Single photon detector quantum efficiency calibration device and method

Abstract

The present invention provides a single-photon detector quantum efficiency calibration device and method, which relate to the field of single-photon detection technology. The single-photon detector quantum efficiency calibration device includes: a pulse excitation source, which is used to generate an excitation pulse; a single-photon source, which can emit single-photon radiation with a specific wavelength under the excitation of the excitation pulse; a photon collector, including a microscope objective lens, which is used to receive single-photon radiation and form an image; a standard single-photon detector, which is used to be alternately placed at the imaging point position of the photon collector with the single-photon detector to be tested, so that the single-photon radiation can be respectively irradiated to the photosensitive surface of the standard single-photon detector and the single-photon detector to be tested, and the single-photon detection quantum efficiency of the standard single-photon detector is calibrated. The single-photon detector quantum efficiency calibration device and method of the present invention use the single-photon source as a standard calibration light source and the single-photon characteristics of the single-photon source to accurately calibrate the quantum efficiency of the single-photon detector, and the calibration accuracy is high.

Description

Technical Field

[0001] The present invention relates to the technical field of single photon detection, and in particular to a single photon detector quantum efficiency calibration device and method. Background Art

[0002] The quantum efficiency of a single-photon detector is one of the most important parameters for evaluating the working performance of a single-photon detector. Accurately calibrating the quantum efficiency of a single-photon detector is crucial in the application of single-photon detectors. At present, the main calibration method for single-photon detectors is to use an attenuated coherent light source, such as an attenuated laser, to calibrate the quantum efficiency of the single-photon detector when the laser power is known. However, the attenuated laser still has coherence. When the average number of photons is attenuated to a very small value, there is still a certain probability that multiple photons will enter the single-photon detector at the same time. Most of the existing single-photon detectors, such as photomultiplier tubes, single-photon avalanche diodes, etc., do not have the ability to resolve the number of photons. When multiple photons enter the single-photon detector at the same time, at most only one photoelectron will be generated, which will cause errors in the measurement results.

[0003] In addition, when calibrating the quantum efficiency of a single-photon detector with a large photosensitive area (such as a single-photon camera), the method of calibrating the quantum efficiency of a single-photon camera at a large photon flux is usually used, that is, a uniform monochromatic light source is generated by a certain means, the camera to be tested and the standard radiometer are placed on the same measurement plane, and the quantum efficiency of different pixels of the camera to be tested is obtained by comparison. This method has a small measurement uncertainty when the photon flux is large, but when the photon flux drops to the single-photon level, the uniformity of the illumination field is difficult to guarantee, which will lead to a large measurement uncertainty. In addition, the existing light source will cause measurement errors due to multiple photons hitting the photosensitive element at the same time. Summary of the invention

[0004] The present invention provides a single-photon detector quantum efficiency calibration device and method, which are used to solve the defect that the quantum efficiency of the single-photon detector cannot be calibrated with high accuracy in the prior art, and to achieve accurate calibration of the quantum efficiency of the single-photon detector.

[0005] The present invention provides a single-photon detector quantum efficiency calibration device, comprising:

[0006] A pulse excitation source, used for generating an excitation pulse;

[0007] A single photon source, which can emit single photon radiation with a specific wavelength under the stimulation of the excitation pulse;

[0008] A photon collector, including a microscope objective lens, for receiving the single photon radiation and forming an image;

[0009] A standard single-photon detector is used to be placed alternately with the single-photon detector to be tested at the imaging point position of the photon collector, so that the single-photon radiation can irradiate the photosensitive surfaces of the standard single-photon detector and the single-photon detector to be tested respectively, and the single-photon detection quantum efficiency of the standard single-photon detector is calibrated.

[0010] According to the single-photon detector quantum efficiency calibration device provided by the present invention, the pulse excitation source can generate one or more of electric pulses, magnetic pulses, electromagnetic wave pulses, acoustic pulses, and high-energy particle pulses.

