This paper is devoted to reviewing the results achieved so far in the application of the single-pixel imaging technique to terahertz(THz)systems.The use of THz radiation for imaging purposes has been largely explored ...This paper is devoted to reviewing the results achieved so far in the application of the single-pixel imaging technique to terahertz(THz)systems.The use of THz radiation for imaging purposes has been largely explored in the last twenty years,due to the unique capabilities of this kind of radiation in interrogating material properties.However,THz imaging systems are still limited by the long acquisition time required to reconstruct the object image and significant efforts have been recently directed to overcome this drawback.One of the most promising approaches in this sense is the so-called“single-pixel”imaging,which in general enables image reconstruction by patterning the beam probing the object and measuring the total transmission(or reflection)with a single-pixel detector(i.e.,with no spatial resolution).The main advantages of such technique are that i)no bulky moving parts are required to raster-scan the object and ii)compressed sensing(CS)algorithms,which allow an appropriate reconstruction of the image with an incomplete set of measurements,can be successfully implemented.Overall,this can result in a reduction of the acquisition time.In this review,we cover the experimental solutions proposed to implement such imaging technique at THz frequencies,as well as some practical uses for typical THz applications.展开更多
We review recent work on broadband RF channelizers based on integrated optical frequency Kerr micro-combs combined with passive micro-ring resonator filters,with microcombs having channel spacings of 200 and 49 GHz.Th...We review recent work on broadband RF channelizers based on integrated optical frequency Kerr micro-combs combined with passive micro-ring resonator filters,with microcombs having channel spacings of 200 and 49 GHz.This approach to realizing RF channelizers offers reduced complexity,size,and potential cost for a wide range of applications to microwave signal detection.展开更多
We review recent work on narrowband orthogonally polarized optical RF single sideband generators as well as dualchannel equalization,both based on high-Q integrated ring resonators.The devices operate in the optical t...We review recent work on narrowband orthogonally polarized optical RF single sideband generators as well as dualchannel equalization,both based on high-Q integrated ring resonators.The devices operate in the optical telecommunications C-band and enable RF operation over a range of either fixed or thermally tuneable frequencies.They operate via TE/TM mode birefringence in the resonator.We achieve a very large dynamic tuning range of over 55 dB for both the optical carrier-to-sideband ratio and the dual-channel RF equalization for both the fixed and tunable devices.展开更多
The ability to generate complex optical photon states involving entanglement between multiple optical modes is not only critical to advancing our understanding of quantum mechanics but will play a key role in generati...The ability to generate complex optical photon states involving entanglement between multiple optical modes is not only critical to advancing our understanding of quantum mechanics but will play a key role in generating many applications in quantum technologies.These include quantum communications,computation,imaging,microscopy and many other novel technologies that are constantly being proposed.However,approaches to generating parallel multiple,customisable bi-and multi-entangled quantum bits(qubits)on a chip are still in the early stages of development.Here,we review recent advances in the realisation of integrated sources of photonic quantum states,focusing on approaches based on nonlinear optics that are compatible with contemporary optical fibre telecommunications and quantum memory platforms as well as with chip-scale semiconductor technology.These new and exciting platforms hold the promise of compact,low-cost,scalable and practical implementations of sources for the generation and manipulation of complex quantum optical states on a chip,which will play a major role in bringing quantum technologies out of the laboratory and into the real world.展开更多
Higher-order topological insulators(HOTIs)are recently discovered topological phases,possessing symmetry-protected corner states with fractional charges.An unexpected connection between these states and the seemingly ...Higher-order topological insulators(HOTIs)are recently discovered topological phases,possessing symmetry-protected corner states with fractional charges.An unexpected connection between these states and the seemingly unrelated phenomenon of bound states in the continuum(BICs)was recently unveiled.When nonlinearity is added to the HOTI system,a number of fundamentally important questions arise.For example,how does nonlinearity couple higher-order topological BICs with the rest of the system,including continuum states?In fact,thus far BICs in nonlinear HOTIs have remained unexplored.Here we unveil the interplay of nonlinearity,higher-order topology,and BICs in a photonic platform.We observe topological corner states that are also BICs in a laser-written second-order topological lattice and further demonstrate their nonlinear coupling with edge(but not bulk)modes under the proper action of both self-focusing and defocusing nonlinearities.Theoretically,we calculate the eigenvalue spectrum and analog of the Zak phase in the nonlinear regime,illustrating that a topological BIC can be actively tuned by nonlinearity in such a photonic HOTI.Our studies are applicable to other nonlinear HOTI systems,with promising applications in emerging topology-driven devices.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
