By utilizing the extended phase-matching(EPM)method,we investigate the generation of single photons with high spectral-purity in a magnesium-doped periodically-poled lithium niobate(MgO:PPLN)crystal via the spontaneou...By utilizing the extended phase-matching(EPM)method,we investigate the generation of single photons with high spectral-purity in a magnesium-doped periodically-poled lithium niobate(MgO:PPLN)crystal via the spontaneous parametric down-conversion(SPDC)process.By adjusting the temperature and pump wavelength,the wavelength of the single photons can be tuned from telecom to mid-infrared(MIR)wavelengths,for which the spectral-purity can be above 0.95 with high transmission filters.In experiments,we engineer a MgO:PPLN with poling period of 20.35µm which emits the EPM photon pair centered at 1496.6 nm and 1644.0 nm and carry out the joint spectral intensity(JSI)and Glauber’s second-order self-correlation measurements to characterize the spectral purity.The results are in good agreement with the numerical simulations.Our work may provide a valuable approach for the generation of spectrally pure single photons at a wide range of wavelengths which is competent for various photonic quantum technologies.展开更多
The SARG04 quantum key distribution protocol can offer greater robustness against photon number splitting attacks than the BB84 protocol that is implemented with weak pulses.In this paper,we propose a tight key analys...The SARG04 quantum key distribution protocol can offer greater robustness against photon number splitting attacks than the BB84 protocol that is implemented with weak pulses.In this paper,we propose a tight key analysis for the SARG04 protocol,by considering the one-decoy method and investigating its performance under the influence of a detector afterpulse.Our results demonstrate that an increase in block size leads to a slight increase in both the secure key rate and the maximum transmission distance.Importantly,the detector afterpulse plays a crucial role in practical applications and has a more pronounced effect on the SARG04 protocol compared to the BB84 protocol.展开更多
基金supported by the National Basic Research Program of China(Grant Nos.2017YFA0303700 and 2019YFA0308700)the National Natural Science Foundation of China(Grant Nos.11627810 and 11690031)。
文摘By utilizing the extended phase-matching(EPM)method,we investigate the generation of single photons with high spectral-purity in a magnesium-doped periodically-poled lithium niobate(MgO:PPLN)crystal via the spontaneous parametric down-conversion(SPDC)process.By adjusting the temperature and pump wavelength,the wavelength of the single photons can be tuned from telecom to mid-infrared(MIR)wavelengths,for which the spectral-purity can be above 0.95 with high transmission filters.In experiments,we engineer a MgO:PPLN with poling period of 20.35µm which emits the EPM photon pair centered at 1496.6 nm and 1644.0 nm and carry out the joint spectral intensity(JSI)and Glauber’s second-order self-correlation measurements to characterize the spectral purity.The results are in good agreement with the numerical simulations.Our work may provide a valuable approach for the generation of spectrally pure single photons at a wide range of wavelengths which is competent for various photonic quantum technologies.
基金supported by the National Natural Science Foundation of China(Grant No.12274233,62371244).
文摘The SARG04 quantum key distribution protocol can offer greater robustness against photon number splitting attacks than the BB84 protocol that is implemented with weak pulses.In this paper,we propose a tight key analysis for the SARG04 protocol,by considering the one-decoy method and investigating its performance under the influence of a detector afterpulse.Our results demonstrate that an increase in block size leads to a slight increase in both the secure key rate and the maximum transmission distance.Importantly,the detector afterpulse plays a crucial role in practical applications and has a more pronounced effect on the SARG04 protocol compared to the BB84 protocol.
