A single-photon post-selection monte carlo photon number imaging method

Abstract

The present application relates to the technical field of photon imaging, in particular to a single-photon post-selection Monte Carlo photon number imaging method. The present application provides a single-photon post-selection Monte Carlo photon number imaging method, comprising: determining reflectivity of a target to be measured and a reference plate respectively; dividing a space where the target to be measured is located into a plurality of spatial grids; shooting a pair of single photons in an entangled state to one of the spatial grids and the reference plate respectively according to a preset number of times to obtain average photon numbers of the spatial grids; assigning values to the spatial grids according to the average photon numbers; and imaging according to the assigned values of the spatial grids. The present application provides a single-photon post-selection Monte Carlo photon number imaging method, which can improve single-photon imaging capability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photon imaging, in particular to a single-photon post-selection Monte Carlo photon number imaging method. BACKGROUND

[0002] The single-photon imaging technology is a kind of super-long distance target imaging technology.

[0003] However, the single-photon imaging capability is weak, and therefore, in order to improve the single-photon imaging capability, a single-photon post-selection Monte Carlo photon number imaging method is proposed. SUMMARY

[0004] The embodiment of the present application provides a single-photon post-selection Monte Carlo photon number imaging method, which can improve the single-photon imaging capability.

[0005] In a first aspect, the embodiment of the present application provides a single-photon post-selection Monte Carlo photon number imaging method, comprising:

[0006] Determine the reflectivity of the target to be measured and the reference plate respectively;

[0007] Divide the space where the target to be measured is located into a plurality of spatial grids;

[0008] According to a preset number of times, a pair of single photons in an entangled state are respectively shot to one of the spatial grids and the reference plate, to obtain the average number of photons of the spatial grid;

[0009] According to the average number of photons, the spatial grid is valued;

[0010] According to the valuation of the spatial grid, imaging is performed.

[0011] In a possible design, the average number of photons of the spatial grid is obtained by respectively shooting a pair of single photons in an entangled state to one of the spatial grids and the reference plate, comprising:

[0012] According to a preset number of times A, a pair of single photons in an entangled state are respectively shot to one of the spatial grids and the reference plate, to obtain a Monte Carlo reference list, the Monte Carlo reference list includes a target photon detection list and a reference plate photon detection list, the target photon detection list includes the order of emitting a pair of single photons and whether the photon reflected by the target to be measured is received in this emission, and the reference plate photon detection list includes the order of emitting a pair of single photons and whether the photon reflected by the reference plate is received in this emission;

[0013] Collect the total number of reflected photons NR of the spatial grid, and collect the number of times N00 when a pair of single photons are not reflected by the spatial grid and the reference plate at the same time;

[0014] According to the NR and the N00, the average photon number of the spatial grid is calculated.

[0015] In a possible design, the average photon number of the spatial grid is calculated according to the NR and the N00, including:

[0016] The average photon number = NR / (A-N00).

[0017] In a possible design, the preset number of times is 1000.

[0018] In a possible design, the adjacent spatial grids are spaced apart by 0.01 m.

[0019] In a second aspect, the present application also provides a single-photon post-selection Monte Carlo photon number imaging device, including:

[0020] A data reading module is configured to read reflectivity of a target to be measured and a reference plate.

[0021] A spatial division module is configured to divide a space where the target to be measured is located into a plurality of spatial grids.

[0022] A single-photon emitting module is configured to emit a pair of single photons in an entangled state to one of the spatial grids and the reference plate according to a preset number of times.

[0023] A data analysis module is configured to calculate an average photon number of the spatial grid.

[0024] An assignment module is configured to assign the spatial grid according to the average photon number.

[0025] A result output module is configured to image according to the assignment of the spatial grid.

[0026] In a third aspect, an electronic device is provided, including a memory and a processor, the memory stores a computer program, and the processor executes the computer program to implement the method in any one of the above aspects.

[0027] In a fourth aspect, a computer readable storage medium is provided, which stores a computer program, and the computer program, when executed in a computer, causes the computer to execute the method in any one of the above aspects.

