Plasmonic modes within metal nanostructures play a pivotal role in various nanophotonic applications.However,a significant challenge arises from the fixed shapes of nanostructures post-fabrication,resulting in limited...Plasmonic modes within metal nanostructures play a pivotal role in various nanophotonic applications.However,a significant challenge arises from the fixed shapes of nanostructures post-fabrication,resulting in limited modes under ordinary illumination.A promising solution lies in far-field control facilitated by spatial light modulators(SLMs),which enable on-site,real-time,and non-destructive manipulation of plasmon excitation.Through the robust modulation of the incident light using SLMs,this approach enables the generation,optimization,and dynamic control of surface plasmon polariton(SPP)and localized surface plasmon(LSP)modes.The versatility of this technique introduces a rich array of tunable degrees of freedom to plasmon-enhanced spectroscopy,offering novel approaches for signal optimization and functional expansion in this field.This paper provides a comprehensive review of the generation and modulation of SPP and LSP modes through far-field control with SLMs and highlights the diverse applications of this optical technology in plasmon-enhanced spectroscopy.展开更多
The basic indexes of all-optical integrated photonic circuits include high-density integration,ultrafast response and ultralow energy consumption.Traditional methods mainly adopt conventional micro/nano-structures.The...The basic indexes of all-optical integrated photonic circuits include high-density integration,ultrafast response and ultralow energy consumption.Traditional methods mainly adopt conventional micro/nano-structures.The overall size of the circuit is large,usually reaches hundreds of microns.Besides,it is difficult to balance the ultrafast response and ultra-low energy consumption problem,and the crosstalk between two traditional devices is difficult to overcome.Here,we propose and experimentally demonstrate an approach based on inverse design method to realize a high-density,ultrafast and ultra-low energy consumption integrated photonic circuit with two all-optical switches controlling the input states of an all-optical XOR logic gate.The feature size of the whole circuit is only 2.5μm×7μm,and that of a single device is 2μm×2μm.The distance between two adjacent devices is as small as 1.5μm,within wavelength magnitude scale.Theoretical response time of the circuit is 150 fs,and the threshold energy is within 10 fJ/bit.We have also considered the crosstalk problem.The circuit also realizes a function of identifying two-digit logic signal results.Our work provides a new idea for the design of ultrafast,ultra-low energy consumption all-optical devices and the implementation of high-density photonic integrated circuits.展开更多
The rapid development of information technology has fueled an ever-increasing demand for ultrafast and ultralow-en-ergy-consumption computing.Existing computing instruments are pre-dominantly electronic processors,whi...The rapid development of information technology has fueled an ever-increasing demand for ultrafast and ultralow-en-ergy-consumption computing.Existing computing instruments are pre-dominantly electronic processors,which use elec-trons as information carriers and possess von Neumann architecture featured by physical separation of storage and pro-cessing.The scaling of computing speed is limited not only by data transfer between memory and processing units,but also by RC delay associated with integrated circuits.Moreover,excessive heating due to Ohmic losses is becoming a severe bottleneck for both speed and power consumption scaling.Using photons as information carriers is a promising alternative.Owing to the weak third-order optical nonlinearity of conventional materials,building integrated photonic com-puting chips under traditional von Neumann architecture has been a challenge.Here,we report a new all-optical comput-ing framework to realize ultrafast and ultralow-energy-consumption all-optical computing based on convolutional neural networks.The device is constructed from cascaded silicon Y-shaped waveguides with side-coupled silicon waveguide segments which we termed“weight modulators”to enable complete phase and amplitude control in each waveguide branch.The generic device concept can be used for equation solving,multifunctional logic operations as well as many other mathematical operations.Multiple computing functions including transcendental equation solvers,multifarious logic gate operators,and half-adders were experimentally demonstrated to validate the all-optical computing performances.The time-of-flight of light through the network structure corresponds to an ultrafast computing time of the order of several picoseconds with an ultralow energy consumption of dozens of femtojoules per bit.Our approach can be further expan-ded to fulfill other complex computing tasks based on non-von Neumann architectures and thus paves a new way for on-chip all-optical computing.展开更多
The rotation control of particles in optical tweezers is often subject to the spin or orbit angular momentum induced optical torque,which is susceptible to the mechanical and morphological properties of individual par...The rotation control of particles in optical tweezers is often subject to the spin or orbit angular momentum induced optical torque,which is susceptible to the mechanical and morphological properties of individual particle.Here we report on a robust and high-speed rotation control in optical tweezers by using a novel linear polarization synthesis based on optical heterodyne interference between two circularly polarized lights with opposite handedness.The synthesized linear polarization can be rotated in a hopping-free scheme at arbitrary speed determined electronically by the heterodyne frequency between two laser fields.The experimental demonstration of a trapped vaterite particle in water shows that the precisely controlled rotation frequency of 300 Hz can be achieved.The proposed method will find promising applications in optically driven micro-gears,fluidic pumps and rotational micro-rheology.展开更多
