Integrated photonics provides unprecedented opportunities to pursue advanced nonlinear light sources with lowpower consumptions and small footprints in a scalable manner,such as microcombs,chip-scale optical parametri...Integrated photonics provides unprecedented opportunities to pursue advanced nonlinear light sources with lowpower consumptions and small footprints in a scalable manner,such as microcombs,chip-scale optical parametric oscillators and integrated quantum light sources.Among a variety of nonlinear optical processes,high-efficiency second harmonic generation(SHG)on-chip is particularly appealing and yet challenging.In this work,we present efficient SHG in highly engineerable semi-nonlinear waveguides consisting of electron-beam resist waveguides and thin-film silicon nitride(SiN)/lithium niobate(LN).By carefully designing octave-separating bound states in the continuum(BICs)for the nonlinear interacting waves in such a hybrid structure,we have simultaneously optimized the losses for both fundamental frequency(FF)and second harmonic(SH)waves and achieved modal phasing matching and maximized the nonlinear modal overlap between the FF and SH waves,which results in an experimental conversion efficiency up to 4.05%W^(-1)cm^(-2).Our work provides a versatile and fabrication-friendly platform to explore on-chip nonlinear optical processes with high effciency in the context of nanophotonics and quantum optics.展开更多
Optical microcavities have widely been employed to enhance either the optical excitation or the photon emission processes for boosting light-matter interactions at the nanoscale.When both the excitation and emission p...Optical microcavities have widely been employed to enhance either the optical excitation or the photon emission processes for boosting light-matter interactions at the nanoscale.When both the excitation and emission processes are simultaneously facilitated by the optical resonances provided by the microcavities,as referred to the dual-resonance condition in this article,the performances of many nanophotonic devices approach to the optima.In this work,we present versatile accessing of dual-resonance conditions in deterministically coupled quantum-dot(QD)-micropillars,which enables emission from neutral exciton(X)—charged exciton(CX)transition with improved single-photon purity.In addition,the rarely observed up-converted single-photon emission process is achieved under dual-resonance conditions.We further exploit the vectorial nature of the high-order cavity modes to significantly improve the excitation efficiency under the dual-resonance condition.The dual-resonance enhanced light-matter interactions in the quantum regime provide a viable path for developing integrated quantum photonic devices based on cavity quantum electrodynamics(QED)effect,e.g.,highly efficient quantum light sources and quantum logical gates.展开更多
Self-assembled semiconductor quantum dots(QDs)are potentially scalable candidates for solid-state single-photon emitters which deterministically generate one single-photon per excitation.Such on-demand single-photon s...Self-assembled semiconductor quantum dots(QDs)are potentially scalable candidates for solid-state single-photon emitters which deterministically generate one single-photon per excitation.Such on-demand single-photon sources serve as one of the key elements in modern photonic quantum technologies[1].Until very recently,near-optimal QD single-photon sources with simultaneous high degree of brightness,single-photon purity and indistin-展开更多
The emerging hybrid integrated quantum photonics combines the advantages of different functional components into a single chip to meet the stringent requirements for quantum information processing.Despite the tremendo...The emerging hybrid integrated quantum photonics combines the advantages of different functional components into a single chip to meet the stringent requirements for quantum information processing.Despite the tremendous progress in hybrid integrations of III-V quantum emitters with silicon-based photonic circuits and superconducting single-photon detectors,on-chip optical excitations of quantum emitters via miniaturized lasers towards single-photon sources(SPSs)with low power consumptions,small device footprints,and excellent coherence properties is highly desirable yet illusive.In this work,we present realizations of bright semiconductor SPSs heterogeneously integrated with on-chip electrically-injected microlasers.Different from previous one-by-one transfer printing technique implemented in hybrid quantum dot(QD)photonic devices,multiple deterministically coupled QD-circular Bragg Grating(CBG)SPSs were integrated with electrically-injected micropillar lasers at one time via a potentially scalable transfer printing process assisted by the wide-field photoluminescence(PL)imaging technique.Optically pumped by electrically-injected microlasers,pure single photons are generated with a high-brightness of a count rate of 3.8 M/s and an extraction efficiency of 25.44%.Such a high-brightness is due to the enhancement by the cavity mode of the CBG,which is confirmed by a Purcell factor of 2.5.Our work provides a powerful tool for advancing hybrid integrated quantum photonics in general and boosts the developments for realizing highly-compact,energy-efficient and coherent SPSs in particular.展开更多