We demonstrate,both analytically and experimentally,free-space pin-like optical vortex beams (POVBs). Such angular-momentum-carrying beams feature tunable peak intensity and undergo robust antidiffracting propagation,...We demonstrate,both analytically and experimentally,free-space pin-like optical vortex beams (POVBs). Such angular-momentum-carrying beams feature tunable peak intensity and undergo robust antidiffracting propagation,realized by judiciously modulating both the amplitude and the phase profile of a standard laser beam.Specifically,they are generated by superimposing a radially symmetric power-law phase on a helical phase structure,which allows the inclusion of an orbital angular momentum term to the POVBs. During propagation in free space,these POVBs initially exhibit autofocusing dynamics,and subsequently their amplitude patterns morph into a high-order Bessel-like profile characterized by a hollow core and an annular main lobe with a constant or tunable width during propagation. In contrast with numerous previous endeavors on Bessel beams,our work represents the first demonstration of long-distance free-space generation of optical vortex "pins" with their peak intensity evolution controlled by the impressed amplitude structure. Both the Poynting vectors and the optical radiation forces associated with these beams are also numerically analyzed,revealing novel properties that may be useful for a wide range of applications.展开更多
Osmotic conditions play an important role in the cell properties of human red blood cells(RBCs),which are crucial for the pathological analysis of some blood diseases such as malaria.Over the past decades,numerous eff...Osmotic conditions play an important role in the cell properties of human red blood cells(RBCs),which are crucial for the pathological analysis of some blood diseases such as malaria.Over the past decades,numerous efforts have mainly focused on the study of the RBC biomechanical properties that arise from the unique deformability of erythrocytes.Here,we demonstrate nonlinear optical effects from human RBCs suspended in different osmotic solutions.Specifically,we observe self-trapping and scattering-resistant nonlinear propagation of a laser beam through RBC suspensions under all three osmotic conditions,where the strength of the optical nonlinearity increases with osmotic pressure on the cells.This tunable nonlinearity is attributed to optical forces,particularly the forward-scattering and gradient forces.Interestingly,in aged blood samples(with lysed cells),a notably different nonlinear behavior is observed due to the presence of free hemoglobin.We use a theoretical model with an optical force-mediated nonlocal nonlinearity to explain the experimental observations.Our work on light self-guiding through scattering biosoft-matter may introduce new photonic tools for noninvasive biomedical imaging and medical diagnosis.展开更多
We demonstrate significantly improved performance of a microwave true time delay line based on an integrated optical frequency comb source. The broadband micro-comb(over 100 nm wide) features a record low free spectra...We demonstrate significantly improved performance of a microwave true time delay line based on an integrated optical frequency comb source. The broadband micro-comb(over 100 nm wide) features a record low free spectral range(FSR) of 49 GHz, resulting in an unprecedented record high channel number(81 over the C band)—the highest number of channels for an integrated comb source used for microwave signal processing. We theoretically analyze the performance of a phased array antenna and show that this large channel count results in a high angular resolution and wide beam-steering tunable range. This demonstrates the feasibility of our approach as a competitive solution toward implementing integrated photonic true time delays in radar and communications systems.展开更多
