The development of quantum networks is paramount towards practical and secure communications.Quantum digital signatures(QDS)offer an information-theoretically secure solution for ensuring data integrity,authenticity,a...The development of quantum networks is paramount towards practical and secure communications.Quantum digital signatures(QDS)offer an information-theoretically secure solution for ensuring data integrity,authenticity,and nonrepudiation,rapidly growing from proof-of-concept to robust demonstrations.However,previous QDS systems relied on expensive and bulky optical equipment,limiting large-scale deployment and reconfigurable networking construction.Here,we introduce and verify a chip-based QDS network,placing the complicated and expensive measurement devices in the central relay while each user needs only a low-cost transmitter.We demonstrate the network with a three-node setup using an integrated encoder chip and decoder chip.By developing a 1-decoy-state one-time universal hashing-QDS protocol,we achieve a maximum signature rate of 0.0414 times per second for a 1 Mbit messages over fiber distances up to 200 km,surpassing all current state-of-the-art QDS experiments.This study validates the feasibility of chip-based QDS,paving the way for large-scale deployment and integration with existing fiber infrastructure.展开更多
The design of a conventional zoom lens is always challenging because it requires not only sophisticated optical design strategy, but also complex and precise mechanical structures for system adjustment. Here, we propo...The design of a conventional zoom lens is always challenging because it requires not only sophisticated optical design strategy, but also complex and precise mechanical structures for system adjustment. Here, we propose a continuous-zoom lens consisting of two chiral geometric metasurfaces with dielectric nanobrick arrays sitting on a transparent substrate. The metalens can continuously vary the focal length by rotating either of the two metasurfaces around its optical axis without changing any other conditions. Due to the polarization dependence of the geometric metasurface, the positive and negative polarities are interchangeable in one identical metalens only by changing the handedness of the incident circularly polarized light, which can generate varying focal lengths ranging from-∞ to +∞ in principle.展开更多
The unwanted zero-order light accompanied by the birth of diffractive optical elements and caused mainly by fabrication errors and wavelength variations is a key factor that deteriorates the performance of diffraction...The unwanted zero-order light accompanied by the birth of diffractive optical elements and caused mainly by fabrication errors and wavelength variations is a key factor that deteriorates the performance of diffraction-related optical devices such as holograms,gratings,beam shapers,beam splitters,optical diffusers,and diffractive microlenses.Here,inspired by the unique characteristic of nano-polarizer-based metasurfaces for both positive and negative amplitude modulation of incident light,we propose a general design paradigm to eliminate zero-order diffraction without burdening the metasurface design and fabrication.The experimentally demonstrated metahologram,which projects a holographic image with a wide angle of 70°×70°in the for field,presents a very low zero-order intensity(only 0.7%of the total energy of the reconstructed image).More importantly,the zero-orderfree meta-hologram has a large tolerance limit for wavelength variations(under a broadband illumination from520 to 660 nm),which brings important technical advances.The strategy proposed could significantly relieve the fabrication difficulty of metasurfaces and be viable for various diffractive-optics-related applications includingholography,laser beam shaping,optical data storage,vortex beam generation,and so on.展开更多
Polarization optics plays a pivotal role in diffractive,refractive,and emerging flat optics,and has been widely employed in contemporary optical industries and daily life.Advanced polarization manipulation leads to ro...Polarization optics plays a pivotal role in diffractive,refractive,and emerging flat optics,and has been widely employed in contemporary optical industries and daily life.Advanced polarization manipulation leads to robust control of the polarization direction of light.Nevertheless,polarization control has been studied largely independent of the phase or intensity of light.Here,we propose and experimentally validate a Malus-metasurface-assisted paradigm to enable simultaneous and independent control of the intensity and phase properties of light simply by polarization modulation.The orientation degeneracy of the classical Malus’s law implies a new degree of freedom and enables us to establish a one-to-many mapping strategy for designing anisotropic plasmonic nanostructures to engineer the Pancharatnam–Berry phase profile,while keeping the continuous intensity modulation unchanged.The proposed Malus metadevice can thus generate a near-field greyscale pattern,and project an independent far-field holographic image using an ultrathin and single-sized metasurface.This concept opens up distinct dimensions for conventional polarization optics,which allows one to merge the functionality of phase manipulation into an amplitudemanipulation-assisted optical component to form a multifunctional nano-optical device without increasing the complexity of the nanostructures.It can empower advanced applications in information multiplexing and encryption,anti-counterfeiting,dual-channel display for virtual/augmented reality,and many other related fields.展开更多
