The geometric phase concept has profound implications in many branches of physics,from condensed matter physics to quantum systems.Although geometric phase has a long research history,novel theories,devices,and applic...The geometric phase concept has profound implications in many branches of physics,from condensed matter physics to quantum systems.Although geometric phase has a long research history,novel theories,devices,and applications are constantly emerging with developments going down to the subwavelength scale.Specifically,as one of the main approaches to implement gradient phase modulation along a thin interface,geometric phase metasurfaces composed of spatially rotated subwavelength artificial structures have been utilized to construct various thin and planar meta-devices.In this paper,we first give a simple overview of the development of geometric phase in optics.Then,we focus on recent advances in continuously shaped geometric phase metasurfaces,geometric–dynamic composite phase metasurfaces,and nonlinear and high-order linear Pancharatnam–Berry phase metasurfaces.Finally,conclusions and outlooks for future developments are presented.展开更多
Free-electron light sources feature extraordinary luminosity,directionality,and coherence,which has enabled significant scientific progress in fields including physics,chemistry,and biology.The next generation of ligh...Free-electron light sources feature extraordinary luminosity,directionality,and coherence,which has enabled significant scientific progress in fields including physics,chemistry,and biology.The next generation of light sources has aimed at compact radiation sources driven by free electrons,with the advantages of reduction in both space and cost.With the rapid development of ultra-intense and ultrashort lasers,great effort has been devoted to the quest for compact free-electron lasers(FELs).This review focuses on the current efforts and advancements in the development of compact FELs,with a particular emphasis on two notable paths:the development of compact accelerators and the construction of micro undulators based on innovative materials/structures or optical modulation of electrons.In addition,the physical essence of inverse Compton scattering is discussed,which offers remarkable capability to develop an optical undulator with a spatial period that matches the optical wavelength.Recent scientific developments and future directions for miniaturized and integrated free-electron coherent light sources are also reviewed.In the future,the prospect of generating ultrashort electron pulses will provide fascinating means of producing superradiant radiation,promising high brilliance and coherence even on a micro scale using optical micro undulators.展开更多
In their recent review article Ghosh et al.provide an overview of room-temperature polaritonics,which may be also referred to as physics of liquid light[1].The quanta of liquid light,exciton polaritons,combine propert...In their recent review article Ghosh et al.provide an overview of room-temperature polaritonics,which may be also referred to as physics of liquid light[1].The quanta of liquid light,exciton polaritons,combine properties of photons and of excitons,electrically neutral semiconductor crystal quasiparticles.Polaritonics made tremendous steps forward in the 21st century thanks to the experimental observation of bosonic condensates and superfluids of exciton polaritons at elevated temperatures in a great variety of material systems.Coherent fluids of exciton polaritons can be efficiently controlled by laser light and/or by applied electric and magnetic fields.This opens ways to many applications,including but not limited to polariton lasing,optical switching,polariton simulators,neuromorphic computing,quantum computing,and polariton-induced superconductivity.Ghoch et al.provide a detailed analysis of the material systems suitable for room temperature polaritonics starting from wide-bandgap inorganic semiconductors such as GaN and ZnO,and carefully discuss also organic microcavities,perovskites,transition metal dichalcogenides,and hybrid structures.They discuss the advantages and disadvantages of these systems emphasizing recent experimental findings in each system.展开更多
Epitaxial quantum dots(QDs)are high-quality semiconductor nanostructures that mimic atoms for their discrete energy levels.Developments of QDs date back to the early 1990s in quest of temperature-insensitive lasers.Si...Epitaxial quantum dots(QDs)are high-quality semiconductor nanostructures that mimic atoms for their discrete energy levels.Developments of QDs date back to the early 1990s in quest of temperature-insensitive lasers.Since then,much effort has been devoted to studying the fundamental physical phenomena observed in those quantum-confined structures.Recently,the QD community has shifted its focus onto quantum photonics applications,motivated by the rapidly developing quantum science.The most prominent application for QDs is their use as a deterministic single-photon source—a non-classical emission of light that underpins quantum computation,communication,and sensing.The field has grown substantially within the last decade,shifting from controlled growth of isolated QDs to a full integration of ultra-pure QD single photon sources with photonic nanostructures[1–6].展开更多
Recent interest in developing fast spintronic devices and laser-controllable magnetic solids has sparked tremendous experimental and theoretical efforts to understand and manipulate ultrafast dynamics in materials.Stu...Recent interest in developing fast spintronic devices and laser-controllable magnetic solids has sparked tremendous experimental and theoretical efforts to understand and manipulate ultrafast dynamics in materials.Studies of spin dynamics in the terahertz(THz)frequency range are particularly important for elucidating microscopic pathways toward novel device functionalities.Here,we review THz phenomena related to spin dynamics in rare-earth orthoferrites,a class of materials promising for antiferromagnetic spintronics.We expand this topic into a description of four key elements.(1)We start by describing THz spectroscopy of spin excitations for probing magnetic phase transitions in thermal equilibrium.While acoustic magnons are useful indicators of spin reorientation transitions,electromagnons that arise from dynamic magnetoelectric couplings serve as a signature of inversion-symmetry-breaking phases at low temperatures.(2)We then review the strong laser driving scenario,where the system is excited far from equilibrium and thereby subject to modifications to the free-energy landscape.Microscopic pathways for ultrafast laser manipulation of magnetic order are discussed.(3)Furthermore,we review a variety of protocols to manipulate coherent THz magnons in time and space,which are useful capabilities for antiferromagnetic spintronic applications.(4)Finally,new insights into the connection between dynamic magnetic coupling in condensed matter and the Dicke superradiant phase transition in quantum optics are provided.By presenting a review on an array of THz spin phenomena occurring in a single class of materials,we hope to trigger interdisciplinary efforts that actively seek connections between subfields of spintronics,which will facilitate the invention of new protocols of active spin control and quantum phase engineering.展开更多
