We experimentally demonstrate a novel ghost imaging experiment utilizing a classical light source, capable of resolving objects with a high visibility. The experimental results show that our scheme can indeed realize ...We experimentally demonstrate a novel ghost imaging experiment utilizing a classical light source, capable of resolving objects with a high visibility. The experimental results show that our scheme can indeed realize ghost imaging with high visibility for a relatively complicated object composed of three near-ellipse-shaped holes with different dimensions. In our experiment, the largest hole is -36 times of the smMlest one in area. Each of the three holes exhibits high-visibility in excess of 80%. The high visibility and high spatial-resolution advantages of this technique could have applications in remote sensing.展开更多
Block copolymers are a class of soft matter that self-assemble to form ordered morphologies on the scale of nanome- ters, making them ideal materials for various applications. These applications directly depend on the...Block copolymers are a class of soft matter that self-assemble to form ordered morphologies on the scale of nanome- ters, making them ideal materials for various applications. These applications directly depend on the shape and size of the self-assembled morphologies, and hence, a high degree of control over the self-assembly is desired. Grafting block copolymer chains onto a substrate to form copolymer brushes is a versatile method to fabricate functional surfaces. Such surfaces demonstrate a response to their environment, i.e., they change their surface topography in response to different external conditions. Furthermore, such surfaces may possess nanoscale patterns, which are important for some applica- tions; however, such patterns may not form with spun-cast films under the same condition. In this review, we summarize the recent progress of the self-assembly of block copolymers grafted onto a flat substrate. We mainly concentrate on the self-assembled morphologies of end-grafted AB dibloek eopolymers, junction p0int-grafted AB diblock copolymers （i.e., Y-shaped brushes）, and end-grafted ABA triblock copolymers. Special emphasis is placed on theoretical and simulation progress.展开更多
A novel symmetric plasmonic structure consisting of a metal-insulator-metal waveguide and a rectangular cavity is proposed to investigate Fano resonance performance by adjusting the size of the structure.The Fano reso...A novel symmetric plasmonic structure consisting of a metal-insulator-metal waveguide and a rectangular cavity is proposed to investigate Fano resonance performance by adjusting the size of the structure.The Fano resonance originates from the interference between a local quadrupolar and a broad spectral line in the rectangular cavity.The tuning of the Fano profile is realized by changing the size of the rectangular cavity.The nanostructure is expected to work as an excellent plasmonic sensor with a high sensitivity of about 530 nm/RIU and a figure of merit of about 650.展开更多
The orbital degrees of freedom play a pivotal role in understanding fundamental phenomena in solid-state materials as well as exotic quantum states of matter including orbital superfluidity and topological semimetals....The orbital degrees of freedom play a pivotal role in understanding fundamental phenomena in solid-state materials as well as exotic quantum states of matter including orbital superfluidity and topological semimetals.Despite tremendous efforts in engineering synthetic cold-atom,as well as electronic and photonic lattices to explore orbital physics,thus far high orbitals in an important class of materials,namely,higher-order topological insulators(HOTIs),have not been realized.Here,we demonstrate p-orbital corner states in a photonic HOTI,unveiling their underlying topological invariant,symmetry protection,and nonlinearity-induced dynamical rotation.In a Kagome-type HOTI,we find that the topological protection of p-orbital corner states demands an orbital-hopping symmetry in addition to generalized chiral symmetry.Due to orbital hybridization,nontrivial topology of the p-orbital HOTI is“hidden”if bulk polarization is used as the topological invariant,but well manifested by the generalized winding number.Our work opens a pathway for the exploration of intriguing orbital phenomena mediated by higher-band topology applicable to a broad spectrum of systems.展开更多
Optical transmission at 532 nm from nonabsorbing disordered porous silicon dioxide has been studied experimentally. The transmission behaviors can be adjusted by filling the pores with liquids of different refractive ...Optical transmission at 532 nm from nonabsorbing disordered porous silicon dioxide has been studied experimentally. The transmission behaviors can be adjusted by filling the pores with liquids of different refractive indics, which are analyzed based on the theory of diffusion in a weak scattering regime. In our experiment, the transmission coefficient changes from a value less than 1% to one that is greater than 75%, that is, the opaque sample becomes transparent, which means that the transport mean free path of light within the material has been effectively adjusted. In addition, this method is a useful nondestructive method to derive the refractive index of an unknown bulk porous material.展开更多
