Encoding information in light polarization is of great importance in facilitating optical data storage(ODS)for information security and data storage capacity escalation.However,despite recent advances in nanophotonic ...Encoding information in light polarization is of great importance in facilitating optical data storage(ODS)for information security and data storage capacity escalation.However,despite recent advances in nanophotonic techniques vastly en-hancing the feasibility of applying polarization channels,the data fidelity in reconstructed bits has been constrained by severe crosstalks occurring between varied polarization angles during data recording and reading process,which gravely hindered the utilization of this technique in practice.In this paper,we demonstrate an ultra-low crosstalk polarization-en-coding multilayer ODS technique for high-fidelity data recording and retrieving by utilizing a nanofibre-based nanocom-posite film involving highly aligned gold nanorods(GNRs).With parallelizing the gold nanorods in the recording medium,the information carrier configuration minimizes miswriting and misreading possibilities for information input and output,respectively,compared with its randomly self-assembled counterparts.The enhanced data accuracy has significantly im-proved the bit recall fidelity that is quantified by a correlation coefficient higher than 0.99.It is anticipated that the demon-strated technique can facilitate the development of multiplexing ODS for a greener future.展开更多
Nonscattering optical anapole condition is corresponding to the excitation of radiationless field distributions in open resonators,which offers new degrees of freedom for tailoring light-matter interaction.Conventiona...Nonscattering optical anapole condition is corresponding to the excitation of radiationless field distributions in open resonators,which offers new degrees of freedom for tailoring light-matter interaction.Conventional mechanisms for achieving such a condition relies on sophisticated manipulation of electromagnetic multipolar moments of all orders to guarantee superpositions of suppressed moment strengths at the same wavelength.In contrast,here we report on the excitation of optical radiationless anapole hidden in a resonant state of a Si nanoparticle utilizing a tightly focused radially polarized(RP)beam.The coexistence of magnetic resonant state and anapole condition at the same wavelength further enables the triggering of resonant state by a tightly focused azimuthally polarized(AP)beam whose corresponding electric multipole coefficient could be zero.As a result,high contrast inter-transition between radiationless anapole condition and ideal magnetic resonant scattering can be achieved experimentally in visible spectrum.The proposed mechanism is general which can be realized in different types of nanostructures.Our results showcase that the unique combination of structured light and structured Mie resonances could provide new degrees of freedom for tailoring light-matter interaction,which might shed new light on functional meta-optics.展开更多
Modification of reduced graphene oxide in a controllable manner provides a promising material platform for producinggraphene based devices. Its fusion with direct laser writing methods has enabled cost-effective and s...Modification of reduced graphene oxide in a controllable manner provides a promising material platform for producinggraphene based devices. Its fusion with direct laser writing methods has enabled cost-effective and scalable production for advanced applications based on tailored optical and electronic properties in the conductivity, the fluorescence and the refractive index during the reduction process. This mini-review summarizes the state-of-the-art status of the mechanisms of reduction of graphene oxides by direct laser writing techniques as well as appealing optical diffractive applications including planar lenses, information storage and holographic displays. Owing to its versatility and up-scalability, the laser reduction method holds enormous potentials for graphene based diffractive photonic devices with diverse functionalities.展开更多
A supercritical lens(SCL) can achieve far-field sub-diffraction-limited focusing by elaborately manipulating the interference effect in the focal region, which makes it strongly dependent on the wavelength of the illu...A supercritical lens(SCL) can achieve far-field sub-diffraction-limited focusing by elaborately manipulating the interference effect in the focal region, which makes it strongly dependent on the wavelength of the illuminating light. In addition to the strong chromatic aberrations it suffers, the micrometer-scale clear aperture of reported SCL represents another compelling challenge that excludes their practical imaging applications demand. In this work, we proposed and experimentally demonstrated an achromatic supercritical lens(ASCL) with a centimeterscale clear aperture. The ASCL was designed by a two-step optimization algorithm and constructed in a multilevel phase configuration which consists of 1251 concentric polymer rings with 52 phase levels. By utilizing the grayscale laser lithography technique, we successfully fabricated an ASCL with a diameter of 10 mm. Such a centimeter-scale ASCL showcases a distinguished performance with full visible working bandwidth covering from 400 nm to 700 nm and simultaneous achromatic sub-diffraction-limited focusing of 0.88 times of the Airy spot.The demonstrations of white light microscopic imaging further validate our design and show decent performance.Our work paves the way for practical applications of SCL in high-density optical data storage, super-resolving optical telescope, and high-precision optical trapping.展开更多