[0011] According to the single-photon detector quantum efficiency calibration device provided by the present invention, the pulse width generated by the pulse excitation source is smaller than the energy level transition relaxation time of the single-photon source.

[0012] According to the single-photon detector quantum efficiency calibration device provided by the present invention, the single-photon source is one of a quantum dot single-photon source, a color center single-photon source, a single-atom single-photon source, a single-molecule single-photon source, a single-ion single-photon source, an atomic ensemble single-photon source, a two-dimensional material single-photon source, and a carbon nanotube single-photon source.

[0013] According to the single-photon detector quantum efficiency calibration device provided by the present invention, the non-bunching characteristics of the single-photon source are determined by HBT experiment.

[0014] According to the single-photon detector quantum efficiency calibration device provided by the present invention, the photon collector also includes a reflector and a scanning galvanometer. In the optical path of the photon collector, the reflector and the scanning galvanometer are located on the side of the microscope objective lens away from the single-photon source, and the scanning galvanometer is used to adjust the imaging point position.

[0015] According to the single-photon detector quantum efficiency calibration device provided by the present invention, the photon collector also includes a filter. In the optical path of the photon collector, the filter is arranged on a side of the microscope objective lens away from the single-photon source, and the filter is used to filter out scattered laser radiation.

[0016] According to the single-photon detector quantum efficiency calibration device provided by the present invention, the single-photon detector quantum efficiency calibration device also includes an optical platform, the standard single-photon detector is installed on the optical platform, and the optical platform is also provided with at least one mounting position, which is used to install the single-photon detector to be tested; the optical platform can move relative to the photon collector to switch the standard single-photon detector or the single-photon detector to be tested to the imaging point position of the photon collector.

[0017] The present invention also provides a single-photon detector quantum efficiency calibration method. Based on any of the single-photon detector quantum efficiency calibration devices described above, the single-photon detector quantum efficiency calibration method comprises the following steps:

[0018] Controlling the pulse excitation source to excite the single photon source to emit single photon radiation;

[0019] Controlling the standard single-photon detector to switch to the imaging point position of the photon collector to obtain the first photoelectron reading of the standard single-photon detector;

[0020] Controlling the single-photon detector to be tested to switch to the imaging point position of the photon collector to obtain a second photoelectron reading of the single-photon detector to be tested;

[0021] Controlling the pulse excitation source to excite a reference sample without a single photon source;

[0022] Controlling the standard single-photon detector to switch to the imaging point position of the photon collector to obtain the third photoelectron reading of the standard single-photon detector;

[0023] Controlling the single-photon detector to be tested to switch to the imaging point position of the photon collector to obtain the fourth photoelectron reading of the single-photon detector to be tested;

[0024] Calculate the quantum efficiency of the single-photon detector under test.

[0025] The present invention also provides a single-photon detector quantum efficiency calibration method, based on any of the single-photon detector quantum efficiency calibration devices described above, the single-photon detector to be tested is a single-photon camera, and the single-photon camera has multiple pixel points; the single-photon detector quantum efficiency calibration method comprises the following steps:

[0026] Control the single-photon camera to switch to the imaging point position of the photon collector, control the pulse excitation source to excite the single-photon source to emit single-photon radiation, the single-photon radiation is imaged on the single-photon camera, and the photoelectron reading of the corresponding imaging pixel point can be obtained;

[0027] Controlling the photon collector to change the imaging point position of the single photon radiation on the single photon camera in a set path, and sequentially recording the positions of multiple imaging points, the number of pixels occupied by each imaging point, and the first average photoelectron reading of the imaging pixel corresponding to each imaging point;

[0028] Controlling the pulse excitation source to excite a reference sample without a single photon source, controlling the photon collector to change the imaging point position of the photon collector according to the set path, and sequentially recording the second average photoelectron readings of the imaging pixel points corresponding to the recorded multiple imaging point positions;

[0029] Controlling the standard single-photon detector to switch to the imaging point position of the photon collector, controlling the pulse excitation source to excite the single-photon source to emit single-photon radiation, and obtaining the fifth photoelectron reading of the standard single-photon detector;

[0030] Controlling the pulse excitation source to excite a reference sample without a single photon source to obtain a sixth photoelectron reading of a standard single photon detector;

[0031] Calculate the average quantum efficiency of each imaging pixel of the single-photon camera.