Beam manipulation by metallic nanoslit arrays with perpendicular cuts inside the slits was investigated numerically.The simulated results performed by the finite element method(FEM)show that perpendicular cuts with di...Beam manipulation by metallic nanoslit arrays with perpendicular cuts inside the slits was investigated numerically.The simulated results performed by the finite element method(FEM)show that perpendicular cuts with different heights can modulate phase retardation of the transmitted light through the slits.With the proper distribution of cut height,a focused beam is achieved in our metallic nanostructure with four-time amplitude at the focus point and half focal length compared to a slit array without cuts inside.By using asymmetric distribution of height amplitude,a beam deflection around 6°can also be realized in our design.展开更多
We report on theoretical investigations of beam control in one-dimensional tri-core photonic lattices （PLs）. Linear splitting is illustrated in tri-core PLs; the effect of defect strength on the splitting is discuss...We report on theoretical investigations of beam control in one-dimensional tri-core photonic lattices （PLs）. Linear splitting is illustrated in tri-core PLs; the effect of defect strength on the splitting is discussed in depth for single-wavelength light. We reveal that splitting disappears when the defect strength trends to zero, while reoccurring under nonlinearity. Multi-color splitting and active control are also proposed in such photonic structures.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
In order to investigate the influence of different heavy metal ions on the formation of the oxyfluoride glasses and glass ceramics, samples with different Pb F2/Cd F2 ratios have been prepared by the melting quenching...In order to investigate the influence of different heavy metal ions on the formation of the oxyfluoride glasses and glass ceramics, samples with different Pb F2/Cd F2 ratios have been prepared by the melting quenching and thermal treatment method. The different effects of Pb2 tand Cd2ton the glass network structure are investigated by FTIR and Raman spectra. During the formation of glass network structure, Pb2 tprefers to break the Sie Oe Si bond and subsequently bond to F for charge compensation, and Cd2 tprefers to break the SieO eA l bond and is surrounded by O2. Pb2 tand F gather together and form the fluoride nanocrystals,while Cd2 tremains in oxide matrix after thermal treatment. Introduction of proper Cd F2 is important to adjust and control the glass network structure and crystallization process in the fabrication of the transparent glass ceramics.展开更多
We have theoretically designed and experimentally observed free-space propagation of topological singular lines of cylindrical vector optical fields with non-integer topological charges. The polarization singular line...We have theoretically designed and experimentally observed free-space propagation of topological singular lines of cylindrical vector optical fields with non-integer topological charges. The polarization singular lines are due to the orientation uncertainty of the polarization states, caused by non-integer topological charges. The results reveal that during propagation, evolution of the polarization singular lines results in the special intensity pattern,distribution of polarization states, and chains of polarization singularities. We have also proposed a method to generate triple straight and spiral singular lines, which may contribute to the research of complex optical fields.展开更多
Femtosecond laser filamentation is generally initialized from unpredictable symmetry breaking caused by random noise, causing it to be barely controlled. However, it is always anticipated for stable and controllable f...Femtosecond laser filamentation is generally initialized from unpredictable symmetry breaking caused by random noise, causing it to be barely controlled. However, it is always anticipated for stable and controllable filamentation.We present and demonstrate the idea that hybridly polarized vector fields with axial symmetry broken polarization, associated with a pair of orthogonally linearly polarized vortices carrying the opposite-handed orbital angular momenta, could achieve controllable and robust multiple filamentation. Here, our motivation is to unveil the underlying physics behind such controllable and robust multiple filamentation. The symmetry breaking should first be actively controllable and then be able to effectively inhibit random noise. Robust multiple filamentation is inseparable from the fact that the phases between the multiple filaments are always locked. In contrast, uncontrollable multiple filamentation is always accompanied with loss of phase, i.e., the multiple filaments become incoherent to each other. Our results may offer a suggestion for achieving controllable and robust multiple filamentation in other systems.展开更多
Femtosecond mode-locked laser frequency combs have served as the cornerstone in precision spectroscopy,alloptical atomic clocks,and measurements of ultrafast dynamics.Recently frequency microcombs based on nonlinear m...Femtosecond mode-locked laser frequency combs have served as the cornerstone in precision spectroscopy,alloptical atomic clocks,and measurements of ultrafast dynamics.Recently frequency microcombs based on nonlinear microresonators have been examined,exhibiting remarkable precision approaching that of laser frequency combs,on a solid-state chip-scale platform and from a fundamentally different physical origin.Despite recent successes,to date,the real-time dynamical origins and high-power stabilities of such frequency microcombs have not been fully addressed.Here,we unravel the transitional dynamics of frequency microcombs from chaotic background routes to femtosecond mode-locking in real time,enabled by our ultrafast temporal magnifier metrology and improved stability of dispersion-managed dissipative solitons.Through our dispersion-managed oscillator,we further report a stability zone that is more than an order-of-magnitude larger than its prior static homogeneous counterparts,providing a novel platform for understanding ultrafast dissipative dynamics and offering a new path towards high-power frequency microcombs.展开更多