Two-dimensional(2D)materials,due to their exotic electromagnetic responses and strong interaction with light,have been intensively studied over the past decades since the discovery of graphene in 2004[1].Except for gr...Two-dimensional(2D)materials,due to their exotic electromagnetic responses and strong interaction with light,have been intensively studied over the past decades since the discovery of graphene in 2004[1].Except for graphene,natural van der Waals(vdW)materials[2]also serve as indispensable members in the library of 2D materials,where adjacent atomic planes are bonded by weak vdW force so that monolayers can be readily obtained through methods such as mechanical exfoliation.展开更多
Light carries energy and momentum,laying the physical foundation of optical manipulation that has facilitated advances in myriad scientific disciplines,ranging from biochemistry and robotics to quantum physics.Utilizi...Light carries energy and momentum,laying the physical foundation of optical manipulation that has facilitated advances in myriad scientific disciplines,ranging from biochemistry and robotics to quantum physics.Utilizing the momentum of light,optical tweezers have exemplified elegant light–matter interactions in which mechanical and optical momenta can be interchanged,whose effects are the most pronounced on micro and nano objects in fluid suspensions.In solid domains,the same momentum transfer becomes futile in the face of dramatically increased adhesion force.Effective implementation of optical manipulation should thereupon switch to the“energy”channel by involving auxiliary physical fields,which also coincides with the irresistible trend of enriching actuation mechanisms beyond sole reliance on light-momentum-based optical force.From this perspective,this review covers the developments of optical manipulation in schemes of both momentum and energy transfer,and we have correspondingly selected representative techniques to present.Theoretical analyses are provided at the beginning of this review followed by experimental embodiments,with special emphasis on the contrast between mechanisms and the practical realization of optical manipulation in fluid and solid domains.展开更多
Diffractive optical elements(DOEs)are intricately designed devices with the purpose of manipulating light fields by precisely modifying their wavefronts.The concept of DOEs has its origins dating back to 1948 when D.G...Diffractive optical elements(DOEs)are intricately designed devices with the purpose of manipulating light fields by precisely modifying their wavefronts.The concept of DOEs has its origins dating back to 1948 when D.Gabor first introduced holography.Subsequently,researchers introduced binary optical elements(BOEs),including computer-generated holograms(CGHs),as a distinct category within the realm of DOEs.This was the first revolution in optical devices.The next major breakthrough in light field manipulation occurred during the early 21st century,marked by the advent of metamaterials and metasurfaces.Metasurfaces are particularly appealing due to their ultra-thin,ultra-compact properties and their capacity to exert precise control over virtually every aspect of light fields,including amplitude,phase,polarization,wavelength/frequency,angular momentum,etc.The advancement of light field manipulation with micro/nano-structures has also enabled various applications in fields such as information acquisition,transmission,storage,processing,and display.In this review,we cover the fundamental science,cutting-edge technologies,and wide-ranging applications associated with micro/nano-scale optical devices for regulating light fields.We also delve into the prevailing challenges in the pursuit of developing viable technology for real-world applications.Furthermore,we offer insights into potential future research trends and directions within the realm of light field manipulation.展开更多
The refractive-lens technique has been well developed over a long period of evolution,offering powerful imaging functionalities,such as microscopes,telescopes,and spectroscopes.Nevertheless,the ever-growing requiremen...The refractive-lens technique has been well developed over a long period of evolution,offering powerful imaging functionalities,such as microscopes,telescopes,and spectroscopes.Nevertheless,the ever-growing requirements continue to urge further enhanced imaging capabilities and upgraded devices that are more compact for convenience.Metamaterial as a fascinating concept has inspired unprecedented new explorations in physics,material science,and optics,not only in fundamental researches but also novel applications.Along with the imaging topic,this paper reviews the progress of the flat lens as an important branch of metamaterials,covering the early superlens with super-diffraction capability and current hot topics of metalenses including a paralleled strategy of multilevel diffractive lenses.Numerous efforts and approaches have been dedicated to areas ranging from the new fascinating physics to feasible applications.This review provides a clear picture of the flat-lens evolution from the perspective of metamaterial design,elucidating the relation and comparison between a superlens and metalens,and addressing derivative designs.Finally,application scenarios that favor the ultrathin lens technique are emphasized with respect to possible revolutionary imaging devices,followed by conclusive remarks and prospects.展开更多
Richard Feynman’s famous 1959 lecture“There is plenty of room at the bottom”inspired scientists and engineers to focus on manipulating matter at the nanoscale[1].Optical tweezers,groundbreaking tools that use light...Richard Feynman’s famous 1959 lecture“There is plenty of room at the bottom”inspired scientists and engineers to focus on manipulating matter at the nanoscale[1].Optical tweezers,groundbreaking tools that use light to trap and move small particles with nanoscale precision,have revolutionized many fields such as materials science,biology,physics,and nanotechnology[2,3].For example,optical tweezers have enabled researchers to investigate the mechanical properties of biological molecules,study the behavior of colloidal suspensions,explore the movement of motor proteins,and investigate the directed assembly of nanoscale structures[4–6].展开更多
