Large field-of-view(FoV) three-dimensional(3 D) photon-counting imaging is demonstrated with a single-pixel single-photon detector based on a Geiger-mode Si-avalanche photodiode. By removing the collecting lens(CL)bef...Large field-of-view(FoV) three-dimensional(3 D) photon-counting imaging is demonstrated with a single-pixel single-photon detector based on a Geiger-mode Si-avalanche photodiode. By removing the collecting lens(CL)before the detector, the FoV is expanded to ±10°. Thanks to the high detection efficiency, the signal-to-noise ratio of the imaging system is as high as 7.8 dB even without the CL when the average output laser pulse energy is about 0.45 pJ/pulse for imaging the targets at a distance of 5 m. A 3 D image overlaid with the reflectivity data is obtained according to the photon-counting time-of-flight measurement and the return photon intensity.展开更多
Photon number resolving detectors with high accuracy bring broad applications in long-distance laser ranging, ultrafast spectroscopy, and quantum optics. In this paper, we observed the non-classical photon number dist...Photon number resolving detectors with high accuracy bring broad applications in long-distance laser ranging, ultrafast spectroscopy, and quantum optics. In this paper, we observed the non-classical photon number distribution directly with a multi-pixel photon counter (MPPC) instead of a classic Hanbury-Brown and Twiss (HBT) system. The detector’s photon-number resolving ability was characterized by quantum detector tomography. To show the quantum feature of the detector, we further plotted the Wigner function, which was obtained corresponding to the positive operator value measure (POVM) elements. Finally, we declared the observation of non-classical photon statistics from a single color center in nanodiamond by using this detector.展开更多
Active mid-infrared(MIR)imagers capable of retrieving three-dimensional(3D)structure and reflectivity information are highly attractive in a wide range of biomedical and industrial applications.However,infrared 3D ima...Active mid-infrared(MIR)imagers capable of retrieving three-dimensional(3D)structure and reflectivity information are highly attractive in a wide range of biomedical and industrial applications.However,infrared 3D imaging at lowlight levels is still challenging due to the deficiency of sensitive and fast MiR sensors.Here we propose and implement a MiR time-of-flight imaging system that operates at single-photon sensitivity and femtosecond timing resolution.Specifically,back-scattered infrared photons from a scene are optically gated by delay-controlled ultrashort pump pulses through nonlinear frequency upconversion.The upconverted images with time stamps are then recorded by a silicon camera to facilitate the 3D reconstruction with high lateral and depth resolutions.Moreover,an effective numerical denoiser based on spatiotemporal correlation allows us to reveal the object profle and reflectivity under photon-starving conditions with a detected flux below 0.05 photons/pixel/second.The presented MIR 3D imager features high detection sensitivity,precise timing resolution,and wide-field operation,which may open new possibilities in life and material sciences.展开更多
We report a frequency-multiplexing method for multi-beam photon-counting light detection and ranging(Li DAR),where only one single-pixel single-photon detector is employed to simultaneously detect the multibeam echoes...We report a frequency-multiplexing method for multi-beam photon-counting light detection and ranging(Li DAR),where only one single-pixel single-photon detector is employed to simultaneously detect the multibeam echoes.In this frequency-multiplexing multi-beam Li DAR,each beam is from an independent laser source with different repetition rates and independent phases.As a result,the photon counts from different beams could be discriminated from each other due to the strong correlation between the laser pulses and their respective echo photons.A 16-beam Li DAR system was demonstrated in three-dimensional laser imaging with 16 pulsed laser diodes at 850 nm and one single-photon detector based on a Si-avalanche photodiode.This frequencymultiplexing method can greatly reduce the number of single-photon detectors in multi-beam Li DAR systems,which may be useful for low-cost and eye-safe Li DAR applications.展开更多