through single-site excitation. By changing the initial to the lattices, periodic oscillations of the localized quadruple state becomes a rotating doubly charged undergo charge-flipping when the rotating direction is ...through single-site excitation. By changing the initial to the lattices, periodic oscillations of the localized quadruple state becomes a rotating doubly charged undergo charge-flipping when the rotating direction is orientation of the incident quadruple beam related quadruple mode may be obtained. The localized optical vortex （DCV） during rotation and should reversed.展开更多
The optical absorption properties of femtosecond-laser-made ＂black silicon＂ as a function of the annealing conditions were investigated. We found that the annealing process changes the surface morphology and absorpt...The optical absorption properties of femtosecond-laser-made ＂black silicon＂ as a function of the annealing conditions were investigated. We found that the annealing process changes the surface morphology and absorption spectroscopy of the ＂black silicon＂ samples, and obtained a maximum sub-band-gap absorptance value of approximately 30% by annealing at 1000 ~C for 30 min. The thermal relaxation and atomic structural transformation mechanisms are used to describe the lat- tice recovery and the increase and decrease of the substitutional dopant atom concentration in the microstructured surface during the annealing. Our results confirm that： i） owing to the ther- mal relaxation, the lattice defects decrease with the increase of the annealing temperature; ii） the quasi-substitutional and interstitial configurations of the doped atoms transform into substitutional arrangements when the annealing temperature increases; iii） the quasi-substitutional and intersti- tial configurations with higher energies of the doped atoms transform into interstitial configurations with the lowest energy after high-temperature annealing for a long period of time, causing the de- activation or reactivation of the sub-band-gap absorptance by diffusion. The results demonstrate that the annealing can improve the properties of ＂black silicon＂, including defects repairing, carrier lifetime lengthening, and retention of a high absorptive performance.展开更多
Crystalline lithium niobate(LN)is an important optical material because of its broad transmission window that spans from ultraviolet to mid-infrared and its large nonlinear and electro-optic coefficients.Furthermore,t...Crystalline lithium niobate(LN)is an important optical material because of its broad transmission window that spans from ultraviolet to mid-infrared and its large nonlinear and electro-optic coefficients.Furthermore,the recent development and commercialization of LN-on-insulator(LNOI)technology has opened an avenue for the realization of integrated on-chip photonic devices with unprecedented performances in terms of propagation loss,optical nonlinearity,and electro-optic tunability.This review begins with a brief introduction of the history and current status of LNOI photonics.We then discuss the fabrication techniques of LNOI-based photonic structures and devices.The recent revolution in the LN photonic industry has been sparked and is still being powered by innovations of the nanofabrication technology of LNOI,which enables the production of building block structures,such as optical microresonators and waveguides of unprecedented optical qualities.The following sections present various on-chip LNOI devices categorized into nonlinear photonic and electro-optic tunable devices and photonic-integrated circuits.Some conclusions and future perspectives are provided.展开更多
In this study, we investigate the fabrication of periodically poled lithium niobate(PPLN) microdisk cavities on a chip. These resonators are fabricated from a PPLN film with a 16 μm poling period on insulator using c...In this study, we investigate the fabrication of periodically poled lithium niobate(PPLN) microdisk cavities on a chip. These resonators are fabricated from a PPLN film with a 16 μm poling period on insulator using conventional microfabrication techniques.The quality factor of the PPLN microdisk resonators with a 40-μm radius and a 700-nm thickness is 6.7×10~5. Second harmonic generation(SHG) with an efficiency of 2.2×10^(-6) mW(-1) is demonstrated in the fabricated PPLN microdisks. The nonlinear conversion efficiency could be considerably enhanced by optimizing the period and pattern of the poled structure and by improving the cavity quality factors.展开更多
Optical activity is the rotation of the plane of linearly polarized light along the propagation direction as the light travels through optically active materials.In existing methods,the strength of the optical activit...Optical activity is the rotation of the plane of linearly polarized light along the propagation direction as the light travels through optically active materials.In existing methods,the strength of the optical activity is determined by the chirality of the materials,which is difficult to control quantitatively.Here we numerically and experimentally investigated an alternative approach to realize and control the optical activity with non-chiral plasmonic metasurfaces.Through judicious design of the structural units of the metasurfaces,the right and left circular polarization components of the linearly polarized light have different phase retardations after transmitting through the metasurfaces,leading to large optical activity.Moreover,the strength of the optical activity can be easily and accurately tuned by directly adjusting the phase difference.The proposed approach based on non-chiral plasmonic metasurfaces exhibits large optical activity with a high controllable degree of freedom,which may provide more possibilities for applications in photonics.展开更多
