Recently the performance of the quantum key distribution (QKD) is substantially improved by the decoy state method and the non-orthogonal encoding protocol, separately. In this paper, a practical non-orthogonal deco...Recently the performance of the quantum key distribution (QKD) is substantially improved by the decoy state method and the non-orthogonal encoding protocol, separately. In this paper, a practical non-orthogonal decoy state protocol with a heralded single photon source (HSPS) for QKD is presented. The protocol is based on 4 states with different intensities. i.e. one signal state and three decoy states. The signal state is for generating keys; the decoy states are for detecting the eavesdropping and estimating the fraction of single-photon and two-photon pulses. We have discussed three cases of this protocol, i.e. the general case, the optimal case and the special case. Moreover, the final key rate over transmission distance is simulated. For the low dark count of the HSPS and the utilization of the two-photon pulses, our protocol has a higher key rate and a longer transmission distance than any other decoy state protocol.展开更多
We investigate metallic microdisk-size dependence of quantum dot (QD) spontaneous emission rate and micro- antenna directional emission effect for the hybrid metM-distributed Bragg reflector structures based on a pa...We investigate metallic microdisk-size dependence of quantum dot (QD) spontaneous emission rate and micro- antenna directional emission effect for the hybrid metM-distributed Bragg reflector structures based on a particular single QD emission. It is found that the measured photolumineseence (PL) intensity is very sensitive to the size of metMlic disk, showing an enhancement factor of 11 when the optimal disk diameter is 2μm and the numerical aperture of microscope objective NA=0.5. It is found that for large metal disks, the Purcell effect is dominant for enhanced PL intensity, whereas for small size disks the main contribution comes from plasmon scattering at the disk edge within the light cone collected by the microscope objective.展开更多
The photostability of a colloidal single photon emitter in near-infrared regime at room temperature is investigated.The fluorescence lifetime,blinking phenomenon,and anti-bunching effect of a single CdTeSe/ZnS quantum...The photostability of a colloidal single photon emitter in near-infrared regime at room temperature is investigated.The fluorescence lifetime,blinking phenomenon,and anti-bunching effect of a single CdTeSe/ZnS quantum dot with an emission wavelength of 800 nm at room temperature are studied.The second-order correlation function at zero delay time is much smaller than 0.1,which proves that the emission from single quantum dots at 800 nm is a highly pure single-photon source.The effects of the irradiation duration on the fluorescence from single quantum dots are analyzed.The experimental results can be explained by a recombination model including a multi-nonradiative recombination center model and a multi-charged model.展开更多
In a two-frequency cavity driving and atom driving atom-cavity system,we find the photon blockade effect.In a truncated eigenstates space,we calculate the zero-delay second-order correlation function of the cavity mod...In a two-frequency cavity driving and atom driving atom-cavity system,we find the photon blockade effect.In a truncated eigenstates space,we calculate the zero-delay second-order correlation function of the cavity mode analytically and obtain an optimal condition for the photon blockade.By including three transition pathways,we find that higher excitations of the cavity mode can be further suppressed and the zero-delay second-order correlation function can be reduced additionally.Based on the master equation,we simulate the system evolution and find that the analytical solutions match well with the numerical results.Our scheme is robust with small fluctuations of parameters and may be used as a new type of single photon source.展开更多
Radiation of an electric dipole(quantum emitter)in vicinity of optical structures still attracts great interest due to emerging of novel application and technological advances.Here we review our recent work on guide...Radiation of an electric dipole(quantum emitter)in vicinity of optical structures still attracts great interest due to emerging of novel application and technological advances.Here we review our recent work on guided and radiation modes of electric dipole and optical fiber system and its applications from single photon source to metadevices.We demonstrate that the relative position and orientation of the dipole and the core diameter of the optical fiber are the two key defining factors of the coupled system application.We demonstrate that such a coupled system has a vast span of applications in nanophotonics;a single photon source,a high-quality factor sensor and the building block of metadevices.展开更多