Integrated photonics provides a promising platform for quantum key distribution(QKD)system in terms of miniaturization,robustness,and scalability.Tremendous QKD works based on integrated photonics have been reported.N...Integrated photonics provides a promising platform for quantum key distribution(QKD)system in terms of miniaturization,robustness,and scalability.Tremendous QKD works based on integrated photonics have been reported.Nonetheless,most current chip-based QKD implementations require additional off-chip hardware to demodulate quantum states or perform auxiliary tasks such as time synchronization and polarization basis tracking.Here,we report a demonstration of resource-efficient chip-based BB84 QKD with a silicon-based encoder and a decoder.In our scheme,the time synchronization and polarization compensation are implemented relying on the preparation and measurement of the quantum states generated by on-chip devices;thus,we need no additional hardware.The experimental tests show that our scheme is highly stable with a low intrinsic quantum bit error rate of 0.50%±0.02%in a 6 h continuous run.Furthermore,over a commercial fiber channel up to150 km,the system enables the realization of secure key distribution at a rate of 866 bit/s.Our demonstration paves the way for a low-cost,wafer-scale manufactured QKD system.展开更多
Silicon-based polarization-encoding quantum key distribution(QKD)has been extensively studied due to its advantageous characteris-tics of its low cost and robustness.However,given the difficulty of fabricating polariz...Silicon-based polarization-encoding quantum key distribution(QKD)has been extensively studied due to its advantageous characteris-tics of its low cost and robustness.However,given the difficulty of fabricating polarized independent components on the chip,previ-ous studies have only adopted off-chip devices to demodulate the quantum states or perform polarization compensation.In the cur-rent work,a fully chip-based decoder for polarization-encoding QKD was proposed.The chip realized a polarization state analyzer and compensated for the BB84 protocol without the requirement of additional hardware,which was based on a polarization-to-path conversion method utilizing a polarization splitter-rotator.The chip was fabricated adopting a standard silicon photonics foundry,which was of a compact design and suitable for mass production.In the experimental stability test,an average quantum bit error rate of 0.59%was achieved through continuous operation for 10 h with-out any polarization feedback.Furthermore,the chip enabled the automatic compensation of the fiber polarization drift when utiliz-ing the developed feedback algorithm,which was emulated by a ran-dom fiber polarization scrambler.Moreover,a finite-key secret rate of 240 bps over a fiber spool of 100 km was achieved in the case of the QKD demonstration.This study marks an important step to-ward the integrated,practical,and large-scale deployment of QKD systems.展开更多
With the rapid progress in computer science,including artificial intelligence,big data and cloud computing,full-space spot generation can be pivotal to many practical applications,such as facial recognition,motion det...With the rapid progress in computer science,including artificial intelligence,big data and cloud computing,full-space spot generation can be pivotal to many practical applications,such as facial recognition,motion detection,augmented reality,etc.These opportunities may be achieved by using diffractive optical elements(DOEs)or light detection and ranging(LIDAR).However,DOEs suffer from intrinsic limitations,such as demanding depth-controlled fabrication techniques,large thicknesses(more than the wavelength),Lambertian operation only in half space,etc.LIDAR nevertheless relies on complex and bulky scanning systems,which hinders the miniaturization of the spot generator.Here,inspired by a Lambertian scatterer,we report a Hermitian-conjugate metasurface scrambling the incident light to a cloud of random points in full space with compressed information density,functioning in both transmission and reflection spaces.Over 4044 random spots are experimentally observed in the entire space,covering angles at nearly 90°.Our scrambling metasurface is made of amorphous silicon with a uniform subwavelength height,a nearly continuous phase coverage,a lightweight,flexible design,and low-heat dissipation.Thus,it may be mass produced by and integrated into existing semiconductor foundry designs.Our work opens important directions for emerging 3D recognition sensors,such as motion sensing,facial recognition,and other applications.展开更多
基金supported by the National Natural Science Foundation of China(Nos.12274223,62171144,62031024,and 62171485)the Guangxi Science Foundation(No.2021GXNSFAA220011)+1 种基金the Open Fund of IPOC(BUPT)(No.IPOC2021A02)the Innovation Project of Guangxi Graduate Education(No.YCBZ2024002).
文摘The development of quantum networks is paramount towards practical and secure communications.Quantum digital signatures(QDS)offer an information-theoretically secure solution for ensuring data integrity,authenticity,and nonrepudiation,rapidly growing from proof-of-concept to robust demonstrations.However,previous QDS systems relied on expensive and bulky optical equipment,limiting large-scale deployment and reconfigurable networking construction.Here,we introduce and verify a chip-based QDS network,placing the complicated and expensive measurement devices in the central relay while each user needs only a low-cost transmitter.We demonstrate the network with a three-node setup using an integrated encoder chip and decoder chip.By developing a 1-decoy-state one-time universal hashing-QDS protocol,we achieve a maximum signature rate of 0.0414 times per second for a 1 Mbit messages over fiber distances up to 200 km,surpassing all current state-of-the-art QDS experiments.This study validates the feasibility of chip-based QDS,paving the way for large-scale deployment and integration with existing fiber infrastructure.