The two-dimensional electron gas(2DEG)generated at the LaAlO3/SrTiO3 interface has been in the focus of oxides re-search since its first discovery.Although oxygen vacancies play an important role in the generation of ...The two-dimensional electron gas(2DEG)generated at the LaAlO3/SrTiO3 interface has been in the focus of oxides re-search since its first discovery.Although oxygen vacancies play an important role in the generation of the insulator-to-metal transition of the SrTiO3 bare surface,their contribution at the LaAlO3/SrTiO3 interface remains unclear.In this work,we investigated a LaAlO3/SrTiO3 heterostructure with regional distribution of defect-based localized polar sites at the interface.Using static and time-resolved threshold photoemission electron microscopy,we prove that oxygen vacan-cies are induced near those polar sites,resulting in the increase of carrier density of the 2DEG states.In addition,oxy-gen-related surface states were uncovered,which we attributed to the release of lattice oxygen during the formation of oxygen vacancies.Such effects are mainly found spatially located around the defect sites at the buried interface,while other regions remain unaffected.Our results confirm that the itinerant electrons induced by oxygen vacancies can coex-ist with the charge transfer mechanism in the LaAlO3/SrTiO3 heterostructure,together leading to the formation of the metallic interface.These observations provide fundamental insights into the nature of LaAlO3/SrTiO3 interface based 2DEG and unique perspectives for potential applications.展开更多
We investigated the plasmon-exciton interactions in an individual gold nanorod(GNR)with monolayer MoS2 at room temperature with the single-particle spectroscopy technique.To control the plasmon-exciton interaction,we ...We investigated the plasmon-exciton interactions in an individual gold nanorod(GNR)with monolayer MoS2 at room temperature with the single-particle spectroscopy technique.To control the plasmon-exciton interaction,we tuned the local surface plasmon resonance of an individual GNR in-situ by employing the photothermal reshaping effect.The scattering spectra of the GNR-MoS2 hybrids exhibited two dips at the frequencies of the A and B excitons of monolayer MoS2,which were caused by the plasmon-induced resonance energy transfer effect.The resonance energy transfer rate increased when the surface plasmon resonance of the nanorod matched well with the exciton transition energy.Also,we demonstrated that the plasmon-enhanced fluorescence process dominated the photoluminescence of the GNR-MoS2 hybrid.These results provide a flexible way to control the plasmon-exciton interaction in an all-solid-state operating system at room temperature.展开更多
Quantum communications aim to share encryption keys between the transmitters and receivers governed by the laws of quantum mechanics.Integrated quantum photonics offers significant advantages of dense integration,high...Quantum communications aim to share encryption keys between the transmitters and receivers governed by the laws of quantum mechanics.Integrated quantum photonics offers significant advantages of dense integration,high stability and scalability,which enables a vital platform for the implementation of quantum information processing and quantum communications.This article reviews recent experimental progress and advances in the development of integrated quantum photonic devices and systems for quantum communications and quantum networks.展开更多
Intrinsic luminescence from metal nanostructures complements conventional scattering and absorption behaviors and has many interesting and unique features. This phenomenon has attracted considerable research attention...Intrinsic luminescence from metal nanostructures complements conventional scattering and absorption behaviors and has many interesting and unique features. This phenomenon has attracted considerable research attention in recent years because of its various potential applications. In this review, we discuss recent advances in this field, summarize potential applications for this type of luminescence, and compare theoretical models to describe the phenomena. On the basis of the excitation process, the characteristic features and corresponding applications are summarized briefly in three parts, namely, continuous-wave light, pulsed laser, and electron excitation. A universal physical mechanism likely operates in all these emission processes regardless of differences in the excitation processes; however, there remains some debate surrounding the details of the theoretical model. Further insight into these luminescence phenomena will not only provide a deeper fundamental understanding of plasmonic nanostructures but will also advance and extend their applications.展开更多
A surrounding electromagnetic environment can engineer spontaneous emissions from quantum emitters through the Purcell effect.For instance,a plasmonic antenna can efficiently confine an electromagnetic field and enhan...A surrounding electromagnetic environment can engineer spontaneous emissions from quantum emitters through the Purcell effect.For instance,a plasmonic antenna can efficiently confine an electromagnetic field and enhance the fluorescent process.In this study,we demonstrate that a photonic microcavity can modulate plasmon-enhanced fluorescence by engineering the local electromagnetic environment.Consequently,we constructed a plasmon-enhanced emitter(PE-emitter),which comprised a nanorod and a nanodiamond,using the nanomanipulation technique.Furthermore,we controlled a polystyrene sphere approaching the PE-emitter and investigated in situ the associated fluorescent spectrum and lifetime.The emission of PE-emitter can be enhanced resonantly at the photonic modes as compared to that within the free spectral range.The spectral shape modulated by photonic modes is independent of the separation between the PS sphere and PEemitter.The band integral of the fluorescence decay rate can be enhanced or suppressed after the PS sphere couples to the PE-emitters,depending on the coupling strength between the plasmonic antenna and the photonic cavity.These findings can be utilized in sensing and imaging applications.展开更多
Modulation of topological phase transition has been pursued by researchers in both condensed matter and optics research fields,and has been realized in Euclidean systems,such as topological photonic crystals,topologic...Modulation of topological phase transition has been pursued by researchers in both condensed matter and optics research fields,and has been realized in Euclidean systems,such as topological photonic crystals,topological metamaterials,and coupled resonator arrays.However,the spin-controlled topological phase transition in non-Euclidean space has not yet been explored.Here,we propose a non-Euclidean configuration based on Mobius rings,and we demonstrate the spin-controlled transition between the topological edge state and the bulk state.The Mobius ring,which is designed to have an 8πperiod,has a square cross section at the twist beginning and the length/width evolves adiabatically along the loop,accompanied by conversion from transverse electric to transverse magnetic modes resulting from the spin-locked effect.The 8πperiod Mobius rings are used to construct Su–Schrieffer–Heeger configuration,and the configuration can support the topological edge states excited by circularly polarized light,and meanwhile a transition from the topological edge state to the bulk state can be realized by controlling circular polarization.In addition,the spin-controlled topological phase transition in non-Euclidean space is feasible for both Hermitian and non-Hermitian cases in 2D systems.This work provides a new degree of polarization to control topological photonic states based on the spin of Mobius rings and opens a way to tune the topological phase in non-Euclidean space.展开更多
