefore,the presented concept opens a path for translating twisted fiber research to on-chip technology,resulting in a new platform for integrated chiral photonics.
基金Australian Research Council(DP220102152,DE220101085,FT200100590)Lee Lucas Chair in Physics+1 种基金Center for NanoScience,Ludwig-Maximilians Universität MünchenAustralian National Fabrication Facility。
文摘Orbital angular momentum(OAM)modes have emerged as a promising solution for enhancing the capacity of optical multiplexing systems,leveraging their theoretically unbounded set of orthogonal spatial modes.However,the generation and detection of OAM multiplexing signals are predominantly reliant on bulky optical components within complex optical setups.We introduce a compact solution for OAM information processing using laser-written glass chips,facilitating efficient multiplexing and demultiplexing of multiple OAM information channels.During the multiplexing process,OAM channels are managed via laser-scribed single-mode waveguides within a glass chip,with their modes converted using laser-written holograms on the side wall of the glass chip.The reciprocal process is employed for OAM demultiplexing.Our chips seamlessly interface with commercial optical fibers,ensuring compatibility with existing fiber-optic communication infrastructure.This work not only establishes,to our knowledge,a novel approach for OAM optical multiplexing but also underscores the potential of laser writing technology in advancing photonics and its practical applications in optical communications.
文摘Strong focusing on diffraction-limited spots is essential for many photonic applications and is particularly relevant for optical trapping;however,all currently used approaches fail to simultaneously provide flexible transportation of light,straightforward implementation,compatibility with waveguide circuitry,and strong focusing.Here,we demonstrate the design and 3D nanoprinting of an ultrahigh numerical aperture meta-fibre for highly flexible optical trapping.Taking into account the peculiarities of the fibre environment,we implemented an ultrathin meta-lens on the facet of a modified single-mode optical fibre via direct laser writing,leading to a diffraction-limited focal spot with a recordhigh numerical aperture of up to NA≈0.9.The unique capabilities of this flexible,cost-effective,bio-and fibre-circuitrycompatible meta-fibre device were demonstrated by optically trapping microbeads and bacteria for the first time with only one single-mode fibre in combination with diffractive optics.Our study highlights the relevance of the unexplored but exciting field of meta-fibre optics to a multitude of fields,such as bioanalytics,quantum technology and life sciences.
基金supported by Australian Research Council(CE200100010,DE220101085,DP220102152)the Office of Naval Research Global(N62909-22-1-2028)(I.A.)+5 种基金the POSCO-POSTECH-RIST Convergence Research Center program funded by POSCOthe Basic Science grant(SSTF-BA2102-05)funded by the Samsung Science and Technology Foundationthe National Research Foundation(NRF)grant(NRF-2022M3C1A3081312)funded by the Ministry of Science and ICT(MSIT)of the Korean governmentthe NRF Sejong Science fellowship(NRF-RS-2023-00209560)funded by the MSIT of Korea governmentthe Institute of Information&Communications Technology Planning&Evaluation(IITP)grant(No.2019-0-01906,the POSTECH Artificial Intelligence Graduate School program)funded by the MSIT of the Korean government,and the POSTECH PIURI fellowshipthe POSTECH Alchemist fellowship.
文摘Structuring light emission from single-photon emitters(SPEs)in multiple degrees of freedom is of great importance for quantum information processing towards higher dimensions.However,traditional control of emission from quantum light sources relies on the use of multiple bulky optical elements or nanostructured resonators with limited functionalities,constraining the potential of multi-dimensional tailoring.Here we introduce the use of an ultrathin polarisation-beam-splitting metalens for the arbitrary structuring of quantum emission at room temperature.Owing to the complete and independent polarisation and phase control at the single meta-atom level,the designed metalens enables simultaneous mapping of quantum emission from ultra-bright defects in hexagonal boron nitride and imprinting of an arbitrary wavefront onto orthogonal polarisation states of the sources.The hybrid quantum metalens enables simultaneous manipulation of multiple degrees of freedom of a quantum light source,including directionality,polarisation,and orbital angular momentum.This could unleash the full potential of solid-state SPEs for their use as high-dimensional quantum sources for advanced quantum photonic applications.