We demonstrate that a dielectric anapole resonator on a metallic mirror can enhance the third harmonic emission by two orders of magnitude compared to a typical anapole resonator on an insulator substrate.By employing...We demonstrate that a dielectric anapole resonator on a metallic mirror can enhance the third harmonic emission by two orders of magnitude compared to a typical anapole resonator on an insulator substrate.By employing a gold mirror under a silicon nanodisk,we introduce a novel characteristic of the anapole mode through the spatial overlap of resonantly excited Cartesian electric and toroidal dipole modes.This is a remarkable improvement on the early demonstrations of the anapole mode in which the electric and toroidal modes interfere off-resonantly.Therefore,our system produces a significant near-field enhancement,facilitating the nonlinear process.Moreover,the mirror surface boosts the nonlinear emission via the free-charge oscillations within the interface,equivalent to producing a mirror image of the nonlinear source and the pump beneath the interface.We found that these improvements result in an extremely high experimentally obtained efficiency of 0.01%.展开更多
We report the first observation, to the best of our knowledge, of sum-frequency generation in on-chip lithium niobate microdisk resonators. The sum-frequency signal in the 780 nm band, distinct in wavelength from seco...We report the first observation, to the best of our knowledge, of sum-frequency generation in on-chip lithium niobate microdisk resonators. The sum-frequency signal in the 780 nm band, distinct in wavelength from secondharmonic signals, was obtained in lithium niobate microresonators under the pump of two individual 1550 nm band lasers. The sum-frequency conversion efficiency was measured to be 1.4 × 10^(-7) mW^(-1). The dependence of the intensities of the nonlinear signals on the total pump power and the wavelength of one pump laser was investigated while fixing the wavelength of the other. This work paves the way for applications of on-chip lithium niobate microdisk resonators ranging from infrared single-photon detection to infrared spectroscopy.展开更多
In single microdisks,embedded active emitters intrinsically affect the cavity modes of the microdisks,resulting in trivial symmetric backscattering and low controllability.Here we demonstrate macroscopic control of th...In single microdisks,embedded active emitters intrinsically affect the cavity modes of the microdisks,resulting in trivial symmetric backscattering and low controllability.Here we demonstrate macroscopic control of the backscattering direction by optimizing the cavity size.The signature of the positive and negative backscattering directions in each single microdisk is confirmed with two strongly coupled microdisks.Furthermore,diabolical points are achieved at the resonance of the two microdisks,which agrees well with theoretical calculations considering the backscattering directions.Diabolical points in active optical structures pave the way for an implementation of quantum information processing with geometric phase in quantum photonic networks.展开更多
基金Supported by the National Basic Research Program of China under Grant No 2012CB921900the National Natural Science Foundation of China under Grant Nos 11534006,11274183 and 11374166the National Scientific Instrument and Equipment Development Project under Grant No 2012YQ17004
文摘We experimentally demonstrate a novel ghost imaging experiment utilizing a classical light source, capable of resolving objects with a high visibility. The experimental results show that our scheme can indeed realize ghost imaging with high visibility for a relatively complicated object composed of three near-ellipse-shaped holes with different dimensions. In our experiment, the largest hole is -36 times of the smMlest one in area. Each of the three holes exhibits high-visibility in excess of 80%. The high visibility and high spatial-resolution advantages of this technique could have applications in remote sensing.
基金supported by the National Natural Science Foundation of China(Grant Nos.20990234,20925414,and 91227121)the Program for Changjiang Scholars and Innovative Research Team in University,China(Grant No.IRT1257)+1 种基金the Programme of Introducing Talents of Discipline to Universities,Chinaby the Tianhe No.1,China
文摘Block copolymers are a class of soft matter that self-assemble to form ordered morphologies on the scale of nanome- ters, making them ideal materials for various applications. These applications directly depend on the shape and size of the self-assembled morphologies, and hence, a high degree of control over the self-assembly is desired. Grafting block copolymer chains onto a substrate to form copolymer brushes is a versatile method to fabricate functional surfaces. Such surfaces demonstrate a response to their environment, i.e., they change their surface topography in response to different external conditions. Furthermore, such surfaces may possess nanoscale patterns, which are important for some applica- tions; however, such patterns may not form with spun-cast films under the same condition. In this review, we summarize the recent progress of the self-assembly of block copolymers grafted onto a flat substrate. We mainly concentrate on the self-assembled morphologies of end-grafted AB dibloek eopolymers, junction p0int-grafted AB diblock copolymers （i.e., Y-shaped brushes）, and end-grafted ABA triblock copolymers. Special emphasis is placed on theoretical and simulation progress.