The topological photonics plays an important role in the fields of fundamental physics and photonic devices.The traditional method of designing topological system is based on the momentum space,which is not a direct a...The topological photonics plays an important role in the fields of fundamental physics and photonic devices.The traditional method of designing topological system is based on the momentum space,which is not a direct and convenient way to grasp the topological properties,especially for the perturbative structures or coupled systems.Here,we propose an interdisciplinary approach to study the topological systems in real space through combining the information entropy and topological photonics.As a proof of concept,the Kagome model has been analyzed with information entropy.We reveal that the bandgap closing does not correspond to the topological edge state disappearing.This method can be used to identify the topological phase conveniently and directly,even the systems with perturbations or couplings.As a promotional validation,Su-Schrieffer-Heeger model and the valley-Hall photonic crystal have also been studied based on the information entropy method.This work provides a method to study topological photonic phase based on information theory,and brings inspiration to analyze the physical properties by taking advantage of interdisciplinarity.展开更多
Simulating the dynamic evolution of physical and molecular systems in a quantum computer is of fundamental interest in many applications.The implementation of dynamics simulation requires efficient quantum algorithms....Simulating the dynamic evolution of physical and molecular systems in a quantum computer is of fundamental interest in many applications.The implementation of dynamics simulation requires efficient quantum algorithms.The Lie-Trotter-Suzuki approximation algorithm,also known as the Trotterization,is basic in Hamiltonian dynamics simulation.A multi-product algorithm that is a linear combination of multiple Trotterizations has been proposed to improve the approximation accuracy.However,implementing such multiproduct Trotterization in quantum computers remains challenging due to the requirements of highly controllable and precise quantum entangling operations with high success probability.Here,we report a programmable integrated-photonic quantum simulator based on a linear combination of unitaries,which can be tailored for implementing the linearly combined multiple Trotterizations,and on the simulator we benchmark quantum simulation of Hamiltonian dynamics.We modify the multi-product algorithm by integrating it with oblivious amplitude amplification to simultaneously reach high simulation precision and high success probability.The quantum simulator is devised and fabricated on a large-scale silicon-photonic quantum chip,which allows the initialization,manipulation,and measurement of arbitrary four-qubit states and linearly combined unitary gates.As an example,the quantum simulator is reprogrammed to emulate the dynamics of an electron spin and nuclear spin coupled system.This work promises the practical dynamics simulations of real-world physical and molecular systems in future large-scale quantum computers.展开更多
Anomalous Floquet topological insulators with vanishing Chern numbers but supporting chiral edge modes are attracting more and more attention.Since the existing anomalous Floquet topological insulators usually support...Anomalous Floquet topological insulators with vanishing Chern numbers but supporting chiral edge modes are attracting more and more attention.Since the existing anomalous Floquet topological insulators usually support only one kind of chiral edge mode even at a large lattice size,they are unscalable and unapplicable for multistate topological quantum systems.Recently,fractal topological insulators with self-similarity have been explored to support more nontrivial modes.Here,we demonstrate the first experimental realization of fractal photonic anomalous Floquet topological insulators based on dual Sierpinski carpet consisting of directional couplers using the femtosecond laser direct writing.The fabricated lattices support much more kinds of chiral edge states with fewer waveguides and enable perfect hopping of quantum states with near unit transfer efficiency.Instead of zero-dimensional bound modes for quantum state transport in previous laser direct-written topological insulators,we generate multiple propagating single-photon chiral edge states in the fractal lattice and observe high-visibility quantum interferences.These suggest the successful realization of highly indistinguishable single-photon chiral edge states,which can be applied in various quantum operations.This work provides the potential for enhancing the multi-fold manipulation of quantum states,enlarging the encodable quantum information capacity in a single lattice via high-dimensional encoding and many other fractal applications.展开更多
Nonreciprocal interlayer coupling is difcult to practically implement in bilayer non-Hermitian topological photonic systems.In this work,we identify a similarity transformation between the Hamiltonians of systems with...Nonreciprocal interlayer coupling is difcult to practically implement in bilayer non-Hermitian topological photonic systems.In this work,we identify a similarity transformation between the Hamiltonians of systems with nonreciprocal interlayer coupling and on-site gain/loss.The similarity transformation is widely applicable,and we show its application in one-and two-dimensional bilayer topological systems as examples.The bilayer non-Hermitian system with nonreciprocal interlayer coupling,whose topological number can be defned using the gauge-smoothed Wilson loop,is topologically equivalent to the bilayer system with on-site gain/loss.We also show that the topological number of bilayer non-Hermitian C6v-typed domaininduced topological interface states can be defned in the same way as in the case of the bilayer non-Hermitian Su–Schrieffer–Heeger model.Our results show the relations between two microscopic provenances of the non-Hermiticity and provide a universal and convenient scheme for constructing and studying nonreciprocal interlayer coupling in bilayer non-Hermitian topological systems.This scheme is useful for observation of non-Hermitian skin efect in three-dimensional systems.展开更多