基金P.M.and M.H.acknowledge the financial support from by National Natural Science Foundation of China(Grant No.11627806,U1909214,11604161)the National Key R&D Program of China(Grant No.2016YFA0201002)+5 种基金P.M.acknowledges the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie Grant(Grant No.752102)C.L.acknowledges the financial support from Humboldt Research Fellowship from Alexander von Humboldt Foundation.P.M.,C.L.and S.Z acknowledge 2020 European Research Council Project Nos.734578(D-SPA)and 648783(TOPOLOGICAL)Leverhulme Trust(grant no.RPG-2012-674)the Royal Society,the Wolfson Foundation.S.A.M.acknowledges funding support from the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)under Germany’s Excellence Strategy,EXC 2089/1-390776260the Solar Energies go Hybrid(SolTech)programme,the EPSRC Reactive Plasmonics Programme(EP/M013812/1)the Lee-Lucas Chair in Physics.X.L.,M.L.and E.S.acknowledge financial support from the Natural Sciences and Engineering Research Council(NSERC)of Canada.
文摘While total internal reflection(TIR)lays the foundation for many important applications,foremost fibre optics that revolutionised information technologies,it is undesirable in some other applications such as light-emitting diodes(LEDs),which are a backbone for energy-efficient light sources.In the case of LEDs,TIR prevents photons from escaping the constituent high-index materials.Advances in material science have led to good efficiencies in generating photons from electron–hole pairs,making light extraction the bottleneck of the overall efficiency of LEDs.In recent years,the extraction efficiency has been improved,using nanostructures at the semiconductor/air interface that outcouple trapped photons to the outside continuum.However,the design of geometrical features for light extraction with sizes comparable to or smaller than the optical wavelength always requires sophisticated and timeconsuming fabrication,which causes a gap between lab demonstration and industrial-level applications.Inspired by lightning bugs,we propose and realise a disordered metasurface for light extraction throughout the visible spectrum,achieved with single-step fabrication.By applying such a cost-effective light extraction layer,we improve the external quantum efficiency by a factor of 1.65 for commercialised GaN LEDs,demonstrating a substantial potential for global energy-saving and sustainability.
基金This work was funded by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)under grant numbers EXC 2089/1-390776260(Germany’s Excellence Strategy)and TI 1063/1(Emmy Noether Program)the Bavarian program Solar Energies Go Hybrid(SolTech),and the Center for NanoScience(CeNS).S.A.Maier additionally acknowledges the EPSRC(EP/W017075/1)+2 种基金the Australian Research Council,and the Lee-Lucas Chair in Physics.The work of M.V.G.and A.A.A.was performed within the State assignment of FSRC“Crystallography and Photonics”RAS.Y.K.acknowledges a support from the Australian Research Council(grant DP210101292)as well as the International Technology Center Indo-Pacific(ITC IPAC)and Army Research Office under Contract No.FA520923C0023Funded by the European Union(ERC,METANEXT,101078018).Views and opinions expressed are however those of the author(s)only and do not necessarily reflect those of the European Union or the European Research Council Executive Agency.Neither the European Union nor the granting authority can be held responsible for them.
文摘The realization of lossless metasurfaces with true chirality crucially requires the fabrication of three-dimensional structures,constraining experimental feasibility and hampering practical implementations.Even though the threedimensional assembly of metallic nanostructures has been demonstrated previously,the resulting plasmonic resonances suffer from high intrinsic and radiative losses.The concept of photonic bound states in the continuum(BICs)is instrumental for tailoring radiative losses in diverse geometries,especially when implemented using lossless dielectrics,but applications have so far been limited to planar structures.Here,we introduce a novel nanofabrication approach to unlock the height of individual resonators within all-dielectric metasurfaces as an accessible parameter for the efficient control of resonance features and nanophotonic functionalities.In particular,we realize out-of-plane symmetry breaking in quasi-BIC metasurfaces and leverage this design degree of freedom to demonstrate an optical all-dielectric quasi-BIC metasurface with maximum intrinsic chirality that responds selectively to light of a particular circular polarization depending on the structural handedness.Our experimental results not only open a new paradigm for all-dielectric BICs and chiral nanophotonics,but also promise advances in the realization of efficient generation of optical angular momentum,holographic metasurfaces,and parity-time symmetry-broken optical systems.
文摘Hyperbolic metamaterials with a unique hyperbolic dispersion relation allow propagating waves with infinitely largewavevectors and a high density of states. Researchers from Korea and Singapore provide a comprehensive review ofhyperbolic metamaterials, including artificially structured hyperbolic media and natural hyperbolic materials. Theyexplain key nanophotonic concepts and describe a range of applications for these versatile materials.
