Photon counting measurement method, apparatus, device, and medium

Abstract

This application relates to a photon counting measurement method, apparatus, device, and medium. The method includes: acquiring the echo light pulse of a sample to be tested; performing photon detection based on the echo light pulse to determine an output signal; sampling the output signal of a single-photon detector using a time-to-digital converter until the time-to-digital converter detects the first output signal or reaches a preset range threshold and stops timing; statistically analyzing the timing values ​​of the time-to-digital converter to determine the periodic peak of the light pulse corresponding to the echo light pulse; determining the probability distribution of each detection peak under different first-peak detection probabilities in the periodic peak of the light pulse based on a Poisson distribution algorithm; determining the probability value of the first periodic peak of the light pulse based on the probability distribution of each detection peak; and calculating the average number of photoelectrons detected by the single-photon detector based on the probability value of the first periodic peak of the light pulse. This application can simultaneously extract information such as the average number of detected photons in a single data acquisition, and the amount of data acquired is small.

Description

Technical Field

[0001] This application relates to the field of photon counting, and more particularly to a photon counting measurement method, a corresponding device, an electronic device, and a computer-readable storage medium. Background Technology

[0002] Single-photon detectors have wide applications in quantum optics, photon time-of-flight measurement, and Raman / fluorescence analysis. In single-photon measurement systems, the dark count rate of the detector, the average number of photoelectrons detected, and the time-domain characteristics of the measured signal are considered important parameters for retrieving effective information from the single-photon measurement system. These parameters are usually obtained using an oscilloscope or a time-correlated single-photon counter (TCSPC).

[0003] Traditional oscilloscope measurement methods require collecting all waveform information of the single-photon signal and processing it using algorithms, such as peak finding, pulse counting, waveform area calculation, and solving the single-photon spectrum, to infer parameters such as the dark count rate, the average number of photoelectrons detected, and the period and time-domain waveform of the measured signal. However, oscilloscope measurements require saving all waveform details, resulting in a large amount of data and cumbersome subsequent data analysis.

[0004] A TCSPC (Single Photon Counter) is a high-precision timing and measurement technique used to obtain the time distribution information of single-photon signals. It boasts high time resolution (down to the picosecond level) and obtains statistical information on photon arrival times by detecting single-photon events. Conventional TCSPCs typically operate in periodic trigger mode, where an external synchronization trigger signal is considered the start (or end) signal for restarting the timing, and the single-photon signal is considered the end (or start) signal. If no single-photon signal is detected within a cycle, the timing is reset and restarted upon the arrival of the next trigger signal. However, in this mode, the start and end signals are limited to the repetition period of a single trigger pulse, ignoring the potential correlation between periods. Therefore, existing TCSPC systems are typically used to measure the time-domain characteristics of the measured signal, but it is difficult to simultaneously obtain parameters such as the average number of photoelectrons detected by the detector.

[0005] In summary, the start and end signals of the existing TCSPC technology are limited to the repetition period of a single trigger pulse, ignoring the possible correlation between the period and the interval, and making it difficult to simultaneously obtain parameters such as the average number of photoelectrons detected by the detector. The applicant has made corresponding explorations to solve this problem. Summary of the Invention

[0006] The purpose of this application is to solve the above-mentioned problems by providing a photon counting measurement method, a corresponding device, an electronic device, and a computer-readable storage medium.

[0007] To achieve the various objectives of this application, the following technical solution is adopted:

[0008] A photon counting measurement method proposed for one of the purposes of this application includes:

[0009] A single-photon detector acquires the echo light pulse of the sample to be detected, and performs photon detection based on the echo light pulse to determine the output signal;

[0010] The time-to-digital converter samples the output signal of the single-photon detector until the time-to-digital converter detects the first output signal or reaches a preset range threshold and stops timing.

[0011] The timing values ​​of the time-to-digital converter are statistically analyzed to determine the optical pulse period peak corresponding to the echo optical pulse. Based on the Poisson distribution algorithm, the probability distribution of each detection peak under different first peak detection probabilities in the optical pulse period peak is determined. The probability value of the first optical pulse period peak is determined according to the probability distribution of each detection peak.

[0012] The average number of photoelectrons detected by the single-photon detector is calculated based on the probability value of the first periodic peak of the light pulse to complete the photon counting measurement.