[0028] Compared with the prior art, the present application has at least the following beneficial effects:

[0029] The space where the target to be detected is located is divided into multiple space grids, a plurality of groups of single photons in entangled states are respectively emitted to the reference plate and the target to be detected, the single photons reflected by the space grids and the reference plate are collected, and the average photon number is obtained. The average photon number is used to value the space grids, the space grids are colored and imaged according to the value, the photon imaging capability is improved, and the purpose of low-photon-number target detection is finally achieved. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings described below are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0031] Figure 1 is a main step schematic diagram of the single-photon post-selection Monte Carlo photon number imaging of the embodiment one of the present application;

[0032] Figure 2 is a main module schematic diagram of the Monte Carlo photon number imaging program of the embodiment two of the present application;

[0033] Figure 3 is a main module schematic diagram of the single-photon post-selection photon number imaging device of the embodiment three of the present application;

[0034] Figure 4a is a schematic diagram of a planar symbol target;

[0035] Figure 4b is an evolution schematic diagram of the total photon number of each group reflected by the target arranged according to the serial number of the emission group;

[0036] Figure 4c is an evolution schematic diagram of the total number N00 of events of single photons without reflection arranged according to the serial number of the emission group.

[0037] Figure 4d is a schematic diagram of the Monte Carlo quantum imaging of the space scanning grid points. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0039] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the terms "first", "second" are only used for the purpose of description, and cannot be understood as indicating or implying relative importance; unless otherwise specified or stated, the term "multiple" refers to two or more; the terms "connection", "fixation" and the like should be understood in a broad sense, for example, "connection" can be fixed connection, or detachable connection, or integral connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0040] In the description of the present specification, it should be understood that the "upper", "lower" and the like described in the embodiments of the present application are described with the angle shown in the drawings, and should not be understood as limiting the embodiments of the present application. In addition, in the context, it should also be understood that when referring to one element connected to another element "on" or "below", it can not only be directly connected to another element "on" or "below", but also indirectly connected to another element "on" or "below" through an intermediate element.

[0041] The embodiment of the present application provides a single photon post-selection Monte Carlo photon number imaging method, comprising:

[0042] The reflectivity of the target to be measured and the reference plate is determined respectively;

[0043] The space where the target to be measured is located is divided into multiple space grids;

[0044] A pair of single photons in an entangled state is respectively emitted to a space grid and a reference plate according to a preset number of times, and the average number of photons of the space grid is obtained;

[0045] The space grid is valued according to the average number of photons;

[0046] The space grid is imaged according to the valuation.

[0047] The space where the target to be measured is located is divided into multiple space grids, a plurality of groups of single photon pairs in an entangled state are respectively emitted to the reference plate and the target to be measured, the situation of the single photons reflected by the space grid and the reference plate is collected, and the average number of photons is obtained. The space grid is valued using the average number of photons, and the space grid is colored and imaged according to the valuation, which improves the ability of photon imaging, and finally realizes the purpose of low-photon-number target detection.

[0048] It should be noted that the target to be measured is fixed at a certain determined position in space, so that the single photons emitted by the single photon source can irradiate the target. The reference plate is placed in another branch.

[0049] In some embodiments of the present application, the average photon number of the spatial grid is obtained by respectively shooting a pair of single photons in an entangled state to a spatial grid and a reference plate, and the average photon number of the spatial grid comprises:

[0050] The average photon number of the spatial grid is obtained by respectively shooting a pair of single photons in an entangled state to a spatial grid and a reference plate for a preset number A, and the Monte Carlo reference list comprises a target photon detection list to be measured and a reference plate photon detection list, the target photon detection list to be measured comprises the order of emitting a pair of single photons and whether the target reflected photon is received in the emission, and the reference plate photon detection list comprises the order of emitting a pair of single photons and whether the reference plate reflected photon is received in the emission;

[0051] The total number NR of reflected photons of the spatial grid is collected, and the number N00 of times that a pair of single photons is not reflected by the spatial grid and the reference plate at the same time is collected;

[0052] The average photon number of the spatial grid is calculated according to NR and N00.