[0032] The single-photon detector quantum efficiency calibration device and method provided by the present invention calibrate a single-photon detector of unknown quantum efficiency by using a single-photon source as a standard calibration light source, and utilize the single-photon characteristics of the single-photon source to remove the single-photon detector quantum efficiency calibration error caused by the simultaneous emission of multiple photons, thereby achieving accurate calibration of the quantum efficiency of the single-photon detector with high calibration accuracy, thereby solving the defect in the prior art that the quantum efficiency of the single-photon detector cannot be calibrated with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 This is one of the structural schematic diagrams of the single-photon detector quantum efficiency calibration device provided in an embodiment of the present invention;

[0035] Figure 2 This is the second structural schematic diagram of the single-photon detector quantum efficiency calibration device provided in an embodiment of the present invention.

[0036] Reference numerals:

[0037] 1: pulse excitation source; 2: single photon source; 3: photon collector; 4: standard single photon detector; 31: microscope objective; 32: reflector; 33: scanning galvanometer;

[0038] 200: Single-photon detector to be tested; 300: Single-photon camera. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] like Figure 1 and Figure 2 As shown, the single-photon detector quantum efficiency calibration device provided by the present invention includes a pulse excitation source 1, a single-photon source 2, a photon collector 3 and a standard single-photon detector 4, wherein the pulse excitation source 1 is used to generate an excitation pulse, and the single-photon source 2 can emit single-photon radiation with a specific wavelength under the excitation of the excitation pulse; the photon collector 3 includes a microscope objective 31, and the microscope objective 31 is used to receive the single-photon radiation of the single-photon source 2 and form an image; the standard single-photon detector 4 is used to be alternately placed at the imaging point position of the photon collector 3 with the single-photon detector 200 to be tested, so that the single-photon radiation of the single-photon source 2 can respectively irradiate the photosensitive surfaces of the standard single-photon detector 4 and the single-photon detector 200 to be tested, and the single-photon detection quantum efficiency of the standard single-photon detector 4 is calibrated.

[0041] In this embodiment, the pulse excitation source 1 emits an excitation pulse to the single-photon source 2, and inputs energy to the single-photon source 2 through the excitation pulse, so that the electrons of the single-photon source 2 transition between specific energy levels, thereby generating single-photon radiation of a specific wavelength. Under each pulse excitation, the single-photon source 2 will emit at most one photon, and will not generate two or more photons at the same time. Therefore, the single-photon source 2 emits single-photon radiation with a specific wavelength under the excitation of the excitation pulse, and this single-photon radiation has significant non-bunching properties, that is, single-photon properties.

[0042] The photon collector 3 includes a microscope objective lens 31, which is arranged opposite to the single-photon source 2, and the microscope objective lens 31 can image the single-photon source 2 to a certain position. After the single-photon radiation generated by the single-photon source 2 is collected and imaged by the microscope objective lens 31 of the photon collector 3, a standard single-photon detector 4 or a single-photon detector 200 to be tested is placed at the imaging point position of the photon collector 3, and the single-photon radiation is irradiated to the photosensitive surfaces of the standard single-photon detector 4 and the single-photon detector 200 to be tested respectively, and the photoelectron counts of the standard single-photon detector 4 and the single-photon detector 200 to be tested can be read respectively.

[0043] The single-photon detection quantum efficiency of the standard single-photon detector 4 is calibrated, and the photon flux entering the standard single-photon detector 4 and the single-photon detector 200 to be tested can be converted through the photoelectron reading of the standard single-photon detector 4; then, the quantum efficiency of the single-photon detector 200 to be tested can be calculated through the photoelectron reading of the single-photon detector 200 to be tested, thereby realizing the calibration of the quantum efficiency of the single-photon detector.