[0013] Optionally, after determining the probability distribution of each detection peak under different first-peak detection probabilities in the periodic peak of the optical pulse based on the Poisson distribution algorithm, the method further includes:

[0014] The time interval between each periodic peak is determined by calculating the probability distribution of each detection peak, and the period or frequency of the signal trigger pulse is determined based on the time interval between each periodic peak.

[0015] Optionally, the step of determining the probability distribution of each detection peak under different first-peak detection probabilities in the periodic peak of the optical pulse based on the Poisson distribution algorithm includes:

[0016] The time-domain linear shape of the echo pulse is determined based on the probability distribution of any detection peak, so as to complete the measurement of the Raman pulse width, fluorescence pulse width or laser pulse width of the sample to be tested.

[0017] Optionally, after the step of statistically analyzing the timing values ​​of the time-to-digital converter to determine the optical pulse period peak corresponding to the echo optical pulse, the method includes:

[0018] The statistical distribution of the dark count of the single-photon detector per unit time is determined based on the Poisson distribution algorithm;

[0019] The dark count of the single-photon detector is determined by fitting the statistical distribution of the dark count over a unit time using the e-exponential function.

[0020] Optionally, the step of determining the probability distribution of each detection peak under different first-peak detection probabilities in the periodic peak of the optical pulse based on the Poisson distribution algorithm, and determining the probability value of the first periodic peak of the optical pulse based on the probability distribution of each detection peak, includes:

[0021] According to the Poisson distribution formula, the probability distribution of the periodic peaks of a light pulse satisfies:

[0022] P n =P (n-1) (k=0,μ)[1-P(k=0,μ)],

[0023] P(k=0,μ)=1-P1=e -μ ,

[0024] Among them, P n Let be the probability of detecting photoelectrons in the nth period, k be the number of photoelectrons detected during the illumination time, and μ be the average number of photoelectrons detected during the illumination time. This can be further expressed as:

[0025]

[0026] Where PDE is the photon detection efficiency of the device, Num in This represents the average number of incident photons during the illumination period;

[0027] By obtaining the average number of photoelectrons μ, and under the condition of the known nominal PDE of the detector, the average number of photons incident on the detector can be further calculated, and then the incident power can be inverted.

[0028] Optionally, the step of determining the statistical distribution of the dark count of the single-photon detector per unit time based on the Poisson distribution algorithm includes:

[0029] According to the Poisson distribution formula, the statistical distribution of the dark count of the single-photon detector satisfies:

[0030] P dark (t)=P(k=0,DCR·t)=e -DCR·t ,

[0031] Among them, P dark (t) represents the probability that the detector generates a dark pulse at time t, k represents the number of dark pulses that occur per unit time, DCR represents the dark pulse count rate, and t represents the time from triggering at time zero to detecting the first dark pulse.

[0032] Optionally, the step of acquiring the echo light pulse of the sample to be detected by a single-photon detector, and performing photon detection based on the echo light pulse to determine the output signal includes:

[0033] The delayed pulse generator generates two synchronization signals: one as a trigger signal for the pulsed laser and the other as a start timing signal for the time-to-digital converter. The repetition period of the trigger signal for the pulsed laser should be less than the maximum range of the time-to-digital converter.

[0034] A pulsed laser generates a laser pulse to excite the sample to be tested. A single-photon detector receives the echo pulse signal of the sample to be tested and inputs it to a time-to-digital converter as the end-of-timing signal for measurement.

[0035] A photon counting measurement device provided for another purpose of this application includes:

[0036] The output signal determination module is configured to acquire the echo light pulse of the sample to be detected by a single photon detector, and perform photon detection based on the echo light pulse to determine the output signal;

[0037] The timing detection module is configured to sample the output signal of the single-photon detector using a time-to-digital converter until the time-to-digital converter detects the first output signal or reaches a preset range threshold to stop timing.

[0038] The periodic peak probability value determination module is configured to statistically analyze the timing values ​​of the time-to-digital converter to determine the periodic peak of the optical pulse corresponding to the echo optical pulse, determine the probability distribution of each detection peak under different first peak detection probabilities in the periodic peak of the optical pulse based on the Poisson distribution algorithm, and determine the probability value of the first periodic peak of the optical pulse based on the probability distribution of each detection peak.