Hybrid metal-dielectric structures combine the advantages of both metal and dielectric materials,enabling high-confined but low-loss magnetic and electric resonances through deliberate arrangements.However,their poten...Hybrid metal-dielectric structures combine the advantages of both metal and dielectric materials,enabling high-confined but low-loss magnetic and electric resonances through deliberate arrangements.However,their potential for enhancing magnetic emission has yet to be fully explored.Here,we study the magnetic and electric Purcell enhancement supported by a hybrid structure composed of a dielectric nanoring and a silver nanorod.This structure enables low Ohmic loss and highlyconfined field under the mode hybridization of magnetic resonances on a nanoring and electric resonances on a nanorod in the optical communication band.Thus,the 60-fold magnetic Purcell enhancement and 45-fold electric Purcell enhancement can be achieved.Over 90%of the radiation can be transmitted to the far field.For the sufficiently large Purcell enhancement,the position of emitter has a tolerance of several tens of nanometers,which brings convenience to experimental fabrications.Moreover,an array formed by this hybrid nanostructure can further enhance the magnetic Purcell factors.The system provides a feasible option to selectively excite magnetic and electric emission in integrated photonic circuits.It may also facilitate brighter magnetic emission sources and light-emitting metasurfaces with a more straightforward design.展开更多
Chiral sum-frequency generation(SFG)has proven to be a versatile spectroscopic and imaging tool for probing chirality.However,due to polarization restriction,the conventional chiral SFG microscopes have mostly adopted...Chiral sum-frequency generation(SFG)has proven to be a versatile spectroscopic and imaging tool for probing chirality.However,due to polarization restriction,the conventional chiral SFG microscopes have mostly adopted noncollinear beam configurations,which only partially cover the aperture of microscope and strongly spoil the spatial resolution.In this study,we report the first experimental demonstration of collinear chiral SFG microscopy,which fundamentally supports diffraction-limited resolution.This advancement is attributed to the collinear focus of a radially polarized vectorial beam and a linearly polarized(LP)beam.The tightly focused vectorial beam has a very strong longitudinal component,which interacts with the LP beam and produces the chiral SFG.The collinear configuration can utilize the full aperture and thus push the spatial resolution close to the diffraction limit.This technique can potentially boost the understanding of chiral systems.展开更多
For crystals, depressed cladding waveguides have advantages such as preservation of the spectroscopic as well as non-linear properties and the capability to guide both horizontal and vertical polarization modes, but f...For crystals, depressed cladding waveguides have advantages such as preservation of the spectroscopic as well as non-linear properties and the capability to guide both horizontal and vertical polarization modes, but fabrication is always quite time consuming. In addition, it is usually difficult to couple modes propagating in different depressed cladding waveguides through evanescent field overlap, so it is often required to dynamically reconfigure photonic waveguide devices using external fields for classical or quantum applications. Here, we experimentally demonstrate the single-scan femtosecond laser transverse writing of depressed cladding waveguides to form a 2 × 2 directional coupler inside lithium niobate crystal, which is integrated with two deeply embedded microelectrodes on both sides of the interaction region to reconfigure the coupling. By focal field engineering of the femtosecond laser, we specially generate a three-dimensional longitudinally oriented ring-shaped focal intensity profile composed of 16 discrete spots to simultaneously write the entire cladding region. The fabricated waveguides exhibit good single guided modes in two orthogonal polarizations at 1550 nm. By applying voltage to the deeply embedded microelectrodes fabricated with the femtosecond laser ablation followed by selective electroless plating, we successfully facilitate the light coupling from the input arm to the cross arm and thus actively tune the splitting ratio. These results open new important perspectives in the efficient fabrication of reconfigurable complex three-dimensional devices in crystals based on depressed cladding waveguides.展开更多
Optical microcavities have attracted strong research interests,for their unique property of confining photons for a long time in small volumes,which significantly enhances light–matter interaction[1].In recent decade...Optical microcavities have attracted strong research interests,for their unique property of confining photons for a long time in small volumes,which significantly enhances light–matter interaction[1].In recent decades,various fabrication techniques of microcavities with higher quality factors(Q)and smaller mode volumes(V_m)have been developed,pushing forward studies from fundamental physics to functional photonics devices.Microcavity optomechanics provides an ideal platform for exploring the quantum nature of macroscopic objects[2]。展开更多
The metal halide perovskite materials demonstrate outstanding performance in photovoltaics because of their excellent optoelectronic properties (1-7)The perovskite solar cells (PSCs) exhibiting outstanding efficiency ...The metal halide perovskite materials demonstrate outstanding performance in photovoltaics because of their excellent optoelectronic properties (1-7)The perovskite solar cells (PSCs) exhibiting outstanding efficiency [8,9], high power-per-weight [10], and excellent radiation resistance[11-13] are considered to be promising for developing the new-generation energy technology for space application.展开更多
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2020B0301030009)the National Key Research and Development Program of China(Grant No.2022YFA1604304)the National Natural Science Foundation of China(Grant No.92250305).
文摘Plasmonic modes within metal nanostructures play a pivotal role in various nanophotonic applications.However,a significant challenge arises from the fixed shapes of nanostructures post-fabrication,resulting in limited modes under ordinary illumination.A promising solution lies in far-field control facilitated by spatial light modulators(SLMs),which enable on-site,real-time,and non-destructive manipulation of plasmon excitation.Through the robust modulation of the incident light using SLMs,this approach enables the generation,optimization,and dynamic control of surface plasmon polariton(SPP)and localized surface plasmon(LSP)modes.The versatility of this technique introduces a rich array of tunable degrees of freedom to plasmon-enhanced spectroscopy,offering novel approaches for signal optimization and functional expansion in this field.This paper provides a comprehensive review of the generation and modulation of SPP and LSP modes through far-field control with SLMs and highlights the diverse applications of this optical technology in plasmon-enhanced spectroscopy.