Since 1992,task groups have used free nerve auto grafts to bridge partially transected nerves from the dominant area of the normal cerebral cortex to nerves that innervate spastic muscles from a diseased cerebral cort...Since 1992,task groups have used free nerve auto grafts to bridge partially transected nerves from the dominant area of the normal cerebral cortex to nerves that innervate spastic muscles from a diseased cerebral cortex,using transplanting sutures to alleviate the muscle spasm of cerebral palsy caused by different diseases. This has facilitated rebuilding of some of its neurological function. In this study,80 such patients were followed up,including 20 patients with traumatic brain injury,32 patients with stroke,and 28 pediatric patients with cerebral palsy. After postoperative follow-up of 3 to 21 years,the efficacy rate of this operation was 100% and the excellent and good spasm relief rate was 82.5%.展开更多
Recent advancements in quantum photonic circuits have significantly influenced the field of quantum information processing.The pursuit of an integrated quantum photonic circuit that offers an active,stable platform fo...Recent advancements in quantum photonic circuits have significantly influenced the field of quantum information processing.The pursuit of an integrated quantum photonic circuit that offers an active,stable platform for large-scale integration and high processing efficiency remains a key objective.The grating coupler,as a crucial element for an efficient transformation output interface in the integrated quantum photonic circuits,presents significant potential for practical applications.Here,we demonstrate the integration block of a highly efficient shallow-etched focusing apodized grating coupler with indium arsenide(InAs)quantum dots(QDs)in gallium arsenide(GaAs)on a SiO2substrate for active quantum photonic circuits.The designed grating couplers possess a high efficiency over 90% in the broadband(900-930 nm)from the circuit to free space,and a nearly-perfect match with the fiber mode.Experimentally,the efficiency to free space reaches 81.8%,and the match degree with the fiber mode is high up to 92.1%.The proposed integration block offers the potential for large-scale integration of active quantum photonic circuits due to its stable solid substrate and highly performant output for quantum measurements.展开更多
基金National Key R&D Program of China(2021YFA1400803)Guangdong Natural Science Funds for Distinguished Young Scholars(2022B1515020067)+2 种基金National Natural Science Foundation of China(11904424,11874437,62035017)Key-Area R&D Program of Guangdong Province(2018B030329001)The Fundamental Research Funds for the Central Universities,Sun Yat-sen University(221gqb32).
文摘Integrated photonics provides unprecedented opportunities to pursue advanced nonlinear light sources with lowpower consumptions and small footprints in a scalable manner,such as microcombs,chip-scale optical parametric oscillators and integrated quantum light sources.Among a variety of nonlinear optical processes,high-efficiency second harmonic generation(SHG)on-chip is particularly appealing and yet challenging.In this work,we present efficient SHG in highly engineerable semi-nonlinear waveguides consisting of electron-beam resist waveguides and thin-film silicon nitride(SiN)/lithium niobate(LN).By carefully designing octave-separating bound states in the continuum(BICs)for the nonlinear interacting waves in such a hybrid structure,we have simultaneously optimized the losses for both fundamental frequency(FF)and second harmonic(SH)waves and achieved modal phasing matching and maximized the nonlinear modal overlap between the FF and SH waves,which results in an experimental conversion efficiency up to 4.05%W^(-1)cm^(-2).Our work provides a versatile and fabrication-friendly platform to explore on-chip nonlinear optical processes with high effciency in the context of nanophotonics and quantum optics.
基金This research was supported by the National Key R&D Program of China(2018YFA0306100)Key-Area Research and Development Program of Guangdong Province(2018B030329001)+3 种基金Science and Technology Program of Guangzhou(202103030001)the National Natural Science Foundation of China(11874437,62035017)the national super-computer center in Guangzhou,the National Natural Science Foundation of China(12074442,91836303)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01X121).
文摘Optical microcavities have widely been employed to enhance either the optical excitation or the photon emission processes for boosting light-matter interactions at the nanoscale.When both the excitation and emission processes are simultaneously facilitated by the optical resonances provided by the microcavities,as referred to the dual-resonance condition in this article,the performances of many nanophotonic devices approach to the optima.In this work,we present versatile accessing of dual-resonance conditions in deterministically coupled quantum-dot(QD)-micropillars,which enables emission from neutral exciton(X)—charged exciton(CX)transition with improved single-photon purity.In addition,the rarely observed up-converted single-photon emission process is achieved under dual-resonance conditions.We further exploit the vectorial nature of the high-order cavity modes to significantly improve the excitation efficiency under the dual-resonance condition.The dual-resonance enhanced light-matter interactions in the quantum regime provide a viable path for developing integrated quantum photonic devices based on cavity quantum electrodynamics(QED)effect,e.g.,highly efficient quantum light sources and quantum logical gates.