[0039] The photon counting measurement module is configured to calculate and determine the average number of photoelectrons detected by the single-photon detector based on the probability value of the first periodic peak of the light pulse, so as to complete the photon counting measurement.

[0040] An electronic device provided for another purpose of this application includes a central processing unit and a memory, the central processing unit being configured to invoke and run a computer program stored in the memory to perform the steps of the photon counting measurement method of this application.

[0041] A computer-readable storage medium is provided for another purpose of this application, which stores, in the form of computer-readable instructions, a computer program implemented according to the photon counting measurement method, which, when invoked by a computer, performs the steps included in the corresponding method.

[0042] Compared to existing technologies, this application addresses the problem that the start and end signals of existing TCSPC technologies are limited to the repetition period of a single trigger pulse, ignoring the possible correlation between periods and intervals, and making it difficult to simultaneously obtain parameters such as the average number of photoelectrons detected by the detector. This application offers the following advantages, including but not limited to:

[0043] First, compared with traditional single-photon counting and timing measurement methods, the photon counting measurement method of this application is simpler and faster. It can simultaneously extract information such as the average number of photoelectrons detected, the number of incident photons, the dark count of the detector, the laser trigger period or the time interval of unequal periods, and the time domain linearity of the measured optical signal in a single data acquisition, and the amount of data collected is small.

[0044] Secondly, the photon counting measurement method of this application has high sensitivity and is especially suitable for the measurement of weak incident light or low PDE single-photon devices. Attached Figure Description

[0045] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0046] Figure 1 This is a schematic flowchart of the photon counting measurement method in the embodiments of this application;

[0047] Figure 2 This is a schematic architecture of the photon counting measurement system connection in the embodiments of this application;

[0048] Figure 3 This is a schematic diagram of the operating timing of the photon counting measurement system in the embodiments of this application;

[0049] Figure 4 This is a schematic diagram illustrating the relationship between the first peak detection probability P1 and the average number of photoelectrons detected μ in the embodiments of this application.

[0050] Figure 5 This is a schematic diagram showing the probability distribution of each detection peak under different first-peak detection probabilities in the embodiments of this application;

[0051] Figure 6 This is a schematic diagram of the measured values ​​and fitting curves of the statistical distribution of the periodic peaks of optical pulses based on TDC in the embodiments of this application;

[0052] Figure 7 This is a schematic diagram of the dark count statistical distribution measurement curve and fitting curve based on TDC in the embodiments of this application;

[0053] Figure 8 This is a schematic block diagram of the photon counting measurement device in the embodiments of this application;

[0054] Figure 9 This is a schematic diagram of the structure of the computer device in the embodiments of this application. Detailed Implementation

[0055] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0056] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this application means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or wireless coupling. The term “and / or” as used herein includes all or any units and all combinations of one or more associated listed items.

[0057] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0058] Those skilled in the art will understand that the terms "client," "terminal," and "terminal device" as used herein include both devices that receive wireless signals, devices that only possess wireless signal receiver capabilities without transmission capabilities, and devices with receiving and transmitting hardware, devices that have receiving and transmitting hardware capable of bidirectional communication over a bidirectional communication link. Such devices may include: cellular or other communication devices such as personal computers or tablets, having single-line displays, multi-line displays, or cellular or other communication devices without multi-line displays; PCS (Personal Communications Service) that can combine voice, data processing, fax, and / or data communication capabilities; PDA (Personal Digital Assistant) that may include a radio frequency receiver, pager, internet / intranet access, web browser, notepad, calendar, and / or GPS (Global Positioning System) receiver; and conventional laptops and / or handheld computers or other devices that have and / or include radio frequency receivers. As used herein, "client," "terminal," and "terminal device" can be portable, transportable, installed in a means of transportation (air, sea, and / or land), or suitable and / or configured to operate locally and / or in a distributed manner, operating in any other location on Earth and / or in space. "Client," "terminal," and "terminal device" as used herein can also be a communication terminal, an internet access terminal, or a music / video playback terminal, such as a PDA, a MID (Mobile Internet Device), and / or a mobile phone with music / video playback capabilities, or a smart TV, set-top box, etc.

[0059] The hardware referred to by the names "server," "client," and "service node" in this application is essentially an electronic device with the equivalent capabilities of a personal computer. It is a hardware device with the necessary components revealed by the von Neumann architecture, such as a central processing unit (including an arithmetic logic unit and a control unit), memory, input devices, and output devices. The computer program is stored in its memory, and the central processing unit loads the program stored in the secondary storage into the main memory to run it, execute the instructions in the program, and interact with the input and output devices to complete specific functions.