基金the National Natural Science Foundation of China under Grant No 61178004the Tianjin Natural Science Foundation under Grant No 12JCQNJC01100+1 种基金the Doctoral Program of Higher Education of China under Grant No 20110031120005the Program for Changjiang Scholars and Innovative Research Team in Nankai University.
文摘A novel symmetric plasmonic structure consisting of a metal-insulator-metal waveguide and a rectangular cavity is proposed to investigate Fano resonance performance by adjusting the size of the structure.The Fano resonance originates from the interference between a local quadrupolar and a broad spectral line in the rectangular cavity.The tuning of the Fano profile is realized by changing the size of the rectangular cavity.The nanostructure is expected to work as an excellent plasmonic sensor with a high sensitivity of about 530 nm/RIU and a figure of merit of about 650.
基金the National Key R&D Program of China(2022YFA1404800)the National Natural Science Foundation of China(12134006,12274242)+4 种基金the Natural Science Foundation of Tianjin(21JCJQJC00050)the QuantiXLie Center of Excellence,a project co-financed by the Croatian Government and the European Union through the European Regional Development Fund the Competitiveness and Cohesion Operational Programme(KK.01.1.1.01.0004)the 66 Postdoctoral Science Grant of Chinathe NSERC Discovery Grantthe Canada Research Chair Programs.
文摘The orbital degrees of freedom play a pivotal role in understanding fundamental phenomena in solid-state materials as well as exotic quantum states of matter including orbital superfluidity and topological semimetals.Despite tremendous efforts in engineering synthetic cold-atom,as well as electronic and photonic lattices to explore orbital physics,thus far high orbitals in an important class of materials,namely,higher-order topological insulators(HOTIs),have not been realized.Here,we demonstrate p-orbital corner states in a photonic HOTI,unveiling their underlying topological invariant,symmetry protection,and nonlinearity-induced dynamical rotation.In a Kagome-type HOTI,we find that the topological protection of p-orbital corner states demands an orbital-hopping symmetry in addition to generalized chiral symmetry.Due to orbital hybridization,nontrivial topology of the p-orbital HOTI is“hidden”if bulk polarization is used as the topological invariant,but well manifested by the generalized winding number.Our work opens a pathway for the exploration of intriguing orbital phenomena mediated by higher-band topology applicable to a broad spectrum of systems.
基金supported by the National Natural Science Foundation of China (Nos. 10874093 and 10804055)the National "973" Program of China (Nos. 2007CB307002, 2010CB934101, and 2010CB933801)+1 种基金the "111"Project of China (No. B07013)the Program for New Century Excellent Talents in University of China
文摘Optical transmission at 532 nm from nonabsorbing disordered porous silicon dioxide has been studied experimentally. The transmission behaviors can be adjusted by filling the pores with liquids of different refractive indics, which are analyzed based on the theory of diffusion in a weak scattering regime. In our experiment, the transmission coefficient changes from a value less than 1% to one that is greater than 75%, that is, the opaque sample becomes transparent, which means that the transport mean free path of light within the material has been effectively adjusted. In addition, this method is a useful nondestructive method to derive the refractive index of an unknown bulk porous material.
基金Supported by the National Natural Science Foundation of China under Grant Nos 60978020,61178004Research Fund for the Doctoral Program of Higher Education of China(20110031120005)+1 种基金Program for Changjiang Scholars and Innovative Research Team in Nankai Universitythe Fundamental Research Funds for the Central Universities.
文摘Beam manipulation by metallic nanoslit arrays with perpendicular cuts inside the slits was investigated numerically.The simulated results performed by the finite element method(FEM)show that perpendicular cuts with different heights can modulate phase retardation of the transmitted light through the slits.With the proper distribution of cut height,a focused beam is achieved in our metallic nanostructure with four-time amplitude at the focus point and half focal length compared to a slit array without cuts inside.By using asymmetric distribution of height amplitude,a beam deflection around 6°can also be realized in our design.