文摘Self-assembled semiconductor quantum dots(QDs)are potentially scalable candidates for solid-state single-photon emitters which deterministically generate one single-photon per excitation.Such on-demand single-photon sources serve as one of the key elements in modern photonic quantum technologies[1].Until very recently,near-optimal QD single-photon sources with simultaneous high degree of brightness,single-photon purity and indistin-
基金National Natural Science Foundation of China(62035017,12074442)National Key Research and Development Program of China(2018YFA0306103)+1 种基金Science and Technology Program of Guangzhou(202103030001)Hisilicon Technologies CO.,LIMITED and the national super-computer center in Guangzhou.
文摘The emerging hybrid integrated quantum photonics combines the advantages of different functional components into a single chip to meet the stringent requirements for quantum information processing.Despite the tremendous progress in hybrid integrations of III-V quantum emitters with silicon-based photonic circuits and superconducting single-photon detectors,on-chip optical excitations of quantum emitters via miniaturized lasers towards single-photon sources(SPSs)with low power consumptions,small device footprints,and excellent coherence properties is highly desirable yet illusive.In this work,we present realizations of bright semiconductor SPSs heterogeneously integrated with on-chip electrically-injected microlasers.Different from previous one-by-one transfer printing technique implemented in hybrid quantum dot(QD)photonic devices,multiple deterministically coupled QD-circular Bragg Grating(CBG)SPSs were integrated with electrically-injected micropillar lasers at one time via a potentially scalable transfer printing process assisted by the wide-field photoluminescence(PL)imaging technique.Optically pumped by electrically-injected microlasers,pure single photons are generated with a high-brightness of a count rate of 3.8 M/s and an extraction efficiency of 25.44%.Such a high-brightness is due to the enhancement by the cavity mode of the CBG,which is confirmed by a Purcell factor of 2.5.Our work provides a powerful tool for advancing hybrid integrated quantum photonics in general and boosts the developments for realizing highly-compact,energy-efficient and coherent SPSs in particular.
基金supported by the Shanghai Science and Technology Project(No.10411953800)
文摘Since 1992,task groups have used free nerve auto grafts to bridge partially transected nerves from the dominant area of the normal cerebral cortex to nerves that innervate spastic muscles from a diseased cerebral cortex,using transplanting sutures to alleviate the muscle spasm of cerebral palsy caused by different diseases. This has facilitated rebuilding of some of its neurological function. In this study,80 such patients were followed up,including 20 patients with traumatic brain injury,32 patients with stroke,and 28 pediatric patients with cerebral palsy. After postoperative follow-up of 3 to 21 years,the efficacy rate of this operation was 100% and the excellent and good spasm relief rate was 82.5%.
基金supported by the National Key R&D Program of China(Grant No.2021YFA1400800)the National Natural Science Foundation of China(Grant No.12334017)the Key-Area Research and Development Program of Guangdong Province(Grant No.2018B030329001)。
文摘Recent advancements in quantum photonic circuits have significantly influenced the field of quantum information processing.The pursuit of an integrated quantum photonic circuit that offers an active,stable platform for large-scale integration and high processing efficiency remains a key objective.The grating coupler,as a crucial element for an efficient transformation output interface in the integrated quantum photonic circuits,presents significant potential for practical applications.Here,we demonstrate the integration block of a highly efficient shallow-etched focusing apodized grating coupler with indium arsenide(InAs)quantum dots(QDs)in gallium arsenide(GaAs)on a SiO2substrate for active quantum photonic circuits.The designed grating couplers possess a high efficiency over 90% in the broadband(900-930 nm)from the circuit to free space,and a nearly-perfect match with the fiber mode.Experimentally,the efficiency to free space reaches 81.8%,and the match degree with the fiber mode is high up to 92.1%.The proposed integration block offers the potential for large-scale integration of active quantum photonic circuits due to its stable solid substrate and highly performant output for quantum measurements.