[0060] It should be noted that the concept of "server" used in this application can also be extended to the case of server clusters. Based on the network deployment principles understood by those skilled in the art, the servers should be logically divided. Physically, these servers can be independent of each other but accessible through interfaces, or they can be integrated into a single physical computer or a computer cluster. Those skilled in the art should understand this flexibility and should not use it to constrain the implementation of the network deployment method in this application.

[0061] One or more of the technical features of this application, unless explicitly specified herein, can be deployed on a server and accessed by a client remotely calling the online service interface provided by the server, or can be directly deployed and run on a client for access.

[0062] Unless otherwise specified, all data involved in this application may be stored remotely on a server or on a local terminal device, as long as it is suitable for use by the technical solution of this application.

[0063] Those skilled in the art will understand that although the various methods in this application are described based on the same concept and thus present commonality among them, they can be performed independently unless otherwise specified. Similarly, the various embodiments disclosed in this application are all based on the same inventive concept; therefore, concepts expressed in the same way, as well as concepts that are appropriately changed for convenience but are expressed differently, should be understood equivalently.

[0064] Unless otherwise expressly stated, the various embodiments disclosed in this application can be combined in a cross-cutting manner to flexibly construct new embodiments, as long as such combination does not depart from the inventive spirit of this application and can meet the needs of the prior art or solve a certain deficiency in the prior art. Those skilled in the art should be aware of such modifications.

[0065] Please see Figure 1 The photon counting measurement method of this application, in one embodiment, includes:

[0066] Step S10: The single-photon detector acquires the echo light pulse of the sample to be detected, and performs photon detection based on the echo light pulse to determine the output signal;

[0067] The steps of acquiring the echo light pulse of the sample to be detected using a single-photon detector, and determining the output signal based on the echo light pulse by performing photon detection, include:

[0068] Step S101: The delay pulse generator generates two synchronization signals, one as the trigger signal of the pulsed laser and the other as the start timing signal of the time-to-digital converter. The repetition period of the trigger signal of the pulsed laser should be less than the maximum range of the time-to-digital converter.

[0069] Step S103: The pulsed laser generates a laser pulse to excite the sample to be tested. The single-photon detector receives the echo light pulse signal of the sample to be tested and inputs it to the time-to-digital converter as the end timing signal for measurement.

[0070] Specifically, please refer to Figure 2 The delayed pulse generator produces two synchronization signals: one serves as the trigger signal for the pulsed laser, and the other as the start signal for the time-to-digital converter (TDC). The repetition period of the trigger signal should be less than the maximum range of the TDC. The pulsed laser generates laser pulses to excite the sample, and the single-photon detector receives the echo pulse signal from the sample and inputs it to the TDC as a stop signal for measurement. Finally, the data acquired by the TDC is transmitted to the host computer via a data transmission interface for data processing and analysis.

[0071] Step S20: The time-to-digital converter samples the output signal of the single-photon detector until the time-to-digital converter detects the first output signal or reaches the preset range threshold and stops timing.

[0072] Please see Figure 3 The trigger signal of the pulsed laser also serves as the start signal of the TDC (Time Difference Detector), while the echo pulse signal received by the single-photon detector serves as the stop signal of the TDC. The output signal of the single-photon detector contains both the useful photon signal and the dark noise signal. Once triggered, the TDC will only stop timing after detecting the first output signal from the detector or reaching full scale, and will wait to restart timing. Otherwise, all start signals during this period will be ignored.

[0073] Step S30: Statistically calculate the timing value of the time-to-digital converter to determine the optical pulse period peak corresponding to the echo optical pulse; determine the probability distribution of each detection peak under different first peak detection probabilities in the optical pulse period peak based on the Poisson distribution algorithm; and determine the probability value of the first optical pulse period peak based on the probability distribution of each detection peak.