基金Project supported by the State Key Program for Basic Research of China (Grant Nos.2013CB632703 and 2010CB934101)the National Natural Science Foundation of China (Grant Nos.10904078 and 60908002)+4 种基金the International Science & Technology Cooperation Program of China (Grant No.2011DFA52870)the International Cooperation Program of Tianjin (Grant No.11ZGHHZ01000)the "111"Project (Grant No.B07013)the Program for New Century Excellent Talents in University of China (Grant No.NCET-10-0507)the Specialized Research Fund for the Doctorial Program of Higher Education of China (Grant No.20120031120031)
文摘We report on theoretical investigations of beam control in one-dimensional tri-core photonic lattices （PLs）. Linear splitting is illustrated in tri-core PLs; the effect of defect strength on the splitting is discussed in depth for single-wavelength light. We reveal that splitting disappears when the defect strength trends to zero, while reoccurring under nonlinearity. Multi-color splitting and active control are also proposed in such photonic structures.
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supported by the National Science Fund for Talent Training in Basic Sciences (No. J1103208)
文摘In order to investigate the influence of different heavy metal ions on the formation of the oxyfluoride glasses and glass ceramics, samples with different Pb F2/Cd F2 ratios have been prepared by the melting quenching and thermal treatment method. The different effects of Pb2 tand Cd2ton the glass network structure are investigated by FTIR and Raman spectra. During the formation of glass network structure, Pb2 tprefers to break the Sie Oe Si bond and subsequently bond to F for charge compensation, and Cd2 tprefers to break the SieO eA l bond and is surrounded by O2. Pb2 tand F gather together and form the fluoride nanocrystals,while Cd2 tremains in oxide matrix after thermal treatment. Introduction of proper Cd F2 is important to adjust and control the glass network structure and crystallization process in the fabrication of the transparent glass ceramics.
基金National Key R&D Program of China(2017YFA0303700,2017YFA0303800)National Natural Science Foundation of China(NSFC)(11534006,11674184,11774183)+1 种基金Natural Science Foundation of Tianjin City(16JCZDJC31300)111 Project(B07013)
文摘We have theoretically designed and experimentally observed free-space propagation of topological singular lines of cylindrical vector optical fields with non-integer topological charges. The polarization singular lines are due to the orientation uncertainty of the polarization states, caused by non-integer topological charges. The results reveal that during propagation, evolution of the polarization singular lines results in the special intensity pattern,distribution of polarization states, and chains of polarization singularities. We have also proposed a method to generate triple straight and spiral singular lines, which may contribute to the research of complex optical fields.
基金973 Program of China(2012CB921900)National Natural Science Foundation of China(NSFC)(11274183,11374166,11504409,11534006)+1 种基金National Scientific Instrument and Equipment Development Project(2012YQ17004)Collaborative Innovation Center of Extreme Optics
文摘Femtosecond laser filamentation is generally initialized from unpredictable symmetry breaking caused by random noise, causing it to be barely controlled. However, it is always anticipated for stable and controllable filamentation.We present and demonstrate the idea that hybridly polarized vector fields with axial symmetry broken polarization, associated with a pair of orthogonally linearly polarized vortices carrying the opposite-handed orbital angular momenta, could achieve controllable and robust multiple filamentation. Here, our motivation is to unveil the underlying physics behind such controllable and robust multiple filamentation. The symmetry breaking should first be actively controllable and then be able to effectively inhibit random noise. Robust multiple filamentation is inseparable from the fact that the phases between the multiple filaments are always locked. In contrast, uncontrollable multiple filamentation is always accompanied with loss of phase, i.e., the multiple filaments become incoherent to each other. Our results may offer a suggestion for achieving controllable and robust multiple filamentation in other systems.
基金supported by the Air Force Office of Scientific Research under award number FA9550-15-1-0081the Office of Naval Research under award number N00014-16-1-2094the National Science Foundation under award numbers 17-41707,18-10506,and 18-24568.
文摘Femtosecond mode-locked laser frequency combs have served as the cornerstone in precision spectroscopy,alloptical atomic clocks,and measurements of ultrafast dynamics.Recently frequency microcombs based on nonlinear microresonators have been examined,exhibiting remarkable precision approaching that of laser frequency combs,on a solid-state chip-scale platform and from a fundamentally different physical origin.Despite recent successes,to date,the real-time dynamical origins and high-power stabilities of such frequency microcombs have not been fully addressed.Here,we unravel the transitional dynamics of frequency microcombs from chaotic background routes to femtosecond mode-locking in real time,enabled by our ultrafast temporal magnifier metrology and improved stability of dispersion-managed dissipative solitons.Through our dispersion-managed oscillator,we further report a stability zone that is more than an order-of-magnitude larger than its prior static homogeneous counterparts,providing a novel platform for understanding ultrafast dissipative dynamics and offering a new path towards high-power frequency microcombs.