Promoting the sensitivity of mid-infrared(MIR) spectroscopy to the single-photon level is a critical need for investigating photosensitive biological samples and chemical reactions. MIR spectroscopy based on frequency...Promoting the sensitivity of mid-infrared(MIR) spectroscopy to the single-photon level is a critical need for investigating photosensitive biological samples and chemical reactions. MIR spectroscopy based on frequency upconversion is a compelling pioneer allowing high-efficiency MIR spectral measurement with well-developed single-photon detectors, which overcomes the main limitations of high thermal noise of current MIR detectors.However, noise from other nonlinear processes caused by strong pump fields hinders the development of the upconversion-based MIR spectroscopy to reach the single-photon level. Here, a broadband MIR single-photon frequency upconversion spectroscopy is demonstrated based on the temporal-spectral quantum correlation of non-degenerate photon pairs, which is well preserved in the frequency upconversion process and is fully used in extracting the signals from tremendous noise caused by the strong pump. A correlation spectrum broader than660 nm is achieved and applied for the demonstration of sample identification under a low incident photon flux of 0.09 average photons per pulse. The system is featured with non-destructive and robust operation, which makes single-photon-level MIR spectroscopy an appealing option in biochemical applications. ? 2022 Chinese Laser Press.展开更多
We investigate the strong coupling from 5,5’,6,6’-tetrachloro-1,1’-diethyl-3,3’-di(4-sulfobutyl)-benzimidazolocarbocyanine(TDBC)molecules near pure nano-triangular Ag prisms or Ag@Au hollow nanoshells.When TDBC mo...We investigate the strong coupling from 5,5’,6,6’-tetrachloro-1,1’-diethyl-3,3’-di(4-sulfobutyl)-benzimidazolocarbocyanine(TDBC)molecules near pure nano-triangular Ag prisms or Ag@Au hollow nanoshells.When TDBC molecules are deposited on pure Ag nanoprisms or Ag@Au hollow nanoshells with the plasmonic resonance peak,matching very closely with the absorption band of TDBC J-aggregates,obvious Rabi splitting can be observed due to the strong coupling regime.Meanwhile,the photoluminescence intensity decreased with the increasing of the temperature,verifying the decreasing plasmon-exciton coupling interaction in the higher temperature.Our experimental results are coincident with the simulation results calculated by finite-difference time-domain method.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11774095,11722431 and 11621404the Shanghai Basic Research Project under Grant No 18JC1412200+2 种基金the National Key R&D Program of China under Grant No2016YFB0400904the Program of Introducing Talents of Discipline to Universities under Grant No B12024the Shanghai International Cooperation Project under Grant No 16520710600
文摘Large field-of-view(FoV) three-dimensional(3 D) photon-counting imaging is demonstrated with a single-pixel single-photon detector based on a Geiger-mode Si-avalanche photodiode. By removing the collecting lens(CL)before the detector, the FoV is expanded to ±10°. Thanks to the high detection efficiency, the signal-to-noise ratio of the imaging system is as high as 7.8 dB even without the CL when the average output laser pulse energy is about 0.45 pJ/pulse for imaging the targets at a distance of 5 m. A 3 D image overlaid with the reflectivity data is obtained according to the photon-counting time-of-flight measurement and the return photon intensity.
基金supported by the National Natural Science Foundation of China under Grants No.11722431,No.11674099,No.11704127,and No.11621404the Program of Introducing Talents of Discipline to Universities under Grant No.B12024+2 种基金the Shanghai International Cooperation Project under Grant No.16520710600the Natural Science Foundation of Shanghai under Grant No.16ZR1409400the Shuguang Program under Grant No.15SG22 by Shanghai Education Development Foundation and Shanghai Municipal Education Commission
文摘Photon number resolving detectors with high accuracy bring broad applications in long-distance laser ranging, ultrafast spectroscopy, and quantum optics. In this paper, we observed the non-classical photon number distribution directly with a multi-pixel photon counter (MPPC) instead of a classic Hanbury-Brown and Twiss (HBT) system. The detector’s photon-number resolving ability was characterized by quantum detector tomography. To show the quantum feature of the detector, we further plotted the Wigner function, which was obtained corresponding to the positive operator value measure (POVM) elements. Finally, we declared the observation of non-classical photon statistics from a single color center in nanodiamond by using this detector.
基金supported by the National Natural Science Foundation of China(Nos.62175064,62235019,62035005)Shanghai Pilot Program for Basic Research(TQ20220104)+1 种基金Shanghai Municipal Science and Technology Major Project(2019SHZDZX01)Fundamental Research Funds for the Central Universities.