基金the National Key Research and Development Program of China under Grant No.2018YFB2200403the National Natural Science Foundation of China under Grant Nos.11734001,91950204,92150302.
文摘The basic indexes of all-optical integrated photonic circuits include high-density integration,ultrafast response and ultralow energy consumption.Traditional methods mainly adopt conventional micro/nano-structures.The overall size of the circuit is large,usually reaches hundreds of microns.Besides,it is difficult to balance the ultrafast response and ultra-low energy consumption problem,and the crosstalk between two traditional devices is difficult to overcome.Here,we propose and experimentally demonstrate an approach based on inverse design method to realize a high-density,ultrafast and ultra-low energy consumption integrated photonic circuit with two all-optical switches controlling the input states of an all-optical XOR logic gate.The feature size of the whole circuit is only 2.5μm×7μm,and that of a single device is 2μm×2μm.The distance between two adjacent devices is as small as 1.5μm,within wavelength magnitude scale.Theoretical response time of the circuit is 150 fs,and the threshold energy is within 10 fJ/bit.We have also considered the crosstalk problem.The circuit also realizes a function of identifying two-digit logic signal results.Our work provides a new idea for the design of ultrafast,ultra-low energy consumption all-optical devices and the implementation of high-density photonic integrated circuits.
基金financial supports from the National Key Research and Development Program of China(2018YFB2200403)National Natural Sci-ence Foundation of China(NSFC)(61775003,11734001,91950204,11527901,11604378,91850117).
文摘The rapid development of information technology has fueled an ever-increasing demand for ultrafast and ultralow-en-ergy-consumption computing.Existing computing instruments are pre-dominantly electronic processors,which use elec-trons as information carriers and possess von Neumann architecture featured by physical separation of storage and pro-cessing.The scaling of computing speed is limited not only by data transfer between memory and processing units,but also by RC delay associated with integrated circuits.Moreover,excessive heating due to Ohmic losses is becoming a severe bottleneck for both speed and power consumption scaling.Using photons as information carriers is a promising alternative.Owing to the weak third-order optical nonlinearity of conventional materials,building integrated photonic com-puting chips under traditional von Neumann architecture has been a challenge.Here,we report a new all-optical comput-ing framework to realize ultrafast and ultralow-energy-consumption all-optical computing based on convolutional neural networks.The device is constructed from cascaded silicon Y-shaped waveguides with side-coupled silicon waveguide segments which we termed“weight modulators”to enable complete phase and amplitude control in each waveguide branch.The generic device concept can be used for equation solving,multifunctional logic operations as well as many other mathematical operations.Multiple computing functions including transcendental equation solvers,multifarious logic gate operators,and half-adders were experimentally demonstrated to validate the all-optical computing performances.The time-of-flight of light through the network structure corresponds to an ultrafast computing time of the order of several picoseconds with an ultralow energy consumption of dozens of femtojoules per bit.Our approach can be further expan-ded to fulfill other complex computing tasks based on non-von Neumann architectures and thus paves a new way for on-chip all-optical computing.
基金the National Natural Science Foundation of China(91750203 and 91850111)State Key Laboratory of Applied Optics,Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences and the High-performance Computing Platform of Peking University.
文摘The rotation control of particles in optical tweezers is often subject to the spin or orbit angular momentum induced optical torque,which is susceptible to the mechanical and morphological properties of individual particle.Here we report on a robust and high-speed rotation control in optical tweezers by using a novel linear polarization synthesis based on optical heterodyne interference between two circularly polarized lights with opposite handedness.The synthesized linear polarization can be rotated in a hopping-free scheme at arbitrary speed determined electronically by the heterodyne frequency between two laser fields.The experimental demonstration of a trapped vaterite particle in water shows that the precisely controlled rotation frequency of 300 Hz can be achieved.The proposed method will find promising applications in optically driven micro-gears,fluidic pumps and rotational micro-rheology.
基金supported by the National Key Research and Development Program of China under Grant Nos.2018YFB2200403 and 2018YFA0704404the National Natural Science Foundation of China under Grant Nos.61775003,11734001,91950204,11527901+1 种基金Beijing Municipal Science&Technology Commission No.Z191100007219001support by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)-TRR 173-268565370(projects A02).
文摘The two-dimensional electron gas(2DEG)generated at the LaAlO3/SrTiO3 interface has been in the focus of oxides re-search since its first discovery.Although oxygen vacancies play an important role in the generation of the insulator-to-metal transition of the SrTiO3 bare surface,their contribution at the LaAlO3/SrTiO3 interface remains unclear.In this work,we investigated a LaAlO3/SrTiO3 heterostructure with regional distribution of defect-based localized polar sites at the interface.Using static and time-resolved threshold photoemission electron microscopy,we prove that oxygen vacan-cies are induced near those polar sites,resulting in the increase of carrier density of the 2DEG states.In addition,oxy-gen-related surface states were uncovered,which we attributed to the release of lattice oxygen during the formation of oxygen vacancies.Such effects are mainly found spatially located around the defect sites at the buried interface,while other regions remain unaffected.Our results confirm that the itinerant electrons induced by oxygen vacancies can coex-ist with the charge transfer mechanism in the LaAlO3/SrTiO3 heterostructure,together leading to the formation of the metallic interface.These observations provide fundamental insights into the nature of LaAlO3/SrTiO3 interface based 2DEG and unique perspectives for potential applications.
