In this paper, using computer simulation and mathematic experiment method to solve the simplified one dimensional thermal conduction equation and to obtain the temperature distribution in a metal bar when its one end ...In this paper, using computer simulation and mathematic experiment method to solve the simplified one dimensional thermal conduction equation and to obtain the temperature distribution in a metal bar when its one end was heated. According to principle of hot expansion, a holograph of temperature distribution in the bar by laser holo-technique was taken. The results of numerical simulation and experiments are in good agreement and a new method for study on thermal conduction by laser holo-technique was found.展开更多
Single-photon laser ranging has widespread applications in remote sensing and target recognition.However,highly sensitive light detection and ranging(lidar)has long been restricted in the visible or near-infrared band...Single-photon laser ranging has widespread applications in remote sensing and target recognition.However,highly sensitive light detection and ranging(lidar)has long been restricted in the visible or near-infrared bands.An appealing quest is to extend the operation wavelength into the mid-infrared(MIR)region,which calls for an infrared photon-counting system at high detection sensitivity and precise temporal resolution.Here,we devise and demonstrate an MIR upconversion lidar based on nonlinear asynchronous optical sampling.Specifically,the infrared probe is interrogated in a nonlinear crystal by a train of pump pulses at a slightly different repetition rate,which favors temporal optical scanning at a picosecond timing resolution and a kilohertz refreshing rate over-50ns.Moreover,the cross-correlation upconversion trace is temporally stretched by a factor of 2×10^(4),which can thus be recorded by a low-bandwidth silicon detector.In combination with the time-correlated photon-counting technique,the achieved effective resolution is about two orders of magnitude better than the timing jitter of the detector itself,which facilitates a ranging precision of 4μm under a low detected flux of 8×10^(−5) photons per pulse.The presented MIR time-of-flight range finder is featured with single-photon sensitivity and high positioning resolution,which would be particularly useful in infrared sensing and imaging in photon-starved scenarios.展开更多
基金supported by the Foundation of Education Research for Youth Scholar of CAAC(No.1998303).
文摘In this paper, using computer simulation and mathematic experiment method to solve the simplified one dimensional thermal conduction equation and to obtain the temperature distribution in a metal bar when its one end was heated. According to principle of hot expansion, a holograph of temperature distribution in the bar by laser holo-technique was taken. The results of numerical simulation and experiments are in good agreement and a new method for study on thermal conduction by laser holo-technique was found.
基金National Key Research and Development Program of China(2021YFB2801100)National Natural Science Foundation of China(12022411,62035005,62175064,62235019)+3 种基金Shanghai Pilot Program for Basic Research(TQ20220104)Natural Science Foundation of Chongqing Municipality(CSTB2022NSCQ-JQX0016,CSTB2022NSCQ-MSX0451,CSTB2023NSCQ-JQX0011)Shanghai Municipal Science and Technology Major Project(2019SHZDZX01)Fundamental Research Funds for the Central Universities.
文摘Single-photon laser ranging has widespread applications in remote sensing and target recognition.However,highly sensitive light detection and ranging(lidar)has long been restricted in the visible or near-infrared bands.An appealing quest is to extend the operation wavelength into the mid-infrared(MIR)region,which calls for an infrared photon-counting system at high detection sensitivity and precise temporal resolution.Here,we devise and demonstrate an MIR upconversion lidar based on nonlinear asynchronous optical sampling.Specifically,the infrared probe is interrogated in a nonlinear crystal by a train of pump pulses at a slightly different repetition rate,which favors temporal optical scanning at a picosecond timing resolution and a kilohertz refreshing rate over-50ns.Moreover,the cross-correlation upconversion trace is temporally stretched by a factor of 2×10^(4),which can thus be recorded by a low-bandwidth silicon detector.In combination with the time-correlated photon-counting technique,the achieved effective resolution is about two orders of magnitude better than the timing jitter of the detector itself,which facilitates a ranging precision of 4μm under a low detected flux of 8×10^(−5) photons per pulse.The presented MIR time-of-flight range finder is featured with single-photon sensitivity and high positioning resolution,which would be particularly useful in infrared sensing and imaging in photon-starved scenarios.