[0074] By repeatedly (e.g., 100,000 times) acquiring and statistically analyzing the detector output pulses using the TDC, the statistical distributions of the optical pulse signal and the dark count can be obtained simultaneously. The acquisition time depends on the repetition frequency of the laser excitation and the magnitude of the dark count rate. By statistically analyzing the timing values ​​of the TDC, the periodic peak of the optical pulse and the statistical distribution of the dark count of the single-photon detector over time can be obtained. The theoretical basis is that the probability of the single-photon detector detecting the number of photoelectrons within the illumination time and the probability of the dark count occurring per unit time follow a Poisson distribution. The timing values ​​of the time-to-digital converter are statistically analyzed to determine the periodic peak of the optical pulse corresponding to the echo optical pulse. Based on the Poisson distribution algorithm, the probability distribution of each detection peak under different first peak detection probabilities in the periodic peak of the optical pulse is determined. The probability value of the first periodic peak of the optical pulse is determined according to the probability distribution of each detection peak.

[0075] The steps of determining the probability distribution of each detection peak under different first-peak detection probabilities in the periodic peak of the optical pulse based on the Poisson distribution algorithm, and determining the probability value of the first periodic peak of the optical pulse based on the probability distribution of each detection peak, include:

[0076] According to the Poisson distribution formula, the probability distribution of the periodic peaks of a light pulse satisfies:

[0077] P n =P (n-1) (k=0,μ)[1-P(k=0,μ)] (1),

[0078] P(k=0,μ)=1-P1=e -μ (2),

[0079] Among them, P n Let be the probability of detecting photoelectrons in the nth period, k be the number of photoelectrons detected during the illumination time, and μ be the average number of photoelectrons detected during the illumination time. This can be further expressed as:

[0080]

[0081] Wherein, PDE represents the photon detection efficiency of the device. This represents the average number of incident photons during the illumination period;

[0082] Combining formulas (1) and (2), we can obtain Figure 4 and Figure 5 The theoretical curve shown is used as a reference for measuring the μ value.

[0083] Figure 4 This represents the relationship between the first peak detection probability P1 and the average number of photoelectrons detected μ. Figure 5This represents the probability distribution of each detection peak under different initial detection probabilities. It can be seen that the magnitude of μ is related to the device's photon detection efficiency (PDE) and the incident light intensity. The magnitude of the peak value determines the probability P1 of the first periodic peak of the light pulse, which in turn determines the probability distribution of each detection peak. Therefore, by measuring the statistical distribution of each detection peak and fitting it according to the above formula (1), the actual value of P1 can be obtained, and then the average number of photoelectrons μ detected by the detector can be calculated.

[0084] By obtaining the average number of photoelectrons μ, and under the condition of the known nominal PDE of the detector, the average number of photons incident on the detector can be further calculated according to formula (3), and then the incident power can be inverted.

[0085] After determining the probability distribution of each detection peak under different first-peak detection probabilities in the periodic peak of the optical pulse based on the Poisson distribution algorithm, the following steps are included:

[0086] The time interval between each periodic peak is determined by calculating the probability distribution of each detection peak, and the period or frequency of the signal trigger pulse is determined based on the time interval between each periodic peak.

[0087] Specifically, based on the statistical distribution of each measured detection peak, the time interval between each periodic peak can be obtained, thereby obtaining the period ΔT or frequency f (f = 1 / ΔT) of the signal trigger pulse, and the interval time between any two pulses of unequal periodic trigger pulses can also be obtained.

[0088] The steps for determining the probability distribution of each detection peak under different first-peak detection probabilities in the periodic peak of the optical pulse based on the Poisson distribution algorithm include:

[0089] The time-domain linear shape of the echo pulse is determined based on the probability distribution of any detection peak, so as to complete the measurement of the Raman pulse width, fluorescence pulse width or laser pulse width of the sample to be tested.

[0090] Specifically, based on the statistical distribution of any measured detection peak, the temporal linearity of the measured light pulse can also be obtained, thereby enabling the measurement of the Raman light, fluorescence, or laser pulse width of the sample.

[0091] After determining the optical pulse period peak corresponding to the echo optical pulse by statistically analyzing the timing value of the time-to-digital converter, the process includes:

[0092] The statistical distribution of the dark count of the single-photon detector per unit time is determined based on the Poisson distribution algorithm;

[0093] The dark count of the single-photon detector is determined by fitting the statistical distribution of the dark count over a unit time using the e-exponential function.