基金supported by the German Research Foundation(DFG)Collaborative Research Center(CRC)SFB 787 project C2,the German Federal Ministry of Education and Research(BMBF)project Qthe DFG Collaborative Research Center(CRC)SFB 951 project B18+5 种基金the DFG projects SCHM2655/8-1,SCHM2655/11-1,SCHM2655/15-1,and MA 4699/2-1support by IRIS Adlershofthe European Commission for the Marie-Sklodowska-Curie action 797044the Lee-Lucas Chair in Experimental Physics at Imperial College Londonsupport by the Open Access Publication Fund of Humboldt-Universität zu BerlinOpen Access funding enabled and organized by Projekt DEAL.
文摘Controlling coherent interaction between optical fields and quantum systems in scalable,integrated platforms is essential for quantum technologies.Miniaturised,warm alkali-vapour cells integrated with on-chip photonic devices represent an attractive system,in particular for delay or storage of a single-photon quantum state.Hollow-core fibres or planar waveguides are widely used to confine light over long distances enhancing light-matter interaction in atomic-vapour cells.However,they suffer from inefficient filling times,enhanced dephasing for atoms near the surfaces,and limited light-matter overlap.We report here on the observation of modified electromagnetically induced transparency for a non-diffractive beam of light in an on-chip,laterally-accessible hollow-core light cage.Atomic layer deposition of an alumina nanofilm onto the light-cage structure was utilised to precisely tune the high-transmission spectral region of the light-cage mode to the operation wavelength of the atomic transition,while additionally protecting the polymer against the corrosive alkali vapour.The experiments show strong,coherent light-matter coupling over lengths substantially exceeding the Rayleigh range.Additionally,the stable non-degrading performance and extreme versatility of the light cage provide an excellent basis for a manifold of quantum-storage and quantumnonlinear applications,highlighting it as a compelling candidate for all-on-chip,integrable,low-cost,vapour-based photon delay.
基金the National Natural Science Foundation of China(62120106001,62275184,61875143,and 62104165)the Natural Science Foundation of Jiangsu Province(BK20200859,BK20200857,and BK20210713)the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions.JGR and PB also acknowledge financial support from Nederlandse Organisatie voor Wetenschappelijk Onderzoek(NWO)(Vici 680-47-628).
文摘Dielectric optical antennas have emerged as a promising nanophotonic architecture for manipulating the propagation and localization of light.However,the optically induced Mie resonances in an isolated nanoantenna are normally with broad spectra and poor𝑄-factors,limiting their performances in sensing,lasing,and nonlinear optics.Here,we dramatically enhance the𝑄-factors of Mie resonances in silicon(Si)nanoparticles across the optical band by arranging the nanoparticles in a periodic lattice.We select monocrystalline Si with negligible material losses and develop a unique method to fabricate nanoparticle arrays on a quartz substrate.By extinction dispersion measurements and electromagnetic analysis,we can identify three types of collective Mie resonances with𝑄-factors∼500 in the same nanocylinder arrays,including surface lattice resonances,bound states in the continuum,and quasi-guided modes.Our work paves the way for fundamental research in strong light-matter interactions and the design of highly efficient light-emitting metasurfaces.
基金supported by the Samsung Research Funding&Incubation Center for Future Technology grant(SRFC-IT1901-52)funded by Samsung ElectronicsJ.R.acknowledges the POSCO-POSTECH-RIST Convergence Research Center program funded by POSCO+4 种基金the National Research Foundation(NRF)grant(RS-2024-00356928)funded by the Ministry of Science and ICT(MSIT)of the Korean governmentthe NRF Sejong Science fellowships(RS-2023-00209560,RS-2023-00252778)respectively,funded by the MSIT of the Korean government.J.J.acknowledges the Hyundai Motor Chung Mong-Koo fellowship.J.K.acknowledges the Asan Foundation Biomedical Science fellowship,and the Presidential Science fellowship funded by the MSIT of the Korean governmentsupport from the Lee-Lucas Chair in Physics,and the Australia Research Council(DP220102152)support from the Australian Research Council(DE220101085 and DP220102152).