The advance of nanophotonics has provided a variety of avenues for light–matter interaction at the nanometer scale through the enriched mechanisms for physical and chemical reactions induced by nanometer-confined opt...The advance of nanophotonics has provided a variety of avenues for light–matter interaction at the nanometer scale through the enriched mechanisms for physical and chemical reactions induced by nanometer-confined optical probes in nanocomposite materials.These emerging nanophotonic devices and materials have enabled researchers to develop disruptive methods of tremendously increasing the storage capacity of current optical memory.In this paper,we present a review of the recent advancements in nanophotonics-enabled optical storage techniques.Particularly,we offer our perspective of using them as optical storage arrays for next-generation exabyte data centers.展开更多
The control of polarization,an essential property of light,is of broad scientific and technological interest.Polarizers are indispensable optical elements for direct polarization generation.However,arbitrary polarizat...The control of polarization,an essential property of light,is of broad scientific and technological interest.Polarizers are indispensable optical elements for direct polarization generation.However,arbitrary polarization generation,except that of common linear and circular polarization,relies heavily on bulky optical components such as cascading linear polarizers and waveplates.Here,we present an effective strategy for designing all-in-one full Poincare sphere polarizers based on perfect arbitrary polarization conversion dichroism and implement it in a monolayer all-dielectric metasurface.This strategy allows preferential transmission and conversion of one polarization state located at an arbitrary position on the Poincare sphere to its handedness-flipped state while completely blocking its orthogonal state.In contrast to previous methods that were limited to only linear or circular polarization,our method manifests perfect dichroism of nearly 100%in theory and greater than 90%experimentally for arbitrary polarization states.By leveraging this attractive dichroism,our demonstration of the generation of polarization beams located at an arbitrary position on a Poincare sphere directly from unpolarized light can substantially extend the scope of meta-optics and dramatically promote state-of-the-art nanophotonic devices.展开更多
The possibility to achieve unprecedented multiplexing of light-matter interaction in nanoscale is of virtue importance from both fundamental science and practical application points of view. Cylindrical vector beams(C...The possibility to achieve unprecedented multiplexing of light-matter interaction in nanoscale is of virtue importance from both fundamental science and practical application points of view. Cylindrical vector beams(CVBs) manifested as polarization vortices represent a robust and emerging degree of freedom for information multiplexing with increased capacities. Here, we propose and demonstrate massivelyencoded optical data storage(ODS) by harnessing spatially variant electric fields mediated by segmented CVBs. By tight focusing polychromatic segmented CVBs to plasmonic nanoparticle aggregates, recordhigh multiplexing channels of ODS through different combinations of polarization states and wavelengths have been experimentally demonstrated with a low error rate. Our result not only casts new perceptions for tailoring light-matter interactions utilizing structured light but also enables a new prospective for ultra-high capacity optical memory with minimalist system complexity by combining CVB’s compatibility with fiber optics.展开更多
The emerging meta-holograms rely on arrays of intractable meta-atoms with various geometries and sizes for customized phase profiles that can precisely modulate the phase of a wavefront at an optimal incident angle fo...The emerging meta-holograms rely on arrays of intractable meta-atoms with various geometries and sizes for customized phase profiles that can precisely modulate the phase of a wavefront at an optimal incident angle for given wavelengths.The stringent and band-limited angle tolerance remains a fundamental obstacle for their practical application,in addition to high fabrication precision demands.Utilizing a different design principle,we determined that facile metagrating holograms based on extraordinary optical diffraction can allow the molding of arbitrary wavefronts with extreme angle tolerances(near-grazing incidence)in the visible–near-infrared regime.By modulating the displacements between uniformly sized meta-atoms rather than the geometrical parameters,the metagratings produce a robust detour phase profile that is irrespective of the wavelength or incident angle.The demonstration of high-fidelity meta-holograms and in-site polarization multiplexing significantly simplifies the metasurface design and lowers the fabrication demand,thereby opening new routes for flat optics with high performances and improved practicality.展开更多