The four-wave mixing process in atomic ensembles has many important applications in quantum information.We review recent progress on the generation of optical quantum states from the four-wave mixing process in hot at...The four-wave mixing process in atomic ensembles has many important applications in quantum information.We review recent progress on the generation of optical quantum states from the four-wave mixing process in hot atomic ensembles,including the production of two-beam,multi-beam,and multiplexed quantum correlated or entangled states.We also review the applications of these optical quantum states in implementing quantum information protocols,constructing SU(1,1)quantum interferometers,and realizing quantum plasmonic sensing.These applications indicate that the four-wave mixing process in hot atomic ensembles is a promising platform for quantum information processing,especially for implementing alloptical quantum information protocols,constructing SU(1,1)interferometers,and realizing quantum sensing.展开更多
Advancements in micro/nanofabrication have enabled the realization of practical micro/nanoscale photonic devices such as absorbers,solar cells,metalenses,and metaholograms.Although the performance of these photonic de...Advancements in micro/nanofabrication have enabled the realization of practical micro/nanoscale photonic devices such as absorbers,solar cells,metalenses,and metaholograms.Although the performance of these photonic devices has been improved by enhancing the design flexibility of structural materials through advanced fabrication methods,achieving large-area and high-throughput fabrication of tiny structural materials remains a challenge.In this aspect,various technologies have been investigated for realizing the mass production of practical devices consisting of micro/nanostructural materials.This review describes the recent advancements in soft lithography,colloidal self-assembly,and block copolymer self-assembly,which are promising methods suitable for commercialization of photonic applications.In addition,we introduce low-cost and large-scale techniques realizing micro/nano devices with specific examples such as display technology and sensors.The inferences presented in this review are expected to function as a guide for promising methods of accelerating the mass production of various sub-wavelength-scale photonic devices.展开更多
Surface plasmons(SPs),or SP polaritons,are electromagnetic(EM)surface waves that propagate freely along metal-dielectric interfaces while being tightly localized in the perpendicular direction due to the interaction w...Surface plasmons(SPs),or SP polaritons,are electromagnetic(EM)surface waves that propagate freely along metal-dielectric interfaces while being tightly localized in the perpendicular direction due to the interaction with collective oscillations of electron plasma in the metal[1].Therefore,SPs become two-dimensional(2D)manifestations of EM waves,with potentially very large wavenumbers near the SP resonance,thereby paving the way for many exciting phenomena,such as light focusing beyond the notorious optical diffraction limit and directing EM energy to the nanoscale[2].展开更多
Metamaterials,due to their incomparable capabilities in manipulating effective material parameters,have been attracting worldwide attention in the past two decades.In previous works,most metamaterials and metasurfaces...Metamaterials,due to their incomparable capabilities in manipulating effective material parameters,have been attracting worldwide attention in the past two decades.In previous works,most metamaterials and metasurfaces focused on the material parameter steering in a continuous scale,which is regarded as“analog metamaterials/metasurfaces.”Since Cui et al.proposed the concept of digital coding and programmable metamaterials/metasurfaces in 2014[1],a new perspective to design metasurfaces has been opened up,bridging between electromagnetic physics and digital information for the first time.Coding metamaterials/metasurfaces have presented diverse physical principles and applications in electromagnetic field manipulations,further deriving many subdirections.In the process of exploration and enrichment in recent years,the coding metasurface has continuously demonstrated its powerful ability in information regulation and combination.Using this as a strong connection,the field has gradually grown into a new system called information metamaterials/metasurfaces[2,3].展开更多
Low symmetry 2D materials with intrinsic in-plane anisotropic optical properties and high tunability provide a promising platform to explore and manipulate light–matter interactions.To date,dozens of in-plane anisotr...Low symmetry 2D materials with intrinsic in-plane anisotropic optical properties and high tunability provide a promising platform to explore and manipulate light–matter interactions.To date,dozens of in-plane anisotropic 2D materials with diverse band structures have been discovered.They exhibit rich optical properties,indicating great potential for novel applications in optics,photonics,and optoelectronics.In this paper,we thoroughly review the anisotropic optical properties and polaritons in many kinds of low symmetry 2D materials,aiming to elicit more research interest in this field.First,the optical properties of anisotropic 2D semiconductors,including interband absorption,photoluminescence,excitons,and band structure engineering for tuning optical responses,are introduced.Then fundamentals and advances in experiments of hyperbolic polaritons in anisotropic 2D materials,including phonon,plasmon,and exciton polaritons,are discussed.Finally,a perspective on promising research directions is given.展开更多