文摘The field of high-bandwidth holography has been extensively studied over the past decade.Orbital angular momentum(OAM)holography,which utilizes vortex beams with theoretically unbounded OAM modes as information carriers,showcases the large capacitance of hologram storage.However,OAM holography has been limited to a single wavelength,restricting its potential for full-color holography and displays.In this study,we propose wavelength and OAM multiplexed holography that utilizes the multiple dimensions of light—wavelength and OAM—to provide a multi-color platform that expands the information capacity of holographic storage devices.The proposed wavelength-OAM multiplexed holography is physically realized by a metasurface,the state-of-the-art optical element consisting of an array of artificially engineered nanostructures.Hydrogenated silicon meta-atoms,the constituents of the metasurface,are engineered to possess wavelength selectivity by tailoring the dispersion of polarization conversion.These meta-atoms are used to encode the calculated OAM-preserved phase maps based on our design.The sampling grid of the phase map is rotated by 45°,which effectively suppress higher-order diffraction,providing a great strategy for achieving large field-of-view(FOV)holography.We successfully demonstrate six holographic images that are selectively reconstructed under the illumination of light with specific wavelengths(λ=450,635 nm)and topological charges(l=-2,0,2),without high-order diffraction.Our work suggests that ultrathin meta-holograms can potentially realize ultrahigh-bandwidth full-color holography and holographic video displays with large FOV.
基金received financial support from the French Agence Nationale de la Recherche via the LABEX WIFI under ANR-10-LABX-24 and ANR-10 IDEX-0001-02 PSLthe ANR SiMpLeLIFe project ANR-17-CE09-0006+1 种基金the ANR MIPTIME project ANR-22-CE09-0030-02It has also received financial support from the UK Engineering and Physical Sciences Research Council(EPSRC)via the following grants:EP/P033369/1 and EP/P033431/1.S.A.M.also acknowledges the Lee-Lucas Chair in Physics.
文摘High refractive index dielectric nanoantennas strongly modify the decay rate via the Purcell effect through the design of radiative channels.Due to their dielectric nature,the field is mainly confined inside the nanostructure and in the gap,which is hard to probe with scanning probe techniques.Here we use single-molecule fluorescence lifetime imaging microscopy(smFLIM)to map the decay rate enhancement in dielectric GaP nanoantenna dimers with a median localization precision of 14 nm.We measure,in the gap of the nanoantenna,decay rates that are almost 30 times larger than on a glass substrate.By comparing experimental results with numerical simulations we show that this large enhancement is essentially radiative,contrary to the case of plasmonic nanoantennas,and therefore has great potential for applications such as quantum optics and biosensing.
文摘Recent advances in understanding the hot-electron dynamics in plasmonic nanostructures have significantly impacted a variety of plasmonically powered physical,chemical,and even biological processes.New insights into their quantum properties and complex relaxation mechanisms enable the efficient generation.
基金S.A.M.acknowledges the Lee Lucas chair in physics and funding by the EPSRC(EP/WO1707511)the Australian Research Council(Centre of Excellence in Future Low-Energy Electronics Technologies-CE 170100039)+1 种基金L.S.further acknowledges funding support through a Humboldt Research Fellowship from the Alexander von Humboldt FoundationOur studies were partially supported by the Center for NanoScience(CeNS)-Faculty of Physics,Ludwig-Maximilians University Munich.
文摘Two-dimensional(2D)semiconductors possess strongly bound excitons,opening novel opportunities for engineering light-matter interaction at the nanoscale.However,their in-plane confinement leads to large non-radiative exciton–exciton annihilation(EEA)processes,setting a fundamental limit for their photonic applications.In this work,we demonstrate suppression of EEA via enhancement of light-matter interaction in hybrid 2D semiconductor-dielectric nanophotonic platforms,by coupling excitons in WS2 monolayers with optical Mie resonances in dielectric nanoantennas.The hybrid system reaches an intermediate light-matter coupling regime,with photoluminescence enhancement factors up to 102.Probing the exciton ultrafast dynamics reveal suppressed EEA for coupled excitons,even under high exciton densities>10^(12)cm^(−2).We extract EEA coefficients in the order of 10^(−3),compared to 10^(−2)for uncoupled monolayers,as well as a Purcell factor of 4.5.Our results highlight engineering the photonic environment as a route to achieve higher quantum efficiencies,for low-power hybrid devices,and larger exciton densities,towards strongly correlated excitonic phases in 2D semiconductors.