Advances in direct laser writing to attain super-resolution are required to improve fabrication performance and develop potential applications for nanophotonics.In this study,a novel technique using single-color perip...Advances in direct laser writing to attain super-resolution are required to improve fabrication performance and develop potential applications for nanophotonics.In this study,a novel technique using single-color peripheral photoinhibition lithography was developed to improve the resolution of direct laser writing while preventing the chromatic aberration characteristics of conventional multicolor photoinhibition lithography,thus offering a robust tool for fabricating 2D and 3D nanophotonic structures.A minimal feature size of 36 nm and a resolution of 140 nm were achieved with a writing speed that was at least 10 times faster than existing photoinhibition lithography.Superresolution and fast scanning enable the fabrication of spin-decoupled metasurfaces in the visible range within a printing duration of a few minutes.Finally,a subwavelength photonic crystal with a near-ultraviolet structural color was fabricated to demonstrate the potential of 3D printing.This technique is a flexible and reliable tool for fabricating ultracompact optical devices.展开更多
We show that a metasurface composed of a subwavelength metallic slit array embedded in an asymmetric dielectric environment can exhibit either diffraction （EOD）. The cascaded refractive extraordinary optical transmi...We show that a metasurface composed of a subwavelength metallic slit array embedded in an asymmetric dielectric environment can exhibit either diffraction （EOD）. The cascaded refractive extraordinary optical transmission （EOT） or extraordinary optical indices of the dielectrics can leverage multiple decaying passages into variant subsections with different diffraction order combinations according to the diffraction order chart in the k-vector space, providing a flexible by changing the wavevector of the efficiencies can be enhanced to near or EOD in a single tional metasurface onstrated. Our findings incident light. As a result, either the unity by the excitation of the localized provide a convenient way components on a single planar device.展开更多
Bound states in the continuum(BICs)are localized states coexisting with extended waves inside the continuous spectrum range,which have infinite lifetimes without any radiation.To extract high-Q quasi-BIC resonances fr...Bound states in the continuum(BICs)are localized states coexisting with extended waves inside the continuous spectrum range,which have infinite lifetimes without any radiation.To extract high-Q quasi-BIC resonances from the symmetry-protected BIC for practical applications,symmetry-breaking approaches are usually exploited,either by slightly breaking the excitation field symmetry or structure symmetry.Here,we introduce an all-dielectric superlattice metasurface that can symmetrycompatibly convert BIC states into high-Q quasi-BIC modes based on the guidedmode resonance coupling by relative displacement tuning.The metasurface is composed of a superlattice of multiple nanobeams,supporting both magnetic mode and toroidal mode with large tunability.Both modes can interact with the incident continuum by mediating the displacement between nanobeams,which empowers dual asymmetric Fano resonances with high Q-factors.The bandwidth of the toroidal mode under y-polarized incidences and that of the magnetic mode under x-polarized incidences can be readily tuned by the local displacement between nanobeams in each unit cell.Such displacement-mediated BIC resonance is promising for various applications such as bio-molecule sensing and low threshold lasing.展开更多
Although photonics presents the fastest and most energy-efficient method of data transfer,magnetism still offers the cheapest and most natural way to store data.The ultrafast and energy-efficient optical control of ma...Although photonics presents the fastest and most energy-efficient method of data transfer,magnetism still offers the cheapest and most natural way to store data.The ultrafast and energy-efficient optical control of magnetism is presently a missing technological link that prevents us from reaching the next evolution in information processing.The discovery of all-optical magnetization reversal in GdFeCo with the help of 100fs laser pulses has further aroused intense interest in this compelling problem.Although the applicability of this approach to high-speed data processing depends vitally on the maximum repetition rate of the switching,the latter remains virtually unknown.Here we experimentally unveil the ultimate frequency of repetitive all-optical magnetization reversal through time-resolved studies of the dual-shot magnetization dynamics in Gd27 Fe63.87 C09.T3.Varying the intensities of the shots and the shotto-shot separation,we reveal the conditions for ultrafast writing and the fastest possible restoration of magnetic bits.It is shown that although magnetic writing launched by the first shot is completed after 100 ps,a reliable rewriting of the bit by the second shot requires separating the shots by at least 300 ps.Using two shots partially overlapping in space and minimally separated by 300 ps,we demonstrate an approach for GHz magnetic writing that can be scaled down to sizes below the diffraction limit.展开更多
Achieving an axial superresolved focus with a single lens by simply inserting a modulation mask in the pupil plane is preferred due to its compact configuration and general applicability. However, lack of a universal ...Achieving an axial superresolved focus with a single lens by simply inserting a modulation mask in the pupil plane is preferred due to its compact configuration and general applicability. However, lack of a universal theoretical model to manifest the superresolved focusing mechanism vastly complicates the mask design and hinders optimal resolution. Here we establish an interference model and find out that the axial resolution closely relates to the Gouy phase gradient(GPG) at the focal point. Using a GPG tuning-based optimization approach, the axial resolution of a ring-mask-modulated beam is readily improved to attain superresolved focal depth for multiple types of pupil function and polarization. In experiment, a focus with an axial resolution of 27% improved from the diffraction limit and 11% finer than the previously reported record is demonstrated for the radially polarized beam. In simulations, a spherical focus with 3D isotropic resolution and a superoscillation-like axial modulation behavior toward extremely high axial resolution is also presented. This approach can be applied for varied types of pupil function, wavelength, and polarization, and can be easily transferred to other traditional or superresolution microscopes to upgrade their axial resolution.展开更多