[0094] The steps for determining the statistical distribution of the dark count of the single-photon detector per unit time based on the Poisson distribution algorithm specifically include:

[0095] According to the Poisson distribution formula, the statistical distribution of the dark count of the single-photon detector satisfies:

[0096] P dark (t)=P(k=0,DCR·t)=e -DCR·t ,

[0097] Among them, P dark (t) represents the probability that the detector generates a dark pulse at time t, k represents the number of dark pulses that occur per unit time, DCR represents the dark pulse count rate, and t represents the time from triggering at time zero to detecting the first dark pulse.

[0098] The dark count rate (DCR) of the detector can be obtained by fitting the statistical distribution of dark counts per unit time using the e-exponential function.

[0099] Step S40: Calculate the average number of photoelectrons detected by the single-photon detector based on the probability value of the first light pulse periodic peak to complete the photon counting measurement.

[0100] After determining the probability value of the first light pulse periodic peak based on the probability distribution of each detection peak, the average number of photoelectrons detected by the single-photon detector is calculated based on the probability value of the first light pulse periodic peak to complete the photon counting measurement.

[0101] like Figure 2 As shown, the delayed pulse generator produces two synchronization signals: one serves as the trigger signal for the pulsed laser, and the other as the start signal for the TDC (Time Diode Controller). The repetition period of the trigger signal should be less than the maximum range of the TDC. The pulsed laser generates laser pulses to excite the sample, and the single-photon detector receives the echo pulse signal from the sample and inputs it to the TDC as a stop signal for measurement. Finally, the data acquired by the TDC is transmitted to the host computer via a data transmission interface for data processing and analysis.

[0102] Furthermore, the working mode of TDC is as follows: Figure 3 As shown, the Trigger signal also serves as the Start signal for the TDC, and the echo pulse signal received by the single-photon detector serves as the Stop signal for the TDC. The output signal of the single-photon detector contains both the useful photon signal and the dark noise signal. Once the TDC is triggered, it will only stop timing and wait to restart after detecting the first signal output by the detector or reaching full scale; otherwise, it will ignore all Start signals during this period.

[0103] Furthermore, by repeatedly (e.g., 100,000 times) acquiring and statistically analyzing the detector output pulses using the TDC, the statistical distribution of the optical pulse signal and the dark count can be obtained simultaneously. The acquisition time depends on the repetition frequency of the laser excitation and the magnitude of the dark count rate.

[0104] Furthermore, by separating the periodic light pulses and dark count information from the statistical results, we can obtain, respectively, the following: Figure 6 and Figure 7 Statistical distribution measurement data, Figure 6 The figure shows the statistical distribution of the periodic peaks of the light pulse. The red line in the figure is the fitting result based on the aforementioned formulas (1) and (2). It can be seen that the probability distribution of each peak conforms to the rule of formula (1). Based on the fitting curve, the probability value P(k=0,μ) can be extracted. Then, according to μ=-ln[P(k=0,μ)], the average number of photoelectrons μ detected by the detector can be calculated.

[0105] Furthermore, according to Figure 6 It is also possible to obtain the time interval ΔT between statistical peaks. If the excitation pulse is a periodic signal, then ΔT is the measured repetition period. If the excitation pulse is a non-periodic signal, then the interval between each trigger can be determined by calculating ΔT between any two peaks.

[0106] Furthermore, by taking the envelope of any statistical peak's bin, the temporal linearity of the measured optical pulse can be obtained.

[0107] Furthermore, Figure 7 The figure shows the statistical distribution of the measured dark counts. The red line in the figure is the fitting result according to formula (3). It can be seen that the probability distribution of the dark counts conforms to the statistical law of the e-exponential. Based on this fitting curve, the dark count rate (DCR) can be extracted.

[0108] As can be seen from the above embodiments, compared with the prior art, this application addresses the problem that the start and end signals of the TCSPC technology in the prior art are limited to the repetition period of one trigger pulse, ignoring the possible correlation between the period and the interval, and making it difficult to simultaneously obtain parameters such as the average number of photoelectrons detected by the detector. This application has, but is not limited to, the following beneficial effects:

[0109] First, compared with traditional single-photon counting and timing measurement methods, the photon counting measurement method of this application is simpler and faster. It can simultaneously extract information such as the average number of photoelectrons detected, the number of incident photons, the dark count of the detector, the laser trigger period or the time interval of unequal periods, and the time domain linearity of the measured optical signal in a single data acquisition, and the amount of data collected is small.