The quest for realizing novel fundamental physical effects and practical applications in ambient conditions has led to tremendous interest in microcavity exciton polaritons working in the strong coupling regime at roo...The quest for realizing novel fundamental physical effects and practical applications in ambient conditions has led to tremendous interest in microcavity exciton polaritons working in the strong coupling regime at room temperature.In the past few decades,a wide range of novel semiconductor systems supporting robust exciton polaritons have emerged,which has led to the realization of various fascinating phenomena and practical applications.This paper aims to review recent theoretical and experimental developments of exciton polaritons operating at room temperature,and includes a comprehensive theoretical background,descriptions of intriguing phenomena observed in various physical systems,as well as accounts of optoelectronic applications.Specifically,an in-depth review of physical systems achieving room temperature exciton polaritons will be presented,including the early development of ZnO and GaN microcavities and other emerging systems such as organics,halide perovskite semiconductors,carbon nanotubes,and transition metal dichalcogenides.Finally,a perspective of outlooking future developments will be elaborated.展开更多
Originally a pure mathematical concept,topology has been vigorously developed in various physical systems in recent years,and underlies many interesting phenomena such as the quantum Hall effect and quantum spin Hall ...Originally a pure mathematical concept,topology has been vigorously developed in various physical systems in recent years,and underlies many interesting phenomena such as the quantum Hall effect and quantum spin Hall effect.Its widespread influence in physics led the award of the 2016 Nobel Prize in Physics to this field.Topological photonics further expands the research field of topology to classical wave systems and holds promise for novel devices and applications,e.g.,topological quantum computation and topological lasers.Here,we review recent developments in topological photonics but focus mainly on their realizations based on metamaterials.Through artificially designed resonant units,metamaterials provide vast degrees of freedom for realizing various topological states,e.g.,the Weyl point,nodal line,Dirac point,topological insulator,and even the Yang monopole and Weyl surface in higher-dimensional synthetic spaces,wherein each specific topological nontrivial state endows novel metamaterial responses that originate from the feature of some high-energy physics.展开更多
Surface plasmons(SPs)are electromagnetic surface waves that propagate at the interface between a conductor and a dielectric.Due to their unique ability to concentrate light on two-dimensional platforms and produce ver...Surface plasmons(SPs)are electromagnetic surface waves that propagate at the interface between a conductor and a dielectric.Due to their unique ability to concentrate light on two-dimensional platforms and produce very high local-field intensity,SPs have rapidly fueled a variety of fundamental advances and practical applications.In parallel,the development of metamaterials and metasurfaces has rapidly revolutionized the design concepts of traditional optical devices,fostering the exciting field of meta-optics.This review focuses on recent progress of meta-optics inspired SP devices,which are implemented by the careful design of subwavelength structures and the arrangement of their spatial distributions.Devices of general interest,including coupling devices,on-chip tailoring devices,and decoupling devices,as well as nascent SP applications empowered by sophisticated usage of meta-optics,are introduced and discussed.展开更多
Epitaxial quantum dots formed by III–V compound semiconductors are excellent sources of nonclassical photons,creating single photons and entangled multi-photon states on demand.Their semiconductor nature allows for a...Epitaxial quantum dots formed by III–V compound semiconductors are excellent sources of nonclassical photons,creating single photons and entangled multi-photon states on demand.Their semiconductor nature allows for a straightforward combination with mature integrated photonic technologies,leading to novel functional devices at the single-photon level.Integrating a quantum dot into a carefully engineered photonic cavity enables control of the radiative decay rate using the Purcell effect and the realization of photon–photon nonlinear gates.In this review,we introduce the basis of epitaxial quantum dots and discuss their applications as non-classical light sources.We highlight two interfaces—one between flying photons and the quantum-dot dipole,and the other between the photons and the spin.We summarize the recent development of integrated photonics and reconfigurable devices that have been combined with quantum dots or are suitable for hybrid integration.Finally,we provide an outlook of employing quantum-dot platforms for practical applications in large-scale quantum computation and the quantum Internet.展开更多
Plasmonics has aroused tremendous interest in photophysics,nanophotonics,and metamaterials.The extreme field concentration of plasmonics offers the ultimate spatial and temporal light control,single-particle detection...Plasmonics has aroused tremendous interest in photophysics,nanophotonics,and metamaterials.The extreme field concentration of plasmonics offers the ultimate spatial and temporal light control,single-particle detection,and optical modulation.Plasmon decay of metal nanostructures into hot carriers extends the application into photocatalysis,photodetectors,photovoltaics,and ultrafast nanooptics.The generated hot electron–hole pairs are transferred into adjacent dielectrics,well known to be more efficient than the hot carrier generation in dielectrics by direct photoexcitations.However,plasmon-induced hot-carrier-based devices are far from practical applications due to the low quantum yield of hot carrier extraction.Emergent challenges include low hot carrier generation efficiency in metals,rapid energy loss of hot carriers,and severe charge recombination at the metal/dielectric interface.In this review,we provide a fundamental insight into the hot carrier generation,transport,injection,and diffusion into dielectrics based on the steady-state and time-resolved spectroscopic studies as well as theoretical calculations.Strategies to enhance hot carrier generation in metals and electron transfer into dielectrics are discussed in detail.Then,applications based on hot carrier transfer are introduced briefly.Finally,we provide our suggestions on future research endeavors.We believe this review will provide a valuable overall physical picture of plasmon-induced hot carrier applications for researchers.展开更多
基金the National Natural Science Foundation of China(61875253,62105338,and U20A20217)National Key Research and Development Program of China(2021YFA1401000)+1 种基金Sichuan Science and Technology Program(2021ZYCD001)Chinese Academy of Sciences Youth Innovation Promotion Association(2019371).