基金supported by the National Natural Science Foundation of China(Nos.11774273,11574240,61640409,and 61805184)the Outstanding Youth Funds of Hubei Province(No.2016CFA034)+2 种基金the Open Foundation of State Key Laboratory of Optical Communication Technologies and Networks,Wuhan Research Institute of Posts and Telecommunications(No.OCTN-201605)the Postdoctoral Innovation Talent Support Program of China(No.BX20180221)the Natural Science Foundation of Guangxi(No.2017GXNSFAA198048)
文摘The design of a conventional zoom lens is always challenging because it requires not only sophisticated optical design strategy, but also complex and precise mechanical structures for system adjustment. Here, we propose a continuous-zoom lens consisting of two chiral geometric metasurfaces with dielectric nanobrick arrays sitting on a transparent substrate. The metalens can continuously vary the focal length by rotating either of the two metasurfaces around its optical axis without changing any other conditions. Due to the polarization dependence of the geometric metasurface, the positive and negative polarities are interchangeable in one identical metalens only by changing the handedness of the incident circularly polarized light, which can generate varying focal lengths ranging from-∞ to +∞ in principle.
基金National Key Research and Development Program of China(2017YFA0205800)National Natural Science Foundation of China(91950110,11774273,11904267,61805184,11674256)+2 种基金Outstanding Youth Funds of Hubei Province(2016CFA034)Postdoctoral Innovation Talent Support Program of China(BX20180221)China Postdoctoral Science Foundation(2019M652688)。
文摘The unwanted zero-order light accompanied by the birth of diffractive optical elements and caused mainly by fabrication errors and wavelength variations is a key factor that deteriorates the performance of diffraction-related optical devices such as holograms,gratings,beam shapers,beam splitters,optical diffusers,and diffractive microlenses.Here,inspired by the unique characteristic of nano-polarizer-based metasurfaces for both positive and negative amplitude modulation of incident light,we propose a general design paradigm to eliminate zero-order diffraction without burdening the metasurface design and fabrication.The experimentally demonstrated metahologram,which projects a holographic image with a wide angle of 70°×70°in the for field,presents a very low zero-order intensity(only 0.7%of the total energy of the reconstructed image).More importantly,the zero-orderfree meta-hologram has a large tolerance limit for wavelength variations(under a broadband illumination from520 to 660 nm),which brings important technical advances.The strategy proposed could significantly relieve the fabrication difficulty of metasurfaces and be viable for various diffractive-optics-related applications includingholography,laser beam shaping,optical data storage,vortex beam generation,and so on.
基金the support from the MOST 2017YFA0205800the funding provided by the National Natural Science Foundation of China(Nos.91950110,11774273,11904267,61805184,and 11674256)+2 种基金the financial support from the Postdoctoral Innovation Talent Support Program of China(BX20180221)the China Postdoctoral Science Foundation(2019M652688)the financial support from the National Research Foundation,Prime Minister’s Office,Singapore under its Competitive Research Program(CRP award NRF CRP15-2015-03).
文摘Polarization optics plays a pivotal role in diffractive,refractive,and emerging flat optics,and has been widely employed in contemporary optical industries and daily life.Advanced polarization manipulation leads to robust control of the polarization direction of light.Nevertheless,polarization control has been studied largely independent of the phase or intensity of light.Here,we propose and experimentally validate a Malus-metasurface-assisted paradigm to enable simultaneous and independent control of the intensity and phase properties of light simply by polarization modulation.The orientation degeneracy of the classical Malus’s law implies a new degree of freedom and enables us to establish a one-to-many mapping strategy for designing anisotropic plasmonic nanostructures to engineer the Pancharatnam–Berry phase profile,while keeping the continuous intensity modulation unchanged.The proposed Malus metadevice can thus generate a near-field greyscale pattern,and project an independent far-field holographic image using an ultrathin and single-sized metasurface.This concept opens up distinct dimensions for conventional polarization optics,which allows one to merge the functionality of phase manipulation into an amplitudemanipulation-assisted optical component to form a multifunctional nano-optical device without increasing the complexity of the nanostructures.It can empower advanced applications in information multiplexing and encryption,anti-counterfeiting,dual-channel display for virtual/augmented reality,and many other related fields.