[0110] Secondly, the photon counting measurement method of this application has high sensitivity and is especially suitable for the measurement of weak incident light or low PDE single-photon devices.

[0111] Please see Figure 8 A photon counting measurement device provided for one of the purposes of this application includes an output signal determination module 1100, a timing detection module 1200, a period peak probability value determination module 1300, and a photon counting measurement module 1400. The output signal determination module 1100 is configured to acquire the echo light pulse of the sample to be detected by a single-photon detector, and perform photon detection based on the echo light pulse to determine the output signal; the timing detection module 1200 is configured to sample the output signal of the single-photon detector by a time-to-digital converter until the time-to-digital converter detects the first output signal or reaches a preset range threshold to stop timing; the periodic peak probability value determination module 1300 is configured to statistically analyze the timing value of the time-to-digital converter to determine the periodic peak of the light pulse corresponding to the echo light pulse, determine the probability distribution of each detection peak under different first peak detection probabilities in the periodic peak of the light pulse based on the Poisson distribution algorithm, and determine the probability value of the first periodic peak of the light pulse based on the probability distribution of each detection peak; the photon counting measurement module 1400 is configured to calculate and determine the average number of photoelectrons detected by the single-photon detector based on the probability value of the first periodic peak of the light pulse to complete the photon counting measurement.

[0112] Based on any embodiment of this application, please refer to Figure 9 Another embodiment of this application also provides an electronic device, which can be implemented by a computer device, such as... Figure 9 The diagram shows the internal structure of a computer device. The computer device includes a processor, a computer-readable storage medium, a memory, and a network interface connected via a system bus. The computer-readable storage medium stores an operating system, a database, and computer-readable instructions. The database may store a sequence of control information. When executed by the processor, the computer-readable instructions enable the processor to implement a photon counting measurement method. The processor provides computational and control capabilities, supporting the operation of the entire computer device. The memory stores computer-readable instructions, which, when executed by the processor, enable the processor to execute the photon counting measurement method of this application. The network interface of the computer device is used for communication with a terminal. Those skilled in the art will understand that… Figure 9 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0113] In this embodiment, the processor is used to execute... Figure 8 The specific functions of each module and its submodules are described, and the memory stores the program code and various data required to execute the aforementioned modules or submodules. The network interface is used for data transmission between the user terminal and the server. In this embodiment, the memory stores the program code and data required to execute all modules / submodules in the photon counting measurement device of this application, and the server can call the server's program code and data to execute the functions of all submodules.

[0114] This application also provides a storage medium storing computer-readable instructions, which, when executed by one or more processors, cause the one or more processors to perform the steps of the photon counting measurement method described in any embodiment of this application.

[0115] This application also provides a computer program product, including a computer program / instructions that, when executed by one or more processors, implement the steps of the photon counting measurement method described in any embodiment of this application.

[0116] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments of this application can be implemented by a computer program instructing related hardware. This computer program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. The aforementioned storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0117] The above description is only a partial embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

[0118] In summary, the photon counting measurement method of this application has high sensitivity and is especially suitable for the measurement of weak incident light or low PDE single-photon devices.

Claims

1. A method of photon counting measurement, characterized by, include: A single-photon detector acquires the echo light pulse of the sample to be detected, and performs photon detection based on the echo light pulse to determine the output signal; The time-to-digital converter samples the output signal of the single-photon detector until the time-to-digital converter detects the first output signal or reaches a preset range threshold and stops timing. The timing values ​​of the time-to-digital converter are statistically analyzed to determine the optical pulse period peak corresponding to the echo optical pulse. Based on the Poisson distribution algorithm, the probability distribution of each detection peak under different first peak detection probabilities in the optical pulse period peak is determined. The probability value of the first optical pulse period peak is determined according to the probability distribution of each detection peak. The average number of photoelectrons detected by the single-photon detector is calculated based on the probability value of the first periodic peak of the light pulse to complete the photon counting measurement.

2. The method of photon counting measurement according to claim 1, characterized in that, After determining the probability distribution of each detection peak under different first-peak detection probabilities in the periodic peak of the optical pulse based on the Poisson distribution algorithm, the following steps are included: The time interval between each periodic peak is determined by calculating the probability distribution of each detection peak, and the period or frequency of the signal trigger pulse is determined based on the time interval between each periodic peak.