基金supported by the National"973"Program of China(Nos.2013CB632703 and 2013CB328702)the National Natural Science Foundation of China(Nos.60908002 and 10904078)+4 种基金the International S&T Cooperation Program of China(No.2011DFA52870)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20120031120031)the International Cooperation Program of Tianjin(No.11ZGHHZ01000)the"111"Project(No.B07013)the Program for New Century Excellent Talents in University(No.NCET-10-0507)
文摘through single-site excitation. By changing the initial to the lattices, periodic oscillations of the localized quadruple state becomes a rotating doubly charged undergo charge-flipping when the rotating direction is orientation of the incident quadruple beam related quadruple mode may be obtained. The localized optical vortex （DCV） during rotation and should reversed.
文摘The optical absorption properties of femtosecond-laser-made ＂black silicon＂ as a function of the annealing conditions were investigated. We found that the annealing process changes the surface morphology and absorption spectroscopy of the ＂black silicon＂ samples, and obtained a maximum sub-band-gap absorptance value of approximately 30% by annealing at 1000 ~C for 30 min. The thermal relaxation and atomic structural transformation mechanisms are used to describe the lat- tice recovery and the increase and decrease of the substitutional dopant atom concentration in the microstructured surface during the annealing. Our results confirm that： i） owing to the ther- mal relaxation, the lattice defects decrease with the increase of the annealing temperature; ii） the quasi-substitutional and interstitial configurations of the doped atoms transform into substitutional arrangements when the annealing temperature increases; iii） the quasi-substitutional and intersti- tial configurations with higher energies of the doped atoms transform into interstitial configurations with the lowest energy after high-temperature annealing for a long period of time, causing the de- activation or reactivation of the sub-band-gap absorptance by diffusion. The results demonstrate that the annealing can improve the properties of ＂black silicon＂, including defects repairing, carrier lifetime lengthening, and retention of a high absorptive performance.
基金Natural Basic Research Program of China(2019YFA0705000)National Natural Science Foundation of China(11674181,11674340,11734009,11822410,11874154,11874375,61590934,61761136006)+5 种基金Key Research Program of Frontier Sciences(QYZDJ-SSWSLH010)Key Project of the Shanghai Science and Technology Committee(17JC1400400,18DZ1112700)Strategic Priority Research Program of Chinese Academy of Sciences(XDB16030300)Higher Education Discipline Innovation Project(B07013)Program for Changjiang Scholars and Innovative Research Team(IRT_13R29)State Key Laboratory of Advanced Optical Communication Systems and Networks(2019GZKF03006).
文摘Crystalline lithium niobate(LN)is an important optical material because of its broad transmission window that spans from ultraviolet to mid-infrared and its large nonlinear and electro-optic coefficients.Furthermore,the recent development and commercialization of LN-on-insulator(LNOI)technology has opened an avenue for the realization of integrated on-chip photonic devices with unprecedented performances in terms of propagation loss,optical nonlinearity,and electro-optic tunability.This review begins with a brief introduction of the history and current status of LNOI photonics.We then discuss the fabrication techniques of LNOI-based photonic structures and devices.The recent revolution in the LN photonic industry has been sparked and is still being powered by innovations of the nanofabrication technology of LNOI,which enables the production of building block structures,such as optical microresonators and waveguides of unprecedented optical qualities.The following sections present various on-chip LNOI devices categorized into nonlinear photonic and electro-optic tunable devices and photonic-integrated circuits.Some conclusions and future perspectives are provided.
基金supported by the National Natural Science Foundation of China(Grant Nos.11734009,11674181,11774182,and 11674184)the 111 Project(Grant No.B07013)+1 种基金PCSIRT(Grant No.IRT 13R29)CAS Interdisciplinary Innovation Team
文摘In this study, we investigate the fabrication of periodically poled lithium niobate(PPLN) microdisk cavities on a chip. These resonators are fabricated from a PPLN film with a 16 μm poling period on insulator using conventional microfabrication techniques.The quality factor of the PPLN microdisk resonators with a 40-μm radius and a 700-nm thickness is 6.7×10~5. Second harmonic generation(SHG) with an efficiency of 2.2×10^(-6) mW(-1) is demonstrated in the fabricated PPLN microdisks. The nonlinear conversion efficiency could be considerably enhanced by optimizing the period and pattern of the poled structure and by improving the cavity quality factors.