文摘The geometric phase concept has profound implications in many branches of physics,from condensed matter physics to quantum systems.Although geometric phase has a long research history,novel theories,devices,and applications are constantly emerging with developments going down to the subwavelength scale.Specifically,as one of the main approaches to implement gradient phase modulation along a thin interface,geometric phase metasurfaces composed of spatially rotated subwavelength artificial structures have been utilized to construct various thin and planar meta-devices.In this paper,we first give a simple overview of the development of geometric phase in optics.Then,we focus on recent advances in continuously shaped geometric phase metasurfaces,geometric–dynamic composite phase metasurfaces,and nonlinear and high-order linear Pancharatnam–Berry phase metasurfaces.Finally,conclusions and outlooks for future developments are presented.
基金supported by the Shanghai Pilot Program for Basic Research-Chinese Academy of Sciences,ShanghaiBranchNational Natural Science Foundation of China(Nos.12104471,U226720057,and 62105346)+3 种基金Key Research Program of Frontier Sciences,Chinese Academy of SciencesYouth Innovation Promotion Association of Chinese Academy of SciencesCAS Project for Young Scientists in Basic Research(No.YSBRO60)Shanghai Sailing Program(No.21YF1453900).
文摘Free-electron light sources feature extraordinary luminosity,directionality,and coherence,which has enabled significant scientific progress in fields including physics,chemistry,and biology.The next generation of light sources has aimed at compact radiation sources driven by free electrons,with the advantages of reduction in both space and cost.With the rapid development of ultra-intense and ultrashort lasers,great effort has been devoted to the quest for compact free-electron lasers(FELs).This review focuses on the current efforts and advancements in the development of compact FELs,with a particular emphasis on two notable paths:the development of compact accelerators and the construction of micro undulators based on innovative materials/structures or optical modulation of electrons.In addition,the physical essence of inverse Compton scattering is discussed,which offers remarkable capability to develop an optical undulator with a spatial period that matches the optical wavelength.Recent scientific developments and future directions for miniaturized and integrated free-electron coherent light sources are also reviewed.In the future,the prospect of generating ultrashort electron pulses will provide fascinating means of producing superradiant radiation,promising high brilliance and coherence even on a micro scale using optical micro undulators.
文摘In their recent review article Ghosh et al.provide an overview of room-temperature polaritonics,which may be also referred to as physics of liquid light[1].The quanta of liquid light,exciton polaritons,combine properties of photons and of excitons,electrically neutral semiconductor crystal quasiparticles.Polaritonics made tremendous steps forward in the 21st century thanks to the experimental observation of bosonic condensates and superfluids of exciton polaritons at elevated temperatures in a great variety of material systems.Coherent fluids of exciton polaritons can be efficiently controlled by laser light and/or by applied electric and magnetic fields.This opens ways to many applications,including but not limited to polariton lasing,optical switching,polariton simulators,neuromorphic computing,quantum computing,and polariton-induced superconductivity.Ghoch et al.provide a detailed analysis of the material systems suitable for room temperature polaritonics starting from wide-bandgap inorganic semiconductors such as GaN and ZnO,and carefully discuss also organic microcavities,perovskites,transition metal dichalcogenides,and hybrid structures.They discuss the advantages and disadvantages of these systems emphasizing recent experimental findings in each system.
文摘Epitaxial quantum dots(QDs)are high-quality semiconductor nanostructures that mimic atoms for their discrete energy levels.Developments of QDs date back to the early 1990s in quest of temperature-insensitive lasers.Since then,much effort has been devoted to studying the fundamental physical phenomena observed in those quantum-confined structures.Recently,the QD community has shifted its focus onto quantum photonics applications,motivated by the rapidly developing quantum science.The most prominent application for QDs is their use as a deterministic single-photon source—a non-classical emission of light that underpins quantum computation,communication,and sensing.The field has grown substantially within the last decade,shifting from controlled growth of isolated QDs to a full integration of ultra-pure QD single photon sources with photonic nanostructures[1–6].
基金X.L.acknowledges support from the Caltech Postdoctoral Prize Fellowship and the Institute for Quantum Information and Matter(IQIM).J.K.acknowledges support from the Robert A.Welch Foundation through Grant No.C-1509 and the U.S.Army Research Office through Grant No.W911NF-17-1-0259.
文摘Recent interest in developing fast spintronic devices and laser-controllable magnetic solids has sparked tremendous experimental and theoretical efforts to understand and manipulate ultrafast dynamics in materials.Studies of spin dynamics in the terahertz(THz)frequency range are particularly important for elucidating microscopic pathways toward novel device functionalities.Here,we review THz phenomena related to spin dynamics in rare-earth orthoferrites,a class of materials promising for antiferromagnetic spintronics.We expand this topic into a description of four key elements.(1)We start by describing THz spectroscopy of spin excitations for probing magnetic phase transitions in thermal equilibrium.While acoustic magnons are useful indicators of spin reorientation transitions,electromagnons that arise from dynamic magnetoelectric couplings serve as a signature of inversion-symmetry-breaking phases at low temperatures.(2)We then review the strong laser driving scenario,where the system is excited far from equilibrium and thereby subject to modifications to the free-energy landscape.Microscopic pathways for ultrafast laser manipulation of magnetic order are discussed.(3)Furthermore,we review a variety of protocols to manipulate coherent THz magnons in time and space,which are useful capabilities for antiferromagnetic spintronic applications.(4)Finally,new insights into the connection between dynamic magnetic coupling in condensed matter and the Dicke superradiant phase transition in quantum optics are provided.By presenting a review on an array of THz spin phenomena occurring in a single class of materials,we hope to trigger interdisciplinary efforts that actively seek connections between subfields of spintronics,which will facilitate the invention of new protocols of active spin control and quantum phase engineering.