Metallic nanostructures have underpinned plasmonic-based advanced photonic devices in a broad range of research fields over the last decade including physics, engineering, material science and bioscience, The key to r...Metallic nanostructures have underpinned plasmonic-based advanced photonic devices in a broad range of research fields over the last decade including physics, engineering, material science and bioscience, The key to realizing functional plasmonie resonances that can manipulate light at the optical frequencies relies on the creation of conductive metallic structures at the nanoscale with low structural defects. Currently, most plasmonic nanostructures are fabricated either by electron beam lithography （EBL） or by focused ion beam （FIB） milling, which are expensive, complicated and time-consuming. In comparison, the direct laser writing （DLW） technique has demonstrated its high spatial resolution and cost-effectiveness in three-dimensional fabrication of micro/nanostrucmres. Furthermore, the recent breakthroughs in superresolution nanofabrication and parallel writing have significantly advanced the fabrication resolution and throughput of the DLW method and made it one of the promising future nanofabrication technologies with low-cost and scalability. In this review, we provide a comprehensive summary of the state-of-the-art DLW fabrication technology for nanometer scale metallic structures. The fabrication mechanisms, different material choices, fabrication capability, including resolution, conductivity and structure surface smoothness, as well as the characterization methods and achievable devices for different applications are presented. In particular, the development trends of the field and the perspectives for future opportunities and challenges are provided at the end of the review. It has been demonstrated that the quality of the metallic structures fabricated using the DLW method is excellent compared with other methods providing a new and enabling platform for functional nanophotonic device fabrication.展开更多
Plasmonic structural colors have plenty of advantages over traditional colors based on colorants.The pulsed laser provides an important method generating plasmonic structural colors with high efficiency and low cost.H...Plasmonic structural colors have plenty of advantages over traditional colors based on colorants.The pulsed laser provides an important method generating plasmonic structural colors with high efficiency and low cost.Here,we present plasmonic color printing Al nanodisc structures through curvature-driven shape transition.We systematically study the mechanism of morphologic evolution of the Al nanodisc below the thermal melting threshold.A multi-pulse-induced accumulated photothermal effect and subsequent curvature-driven surface atom diffusion model are adopted to explain the controllable shape transition.The shape transition and corresponding plasmonic resonances of the nanodisc can be independently and precisely modulated by controlled irradiations.This method opens new ways towards high-fidelity color prints in a highly efficient and facile laser writing fashion.展开更多
基金financial supports from the National Natural Science Foundation of China(Grant Nos.62174073,61875073,11674130,91750110 and 61522504)the National Key R&D Program of China(Grant No.2018YFB1107200)+3 种基金the Guangdong Provincial Innovation and Entrepren-eurship Project(Grant No.2016ZT06D081)the Natural Science Founda-tion of Guangdong Province,China(Grant Nos.2016A030306016 and 2016TQ03X981)the Pearl River Nova Program of Guangzhou(Grant No.201806010040)the Technology Innovation and Development Plan of Yantai(Grant No.2020XDRH095).
文摘Encoding information in light polarization is of great importance in facilitating optical data storage(ODS)for information security and data storage capacity escalation.However,despite recent advances in nanophotonic techniques vastly en-hancing the feasibility of applying polarization channels,the data fidelity in reconstructed bits has been constrained by severe crosstalks occurring between varied polarization angles during data recording and reading process,which gravely hindered the utilization of this technique in practice.In this paper,we demonstrate an ultra-low crosstalk polarization-en-coding multilayer ODS technique for high-fidelity data recording and retrieving by utilizing a nanofibre-based nanocom-posite film involving highly aligned gold nanorods(GNRs).With parallelizing the gold nanorods in the recording medium,the information carrier configuration minimizes miswriting and misreading possibilities for information input and output,respectively,compared with its randomly self-assembled counterparts.The enhanced data accuracy has significantly im-proved the bit recall fidelity that is quantified by a correlation coefficient higher than 0.99.It is anticipated that the demon-strated technique can facilitate the development of multiplexing ODS for a greener future.