[0053] The reflectivity of the reference plate is determined by selecting different reference plates. Different reflectivity of the reference plate is used to generate different Monte Carlo reference list. The Monte Carlo reference list is formed: in experiment, a single photon source is used to irradiate the reference plate, and the event sequence of the reflected photon detection result is recorded; in simulation, a pseudo-random number is used to sample to generate the Monte Carlo reference list, etc.

[0054] In some embodiments of the present application, the average photon number of the spatial grid is calculated according to NR and N00, comprising:

[0055] The average photon number = NR / (A-N00).

[0056] In some embodiments of the present application, the preset number is 1000.

[0057] In some embodiments of the present application, the interval between adjacent spatial grids is 0.01 m.

[0058] In this embodiment, one branch of the single photon light path modulates the propagation direction of the single photon by a swing mirror, a scanning space of 1 meter by 1 meter is set, the interval is 0.01 meter, the space to be imaged is scanned at equal intervals, the reflected photon number of the target and the reference plate is recorded for each spatial grid, after the scanning is completed, the average photon number is calculated to statistically analyze the spatial grid, and the Monte Carlo imaging is completed.

[0059] The present application also provides a single photon post-selection Monte Carlo photon number imaging device, comprising:

[0060] A data reading module is configured to read the reflectivity of the target to be measured and the reference plate;

[0061] A spatial division module is configured to divide the space where the target to be measured is located into a plurality of spatial grids;

[0062] a single photon emitting module for emitting a pair of single photons of an entangled state to a spatial grid and a reference plate respectively by a preset number of times;

[0063] a data analysis module for calculating an average photon number of the spatial grid;

[0064] an assignment module for assigning the spatial grid according to the average photon number;

[0065] a result output module for imaging according to the assignment of the spatial grid.

[0066] In simulating the above experimental method, the data analysis module can be used to replace the single photon emitting module, the data analysis module and the assignment module to complete the simulation of the experiment.

[0067] In implementing the above experimental method, the imaging device further comprises a single photon calculator and a result display module.

[0068] The embodiment of the present application further provides an electronic device comprising a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to realize the method in any of the embodiments of the present application.

[0069] The embodiment of the present application further provides a computer readable storage medium, wherein the computer readable storage medium stores a computer program, and the computer program is executed by a processor to make the processor execute the method in any of the embodiments of the present application.

[0070] Specifically, a system or device provided with a storage medium can be provided, wherein the storage medium stores a software program code realizing the function of any of the above embodiments, and the computer (or CPU or MPU) of the system or device reads and executes the program code stored in the storage medium.

[0071] In this case, the program code read from the storage medium itself can realize the function of any of the above embodiments, and thus the program code and the storage medium storing the program code constitute a part of the present application.

[0072] The storage medium for providing the program code includes a floppy disk, a hard disk, a magneto-optical disk, an optical disk (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), a magnetic tape, a nonvolatile memory card and a ROM. Alternatively, the program code can be downloaded from a server computer through a communication network.

[0073] Moreover, it should be appreciated that, in some embodiments, the functions described can be implemented in software, firmware, hardware, or any combination thereof. In some embodiments, the functions described can be implemented in program code that can be executed by one or more computers.

[0074] Moreover, it should be appreciated that, in some embodiments, the functions described can be implemented in software, firmware, hardware, or any combination thereof. In some embodiments, the functions described can be implemented in program code that can be executed by one or more computers.

[0075] It should be noted that, in the description, relative terms such as first and second are used merely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0076] Those skilled in the art can understand that all or part of the steps of the above-mentioned method embodiments can be completed by program instruction-related hardware, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs steps including the above-mentioned method embodiments; and the aforementioned storage medium includes various storage media that can store program codes, such as ROM, RAM, magnetic disc, or optical disc.

[0077] Embodiment one

[0078] As shown in Figure 1 The imaging method provided by the embodiment of the present application comprises the following steps:

[0079] Step S101, setting a target and determining a reference plate reflectivity.

[0080] The single-photon reflectivity of the reference plate is set as P, and the reflectivity of the planar target is set as R. The planar target can be represented by any symbol, such as a number 207 as shown in Figure 4a The target is directly placed in the air, and the single-photon beam is much smaller than the target.