文摘Two-dimensional(2D)materials,due to their exotic electromagnetic responses and strong interaction with light,have been intensively studied over the past decades since the discovery of graphene in 2004[1].Except for graphene,natural van der Waals(vdW)materials[2]also serve as indispensable members in the library of 2D materials,where adjacent atomic planes are bonded by weak vdW force so that monolayers can be readily obtained through methods such as mechanical exfoliation.
基金supported by the National Natural Science Foundation of China (Nos.61927820,61905201,and 62275221).
文摘Light carries energy and momentum,laying the physical foundation of optical manipulation that has facilitated advances in myriad scientific disciplines,ranging from biochemistry and robotics to quantum physics.Utilizing the momentum of light,optical tweezers have exemplified elegant light–matter interactions in which mechanical and optical momenta can be interchanged,whose effects are the most pronounced on micro and nano objects in fluid suspensions.In solid domains,the same momentum transfer becomes futile in the face of dramatically increased adhesion force.Effective implementation of optical manipulation should thereupon switch to the“energy”channel by involving auxiliary physical fields,which also coincides with the irresistible trend of enriching actuation mechanisms beyond sole reliance on light-momentum-based optical force.From this perspective,this review covers the developments of optical manipulation in schemes of both momentum and energy transfer,and we have correspondingly selected representative techniques to present.Theoretical analyses are provided at the beginning of this review followed by experimental embodiments,with special emphasis on the contrast between mechanisms and the practical realization of optical manipulation in fluid and solid domains.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030009)the National Natural Science Foundation of China(Nos.62235009,62035003,62205173,61935013,62375181,61975133,and 12104318)+1 种基金the Science and Technology Innovation Commission of Shenzhen(Nos.KQTD20170330110444030 and JCYJ20200109114018750)the Scientific Instrument Developing Project of Shenzhen University(No.2023YQ001).
文摘Diffractive optical elements(DOEs)are intricately designed devices with the purpose of manipulating light fields by precisely modifying their wavefronts.The concept of DOEs has its origins dating back to 1948 when D.Gabor first introduced holography.Subsequently,researchers introduced binary optical elements(BOEs),including computer-generated holograms(CGHs),as a distinct category within the realm of DOEs.This was the first revolution in optical devices.The next major breakthrough in light field manipulation occurred during the early 21st century,marked by the advent of metamaterials and metasurfaces.Metasurfaces are particularly appealing due to their ultra-thin,ultra-compact properties and their capacity to exert precise control over virtually every aspect of light fields,including amplitude,phase,polarization,wavelength/frequency,angular momentum,etc.The advancement of light field manipulation with micro/nano-structures has also enabled various applications in fields such as information acquisition,transmission,storage,processing,and display.In this review,we cover the fundamental science,cutting-edge technologies,and wide-ranging applications associated with micro/nano-scale optical devices for regulating light fields.We also delve into the prevailing challenges in the pursuit of developing viable technology for real-world applications.Furthermore,we offer insights into potential future research trends and directions within the realm of light field manipulation.
基金the financial support from the National Key R&D Program of China(2022YFA1404300)National Natural Science Foundation of China(91850204,92250304,62288101).
文摘The refractive-lens technique has been well developed over a long period of evolution,offering powerful imaging functionalities,such as microscopes,telescopes,and spectroscopes.Nevertheless,the ever-growing requirements continue to urge further enhanced imaging capabilities and upgraded devices that are more compact for convenience.Metamaterial as a fascinating concept has inspired unprecedented new explorations in physics,material science,and optics,not only in fundamental researches but also novel applications.Along with the imaging topic,this paper reviews the progress of the flat lens as an important branch of metamaterials,covering the early superlens with super-diffraction capability and current hot topics of metalenses including a paralleled strategy of multilevel diffractive lenses.Numerous efforts and approaches have been dedicated to areas ranging from the new fascinating physics to feasible applications.This review provides a clear picture of the flat-lens evolution from the perspective of metamaterial design,elucidating the relation and comparison between a superlens and metalens,and addressing derivative designs.Finally,application scenarios that favor the ultrathin lens technique are emphasized with respect to possible revolutionary imaging devices,followed by conclusive remarks and prospects.
文摘Richard Feynman’s famous 1959 lecture“There is plenty of room at the bottom”inspired scientists and engineers to focus on manipulating matter at the nanoscale[1].Optical tweezers,groundbreaking tools that use light to trap and move small particles with nanoscale precision,have revolutionized many fields such as materials science,biology,physics,and nanotechnology[2,3].For example,optical tweezers have enabled researchers to investigate the mechanical properties of biological molecules,study the behavior of colloidal suspensions,explore the movement of motor proteins,and investigate the directed assembly of nanoscale structures[4–6].
基金the Innovation Program of Shanghai Municipal Education Commission(2021-01-07-00-08-E00100)National Natural Science Foundation of China(11874155,91436211,11374104,12174110)+8 种基金Basic Research Project of Shanghai Science and Technology Commission(20JC1416100)Natural Science Foundation of Shanghai(17ZR1442900)Minhang Leading Talents(201971)Program of Scientific and Technological Innovation of Shanghai(17JC1400401)Shanghai Sailing Program(21YF1410800)China Post-doctoral Science Foundation(2020M681224)National Basic Research Program of China(2016YFA0302103)Shanghai Municipal Science and Technology Major Project(2019SHZDZX01)111 Project(B12024).