基金This work was supported by the National Key Research and Development Program of China(grant No.2018YFB2200401)the National Natural Science Foundation of China(grant Nos.91950111,61521004 and 11527901).
文摘We investigated the plasmon-exciton interactions in an individual gold nanorod(GNR)with monolayer MoS2 at room temperature with the single-particle spectroscopy technique.To control the plasmon-exciton interaction,we tuned the local surface plasmon resonance of an individual GNR in-situ by employing the photothermal reshaping effect.The scattering spectra of the GNR-MoS2 hybrids exhibited two dips at the frequencies of the A and B excitons of monolayer MoS2,which were caused by the plasmon-induced resonance energy transfer effect.The resonance energy transfer rate increased when the surface plasmon resonance of the nanorod matched well with the exciton transition energy.Also,we demonstrated that the plasmon-enhanced fluorescence process dominated the photoluminescence of the GNR-MoS2 hybrid.These results provide a flexible way to control the plasmon-exciton interaction in an all-solid-state operating system at room temperature.
基金support from the Natural Science Foundation of China(61975001)National Key R&D Program of China(2018YFB1107205)+1 种基金Beijing Natural Science Foundation(Z190005)the Key R&D Program of Guangdong Province(2018B030329001).
文摘Quantum communications aim to share encryption keys between the transmitters and receivers governed by the laws of quantum mechanics.Integrated quantum photonics offers significant advantages of dense integration,high stability and scalability,which enables a vital platform for the implementation of quantum information processing and quantum communications.This article reviews recent experimental progress and advances in the development of integrated quantum photonic devices and systems for quantum communications and quantum networks.
文摘Intrinsic luminescence from metal nanostructures complements conventional scattering and absorption behaviors and has many interesting and unique features. This phenomenon has attracted considerable research attention in recent years because of its various potential applications. In this review, we discuss recent advances in this field, summarize potential applications for this type of luminescence, and compare theoretical models to describe the phenomena. On the basis of the excitation process, the characteristic features and corresponding applications are summarized briefly in three parts, namely, continuous-wave light, pulsed laser, and electron excitation. A universal physical mechanism likely operates in all these emission processes regardless of differences in the excitation processes; however, there remains some debate surrounding the details of the theoretical model. Further insight into these luminescence phenomena will not only provide a deeper fundamental understanding of plasmonic nanostructures but will also advance and extend their applications.
基金Project supported by the National Key Research and Development Program of China(Grant No.2018YFB2200401)the Major Project of Basic and Applied Basic Research of Guangdong Province,China(Grant No.2020B0301030009)the National Natural Science Foundation of China(Grant Nos.91950111,61521004,and 11527901).
文摘A surrounding electromagnetic environment can engineer spontaneous emissions from quantum emitters through the Purcell effect.For instance,a plasmonic antenna can efficiently confine an electromagnetic field and enhance the fluorescent process.In this study,we demonstrate that a photonic microcavity can modulate plasmon-enhanced fluorescence by engineering the local electromagnetic environment.Consequently,we constructed a plasmon-enhanced emitter(PE-emitter),which comprised a nanorod and a nanodiamond,using the nanomanipulation technique.Furthermore,we controlled a polystyrene sphere approaching the PE-emitter and investigated in situ the associated fluorescent spectrum and lifetime.The emission of PE-emitter can be enhanced resonantly at the photonic modes as compared to that within the free spectral range.The spectral shape modulated by photonic modes is independent of the separation between the PS sphere and PEemitter.The band integral of the fluorescence decay rate can be enhanced or suppressed after the PS sphere couples to the PE-emitters,depending on the coupling strength between the plasmonic antenna and the photonic cavity.These findings can be utilized in sensing and imaging applications.
基金supported by the National Natural Science Foundation of China(Grant Nos.91950204,92150302,and 12274031)the Innovation Program for Quantum Science and Technology(No.2021ZD0301502)Beijing Institute of Technology Research Fund Program for Teli Young Fellows,Beijing Institute of Technology Science and Technology Innovation Plan Innovative Talents Science,and Technology Funding Special Plan(No.2022CX01006).
文摘Modulation of topological phase transition has been pursued by researchers in both condensed matter and optics research fields,and has been realized in Euclidean systems,such as topological photonic crystals,topological metamaterials,and coupled resonator arrays.However,the spin-controlled topological phase transition in non-Euclidean space has not yet been explored.Here,we propose a non-Euclidean configuration based on Mobius rings,and we demonstrate the spin-controlled transition between the topological edge state and the bulk state.The Mobius ring,which is designed to have an 8πperiod,has a square cross section at the twist beginning and the length/width evolves adiabatically along the loop,accompanied by conversion from transverse electric to transverse magnetic modes resulting from the spin-locked effect.The 8πperiod Mobius rings are used to construct Su–Schrieffer–Heeger configuration,and the configuration can support the topological edge states excited by circularly polarized light,and meanwhile a transition from the topological edge state to the bulk state can be realized by controlling circular polarization.In addition,the spin-controlled topological phase transition in non-Euclidean space is feasible for both Hermitian and non-Hermitian cases in 2D systems.This work provides a new degree of polarization to control topological photonic states based on the spin of Mobius rings and opens a way to tune the topological phase in non-Euclidean space.