文摘Active mid-infrared(MIR)imagers capable of retrieving three-dimensional(3D)structure and reflectivity information are highly attractive in a wide range of biomedical and industrial applications.However,infrared 3D imaging at lowlight levels is still challenging due to the deficiency of sensitive and fast MiR sensors.Here we propose and implement a MiR time-of-flight imaging system that operates at single-photon sensitivity and femtosecond timing resolution.Specifically,back-scattered infrared photons from a scene are optically gated by delay-controlled ultrashort pump pulses through nonlinear frequency upconversion.The upconverted images with time stamps are then recorded by a silicon camera to facilitate the 3D reconstruction with high lateral and depth resolutions.Moreover,an effective numerical denoiser based on spatiotemporal correlation allows us to reveal the object profle and reflectivity under photon-starving conditions with a detected flux below 0.05 photons/pixel/second.The presented MIR 3D imager features high detection sensitivity,precise timing resolution,and wide-field operation,which may open new possibilities in life and material sciences.
基金National Natural Science Foundation of China(11621404,11774095,11804099)Shanghai Basic Research Project(18JC1412200)Program of Introducing Talents of Discipline to Universities(B12024)
文摘We report a frequency-multiplexing method for multi-beam photon-counting light detection and ranging(Li DAR),where only one single-pixel single-photon detector is employed to simultaneously detect the multibeam echoes.In this frequency-multiplexing multi-beam Li DAR,each beam is from an independent laser source with different repetition rates and independent phases.As a result,the photon counts from different beams could be discriminated from each other due to the strong correlation between the laser pulses and their respective echo photons.A 16-beam Li DAR system was demonstrated in three-dimensional laser imaging with 16 pulsed laser diodes at 850 nm and one single-photon detector based on a Si-avalanche photodiode.This frequencymultiplexing method can greatly reduce the number of single-photon detectors in multi-beam Li DAR systems,which may be useful for low-cost and eye-safe Li DAR applications.
基金National Key Research and Development Program of China(2021YFA1201503)National Natural Science Foundation of China(11621404,12204174,62175064)+2 种基金Natural Scienceof CQ CSTC2021JCYJ-MAXMX0356Research Funds of Happiness Flower ECNU(2021ST2110)Fundamental Research Funds for the Central Universities。
文摘Promoting the sensitivity of mid-infrared(MIR) spectroscopy to the single-photon level is a critical need for investigating photosensitive biological samples and chemical reactions. MIR spectroscopy based on frequency upconversion is a compelling pioneer allowing high-efficiency MIR spectral measurement with well-developed single-photon detectors, which overcomes the main limitations of high thermal noise of current MIR detectors.However, noise from other nonlinear processes caused by strong pump fields hinders the development of the upconversion-based MIR spectroscopy to reach the single-photon level. Here, a broadband MIR single-photon frequency upconversion spectroscopy is demonstrated based on the temporal-spectral quantum correlation of non-degenerate photon pairs, which is well preserved in the frequency upconversion process and is fully used in extracting the signals from tremendous noise caused by the strong pump. A correlation spectrum broader than660 nm is achieved and applied for the demonstration of sample identification under a low incident photon flux of 0.09 average photons per pulse. The system is featured with non-destructive and robust operation, which makes single-photon-level MIR spectroscopy an appealing option in biochemical applications. ? 2022 Chinese Laser Press.
基金supported by the National Key R&D Program of China(No.2017YFA0303403)the National Natural Science Foundation of China(Nos.11874015,12074012,11674099+2 种基金11722431)the Shanghai International CooperationProject(No.16520710600)the Program of Introducing Talents of Discipline to Universities(No.B12024)。
文摘We investigate the strong coupling from 5,5’,6,6’-tetrachloro-1,1’-diethyl-3,3’-di(4-sulfobutyl)-benzimidazolocarbocyanine(TDBC)molecules near pure nano-triangular Ag prisms or Ag@Au hollow nanoshells.When TDBC molecules are deposited on pure Ag nanoprisms or Ag@Au hollow nanoshells with the plasmonic resonance peak,matching very closely with the absorption band of TDBC J-aggregates,obvious Rabi splitting can be observed due to the strong coupling regime.Meanwhile,the photoluminescence intensity decreased with the increasing of the temperature,verifying the decreasing plasmon-exciton coupling interaction in the higher temperature.Our experimental results are coincident with the simulation results calculated by finite-difference time-domain method.