文摘The four-wave mixing process in atomic ensembles has many important applications in quantum information.We review recent progress on the generation of optical quantum states from the four-wave mixing process in hot atomic ensembles,including the production of two-beam,multi-beam,and multiplexed quantum correlated or entangled states.We also review the applications of these optical quantum states in implementing quantum information protocols,constructing SU(1,1)quantum interferometers,and realizing quantum plasmonic sensing.These applications indicate that the four-wave mixing process in hot atomic ensembles is a promising platform for quantum information processing,especially for implementing alloptical quantum information protocols,constructing SU(1,1)interferometers,and realizing quantum sensing.
基金supported by the POSCOPOSTECH-RIST Convergence Research Center program funded by POSCO,and the National Research Foundation (NRF)grant (NRF-2022M3C1A3081312)Y.Y.and D.K.O.acknowledge Hyundai Motor Chung Mong-Koo fellowships.Y.Y.acknowledges the NRF fellowship (NRF-2021R1A6A3A13038935)funded by the Ministry of Education,Republic of Korea.H.K.and N.J.acknowledge POSTECHIAN fellowships.
文摘Advancements in micro/nanofabrication have enabled the realization of practical micro/nanoscale photonic devices such as absorbers,solar cells,metalenses,and metaholograms.Although the performance of these photonic devices has been improved by enhancing the design flexibility of structural materials through advanced fabrication methods,achieving large-area and high-throughput fabrication of tiny structural materials remains a challenge.In this aspect,various technologies have been investigated for realizing the mass production of practical devices consisting of micro/nanostructural materials.This review describes the recent advancements in soft lithography,colloidal self-assembly,and block copolymer self-assembly,which are promising methods suitable for commercialization of photonic applications.In addition,we introduce low-cost and large-scale techniques realizing micro/nano devices with specific examples such as display technology and sensors.The inferences presented in this review are expected to function as a guide for promising methods of accelerating the mass production of various sub-wavelength-scale photonic devices.
文摘Surface plasmons(SPs),or SP polaritons,are electromagnetic(EM)surface waves that propagate freely along metal-dielectric interfaces while being tightly localized in the perpendicular direction due to the interaction with collective oscillations of electron plasma in the metal[1].Therefore,SPs become two-dimensional(2D)manifestations of EM waves,with potentially very large wavenumbers near the SP resonance,thereby paving the way for many exciting phenomena,such as light focusing beyond the notorious optical diffraction limit and directing EM energy to the nanoscale[2].
文摘Metamaterials,due to their incomparable capabilities in manipulating effective material parameters,have been attracting worldwide attention in the past two decades.In previous works,most metamaterials and metasurfaces focused on the material parameter steering in a continuous scale,which is regarded as“analog metamaterials/metasurfaces.”Since Cui et al.proposed the concept of digital coding and programmable metamaterials/metasurfaces in 2014[1],a new perspective to design metasurfaces has been opened up,bridging between electromagnetic physics and digital information for the first time.Coding metamaterials/metasurfaces have presented diverse physical principles and applications in electromagnetic field manipulations,further deriving many subdirections.In the process of exploration and enrichment in recent years,the coding metasurface has continuously demonstrated its powerful ability in information regulation and combination.Using this as a strong connection,the field has gradually grown into a new system called information metamaterials/metasurfaces[2,3].
基金the National Key Research and Development Program of China(2022YFA1404700 and 2021YFA1400100)National Natural Science Foundation of China(12074085)+4 种基金Natural Science Foundation of Shanghai(20JC1414601)Strategic Priority Research Program of Chinese Academy of Sciences(XDB30000000)the National Key Research and Development Program of China(2022YFA1403400)the National Natural Science Foundation of China(12274030 and 11704075)the China Postdoctoral Science Foundation(2020TQ0078).
文摘Low symmetry 2D materials with intrinsic in-plane anisotropic optical properties and high tunability provide a promising platform to explore and manipulate light–matter interactions.To date,dozens of in-plane anisotropic 2D materials with diverse band structures have been discovered.They exhibit rich optical properties,indicating great potential for novel applications in optics,photonics,and optoelectronics.In this paper,we thoroughly review the anisotropic optical properties and polaritons in many kinds of low symmetry 2D materials,aiming to elicit more research interest in this field.First,the optical properties of anisotropic 2D semiconductors,including interband absorption,photoluminescence,excitons,and band structure engineering for tuning optical responses,are introduced.Then fundamentals and advances in experiments of hyperbolic polaritons in anisotropic 2D materials,including phonon,plasmon,and exciton polaritons,are discussed.Finally,a perspective on promising research directions is given.
基金Q.Xiong gratefully acknowledges funding support from the National Natural Science Foundation of China(12020101003)the State Key Laboratory of Low-Dimensional Quantum Physics at Tsinghua University.S.Ghosh gratefully acknowledges the support from the Excellent Young Scientists Fund Program(Overseas)of the National Natural Science Foundation of China.R.Su and T.Liew gratefully acknowledge the funding support from Nanyang Technological University via a start-up grant and the Singapore Ministry of Education via the AcRF Tier 3 Programme“Geometrical Quantum Materials”(MOE2018-T3-1-002).