The authors demonstrate a Bull's eye cavity design that is composed of circular Bragg gratings and micropillar optical cavity in 4H silicon carbide(4H-SiC) for single photon emission. Numerical calculations are us...The authors demonstrate a Bull's eye cavity design that is composed of circular Bragg gratings and micropillar optical cavity in 4H silicon carbide(4H-SiC) for single photon emission. Numerical calculations are used to investigate and optimize the emission rate and directionality of emission. Thanks to the optical mode resonances and Bragg reflections,the radiative decay rates of a dipole embedded in the cavity center is enhanced by 12.8 times as compared to that from a bulk 4H-SiC. In particular, a convergent angular distribution of the emission in far field is simultaneously achieved, which remarkably boost the collection efficiency. The findings of this work provide an alternative architecture to manipulate light-matter interactions for achieving high-efficient SiC single photon sources towards applications in quantum information technologies.展开更多
We experimentally demonstrate a heralded single photon source at 1290 nm by exploiting the spontaneous four wave mixing in a taper-drawn micro/nano-fiber(MNF). Because the frequency detuning between the pump and her...We experimentally demonstrate a heralded single photon source at 1290 nm by exploiting the spontaneous four wave mixing in a taper-drawn micro/nano-fiber(MNF). Because the frequency detuning between the pump and heralded single photons is ~58 THz, the contamination by Raman scattering is significantly reduced at room temperature. Since the MNF is naturally connected to standard single mode fibers via fiber tapers, the source would be compatible with the existing fiber networks. When the emission rate of heralded signal photons is about 4.6 kHz, the measured second-order intensity correlation function g(2)(0) is 0.017 ± 0.002, which is suppressed by a factor of more than 55, relative to the classical limit.展开更多
Integrated photonic quantum circuits(IPQCs)have attracted increasing attention in recent years due to their widespread applications in quantum information science.While the most envisioned quantum technologies such as...Integrated photonic quantum circuits(IPQCs)have attracted increasing attention in recent years due to their widespread applications in quantum information science.While the most envisioned quantum technologies such as quantum communications,quantum computer and quantum simulations have placed a strict constraint on the scalability of chip-integrated quantum light sources.By introducing sizeconfined nanostructures or crystal imperfections,low-dimensional semiconductors have been broadly explored as chip-scale deterministic single-photon sources(SPSs).Thus far a variety of chip-integrated deterministic SPSs have been investigated across both monolithic and hybrid photonic platforms,including molecules,quantum dots,color centers and two-dimensional materials.With the rapid development of the chip-scale generation of single photons with deterministic quantum emitters,the field of IPQCs has raised new challenges and opportunities.In this paper,we highlight recent progress in the development of waveguide-coupled deterministic SPSs towards scalable IPQCs,and review the post-growth tuning techniques that are specifically developed to engineer the optical properties of these WG-coupled SPSs.Future prospects on stringent requirement for the quantum engineering toolbox in the burgeoning field of integrated photonics are also discussed.展开更多
A central goal in quantum information science is to efficiently interface photons with single optical modes for quantum networking and distributed quantum computing.Here,we introduce and experimentally demonstrate a c...A central goal in quantum information science is to efficiently interface photons with single optical modes for quantum networking and distributed quantum computing.Here,we introduce and experimentally demonstrate a compact and efficient method for the low-loss coupling of a solid-state qubit,the nitrogen vacancy(NV)center in diamond,with a single-mode optical fiber.In this approach,single-mode tapered diamond waveguides containing exactly one high quality NV memory are selected and integrated on tapered silica fibers.Numerical optimization of an adiabatic coupler indicates that near-unity-efficiency photon transfer is possible between the two modes.Experimentally,we find an overall collection efficiency between 16%and 37%and estimate a single photon count rate at saturation above 700 kHz.This integrated system enables robust,alignment-free,and efficient interfacing of single-mode optical fibers with single photon emitters and quantum memories in solids.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No 60578055)the State Key Development Program for Basic Research of China (Grant No 2007CB307001)
文摘Recently the performance of the quantum key distribution (QKD) is substantially improved by the decoy state method and the non-orthogonal encoding protocol, separately. In this paper, a practical non-orthogonal decoy state protocol with a heralded single photon source (HSPS) for QKD is presented. The protocol is based on 4 states with different intensities. i.e. one signal state and three decoy states. The signal state is for generating keys; the decoy states are for detecting the eavesdropping and estimating the fraction of single-photon and two-photon pulses. We have discussed three cases of this protocol, i.e. the general case, the optimal case and the special case. Moreover, the final key rate over transmission distance is simulated. For the low dark count of the HSPS and the utilization of the two-photon pulses, our protocol has a higher key rate and a longer transmission distance than any other decoy state protocol.