基金supported by the National Natural Science Foundation of China(Grant Nos.92150302,12274031 and 62175009)the Innovation Program for Quantum Science and Technology(No.2021ZD0301500)+3 种基金Beijing Institute of Technology Research Fund Program for Teli Young Fellows,Beijing Institute of Technology Science and Technology Innovation Plan Innovative Talents Science and Technology Funding Special Plan(2022CX01006)Open Research Fund Program of the State Key Laboratory of Low-Dimensional Quantum Physics(No.KF202114)the Natural Science Foundation of Hebei Province(No.A2021201009)China Postdoctoral Science Foundation(2023M740121).
文摘The topological photonics plays an important role in the fields of fundamental physics and photonic devices.The traditional method of designing topological system is based on the momentum space,which is not a direct and convenient way to grasp the topological properties,especially for the perturbative structures or coupled systems.Here,we propose an interdisciplinary approach to study the topological systems in real space through combining the information entropy and topological photonics.As a proof of concept,the Kagome model has been analyzed with information entropy.We reveal that the bandgap closing does not correspond to the topological edge state disappearing.This method can be used to identify the topological phase conveniently and directly,even the systems with perturbations or couplings.As a promotional validation,Su-Schrieffer-Heeger model and the valley-Hall photonic crystal have also been studied based on the information entropy method.This work provides a method to study topological photonic phase based on information theory,and brings inspiration to analyze the physical properties by taking advantage of interdisciplinarity.
基金Innovation Program for Quantum Science and Technology(2021ZD0301500)Key R&D Program of Guangdong Province(2018B030329001)+2 种基金Beijing Natural Science Foundation(Z190005,Z220008)National Natural Science Foundation of China(12325410,61975001,62235001)National Key Research and Development Program of China(2019YFA0308702)。
文摘Simulating the dynamic evolution of physical and molecular systems in a quantum computer is of fundamental interest in many applications.The implementation of dynamics simulation requires efficient quantum algorithms.The Lie-Trotter-Suzuki approximation algorithm,also known as the Trotterization,is basic in Hamiltonian dynamics simulation.A multi-product algorithm that is a linear combination of multiple Trotterizations has been proposed to improve the approximation accuracy.However,implementing such multiproduct Trotterization in quantum computers remains challenging due to the requirements of highly controllable and precise quantum entangling operations with high success probability.Here,we report a programmable integrated-photonic quantum simulator based on a linear combination of unitaries,which can be tailored for implementing the linearly combined multiple Trotterizations,and on the simulator we benchmark quantum simulation of Hamiltonian dynamics.We modify the multi-product algorithm by integrating it with oblivious amplitude amplification to simultaneously reach high simulation precision and high success probability.The quantum simulator is devised and fabricated on a large-scale silicon-photonic quantum chip,which allows the initialization,manipulation,and measurement of arbitrary four-qubit states and linearly combined unitary gates.As an example,the quantum simulator is reprogrammed to emulate the dynamics of an electron spin and nuclear spin coupled system.This work promises the practical dynamics simulations of real-world physical and molecular systems in future large-scale quantum computers.
基金National Natural Science Foundation of China(12134001,11527901,61590933)National Key Research and Development Program of China(2018YFB1107205,2016YFA0301302)+1 种基金Joint Fund for Equipment Pre-research Space Science and Technology(6141B06140601)the Innovation Program for Quantum Science and Technology(No.2021ZD0301500).M.L.and Y.L.thank Tianxiang Dai for helpful discussion on the theory.
文摘Anomalous Floquet topological insulators with vanishing Chern numbers but supporting chiral edge modes are attracting more and more attention.Since the existing anomalous Floquet topological insulators usually support only one kind of chiral edge mode even at a large lattice size,they are unscalable and unapplicable for multistate topological quantum systems.Recently,fractal topological insulators with self-similarity have been explored to support more nontrivial modes.Here,we demonstrate the first experimental realization of fractal photonic anomalous Floquet topological insulators based on dual Sierpinski carpet consisting of directional couplers using the femtosecond laser direct writing.The fabricated lattices support much more kinds of chiral edge states with fewer waveguides and enable perfect hopping of quantum states with near unit transfer efficiency.Instead of zero-dimensional bound modes for quantum state transport in previous laser direct-written topological insulators,we generate multiple propagating single-photon chiral edge states in the fractal lattice and observe high-visibility quantum interferences.These suggest the successful realization of highly indistinguishable single-photon chiral edge states,which can be applied in various quantum operations.This work provides the potential for enhancing the multi-fold manipulation of quantum states,enlarging the encodable quantum information capacity in a single lattice via high-dimensional encoding and many other fractal applications.
基金supported by the National Natural Science Foundation of China(Nos.91950204,92150302,and 62175009)Innovation Program for Quantum Science and Technology(No.2021ZD0301500)Open Research Fund Program of the State Key Laboratory of Low-Dimensional Quantum Physics(No.KF202114).
文摘Nonreciprocal interlayer coupling is difcult to practically implement in bilayer non-Hermitian topological photonic systems.In this work,we identify a similarity transformation between the Hamiltonians of systems with nonreciprocal interlayer coupling and on-site gain/loss.The similarity transformation is widely applicable,and we show its application in one-and two-dimensional bilayer topological systems as examples.The bilayer non-Hermitian system with nonreciprocal interlayer coupling,whose topological number can be defned using the gauge-smoothed Wilson loop,is topologically equivalent to the bilayer system with on-site gain/loss.We also show that the topological number of bilayer non-Hermitian C6v-typed domaininduced topological interface states can be defned in the same way as in the case of the bilayer non-Hermitian Su–Schrieffer–Heeger model.Our results show the relations between two microscopic provenances of the non-Hermiticity and provide a universal and convenient scheme for constructing and studying nonreciprocal interlayer coupling in bilayer non-Hermitian topological systems.This scheme is useful for observation of non-Hermitian skin efect in three-dimensional systems.