Compact terahertz(THz)functional devices are greatly sought after for high-speed wireless communication,biochemical sensing,and non-destructive inspection.However,controlled THz generation,along with transport and det...Compact terahertz(THz)functional devices are greatly sought after for high-speed wireless communication,biochemical sensing,and non-destructive inspection.However,controlled THz generation,along with transport and detection,has remained a challenge especially for chip-scale devices due to low-coupling efficiency and unavoidable absorption losses.Here,based on the topological protection of electromagnetic waves,we demonstrate nonlinear generation and topologically tuned confinement of THz waves in an engineered lithium niobate chip forming a wedge-shaped Su-Schrieffer-Heeger lattice.Experimentally measured band structures provide direct visualization of the THz localization in the momentum space,while robustness of the confined mode against chiral perturbations is also analyzed and compared for both topologically trivial and nontrivial regimes.Such topological control of THz waves may bring about new possibilities in the realization of THz integrated circuits,promising for advanced photonic applications.展开更多
Single-shot 2-dimensional optical imaging of transient phenomena is indispensable for numerous areas of study.Among existing techniques,compressed ultrafast photography(CUP)using a chirped ultrashort pulse as active i...Single-shot 2-dimensional optical imaging of transient phenomena is indispensable for numerous areas of study.Among existing techniques,compressed ultrafast photography(CUP)using a chirped ultrashort pulse as active illumination can acquire nonrepetitive time-evolving events at hundreds of trillions of frames per second.However,the bulky size and conventional configurations limit its reliability and application scopes.Superdispersive metalenses offer a promising solution for an ultracompact design with a stable performance by integrating the functions of a focusing lens and dispersive optical components into a single device.Nevertheless,existing metalens designs,typically optimized for the full visible spectrum with a relatively low spectral resolution,cannot be readily applied to active-illumination CUP.To address these limitations,here,we propose single-shot compressed ultracompact femtophotography(CUF)that synergically combines the fields of nanophotonics,optical imaging,compressed sensing,and deep learning.We develop the theory of CUF’s data acquisition composed of temporal–spectral mapping,spatial encoding,temporal shearing,and spatiotemporal integration.We also develop CUF’s image reconstruction via deep learning.Moreover,we design and evaluate CUF’s crucial components—a static binary transmissive mask,a superdispersive metalens,and a 2-dimensional sensor.Finally,using numerical simulations,CUF’s feasibility is verified using 2 synthetic scenes:an ultrafast beam sweeping across a surface and the propagation of a terahertz Cherenkov wave.展开更多
As our modern society continuously embraces the captivating concepts of automation,artificial intelligence,virtual/augmented reality,and machine learning,information technology has extensively influenced all aspects o...As our modern society continuously embraces the captivating concepts of automation,artificial intelligence,virtual/augmented reality,and machine learning,information technology has extensively influenced all aspects of our personal,professional,and social lives.Information technology will continue to transform the world for decades to come.However,the innovation of information technology not only relies on the development of sophisticated algorithms and programming but also requires novel materials and high-performance devices to achieve interactions between humans and machines.With microprocessors and other key components shrinking down to nanoscale,electronic devices have fundamentally altered our communication and working patterns,ushering in a new era of the“Internet of Things.”However,current microelectronic technologies still need to overcome the physical limitations of traditional semiconductor materials to keep“Moore's law”alive.Researchers from different fields have realized that developing novel and reliable materials is essential to improving computing capability and device portability and functionality while reducing energy consumption.The unremitting efforts of cross-field research works have broadened the academic horizon and brought together materials scientists,chemists,applied and theoretical physicists,and electrical engineers,designing new material paradigms and state-of-the-art manufacturing methods or reviving present materials for brand-new applications for next-generation information technology.展开更多
We experimentally demonstrate the generation of highly coherent Type-II micro-combs based on a microresonator nested in a fiber cavity loop, known as the filter-driven four wave mixing （FD-FWM） laser scheme. In this...We experimentally demonstrate the generation of highly coherent Type-II micro-combs based on a microresonator nested in a fiber cavity loop, known as the filter-driven four wave mixing （FD-FWM） laser scheme. In this system, the frequency spacing of the comb can be adjusted to integer multiples of the free-spectral range （FSR） of the nested mlcro-resonator by properly tuning the fiber cavity length. Sub-comb lines with single FSR spacing around the primary comb lines can be generated. Such a spectral emission is known as a ＂Type-II comb＂. Our system achieves a fully coherent output. This behavior is verified by numerical simulations. This study represents an important step forward in controlling and manipulating the dynamics of an FD-FWM laser.展开更多