[0081] Step S102, acquiring the number of reflected photons of the target and the reference plate.

[0082] A pair of single photon beams respectively irradiate on the target and reference plate, and the number of single photons reflected by the target and reference plate is obtained. The single photon source emits a group of 1000 pairs of single photons, half of which irradiate on the target, and the reflectivity of the target is R=0.04. The single photon detector records the time sequence of each group of photon detection and the total number of photons NR corresponding to the group. The total number of photons in each group is arranged according to the sequence number (NS) of the emission group, as shown in Figure 4b The other half of the single photons irradiate on the reference plate, and the reflectivity of the reference plate is P=0.09. The reflected single photons reach the detector and record the single photon detection sequence as a Monte Carlo abstract list. By comparing the single photon detection sequence lists of the target and the reference plate, the total number of events N00 in which neither the target nor the reference plate reflects a single photon in each group is obtained. The total number of events N00 in which neither the target nor the reference plate reflects a single photon is arranged according to the sequence number of the emission group, as shown in Figure 4c .

[0083] Step S103, set the scanning space interval, scan the space to be imaged at equal intervals, and complete the average photon number statistics and imaging.

[0084] The space where the target is located is divided into 32x68 space grids, and the single photon beam is scanned point by point. Each space grid point irradiates a group of photons, and the single photon detection sequence list of the target and the reference plate is recorded. The total number of photons NR and the total number of events N00 in which neither the target nor the reference plate reflects a single photon in the corresponding list are determined, and the average photon number NR / (1000-N00) is calculated according to the corresponding grid point to complete the Monte Carlo quantum imaging, as shown in Figure 4d .

[0085] Exemplarily, for other forms of planar symbol targets, such as S, LU, 789, etc., the planar target can be replaced.

[0086] Embodiment two

[0087] As shown in Figure 2 , the embodiment of the present application provides a Monte Carlo photon number imaging program 200, which specifically comprises a data reading module 201, a data analysis module 202 and a result output module 203.

[0088] The data reading module 201 is used to read the planar target distribution to be measured and the reflectivity of the reference plate.

[0089] The target grid model to be measured and the reflectivity data of the reference plate are stored in a CD, a floppy disk or a computer hard disk. The planar target distribution and the reflectivity data can be read into the software and converted into an executable format.

[0090] The data analysis module 202 is used to simulate the detection photon number sequence of the planar target and the reference plate.

[0091] For example, after the planar target and reference plate data are read in, the program will obtain the simulated photon number sequence according to the following steps:

[0092] Step 1, set the reflectivity of the target and the reference plate.

[0093] Step 2, generate a single-photon detection sequence list of the target and the reference plate by Monte Carlo. A pair of photons is generated, one of which irradiates the reference plate and reflects with a probability of P, and the other of which irradiates the target and reflects with a probability of R. If the Monte Carlo sampling result makes the reference plate and the target have no reflected photon count, a zero-photon event is recorded. If the Monte Carlo sampling result makes the target have a reflected photon count, a photon event is recorded. Statistics of each group of Np pairs of photons are obtained, and the total number of photons NR and the total number of events without reflected single photons N00 of the group are obtained.

[0094] Step 3, determine the total number of photons and the total number of events without reflected single photons of the group from the corresponding list, assign values to the corresponding grid points by calculating the average photon number NR / (Np-N00), and complete the Monte Carlo quantum imaging simulation.

[0095] The result output module 203 is used for the simulation process and the imaging data.

[0096] The photon number list and the imaging data simulated by the data analysis module 202 are output to a data window, and the results are stored in a designated storage medium.

[0097] Embodiment three

[0098] As shown in Figure 3 , the embodiment of the present application provides a single-photon post-selection photon number imaging device 300, which specifically comprises a single-photon counter 301, a data reading module 302, a data analysis module 303, a result display module 304, and a result output module 305.

[0099] The single-photon counter 301 is used for measuring the reflected photons of the target and the reference plate.

[0100] The data reading module 302 is used for reading the photon number record data to be measured.