基金financial support from the National Key R&D Program of China (YS2018YFB110012)National Natural Science Foundation of China (NSFC) (Grant Nos. 11674130, 91750110, 61522504 and 61975067)+2 种基金Guangdong Provincial Innovation and Entrepreneurship Project (Grant 2016ZT06D081)Natural Science Foundation of Guangdong Province, China (Grant Nos. 2016A030306016, 2016TQ03X981 and 2016A030308010)Pearl River Nova Program of Guangzhou (No. 201806010040)
文摘Nonscattering optical anapole condition is corresponding to the excitation of radiationless field distributions in open resonators,which offers new degrees of freedom for tailoring light-matter interaction.Conventional mechanisms for achieving such a condition relies on sophisticated manipulation of electromagnetic multipolar moments of all orders to guarantee superpositions of suppressed moment strengths at the same wavelength.In contrast,here we report on the excitation of optical radiationless anapole hidden in a resonant state of a Si nanoparticle utilizing a tightly focused radially polarized(RP)beam.The coexistence of magnetic resonant state and anapole condition at the same wavelength further enables the triggering of resonant state by a tightly focused azimuthally polarized(AP)beam whose corresponding electric multipole coefficient could be zero.As a result,high contrast inter-transition between radiationless anapole condition and ideal magnetic resonant scattering can be achieved experimentally in visible spectrum.The proposed mechanism is general which can be realized in different types of nanostructures.Our results showcase that the unique combination of structured light and structured Mie resonances could provide new degrees of freedom for tailoring light-matter interaction,which might shed new light on functional meta-optics.
基金The authors thank National Natural Science Foundation of China （61522504, 61420106014, 61432007, 11604123） and Guangdong Provincial Innovation and Entrepreneurship Project （2016ZT06D081） for funding supports. M Gu acknowledges the supports from the Australian Research Council （ARC） through the Discovery Project （DP140100849） and Laureate Fellowship Scheme （FL100100099）.
文摘Modification of reduced graphene oxide in a controllable manner provides a promising material platform for producinggraphene based devices. Its fusion with direct laser writing methods has enabled cost-effective and scalable production for advanced applications based on tailored optical and electronic properties in the conductivity, the fluorescence and the refractive index during the reduction process. This mini-review summarizes the state-of-the-art status of the mechanisms of reduction of graphene oxides by direct laser writing techniques as well as appealing optical diffractive applications including planar lenses, information storage and holographic displays. Owing to its versatility and up-scalability, the laser reduction method holds enormous potentials for graphene based diffractive photonic devices with diverse functionalities.
基金National Key Research and Development Program of China(2023YFF0718101)National Natural Science Foundation of China(62475102,62375109,62275108)Basic and Applied Basic Research Foundation of GuangdongProvince(2020B1515020058).
文摘A supercritical lens(SCL) can achieve far-field sub-diffraction-limited focusing by elaborately manipulating the interference effect in the focal region, which makes it strongly dependent on the wavelength of the illuminating light. In addition to the strong chromatic aberrations it suffers, the micrometer-scale clear aperture of reported SCL represents another compelling challenge that excludes their practical imaging applications demand. In this work, we proposed and experimentally demonstrated an achromatic supercritical lens(ASCL) with a centimeterscale clear aperture. The ASCL was designed by a two-step optimization algorithm and constructed in a multilevel phase configuration which consists of 1251 concentric polymer rings with 52 phase levels. By utilizing the grayscale laser lithography technique, we successfully fabricated an ASCL with a diameter of 10 mm. Such a centimeter-scale ASCL showcases a distinguished performance with full visible working bandwidth covering from 400 nm to 700 nm and simultaneous achromatic sub-diffraction-limited focusing of 0.88 times of the Airy spot.The demonstrations of white light microscopic imaging further validate our design and show decent performance.Our work paves the way for practical applications of SCL in high-density optical data storage, super-resolving optical telescope, and high-precision optical trapping.
基金The authors thank the Australian Research Council for its support through the Laureate Fellowship project(FL100100099).
文摘The advance of nanophotonics has provided a variety of avenues for light–matter interaction at the nanometer scale through the enriched mechanisms for physical and chemical reactions induced by nanometer-confined optical probes in nanocomposite materials.These emerging nanophotonic devices and materials have enabled researchers to develop disruptive methods of tremendously increasing the storage capacity of current optical memory.In this paper,we present a review of the recent advancements in nanophotonics-enabled optical storage techniques.Particularly,we offer our perspective of using them as optical storage arrays for next-generation exabyte data centers.