Synthetic dimensions(SDs)opened the door for exploring previously inaccessible phenomena in high-dimensional space.However,construction of synthetic lattices with desired coupling properties is a challenging and unint...Synthetic dimensions(SDs)opened the door for exploring previously inaccessible phenomena in high-dimensional space.However,construction of synthetic lattices with desired coupling properties is a challenging and unintuitive task.Here,we use deep learning artificial neural networks(ANNs)to construct lattices in real space with a predesigned spectrum of mode eigenvalues,and thus to validly design the dynamics in synthetic mode dimensions.By employing judiciously chosen perturbations(wiggling of waveguides at desired frequencies),we show resonant mode coupling and tailored dynamics in SDs.Two distinct examples are illustrated:one features uniform synthetic mode coupling,and the other showcases the edge defects that allow for tailored light transport and confinement.Furthermore,we demonstrate morphing of light into a topologically protected edge mode with modified Su-Schrieffer-Heeger photonic lattices.Such an ANN-assisted construction of SDs may advance toward“utopian networks,”opening new avenues for fundamental research beyond geometric limitations as well as for applications in mode lasing,optical switching,and communication technologies.展开更多
Entangled optical quantum states are essential towards solving questions in fundamental physics and are at the heart of applications in quantum information science. For advancing the research and development of quantu...Entangled optical quantum states are essential towards solving questions in fundamental physics and are at the heart of applications in quantum information science. For advancing the research and development of quantum technologies, practical access to the generation and manipulation of photon states carrying significant quantum resources is required. Recently, integrated photonics has become a leading platform for the compact and cost- efficient generation and processing of optical quantum states. Despite significant advances, most on-chip non- classical light sources are still limited to basic bi-photon systems formed by two-dimensional states （i.e., qubits）. An interesting approach beating large potential is the use of the time or frequency domain to enabled the scalable on- chip generation of complex states. In this manuscript, we review recent efforts in using on-chip optical frequency combs for quantum state generation and telecommunica- tions components for their coherent control. In particular, the generation of bi- and multi-photon entangled qubit states has been demonstrated, based on a discrete time domain approach. Moreover, the on-chip generation of high-dimensional entangled states （quDits） has recentlybeen realized, wherein the photons are created in a coherent superposition of multiple pure frequency modes. The time- and frequency-domain states formed with on-chip frequency comb sources were coherently manipulated via off-the-shelf telecommunications compo- nents. Our results suggest that microcavity-based entangled photon states and their coherent control using accessible telecommunication infrastructures can open up new venues for scalable quantum information science.展开更多
文摘This paper is devoted to reviewing the results achieved so far in the application of the single-pixel imaging technique to terahertz(THz)systems.The use of THz radiation for imaging purposes has been largely explored in the last twenty years,due to the unique capabilities of this kind of radiation in interrogating material properties.However,THz imaging systems are still limited by the long acquisition time required to reconstruct the object image and significant efforts have been recently directed to overcome this drawback.One of the most promising approaches in this sense is the so-called“single-pixel”imaging,which in general enables image reconstruction by patterning the beam probing the object and measuring the total transmission(or reflection)with a single-pixel detector(i.e.,with no spatial resolution).The main advantages of such technique are that i)no bulky moving parts are required to raster-scan the object and ii)compressed sensing(CS)algorithms,which allow an appropriate reconstruction of the image with an incomplete set of measurements,can be successfully implemented.Overall,this can result in a reduction of the acquisition time.In this review,we cover the experimental solutions proposed to implement such imaging technique at THz frequencies,as well as some practical uses for typical THz applications.
文摘We review recent work on broadband RF channelizers based on integrated optical frequency Kerr micro-combs combined with passive micro-ring resonator filters,with microcombs having channel spacings of 200 and 49 GHz.This approach to realizing RF channelizers offers reduced complexity,size,and potential cost for a wide range of applications to microwave signal detection.