[0044] The single-photon detector 200 to be tested may be a single-pixel single-photon detector or a multi-pixel single-photon camera 300. The single-photon camera 300 has a certain photosensitive area and pixel distribution. When calibrating the single-photon camera 300, by moving the single-photon source 2 or controlling the photon collector 3, the single-photon radiation of the single-photon source 2 can be focused to different areas of the photosensitive surface of the single-photon camera 300, and the photoelectron readings of different areas of the photosensitive surface of the single-photon camera 300 are recorded, so that the quantum efficiency distribution of different areas of the photosensitive surface of the single-photon camera 300 can be calculated, and the calibration of the quantum efficiency and distribution of the pixels of the single-photon camera 300 can be achieved.

[0045] The single-photon detector quantum efficiency calibration device of the present invention calibrates a single-photon detector of unknown quantum efficiency by using a single-photon source 2 as a standard calibration light source, and utilizes the single-photon characteristics of the single-photon source 2 to remove the single-photon detector quantum efficiency calibration error caused by the simultaneous emission of multiple photons, thereby achieving accurate calibration of the quantum efficiency of the single-photon detector with high calibration accuracy, thereby solving the defect in the prior art that the quantum efficiency of the single-photon detector cannot be calibrated with high accuracy.

[0046] Specifically, the pulse excitation source 1 can generate one or more of electric pulses, magnetic pulses, electromagnetic wave pulses, acoustic pulses, and high-energy particle pulses.

[0047] In this embodiment, the pulse excitation source 1 that excites the single-photon source 2 to generate single-photon radiation can be of various types, such as electric pulses, magnetic pulses, electromagnetic wave pulses, acoustic pulses, high-energy particle pulses, etc. The main principle is to input energy to the single-photon source 2 through an excitation pulse, so that the electrons of the single-photon source 2 transition between specific energy levels, and generate single-photon radiation of a specific wavelength. By setting the pulse excitation source 1 to generate various types of excitation pulses, a suitable excitation pulse can be selected according to the type of the single-photon source 2 to ensure that the single-photon radiation emitted by the single-photon source 2 meets the single-photon characteristics and ensure the accuracy of the single-photon detector quantum efficiency calibration.

[0048] The electromagnetic wave pulses may be one or more of X-rays, ultraviolet rays, visible rays, infrared rays, and microwaves.

[0049] Specifically, the pulse width generated by the pulse excitation source 1 is smaller than the energy level transition relaxation time of the single photon source 2 .

[0050] In this embodiment, according to the principle of the single-photon source 2: considering an ideal two-level system, such as quantum dots, electrons are fermions. According to the Pauli exclusion principle, when an electron occupies an excited state but has not yet generated spontaneous radiation, it is impossible to excite the next electron to the same excited state; that is to say, no matter how the outside world excites (continuous laser or pulsed laser or electro-excitation), the two-level system can only emit one photon during the lifetime of spontaneous radiation (about picosecond to nanosecond time scale), that is, it is impossible to emit two or more photons at the same time at a certain moment, that is, the non-bunching nature of the single-photon source 2, in layman's terms, photons are emitted one after another, and the time interval between each emission is related to the lifetime of spontaneous radiation.

[0051] Therefore, the pulse width of the pulse excitation source 1 should be as small as possible, less than the energy level transition relaxation time of the general single-photon source 2, to ensure that the single-photon source 2 can controllably stimulate radiation and emit single-photon radiation of a specific wavelength at the set time, thereby ensuring that the single-photon detector quantum efficiency calibration process is stable and reliable with high calibration accuracy.

[0052] The typical pulse width should be less than 1 nanosecond. For example, when the pulse excitation source 1 is an electric pulse source, the electric pulse width is less than 1 nanosecond; when the pulse excitation source 1 is a laser pulse source, the pulse width is less than 1 nanosecond.