基金supported by the National Key R&D Program of China(2018YFB1107200)the National Natural Science Foundation of China(NSFC)(Grants 62075084,61522504,61420106014,11734012,and 11574218)+3 种基金the Guangdong Provincial Innovation and Entrepreneurship Project(Grant 2016ZT06D081)the Guangdong Basic and Applied Basic Research Foundation(2020A1515010615)the Fundamental Research Funds for the Central Universities(21620415)the China Scholarship Council(201906785011).
文摘The control of polarization,an essential property of light,is of broad scientific and technological interest.Polarizers are indispensable optical elements for direct polarization generation.However,arbitrary polarization generation,except that of common linear and circular polarization,relies heavily on bulky optical components such as cascading linear polarizers and waveplates.Here,we present an effective strategy for designing all-in-one full Poincare sphere polarizers based on perfect arbitrary polarization conversion dichroism and implement it in a monolayer all-dielectric metasurface.This strategy allows preferential transmission and conversion of one polarization state located at an arbitrary position on the Poincare sphere to its handedness-flipped state while completely blocking its orthogonal state.In contrast to previous methods that were limited to only linear or circular polarization,our method manifests perfect dichroism of nearly 100%in theory and greater than 90%experimentally for arbitrary polarization states.By leveraging this attractive dichroism,our demonstration of the generation of polarization beams located at an arbitrary position on a Poincare sphere directly from unpolarized light can substantially extend the scope of meta-optics and dramatically promote state-of-the-art nanophotonic devices.
基金the financial support from the National Key R&D Program of China (2018YFB1107200)the National Natural Science Foundation of China (91750110, 11674130, 61605061, 11674110 and 11874020)+2 种基金the Guangdong Provincial Innovation and Entrepreneurship Project (2016ZT06D081)the Natural Science Foundation of Guangdong Province (2016A030306016, 2016TQ03X981 and 2016A030308010)Pearl River S and T Nova Program of Guangzhou (201806010040)。
文摘The possibility to achieve unprecedented multiplexing of light-matter interaction in nanoscale is of virtue importance from both fundamental science and practical application points of view. Cylindrical vector beams(CVBs) manifested as polarization vortices represent a robust and emerging degree of freedom for information multiplexing with increased capacities. Here, we propose and demonstrate massivelyencoded optical data storage(ODS) by harnessing spatially variant electric fields mediated by segmented CVBs. By tight focusing polychromatic segmented CVBs to plasmonic nanoparticle aggregates, recordhigh multiplexing channels of ODS through different combinations of polarization states and wavelengths have been experimentally demonstrated with a low error rate. Our result not only casts new perceptions for tailoring light-matter interactions utilizing structured light but also enables a new prospective for ultra-high capacity optical memory with minimalist system complexity by combining CVB’s compatibility with fiber optics.
基金supported by the National Key R&D Program of China(YS2018YFB110012)the National Natural Science Foundation of China(NSFC)(Grant 11604217,61522504,61420106014,11774145,11734012,11574218)+3 种基金the Fundamental Research Funds for the Central Universities(Grant 21617410)the Guangdong Provincial Innovation and Entrepreneurship Project(Grant 2016ZT06D081,2017ZT07C071)the Applied Science and Technology Project of the Guangdong Science and Technology Department(2017B090918001)the Natural Science Foundation of the Shenzhen Innovation Committee(JCYJ20170412153113701).
文摘The emerging meta-holograms rely on arrays of intractable meta-atoms with various geometries and sizes for customized phase profiles that can precisely modulate the phase of a wavefront at an optimal incident angle for given wavelengths.The stringent and band-limited angle tolerance remains a fundamental obstacle for their practical application,in addition to high fabrication precision demands.Utilizing a different design principle,we determined that facile metagrating holograms based on extraordinary optical diffraction can allow the molding of arbitrary wavefronts with extreme angle tolerances(near-grazing incidence)in the visible–near-infrared regime.By modulating the displacements between uniformly sized meta-atoms rather than the geometrical parameters,the metagratings produce a robust detour phase profile that is irrespective of the wavelength or incident angle.The demonstration of high-fidelity meta-holograms and in-site polarization multiplexing significantly simplifies the metasurface design and lowers the fabrication demand,thereby opening new routes for flat optics with high performances and improved practicality.
基金supported by the National Natural Science Foundation of China(62125504,61827825,and 22105180)National Key R&D Program of China(2021YFF0502700)+2 种基金Major Program of the Natural Science Foundation of Zhejiang Province(LD21F050002)Major Scientific Project of Zhejiang Lab(2020MC0AE01),China Postdoctoral Science Foundation(BX2021272 and 2020M681956)Zhejiang Postdoctoral Science Fund for Excellent Project(511300-X82101).