文摘We review recent work on narrowband orthogonally polarized optical RF single sideband generators as well as dualchannel equalization,both based on high-Q integrated ring resonators.The devices operate in the optical telecommunications C-band and enable RF operation over a range of either fixed or thermally tuneable frequencies.They operate via TE/TM mode birefringence in the resonator.We achieve a very large dynamic tuning range of over 55 dB for both the optical carrier-to-sideband ratio and the dual-channel RF equalization for both the fixed and tunable devices.
基金supported by the Natural Sciences and Engineering Research Council of Canada(NSERC)through the Steacie Memorial Fellowship as well as through the Canada Research Chair Program and the MEIE in Quebecsupported through the Australian Research Council Discovery Projects programme(DP150104327)+4 种基金the support of the People Programme(Marie Curie Actions)of the European Union’s FP7 Programme under REA Grant Agreements No.627478(THREEPLE)the Australian Research Council(ARC)Centre of Excellence(CUDOS,CE110001018)Laureate Fellowship(FL120100029)the Discovery Early Career Researcher Award(DE120100226)programmessupport from the ITMO and Professorship Program(grant 074-U 01)and the 1000 Talents Sichuan Program.
文摘The ability to generate complex optical photon states involving entanglement between multiple optical modes is not only critical to advancing our understanding of quantum mechanics but will play a key role in generating many applications in quantum technologies.These include quantum communications,computation,imaging,microscopy and many other novel technologies that are constantly being proposed.However,approaches to generating parallel multiple,customisable bi-and multi-entangled quantum bits(qubits)on a chip are still in the early stages of development.Here,we review recent advances in the realisation of integrated sources of photonic quantum states,focusing on approaches based on nonlinear optics that are compatible with contemporary optical fibre telecommunications and quantum memory platforms as well as with chip-scale semiconductor technology.These new and exciting platforms hold the promise of compact,low-cost,scalable and practical implementations of sources for the generation and manipulation of complex quantum optical states on a chip,which will play a major role in bringing quantum technologies out of the laboratory and into the real world.
基金This research is supported by the National Key R&D Program of China under Grant No.2017YFA0303800the National Natural Science Foundation(11922408,91750204,11674180)+2 种基金PCSIRT,and the 111 Project(No.B07013)in ChinaD.B.acknowledges support from the 66 Postdoctoral Science Grant of ChinaD.J.and H.B.acknowledge support in part by the Croatian Science Foundation Grant No.IP-2016-06-5885 SynthMagIA and the QuantiXLie Center of Excellence,a project co-financed by the Croatian Government and European Union through the European Regional Development Fund-the Competitiveness and Cohesion Operational Programme(Grant KK.01.1.1.01.0004)。
文摘Higher-order topological insulators(HOTIs)are recently discovered topological phases,possessing symmetry-protected corner states with fractional charges.An unexpected connection between these states and the seemingly unrelated phenomenon of bound states in the continuum(BICs)was recently unveiled.When nonlinearity is added to the HOTI system,a number of fundamentally important questions arise.For example,how does nonlinearity couple higher-order topological BICs with the rest of the system,including continuum states?In fact,thus far BICs in nonlinear HOTIs have remained unexplored.Here we unveil the interplay of nonlinearity,higher-order topology,and BICs in a photonic platform.We observe topological corner states that are also BICs in a laser-written second-order topological lattice and further demonstrate their nonlinear coupling with edge(but not bulk)modes under the proper action of both self-focusing and defocusing nonlinearities.Theoretically,we calculate the eigenvalue spectrum and analog of the Zak phase in the nonlinear regime,illustrating that a topological BIC can be actively tuned by nonlinearity in such a photonic HOTI.Our studies are applicable to other nonlinear HOTI systems,with promising applications in emerging topology-driven devices.