[0101] The photon number record data to be measured is stored in a CD, a floppy disk, or a computer hard disk, and software can be run to read in the photon number record data and convert it into an executable format.

[0102] The data analysis module 303 is used for analyzing the read-in photon number record data.

[0103] For example, after the photon number recorded data is read in, the software will analyze the single photon post-selection effect according to the following steps: Step 1, setting the target and determining the reflectivity of the reference plate; Step 2, obtaining the reflected photon number of the target and the reference plate; Step 3, setting the scanning space interval, scanning the space to be imaged at equal intervals, and completing the average photon number statistics and imaging.

[0104] The result display module 304 is a screen integrated in the single photon post-selection photon number imaging device, which has text and graphic display capability and is used to directly display the average photon number image calculated by the data analysis module 303.

[0105] The result output module 305 is used to output the average photon number image.

[0106] The average photon number image calculated by the data analysis module 303 is output to the display window, and the result is accessed to the designated storage medium.

[0107] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A single-photon post-selective Monte Carlo photon number imaging method, characterized in that, include: Determine the reflectivity of the target and the reference plate respectively; The space containing the target to be tested is divided into multiple spatial grids; A pair of entangled single photons are directed at a spatial grid and a reference plate respectively a preset number of times to obtain the average number of photons in the spatial grid; The spatial grid is assigned a value based on the average photon number; Imaging is performed based on the assigned values ​​of the spatial grid; The step of firing a pair of entangled single photons at a predetermined number of times onto a spatial grid and a reference plate respectively, to obtain the average number of photons in the spatial grid, includes: A pair of entangled single photons are directed at a spatial grid and a reference plate a predetermined number of times (A) to obtain a Monte Carlo reference list. The Monte Carlo reference list includes a target photon detection list and a reference plate photon detection list. The target photon detection list includes the order in which the single photon pairs are emitted and whether a photon reflected from the target photon is received during that emission. The reference plate photon detection list includes the order in which the single photon pairs are emitted and whether a photon reflected from the reference plate is received during that emission. The total number of photons reflected by the spatial grid (NR) is collected, and the number of times a pair of single photons is not reflected by both the spatial grid and the reference plate (N00) is collected. The average photon number of the spatial grid is calculated based on NR and N00.

2. The method according to claim 1, characterized in that, The calculation of the average photon number of the spatial grid based on NR and N00 includes: Average photon number = NR / (A - N00).

3. The method according to claim 1, characterized in that, The preset number of times is 1000.

4. The method according to claim 1, characterized in that, The adjacent spatial grids are spaced 0.01m apart.

5. A single-photon post-selective Monte Carlo photon number imaging device, characterized in that, include: The data reading module is used to read the reflectance of the target under test and the reference plate; The spatial partitioning module is used to divide the space where the target to be tested is located into multiple spatial grids; A single-photon emission module is used to emit a pair of entangled single photons toward a spatial grid and a reference plate respectively, according to a preset number of times; The data analysis module is used to calculate the average photon number of the spatial grid. The assignment module is used to assign values ​​to the spatial grid according to the average photon number; The result output module is used for imaging based on the assigned values ​​of the spatial grid; The step of firing a pair of entangled single photons at a predetermined number of times onto a spatial grid and a reference plate respectively, to obtain the average number of photons in the spatial grid, includes: A pair of entangled single photons are directed at a spatial grid and a reference plate a predetermined number of times (A) to obtain a Monte Carlo reference list. The Monte Carlo reference list includes a target photon detection list and a reference plate photon detection list. The target photon detection list includes the order in which the single photon pairs are emitted and whether a photon reflected from the target photon is received during that emission. The reference plate photon detection list includes the order in which the single photon pairs are emitted and whether a photon reflected from the reference plate is received during that emission. The total number of photons reflected by the spatial grid (NR) is collected, and the number of times a pair of single photons is not reflected by both the spatial grid and the reference plate (N00) is collected. The average photon number of the spatial grid is calculated based on NR and N00.

6. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, and the processor, when executing the computer program, implements the method as described in any one of claims 1-4.

7. A computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to perform the method of any one of claims 1-4.

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