文摘Advances in direct laser writing to attain super-resolution are required to improve fabrication performance and develop potential applications for nanophotonics.In this study,a novel technique using single-color peripheral photoinhibition lithography was developed to improve the resolution of direct laser writing while preventing the chromatic aberration characteristics of conventional multicolor photoinhibition lithography,thus offering a robust tool for fabricating 2D and 3D nanophotonic structures.A minimal feature size of 36 nm and a resolution of 140 nm were achieved with a writing speed that was at least 10 times faster than existing photoinhibition lithography.Superresolution and fast scanning enable the fabrication of spin-decoupled metasurfaces in the visible range within a printing duration of a few minutes.Finally,a subwavelength photonic crystal with a near-ultraviolet structural color was fabricated to demonstrate the potential of 3D printing.This technique is a flexible and reliable tool for fabricating ultracompact optical devices.
基金National Natural Science Foundation of China(NSFC)(11604217,11574218,11734012,61420106014,61522504)Fundamental Research Funds for the Central Universities(21617410)Guangdong Provincial Innovation and Entrepreneurship Project(2016ZT06D081)
文摘We show that a metasurface composed of a subwavelength metallic slit array embedded in an asymmetric dielectric environment can exhibit either diffraction （EOD）. The cascaded refractive extraordinary optical transmission （EOT） or extraordinary optical indices of the dielectrics can leverage multiple decaying passages into variant subsections with different diffraction order combinations according to the diffraction order chart in the k-vector space, providing a flexible by changing the wavevector of the efficiencies can be enhanced to near or EOD in a single tional metasurface onstrated. Our findings incident light. As a result, either the unity by the excitation of the localized provide a convenient way components on a single planar device.
基金support provided by the National Key R&D Program of China(2018YFB1107200)Guangdong Basic and Applied Basic Research Foundation(2020A1515010615)+3 种基金the Fundamental Research Funds for the Central Universities(21620415)the National Natural Science Foundation of China(NSFC)(62075084,61522504,61420106014,11734012,and 11574218)Guangzhou Science and Technology Program(202102020566)the Guangdong Provincial Innovation and Entrepreneurship Project(2016ZT06D081).
文摘Bound states in the continuum(BICs)are localized states coexisting with extended waves inside the continuous spectrum range,which have infinite lifetimes without any radiation.To extract high-Q quasi-BIC resonances from the symmetry-protected BIC for practical applications,symmetry-breaking approaches are usually exploited,either by slightly breaking the excitation field symmetry or structure symmetry.Here,we introduce an all-dielectric superlattice metasurface that can symmetrycompatibly convert BIC states into high-Q quasi-BIC modes based on the guidedmode resonance coupling by relative displacement tuning.The metasurface is composed of a superlattice of multiple nanobeams,supporting both magnetic mode and toroidal mode with large tunability.Both modes can interact with the incident continuum by mediating the displacement between nanobeams,which empowers dual asymmetric Fano resonances with high Q-factors.The bandwidth of the toroidal mode under y-polarized incidences and that of the magnetic mode under x-polarized incidences can be readily tuned by the local displacement between nanobeams in each unit cell.Such displacement-mediated BIC resonance is promising for various applications such as bio-molecule sensing and low threshold lasing.
基金We are grateful to Dr.Dmytro V.Afanasiev,Tonnie Toonen,Dr.Bowen Jiang,and Dr.Sergey Semin for their professional technical support This research is financially supported by the National Key R&D Program of China(2018YFB1107200)Ministry of Science and Technology of the Peopled Republic of China(MOST)(Grant numbers 2016丫FA0300802 and 2018YFE0109200)+6 种基金National Natural Science Foundation of China(NSFC)(61975066 and 11604123)Guangdong Basic and Applied Basic Research Foundation(2019A1515010864)Fundamental Research Funds for the Central Universities(21620413)Guangdong Provincial Innovation and Entrepreneurship Project(Grant 2016ZT06D081)Grant-in-Aid for Scientific Research on Innovative Area,Nano Spin Conversion Science1(Grant number 26103005)‘Nano Spin Conversion Science'(Grant number 26103004)European Research Council ERC,Grant agreement number 339813(Exchange),and Netherlands Organization for Scientific Research(NWO).