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National Key Research and Development Program of China (2017YFA0303800)National Natural Science Foundation of China (11674180,61575098,91750204)+3 种基金111 Project in China (B07013)NSERC Discovery and Strategic grants in CanadaMESI in Quebec66 Postdoctoral Science Grant of China。
文摘We demonstrate,both analytically and experimentally,free-space pin-like optical vortex beams (POVBs). Such angular-momentum-carrying beams feature tunable peak intensity and undergo robust antidiffracting propagation,realized by judiciously modulating both the amplitude and the phase profile of a standard laser beam.Specifically,they are generated by superimposing a radially symmetric power-law phase on a helical phase structure,which allows the inclusion of an orbital angular momentum term to the POVBs. During propagation in free space,these POVBs initially exhibit autofocusing dynamics,and subsequently their amplitude patterns morph into a high-order Bessel-like profile characterized by a hollow core and an annular main lobe with a constant or tunable width during propagation. In contrast with numerous previous endeavors on Bessel beams,our work represents the first demonstration of long-distance free-space generation of optical vortex "pins" with their peak intensity evolution controlled by the impressed amplitude structure. Both the Poynting vectors and the optical radiation forces associated with these beams are also numerically analyzed,revealing novel properties that may be useful for a wide range of applications.
基金the National Key R&D Program of China(2017YFA0303800)the National Natural Science Foundation of China(91750204,11504184,11604058)+3 种基金the NSERC through the Steacie,Strategic,Discovery and Acceleration Grants Schemesthe Canada Research Chair Program(Canada)additional support by the Government of the Russian Federation through the ITMO Fellowship and Professorship Program(grant 074-U 01)the 1000 Talents Sichuan Program in China.
文摘Osmotic conditions play an important role in the cell properties of human red blood cells(RBCs),which are crucial for the pathological analysis of some blood diseases such as malaria.Over the past decades,numerous efforts have mainly focused on the study of the RBC biomechanical properties that arise from the unique deformability of erythrocytes.Here,we demonstrate nonlinear optical effects from human RBCs suspended in different osmotic solutions.Specifically,we observe self-trapping and scattering-resistant nonlinear propagation of a laser beam through RBC suspensions under all three osmotic conditions,where the strength of the optical nonlinearity increases with osmotic pressure on the cells.This tunable nonlinearity is attributed to optical forces,particularly the forward-scattering and gradient forces.Interestingly,in aged blood samples(with lysed cells),a notably different nonlinear behavior is observed due to the presence of free hemoglobin.We use a theoretical model with an optical force-mediated nonlocal nonlinearity to explain the experimental observations.Our work on light self-guiding through scattering biosoft-matter may introduce new photonic tools for noninvasive biomedical imaging and medical diagnosis.
基金Australian Research Council(ARC)Discovery Projects Program(DP150104327)Strategic,Discovery and Acceleration Grants Schemes of Natural Sciences and Engineering Research Council of Canada(NSERC)+4 种基金MESI PSR-SIIRI Initiative in QuebecCanada Research Chairs ProgramITMO Fellowship and Professorship Program of the Government of the Russian Federation(074-U 01)1000 Talents Sichuan Program in ChinaStrategic Priority Research Program of the Chinese Academy of Sciences(CAS)(XDB24030000)
文摘We demonstrate significantly improved performance of a microwave true time delay line based on an integrated optical frequency comb source. The broadband micro-comb(over 100 nm wide) features a record low free spectral range(FSR) of 49 GHz, resulting in an unprecedented record high channel number(81 over the C band)—the highest number of channels for an integrated comb source used for microwave signal processing. We theoretically analyze the performance of a phased array antenna and show that this large channel count results in a high angular resolution and wide beam-steering tunable range. This demonstrates the feasibility of our approach as a competitive solution toward implementing integrated photonic true time delays in radar and communications systems.
基金This work was supported by the National Key Research and Development Program of China(2017YFA0303800,2017YFA0305100)PCSIRT(IRT_13R29)+3 种基金Higher Education Discipline Innovation Project(B07013)the National Natural Science Foundation of China(12134006,12074201,11922408)the China Postdoctoral Science Foundation(BX2021134,2021M701790)as well as NSERC and the CRC program in Canada.