基金Supported by the National Key Basic Research Program of China under Grant No 2013CB922304the National Natural Science Foundation of China under Grant Nos 11474275 and 11464034
文摘We investigate metallic microdisk-size dependence of quantum dot (QD) spontaneous emission rate and micro- antenna directional emission effect for the hybrid metM-distributed Bragg reflector structures based on a particular single QD emission. It is found that the measured photolumineseence (PL) intensity is very sensitive to the size of metMlic disk, showing an enhancement factor of 11 when the optimal disk diameter is 2μm and the numerical aperture of microscope objective NA=0.5. It is found that for large metal disks, the Purcell effect is dominant for enhanced PL intensity, whereas for small size disks the main contribution comes from plasmon scattering at the disk edge within the light cone collected by the microscope objective.
基金Project supported by the National Natural Science Foundation of China(Grant No.92165202)the Innovation Program for Quantum Science and Technology,China(Grant No.2021ZD0300701)the Strategic Priority Research Program(A)of Chinese Academy of Sciences(Grant No.XDA18040300).
文摘The photostability of a colloidal single photon emitter in near-infrared regime at room temperature is investigated.The fluorescence lifetime,blinking phenomenon,and anti-bunching effect of a single CdTeSe/ZnS quantum dot with an emission wavelength of 800 nm at room temperature are studied.The second-order correlation function at zero delay time is much smaller than 0.1,which proves that the emission from single quantum dots at 800 nm is a highly pure single-photon source.The effects of the irradiation duration on the fluorescence from single quantum dots are analyzed.The experimental results can be explained by a recombination model including a multi-nonradiative recombination center model and a multi-charged model.
基金Project supported by the National Natural Science Foundation of China(Grant No.61601196).
文摘In a two-frequency cavity driving and atom driving atom-cavity system,we find the photon blockade effect.In a truncated eigenstates space,we calculate the zero-delay second-order correlation function of the cavity mode analytically and obtain an optimal condition for the photon blockade.By including three transition pathways,we find that higher excitations of the cavity mode can be further suppressed and the zero-delay second-order correlation function can be reduced additionally.Based on the master equation,we simulate the system evolution and find that the analytical solutions match well with the numerical results.Our scheme is robust with small fluctuations of parameters and may be used as a new type of single photon source.
文摘Radiation of an electric dipole(quantum emitter)in vicinity of optical structures still attracts great interest due to emerging of novel application and technological advances.Here we review our recent work on guided and radiation modes of electric dipole and optical fiber system and its applications from single photon source to metadevices.We demonstrate that the relative position and orientation of the dipole and the core diameter of the optical fiber are the two key defining factors of the coupled system application.We demonstrate that such a coupled system has a vast span of applications in nanophotonics;a single photon source,a high-quality factor sensor and the building block of metadevices.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 91850112, 61774081, 62004099, and 61921005)in part by Shenzhen Fundamental Research Program (Grant Nos. JCYJ20180307163240991 and JCYJ20180307154632609)+3 种基金in part by the State Key Research and Development Project of Jiangsu Province, China (Grant No. BE2018115)in part by the Natural Science Foundation of Jiangsu Province, China (Grant No. BK20201253)in part by the State Key Research and Development Project of Guangdong Province, China (Grant No. 2020B010174002)in part by Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB43020500)。
文摘The authors demonstrate a Bull's eye cavity design that is composed of circular Bragg gratings and micropillar optical cavity in 4H silicon carbide(4H-SiC) for single photon emission. Numerical calculations are used to investigate and optimize the emission rate and directionality of emission. Thanks to the optical mode resonances and Bragg reflections,the radiative decay rates of a dipole embedded in the cavity center is enhanced by 12.8 times as compared to that from a bulk 4H-SiC. In particular, a convergent angular distribution of the emission in far field is simultaneously achieved, which remarkably boost the collection efficiency. The findings of this work provide an alternative architecture to manipulate light-matter interactions for achieving high-efficient SiC single photon sources towards applications in quantum information technologies.