基金supported by the National Natural Science Foundation of China(Nos.11974032,11734001,and 11525414)the Key R&D Program of Guangdong Province(No.2018B030329001).
文摘Hybrid metal-dielectric structures combine the advantages of both metal and dielectric materials,enabling high-confined but low-loss magnetic and electric resonances through deliberate arrangements.However,their potential for enhancing magnetic emission has yet to be fully explored.Here,we study the magnetic and electric Purcell enhancement supported by a hybrid structure composed of a dielectric nanoring and a silver nanorod.This structure enables low Ohmic loss and highlyconfined field under the mode hybridization of magnetic resonances on a nanoring and electric resonances on a nanorod in the optical communication band.Thus,the 60-fold magnetic Purcell enhancement and 45-fold electric Purcell enhancement can be achieved.Over 90%of the radiation can be transmitted to the far field.For the sufficiently large Purcell enhancement,the position of emitter has a tolerance of several tens of nanometers,which brings convenience to experimental fabrications.Moreover,an array formed by this hybrid nanostructure can further enhance the magnetic Purcell factors.The system provides a feasible option to selectively excite magnetic and electric emission in integrated photonic circuits.It may also facilitate brighter magnetic emission sources and light-emitting metasurfaces with a more straightforward design.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research (Grant No.2020B0301030009)the National Natural Science Foundation of China (Grant Nos.91750203,91850111,11174019,12004013,92150301,and 61322509)+1 种基金the Ministry of Science and Technology of China[National Basic Research Program of China (Grant No.2013CB921904)]the China Postdoctoral Science Foundation (Grant No.2020M680220).
文摘Chiral sum-frequency generation(SFG)has proven to be a versatile spectroscopic and imaging tool for probing chirality.However,due to polarization restriction,the conventional chiral SFG microscopes have mostly adopted noncollinear beam configurations,which only partially cover the aperture of microscope and strongly spoil the spatial resolution.In this study,we report the first experimental demonstration of collinear chiral SFG microscopy,which fundamentally supports diffraction-limited resolution.This advancement is attributed to the collinear focus of a radially polarized vectorial beam and a linearly polarized(LP)beam.The tightly focused vectorial beam has a very strong longitudinal component,which interacts with the LP beam and produces the chiral SFG.The collinear configuration can utilize the full aperture and thus push the spatial resolution close to the diffraction limit.This technique can potentially boost the understanding of chiral systems.
基金National Key R&D Program of China(2016YFA0301302,2018YFB1107205)National Natural Science Foundation of China(NSFC)(11474010,11627803,61590933)
文摘For crystals, depressed cladding waveguides have advantages such as preservation of the spectroscopic as well as non-linear properties and the capability to guide both horizontal and vertical polarization modes, but fabrication is always quite time consuming. In addition, it is usually difficult to couple modes propagating in different depressed cladding waveguides through evanescent field overlap, so it is often required to dynamically reconfigure photonic waveguide devices using external fields for classical or quantum applications. Here, we experimentally demonstrate the single-scan femtosecond laser transverse writing of depressed cladding waveguides to form a 2 × 2 directional coupler inside lithium niobate crystal, which is integrated with two deeply embedded microelectrodes on both sides of the interaction region to reconfigure the coupling. By focal field engineering of the femtosecond laser, we specially generate a three-dimensional longitudinally oriented ring-shaped focal intensity profile composed of 16 discrete spots to simultaneously write the entire cladding region. The fabricated waveguides exhibit good single guided modes in two orthogonal polarizations at 1550 nm. By applying voltage to the deeply embedded microelectrodes fabricated with the femtosecond laser ablation followed by selective electroless plating, we successfully facilitate the light coupling from the input arm to the cross arm and thus actively tune the splitting ratio. These results open new important perspectives in the efficient fabrication of reconfigurable complex three-dimensional devices in crystals based on depressed cladding waveguides.
文摘Optical microcavities have attracted strong research interests,for their unique property of confining photons for a long time in small volumes,which significantly enhances light–matter interaction[1].In recent decades,various fabrication techniques of microcavities with higher quality factors(Q)and smaller mode volumes(V_m)have been developed,pushing forward studies from fundamental physics to functional photonics devices.Microcavity optomechanics provides an ideal platform for exploring the quantum nature of macroscopic objects[2]。
基金supported by the National Basic Research Program of China(Grant No.2015CB932203)the National Natural Science Foundation of China(Grant Nos.61722501,and 61377025)+2 种基金the Beijing Natural Science Foundation(Grant No.4164106)the Scientific Experimental System in Near Space of Chinese Academy of Sciences(Grant No.XDA17000000)the General Financial Grant from the China Postdoctoral Science Foundation(Grant No.2017M620519)
文摘The metal halide perovskite materials demonstrate outstanding performance in photovoltaics because of their excellent optoelectronic properties (1-7)The perovskite solar cells (PSCs) exhibiting outstanding efficiency [8,9], high power-per-weight [10], and excellent radiation resistance[11-13] are considered to be promising for developing the new-generation energy technology for space application.