文摘Although photonics presents the fastest and most energy-efficient method of data transfer,magnetism still offers the cheapest and most natural way to store data.The ultrafast and energy-efficient optical control of magnetism is presently a missing technological link that prevents us from reaching the next evolution in information processing.The discovery of all-optical magnetization reversal in GdFeCo with the help of 100fs laser pulses has further aroused intense interest in this compelling problem.Although the applicability of this approach to high-speed data processing depends vitally on the maximum repetition rate of the switching,the latter remains virtually unknown.Here we experimentally unveil the ultimate frequency of repetitive all-optical magnetization reversal through time-resolved studies of the dual-shot magnetization dynamics in Gd27 Fe63.87 C09.T3.Varying the intensities of the shots and the shotto-shot separation,we reveal the conditions for ultrafast writing and the fastest possible restoration of magnetic bits.It is shown that although magnetic writing launched by the first shot is completed after 100 ps,a reliable rewriting of the bit by the second shot requires separating the shots by at least 300 ps.Using two shots partially overlapping in space and minimally separated by 300 ps,we demonstrate an approach for GHz magnetic writing that can be scaled down to sizes below the diffraction limit.
基金National Natural Science Foundation of China(61875073,61905097)National Key Research and Development Program of China(2021YFB2802000)+1 种基金Guangdong Provincial Innovation and Entrepreneurship Project(2016ZT06D081)Zhejiang Lab(2020MC0AE01)。
文摘Achieving an axial superresolved focus with a single lens by simply inserting a modulation mask in the pupil plane is preferred due to its compact configuration and general applicability. However, lack of a universal theoretical model to manifest the superresolved focusing mechanism vastly complicates the mask design and hinders optimal resolution. Here we establish an interference model and find out that the axial resolution closely relates to the Gouy phase gradient(GPG) at the focal point. Using a GPG tuning-based optimization approach, the axial resolution of a ring-mask-modulated beam is readily improved to attain superresolved focal depth for multiple types of pupil function and polarization. In experiment, a focus with an axial resolution of 27% improved from the diffraction limit and 11% finer than the previously reported record is demonstrated for the radially polarized beam. In simulations, a spherical focus with 3D isotropic resolution and a superoscillation-like axial modulation behavior toward extremely high axial resolution is also presented. This approach can be applied for varied types of pupil function, wavelength, and polarization, and can be easily transferred to other traditional or superresolution microscopes to upgrade their axial resolution.
基金supported by the Australian Research Council through the Discovery Early Career Researcher Award Scheme(Grant No.DE120100291)the Discovery Project Scheme(Grant No.DP150102972)
文摘Metallic nanostructures have underpinned plasmonic-based advanced photonic devices in a broad range of research fields over the last decade including physics, engineering, material science and bioscience, The key to realizing functional plasmonie resonances that can manipulate light at the optical frequencies relies on the creation of conductive metallic structures at the nanoscale with low structural defects. Currently, most plasmonic nanostructures are fabricated either by electron beam lithography （EBL） or by focused ion beam （FIB） milling, which are expensive, complicated and time-consuming. In comparison, the direct laser writing （DLW） technique has demonstrated its high spatial resolution and cost-effectiveness in three-dimensional fabrication of micro/nanostrucmres. Furthermore, the recent breakthroughs in superresolution nanofabrication and parallel writing have significantly advanced the fabrication resolution and throughput of the DLW method and made it one of the promising future nanofabrication technologies with low-cost and scalability. In this review, we provide a comprehensive summary of the state-of-the-art DLW fabrication technology for nanometer scale metallic structures. The fabrication mechanisms, different material choices, fabrication capability, including resolution, conductivity and structure surface smoothness, as well as the characterization methods and achievable devices for different applications are presented. In particular, the development trends of the field and the perspectives for future opportunities and challenges are provided at the end of the review. It has been demonstrated that the quality of the metallic structures fabricated using the DLW method is excellent compared with other methods providing a new and enabling platform for functional nanophotonic device fabrication.
基金the National Key R&D Program of China(No.YS2018YFB110012)the Guangdong Provincial Innovation and Entrepreneurship Project(No.2016ZT06D081)。
文摘Plasmonic structural colors have plenty of advantages over traditional colors based on colorants.The pulsed laser provides an important method generating plasmonic structural colors with high efficiency and low cost.Here,we present plasmonic color printing Al nanodisc structures through curvature-driven shape transition.We systematically study the mechanism of morphologic evolution of the Al nanodisc below the thermal melting threshold.A multi-pulse-induced accumulated photothermal effect and subsequent curvature-driven surface atom diffusion model are adopted to explain the controllable shape transition.The shape transition and corresponding plasmonic resonances of the nanodisc can be independently and precisely modulated by controlled irradiations.This method opens new ways towards high-fidelity color prints in a highly efficient and facile laser writing fashion.