文摘We experimentally demonstrate a heralded single photon source at 1290 nm by exploiting the spontaneous four wave mixing in a taper-drawn micro/nano-fiber(MNF). Because the frequency detuning between the pump and heralded single photons is ~58 THz, the contamination by Raman scattering is significantly reduced at room temperature. Since the MNF is naturally connected to standard single mode fibers via fiber tapers, the source would be compatible with the existing fiber networks. When the emission rate of heralded signal photons is about 4.6 kHz, the measured second-order intensity correlation function g(2)(0) is 0.017 ± 0.002, which is suppressed by a factor of more than 55, relative to the classical limit.
基金supported by National Key R&D Program of China(No.2017YFE0131300)Science and Technology Commission of Shanghai Municipality(Nos.16ZR1442600,20JC1416200)+3 种基金Shanghai Rising-Star Program(No.19QA1410600)Program of Shanghai Academic/Technology Research Leader(No.19XD1404600)National Natural Science Foundation of China(Nos.12074400,U1732268,61874128,61851406,11705262,11774326)Frontier Science Key Program of Chinese Academy of Sciences(No.QYZDY-SSW-JSC032).
文摘Integrated photonic quantum circuits(IPQCs)have attracted increasing attention in recent years due to their widespread applications in quantum information science.While the most envisioned quantum technologies such as quantum communications,quantum computer and quantum simulations have placed a strict constraint on the scalability of chip-integrated quantum light sources.By introducing sizeconfined nanostructures or crystal imperfections,low-dimensional semiconductors have been broadly explored as chip-scale deterministic single-photon sources(SPSs).Thus far a variety of chip-integrated deterministic SPSs have been investigated across both monolithic and hybrid photonic platforms,including molecules,quantum dots,color centers and two-dimensional materials.With the rapid development of the chip-scale generation of single photons with deterministic quantum emitters,the field of IPQCs has raised new challenges and opportunities.In this paper,we highlight recent progress in the development of waveguide-coupled deterministic SPSs towards scalable IPQCs,and review the post-growth tuning techniques that are specifically developed to engineer the optical properties of these WG-coupled SPSs.Future prospects on stringent requirement for the quantum engineering toolbox in the burgeoning field of integrated photonics are also discussed.
基金supported in part by the MIT SuperUROP(Undergraduate Research Opportunities Program)supported by the Alexander von Humboldt-Foundation+3 种基金supported by the NASA Office of the Chief Technologist’s Space Technology Research Fellowshipsupport from the Air Force Office of Scientific Research PECASE(supervised by G.Pomrenke)supported in part by the AFOSR Quantum Memories MURI and by a fellowship from the NSF iQuISE program,award number 0801525supported by the US Department of Energy,Office of Basic Energy Sciences,under Contract No.DE-AC02-98CH10886.
文摘A central goal in quantum information science is to efficiently interface photons with single optical modes for quantum networking and distributed quantum computing.Here,we introduce and experimentally demonstrate a compact and efficient method for the low-loss coupling of a solid-state qubit,the nitrogen vacancy(NV)center in diamond,with a single-mode optical fiber.In this approach,single-mode tapered diamond waveguides containing exactly one high quality NV memory are selected and integrated on tapered silica fibers.Numerical optimization of an adiabatic coupler indicates that near-unity-efficiency photon transfer is possible between the two modes.Experimentally,we find an overall collection efficiency between 16%and 37%and estimate a single photon count rate at saturation above 700 kHz.This integrated system enables robust,alignment-free,and efficient interfacing of single-mode optical fibers with single photon emitters and quantum memories in solids.