文摘Compact terahertz(THz)functional devices are greatly sought after for high-speed wireless communication,biochemical sensing,and non-destructive inspection.However,controlled THz generation,along with transport and detection,has remained a challenge especially for chip-scale devices due to low-coupling efficiency and unavoidable absorption losses.Here,based on the topological protection of electromagnetic waves,we demonstrate nonlinear generation and topologically tuned confinement of THz waves in an engineered lithium niobate chip forming a wedge-shaped Su-Schrieffer-Heeger lattice.Experimentally measured band structures provide direct visualization of the THz localization in the momentum space,while robustness of the confined mode against chiral perturbations is also analyzed and compared for both topologically trivial and nontrivial regimes.Such topological control of THz waves may bring about new possibilities in the realization of THz integrated circuits,promising for advanced photonic applications.
基金supported in part by Natural Sciences and Engineering Research Council of Canada(RGPIN-2017-05959,RGPAS-2017-507845,I2IPJ-555593-20,RGPIN-2018-06217,RGPAS-2018-522650,and RGPIN-2019-06138)Canada Foundation for Innovation and Ministere de P'Economie et de P'Innovation du Quebec(37146)+1 种基金Fonds de Recherche du Quebec-Nature et Technologies(203345-Centre d'Optique,Photonique,et Lasers)Canada Research Chairs Program(CRC-2022-00119)。
文摘Single-shot 2-dimensional optical imaging of transient phenomena is indispensable for numerous areas of study.Among existing techniques,compressed ultrafast photography(CUP)using a chirped ultrashort pulse as active illumination can acquire nonrepetitive time-evolving events at hundreds of trillions of frames per second.However,the bulky size and conventional configurations limit its reliability and application scopes.Superdispersive metalenses offer a promising solution for an ultracompact design with a stable performance by integrating the functions of a focusing lens and dispersive optical components into a single device.Nevertheless,existing metalens designs,typically optimized for the full visible spectrum with a relatively low spectral resolution,cannot be readily applied to active-illumination CUP.To address these limitations,here,we propose single-shot compressed ultracompact femtophotography(CUF)that synergically combines the fields of nanophotonics,optical imaging,compressed sensing,and deep learning.We develop the theory of CUF’s data acquisition composed of temporal–spectral mapping,spatial encoding,temporal shearing,and spatiotemporal integration.We also develop CUF’s image reconstruction via deep learning.Moreover,we design and evaluate CUF’s crucial components—a static binary transmissive mask,a superdispersive metalens,and a 2-dimensional sensor.Finally,using numerical simulations,CUF’s feasibility is verified using 2 synthetic scenes:an ultrafast beam sweeping across a surface and the propagation of a terahertz Cherenkov wave.
文摘As our modern society continuously embraces the captivating concepts of automation,artificial intelligence,virtual/augmented reality,and machine learning,information technology has extensively influenced all aspects of our personal,professional,and social lives.Information technology will continue to transform the world for decades to come.However,the innovation of information technology not only relies on the development of sophisticated algorithms and programming but also requires novel materials and high-performance devices to achieve interactions between humans and machines.With microprocessors and other key components shrinking down to nanoscale,electronic devices have fundamentally altered our communication and working patterns,ushering in a new era of the“Internet of Things.”However,current microelectronic technologies still need to overcome the physical limitations of traditional semiconductor materials to keep“Moore's law”alive.Researchers from different fields have realized that developing novel and reliable materials is essential to improving computing capability and device portability and functionality while reducing energy consumption.The unremitting efforts of cross-field research works have broadened the academic horizon and brought together materials scientists,chemists,applied and theoretical physicists,and electrical engineers,designing new material paradigms and state-of-the-art manufacturing methods or reviving present materials for brand-new applications for next-generation information technology.