基金supported by the National Basic Research Program(973 Program)of China(2012CB921900)the Chinese National Key Basic Research Special Fund(2011CB922003)+3 种基金the Natural Science Foundation of China(11574163,61378006,11304163 and 91323304)the Program for New Century Excellent Talents in University(NCET-13-0294)the 111 project(B07013)the National Science Fund for Talent Training in Basic Sciences(J1103208).
文摘Optical activity is the rotation of the plane of linearly polarized light along the propagation direction as the light travels through optically active materials.In existing methods,the strength of the optical activity is determined by the chirality of the materials,which is difficult to control quantitatively.Here we numerically and experimentally investigated an alternative approach to realize and control the optical activity with non-chiral plasmonic metasurfaces.Through judicious design of the structural units of the metasurfaces,the right and left circular polarization components of the linearly polarized light have different phase retardations after transmitting through the metasurfaces,leading to large optical activity.Moreover,the strength of the optical activity can be easily and accurately tuned by directly adjusting the phase difference.The proposed approach based on non-chiral plasmonic metasurfaces exhibits large optical activity with a high controllable degree of freedom,which may provide more possibilities for applications in photonics.
基金support provided by the Australian Research Council(ARC)and participation in the Erasmus Mundus NANOPHI project,contract number 20135659/002-001from an ARC Discovery Early Career Research Fellowship(DE170100250)+4 种基金supported by a UNSW Scientia Fellowshipfunding from the Australia-Germany Joint Research Cooperation Schemefrom Consejo Nacional de Ciencia y Tecnologıa(CONACYT)the financial support by NSFC(No.11774182,No.91750204)support by the German Research Foundation(STA 1426/2-1)。
文摘We demonstrate that a dielectric anapole resonator on a metallic mirror can enhance the third harmonic emission by two orders of magnitude compared to a typical anapole resonator on an insulator substrate.By employing a gold mirror under a silicon nanodisk,we introduce a novel characteristic of the anapole mode through the spatial overlap of resonantly excited Cartesian electric and toroidal dipole modes.This is a remarkable improvement on the early demonstrations of the anapole mode in which the electric and toroidal modes interfere off-resonantly.Therefore,our system produces a significant near-field enhancement,facilitating the nonlinear process.Moreover,the mirror surface boosts the nonlinear emission via the free-charge oscillations within the interface,equivalent to producing a mirror image of the nonlinear source and the pump beneath the interface.We found that these improvements result in an extremely high experimentally obtained efficiency of 0.01%.
基金National Natural Science Foundation of China(NSFC)(11374165,11674181,11674184,61475077)Ministry of Science and Technology of the People’s Republic of China(MOST)(2013CB328702)+1 种基金Ministry of Education of the People’s Republic of China(MOE)(B07013)PCSIRT(IRT_13R29)
文摘We report the first observation, to the best of our knowledge, of sum-frequency generation in on-chip lithium niobate microdisk resonators. The sum-frequency signal in the 780 nm band, distinct in wavelength from secondharmonic signals, was obtained in lithium niobate microresonators under the pump of two individual 1550 nm band lasers. The sum-frequency conversion efficiency was measured to be 1.4 × 10^(-7) mW^(-1). The dependence of the intensities of the nonlinear signals on the total pump power and the wavelength of one pump laser was investigated while fixing the wavelength of the other. This work paves the way for applications of on-chip lithium niobate microdisk resonators ranging from infrared single-photon detection to infrared spectroscopy.
基金supported by the National Natural Science Foundation of China under Grant No.11934019,No.11721404,No.51761145104,No.61675228,and No.11874419the Ministry of Science and Technology of China under Grant No.2016YFA0200400+3 种基金the Strategic Priority Research Program under Grant No.XDB07030200,No.XDB28000000,and No.XDB07020200the Instrument Developing Project under Grant No.YJKYYQ20180036the Interdisciplinary Innovation Team of the Chinese Academy of Sciencesthe Key R&D Program of Guangdong Province under Grant No.2018B030329001.
文摘In single microdisks,embedded active emitters intrinsically affect the cavity modes of the microdisks,resulting in trivial symmetric backscattering and low controllability.Here we demonstrate macroscopic control of the backscattering direction by optimizing the cavity size.The signature of the positive and negative backscattering directions in each single microdisk is confirmed with two strongly coupled microdisks.Furthermore,diabolical points are achieved at the resonance of the two microdisks,which agrees well with theoretical calculations considering the backscattering directions.Diabolical points in active optical structures pave the way for an implementation of quantum information processing with geometric phase in quantum photonic networks.