3. The method of photon counting measurement according to claim 1, wherein, The steps for determining the probability distribution of each detection peak under different first-peak detection probabilities in the periodic peak of the optical pulse based on the Poisson distribution algorithm include: The temporal shape of the echo pulse is determined based on the probability distribution of any detection peak, so as to complete the measurement of the Raman pulse width, fluorescence pulse width or laser pulse width of the sample to be tested.

4. The method of photon counting measurement according to claim 1, wherein, After determining the optical pulse period peak corresponding to the echo optical pulse by statistically analyzing the timing value of the time-to-digital converter, the process includes: The statistical distribution of the dark count of the single-photon detector per unit time is determined based on the Poisson distribution algorithm; The dark count of the single-photon detector is determined by fitting the statistical distribution of the dark count over a unit time using the e-exponential function.

5. The method of photon counting measurement according to claim 1, wherein, The steps of determining the probability distribution of each detection peak under different first-peak detection probabilities in the periodic peak of the optical pulse based on the Poisson distribution algorithm, and determining the probability value of the first periodic peak of the optical pulse based on the probability distribution of each detection peak, include: According to the Poisson distribution formula, the probability distribution of the periodic peaks of a light pulse satisfies: P n = P (n-1) (k = 0, μ) [1 - P(k = 0, μ)], P(k=0,μ)=1-P1=e -μ , Among them, P n Let be the probability of detecting photoelectrons in the nth period, k be the number of photoelectrons detected during the illumination time, and μ be the average number of photoelectrons detected during the illumination time. This can be further expressed as: Wherein, PDE represents the photon detection efficiency of the device. This represents the average number of incident photons during the illumination period; By obtaining the average number of photoelectrons μ, and under the condition of a known nominal PDE of the detector, the average number of photons incident on the detector can be further calculated. Then the incident power is inverted.

6. The photon counting measurement method according to claim 4, characterized in that, The steps for determining the statistical distribution of the dark count of the single-photon detector per unit time based on the Poisson distribution algorithm include: According to the Poisson distribution formula, the statistical distribution of the dark count of the single-photon detector satisfies: P dark (t)=P(k=0,DCR·t)=e -DCR·t , Among them, P dark (t) represents the probability that the detector generates a dark pulse at time t, k represents the number of dark pulses that occur per unit time, DCR represents the dark pulse count rate, and t represents the time from triggering at time zero to detecting the first dark pulse.

7. The method of photon counting measurement according to any one of claims 1 to 6, characterized in that, The steps of acquiring the echo light pulse of the sample to be detected by a single-photon detector, and determining the output signal by performing photon detection based on the echo light pulse include: The delayed pulse generator generates two synchronization signals: one as a trigger signal for the pulsed laser and the other as a start timing signal for the time-to-digital converter. The repetition period of the trigger signal for the pulsed laser should be less than the maximum range of the time-to-digital converter. A pulsed laser generates a laser pulse to excite the sample to be tested. A single-photon detector receives the echo pulse signal of the sample to be tested and inputs it to a time-to-digital converter as the end-of-timing signal for measurement.

8. A photon counting measurement device, characterized by include: The output signal determination module is configured to acquire the echo light pulse of the sample to be detected by a single photon detector, and perform photon detection based on the echo light pulse to determine the output signal; The timing detection module is configured to sample the output signal of the single-photon detector using a time-to-digital converter until the time-to-digital converter detects the first output signal or reaches a preset range threshold to stop timing. The periodic peak probability value determination module is configured to statistically analyze the timing values ​​of the time-to-digital converter to determine the periodic peak of the optical pulse corresponding to the echo optical pulse, determine the probability distribution of each detection peak under different first peak detection probabilities in the periodic peak of the optical pulse based on the Poisson distribution algorithm, and determine the probability value of the first periodic peak of the optical pulse based on the probability distribution of each detection peak. The photon counting measurement module is configured to calculate and determine the average number of photoelectrons detected by the single-photon detector based on the probability value of the first periodic peak of the light pulse, so as to complete the photon counting measurement.

9. An electronic device comprising a central processing unit and a memory, characterized in that The central processing unit is used to invoke and run a computer program stored in the memory to perform the steps of the method as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, It stores, in the form of computer-readable instructions, a computer program implemented according to any one of claims 1 to 7, which, when invoked by a computer, executes the steps included in the corresponding method.

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