基金National Natural Science Foundation of China(62171144,62031024)Guangxi Science Foundation(2021GXNSFAA220011)Open Fund of IPOC(BUPT)(IPOC2021A02)。
文摘Integrated photonics provides a promising platform for quantum key distribution(QKD)system in terms of miniaturization,robustness,and scalability.Tremendous QKD works based on integrated photonics have been reported.Nonetheless,most current chip-based QKD implementations require additional off-chip hardware to demodulate quantum states or perform auxiliary tasks such as time synchronization and polarization basis tracking.Here,we report a demonstration of resource-efficient chip-based BB84 QKD with a silicon-based encoder and a decoder.In our scheme,the time synchronization and polarization compensation are implemented relying on the preparation and measurement of the quantum states generated by on-chip devices;thus,we need no additional hardware.The experimental tests show that our scheme is highly stable with a low intrinsic quantum bit error rate of 0.50%±0.02%in a 6 h continuous run.Furthermore,over a commercial fiber channel up to150 km,the system enables the realization of secure key distribution at a rate of 866 bit/s.Our demonstration paves the way for a low-cost,wafer-scale manufactured QKD system.
基金This study was supported by the National Natural Science Founda-tion of China(Nos.62171144,62031024,and 62171485)the Guangxi Sci-ence Foundation(No.2021GXNSFAA220011)the Open Fund of IPOC(BUPT)(No.IPOC2021A02).
文摘Silicon-based polarization-encoding quantum key distribution(QKD)has been extensively studied due to its advantageous characteris-tics of its low cost and robustness.However,given the difficulty of fabricating polarized independent components on the chip,previ-ous studies have only adopted off-chip devices to demodulate the quantum states or perform polarization compensation.In the cur-rent work,a fully chip-based decoder for polarization-encoding QKD was proposed.The chip realized a polarization state analyzer and compensated for the BB84 protocol without the requirement of additional hardware,which was based on a polarization-to-path conversion method utilizing a polarization splitter-rotator.The chip was fabricated adopting a standard silicon photonics foundry,which was of a compact design and suitable for mass production.In the experimental stability test,an average quantum bit error rate of 0.59%was achieved through continuous operation for 10 h with-out any polarization feedback.Furthermore,the chip enabled the automatic compensation of the fiber polarization drift when utiliz-ing the developed feedback algorithm,which was emulated by a ran-dom fiber polarization scrambler.Moreover,a finite-key secret rate of 240 bps over a fiber spool of 100 km was achieved in the case of the QKD demonstration.This study marks an important step to-ward the integrated,practical,and large-scale deployment of QKD systems.
基金supports from the National Natural Science Foundation of China(Numbers 11574240 and 11774273)the Outstanding Youth Funds of Hubei Province(Number 2016CFA034)+4 种基金the Open Foundation of State Key Laboratory of Optical Communication Technologies and Networks,Wuhan Research Institute of Posts and Telecommunications(Number OCTN-201605)the financial supports from the Postdoctoral Innovation Talent Support Program of China(BX20180221)the Global Ph.D.fellowship from the Korean government(NRF-2016H1A2A1906519)the financial support from the National Research Foundation(NRF)grants(NRF-2017R1E1A1A03070501,NRF-2017R1E1A2A01076613,NRF-2018M3D1A1058998,NRF-2015R1A5A1037668,and CAMM-2014M3A6B3063708)funded by the Ministry of Science and ICT(MSIT)of the Korean governmentthe financial support from the National Research Foundation,Prime Minister’s Office,Singapore under its Competitive Research Program(CRP award NRF CRP15-2015-03).
文摘With the rapid progress in computer science,including artificial intelligence,big data and cloud computing,full-space spot generation can be pivotal to many practical applications,such as facial recognition,motion detection,augmented reality,etc.These opportunities may be achieved by using diffractive optical elements(DOEs)or light detection and ranging(LIDAR).However,DOEs suffer from intrinsic limitations,such as demanding depth-controlled fabrication techniques,large thicknesses(more than the wavelength),Lambertian operation only in half space,etc.LIDAR nevertheless relies on complex and bulky scanning systems,which hinders the miniaturization of the spot generator.Here,inspired by a Lambertian scatterer,we report a Hermitian-conjugate metasurface scrambling the incident light to a cloud of random points in full space with compressed information density,functioning in both transmission and reflection spaces.Over 4044 random spots are experimentally observed in the entire space,covering angles at nearly 90°.Our scrambling metasurface is made of amorphous silicon with a uniform subwavelength height,a nearly continuous phase coverage,a lightweight,flexible design,and low-heat dissipation.Thus,it may be mass produced by and integrated into existing semiconductor foundry designs.Our work opens important directions for emerging 3D recognition sensors,such as motion sensing,facial recognition,and other applications.