基金Engineering and Physical Sciences Research Council(EPSRC)(EP/M013294/1)MC REA(630833,327627)+3 种基金Horizon 2020 Framework Programme(H2020)(725046)CRC,Natural Sciences and Engineering Research Council of Canada(NSERC)(074-U 01)MEIE,the ITMO and its Professorship Program1000 Talents Sichuan Program,China
文摘We experimentally demonstrate the generation of highly coherent Type-II micro-combs based on a microresonator nested in a fiber cavity loop, known as the filter-driven four wave mixing （FD-FWM） laser scheme. In this system, the frequency spacing of the comb can be adjusted to integer multiples of the free-spectral range （FSR） of the nested mlcro-resonator by properly tuning the fiber cavity length. Sub-comb lines with single FSR spacing around the primary comb lines can be generated. Such a spectral emission is known as a ＂Type-II comb＂. Our system achieves a fully coherent output. This behavior is verified by numerical simulations. This study represents an important step forward in controlling and manipulating the dynamics of an FD-FWM laser.
基金supported by the National Key R&D Program of China(Grant No.2022YFA1404800)the National Natural Science Foundation of China(Grant Nos.12134006,12274242,11922408,and 12204252)+7 种基金the China Postdoctoral Science Foundation(Grant Nos.BX2021134 and 2021M701790)the Natural Science Foundation of Tianjin for Distinguished Young Scholars(Grant No.21JCJQJC00050)PCSIRT(Grant No.IRT_13R29)the 111 Project(Grant No.B23045)in Chinasupport from the Croatian-Chinese bilateral project funded by the Ministry of Science and Education in Croatia and the Ministry of Science and Technology in Chinasupport from the project“Implementation of cutting-edge research and its application as part of the Scientific Center of Excellence for Quantum and Complex Systems,and Representations of Lie Algebras,”European UnionEuropean Regional Development Fundsupport from the Canada Research Chair program and from NSERC via the Discovery Grant program
文摘Synthetic dimensions(SDs)opened the door for exploring previously inaccessible phenomena in high-dimensional space.However,construction of synthetic lattices with desired coupling properties is a challenging and unintuitive task.Here,we use deep learning artificial neural networks(ANNs)to construct lattices in real space with a predesigned spectrum of mode eigenvalues,and thus to validly design the dynamics in synthetic mode dimensions.By employing judiciously chosen perturbations(wiggling of waveguides at desired frequencies),we show resonant mode coupling and tailored dynamics in SDs.Two distinct examples are illustrated:one features uniform synthetic mode coupling,and the other showcases the edge defects that allow for tailored light transport and confinement.Furthermore,we demonstrate morphing of light into a topologically protected edge mode with modified Su-Schrieffer-Heeger photonic lattices.Such an ANN-assisted construction of SDs may advance toward“utopian networks,”opening new avenues for fundamental research beyond geometric limitations as well as for applications in mode lasing,optical switching,and communication technologies.
文摘Entangled optical quantum states are essential towards solving questions in fundamental physics and are at the heart of applications in quantum information science. For advancing the research and development of quantum technologies, practical access to the generation and manipulation of photon states carrying significant quantum resources is required. Recently, integrated photonics has become a leading platform for the compact and cost- efficient generation and processing of optical quantum states. Despite significant advances, most on-chip non- classical light sources are still limited to basic bi-photon systems formed by two-dimensional states （i.e., qubits）. An interesting approach beating large potential is the use of the time or frequency domain to enabled the scalable on- chip generation of complex states. In this manuscript, we review recent efforts in using on-chip optical frequency combs for quantum state generation and telecommunica- tions components for their coherent control. In particular, the generation of bi- and multi-photon entangled qubit states has been demonstrated, based on a discrete time domain approach. Moreover, the on-chip generation of high-dimensional entangled states （quDits） has recentlybeen realized, wherein the photons are created in a coherent superposition of multiple pure frequency modes. The time- and frequency-domain states formed with on-chip frequency comb sources were coherently manipulated via off-the-shelf telecommunications compo- nents. Our results suggest that microcavity-based entangled photon states and their coherent control using accessible telecommunication infrastructures can open up new venues for scalable quantum information science.