文摘The quest for realizing novel fundamental physical effects and practical applications in ambient conditions has led to tremendous interest in microcavity exciton polaritons working in the strong coupling regime at room temperature.In the past few decades,a wide range of novel semiconductor systems supporting robust exciton polaritons have emerged,which has led to the realization of various fascinating phenomena and practical applications.This paper aims to review recent theoretical and experimental developments of exciton polaritons operating at room temperature,and includes a comprehensive theoretical background,descriptions of intriguing phenomena observed in various physical systems,as well as accounts of optoelectronic applications.Specifically,an in-depth review of physical systems achieving room temperature exciton polaritons will be presented,including the early development of ZnO and GaN microcavities and other emerging systems such as organics,halide perovskite semiconductors,carbon nanotubes,and transition metal dichalcogenides.Finally,a perspective of outlooking future developments will be elaborated.
基金the Horizon 2020 Action Projects(648783(TOPOLOGICAL),734578(D-SPA),and 777714(NOCTORNO))the Research Grants Council of Hong Kong(AoE/P-502/20).
文摘Originally a pure mathematical concept,topology has been vigorously developed in various physical systems in recent years,and underlies many interesting phenomena such as the quantum Hall effect and quantum spin Hall effect.Its widespread influence in physics led the award of the 2016 Nobel Prize in Physics to this field.Topological photonics further expands the research field of topology to classical wave systems and holds promise for novel devices and applications,e.g.,topological quantum computation and topological lasers.Here,we review recent developments in topological photonics but focus mainly on their realizations based on metamaterials.Through artificially designed resonant units,metamaterials provide vast degrees of freedom for realizing various topological states,e.g.,the Weyl point,nodal line,Dirac point,topological insulator,and even the Yang monopole and Weyl surface in higher-dimensional synthetic spaces,wherein each specific topological nontrivial state endows novel metamaterial responses that originate from the feature of some high-energy physics.
基金supported by the National Natural Science Foundation of China(Nos.62005193,62135008,62075158,62175180,61735012,61935015,and 62025504)the U.S.National Science Foundation(No.2114103).
文摘Surface plasmons(SPs)are electromagnetic surface waves that propagate at the interface between a conductor and a dielectric.Due to their unique ability to concentrate light on two-dimensional platforms and produce very high local-field intensity,SPs have rapidly fueled a variety of fundamental advances and practical applications.In parallel,the development of metamaterials and metasurfaces has rapidly revolutionized the design concepts of traditional optical devices,fostering the exciting field of meta-optics.This review focuses on recent progress of meta-optics inspired SP devices,which are implemented by the careful design of subwavelength structures and the arrangement of their spatial distributions.Devices of general interest,including coupling devices,on-chip tailoring devices,and decoupling devices,as well as nascent SP applications empowered by sophisticated usage of meta-optics,are introduced and discussed.
基金the National Natural Science Foundation of China(NSFC)(62005195)L.Z.acknowledges support from NCCR QSIT and SNF project(200020_204069)J.L.acknowledges support from the National Key R&D Program of China(2018YFA0306100).
文摘Epitaxial quantum dots formed by III–V compound semiconductors are excellent sources of nonclassical photons,creating single photons and entangled multi-photon states on demand.Their semiconductor nature allows for a straightforward combination with mature integrated photonic technologies,leading to novel functional devices at the single-photon level.Integrating a quantum dot into a carefully engineered photonic cavity enables control of the radiative decay rate using the Purcell effect and the realization of photon–photon nonlinear gates.In this review,we introduce the basis of epitaxial quantum dots and discuss their applications as non-classical light sources.We highlight two interfaces—one between flying photons and the quantum-dot dipole,and the other between the photons and the spin.We summarize the recent development of integrated photonics and reconfigurable devices that have been combined with quantum dots or are suitable for hybrid integration.Finally,we provide an outlook of employing quantum-dot platforms for practical applications in large-scale quantum computation and the quantum Internet.
基金supported by the National Key Research and Development Program of China(Nos.2021YFA1400700 and 2022YFA1404300)the National Natural Science Foundation of China(Nos.51925204,12022403,22003066,62375123,and 12375008)the Excellent Research Program of Nanjing University(No.ZYJH005).
文摘Plasmonics has aroused tremendous interest in photophysics,nanophotonics,and metamaterials.The extreme field concentration of plasmonics offers the ultimate spatial and temporal light control,single-particle detection,and optical modulation.Plasmon decay of metal nanostructures into hot carriers extends the application into photocatalysis,photodetectors,photovoltaics,and ultrafast nanooptics.The generated hot electron–hole pairs are transferred into adjacent dielectrics,well known to be more efficient than the hot carrier generation in dielectrics by direct photoexcitations.However,plasmon-induced hot-carrier-based devices are far from practical applications due to the low quantum yield of hot carrier extraction.Emergent challenges include low hot carrier generation efficiency in metals,rapid energy loss of hot carriers,and severe charge recombination at the metal/dielectric interface.In this review,we provide a fundamental insight into the hot carrier generation,transport,injection,and diffusion into dielectrics based on the steady-state and time-resolved spectroscopic studies as well as theoretical calculations.Strategies to enhance hot carrier generation in metals and electron transfer into dielectrics are discussed in detail.Then,applications based on hot carrier transfer are introduced briefly.Finally,we provide our suggestions on future research endeavors.We believe this review will provide a valuable overall physical picture of plasmon-induced hot carrier applications for researchers.