[0053] Specifically, the single-photon source 2 is one of a quantum dot single-photon source, a color center single-photon source, a single-atom single-photon source, a single-molecule single-photon source, a single-ion single-photon source, an atomic ensemble single-photon source, a two-dimensional material single-photon source, and a carbon nanotube single-photon source.

[0054] In this embodiment, the ideal single-photon source 2 emits only one photon per excitation pulse, and the photon has good non-bunching properties. The single-photon source 2 can be a single-photon source 2 of the type of quantum dots, color centers, single atoms / molecules / ions, atomic systems, two-dimensional materials, carbon nanotubes, etc., and has one or more characteristic spectra. The single-photon source 2 is required to be reliable and stable, meet the quantum dot measurement standards, and conform to the single-photon characteristics. The single-photon source 2 only emits one photon within the spontaneous radiation lifetime.

[0055] Specifically, the non-bunching characteristics of the single photon source 2 are determined by HBT experiments.

[0056] In this embodiment, the standard single-photon source 2 used as the calibration light source needs to be subjected to an HBT experiment to determine the non-bunching characteristics. The HBT (Hanbury Brown-Twiss) experiment is a high-order correlation experiment of the light field, which can measure the correlation of the light intensity of two beams of light. By measuring the second-order coherence of the photon radiation of the single-photon source 2 through the HBT experiment, the non-bunching characteristics of the single-photon source 2 can be measured, thereby ensuring that the single-photon radiation emitted by the single-photon source 2 meets the single-photon characteristics and ensuring the accuracy of the single-photon detector quantum efficiency calibration.

[0057] Specifically, in one embodiment, Figure 1 As shown, the excitation pulse generated by the pulse excitation source 1 can be excited in a paraxial manner, that is, the excitation pulse is injected from the side of the single photon source 2, and the central axis of the excitation pulse and the photon collector 3 are not on the same straight line.

[0058] In another embodiment, Figure 2 As shown, the excitation pulse generated by the pulse excitation source 1 can also be excited in a coaxial manner through the microscope objective 31, that is, the incident direction of the excitation pulse of the single photon source 2 and the photon collection direction are on the same straight line, and the excitation pulse passes through the central axis of the photon collector 3.

[0059] Specifically, Figure 2 As shown, the photon collector 3 also includes a reflector 32 and a scanning galvanometer 33. In the optical path of the photon collector 3, the reflector 32 and the scanning galvanometer 33 are located on the side of the microscope objective 31 away from the single photon source 2. The scanning galvanometer 33 is used to adjust the imaging point position of the photon collector 3.

[0060] In this embodiment, optical elements such as a reflector 32 and a scanning galvanometer 33 are added to the optical path of the photon collector 3. The reflector 32 and the scanning galvanometer 33 are both located on the side of the microscope objective 31 away from the single-photon source 2, that is, the reflector 32 and the scanning galvanometer 33 are located between the microscope objective 31 and the single-photon detector; by rotating the reflector 32 and controlling the scanning galvanometer 33, the imaging position of the single-photon source 2 on the single-photon detector can be adjusted, so that the quantum efficiency calibration of the single-photon detector with multiple pixels can be achieved without moving the single-photon source 2. The use is simple and convenient, and the calibration efficiency is improved.

[0061] Specifically, the photon collector 3 further includes a filter. In the optical path of the photon collector 3 , the filter is arranged on a side of the microscope objective 31 away from the single-photon source 2 . The filter is used to filter out scattered filter radiation.

[0062] In this embodiment, a filter is added to the optical path of the photon collector 3, and the filter is located on the side of the microscope objective 31 away from the single-photon source 2, that is, the filter is located between the microscope objective 31 and the single-photon detector. When a pulse excitation source 1 that emits laser pulses is used, the scattered laser pulses can be filtered out to avoid unnecessary interference with the reading of the single-photon detector, thereby ensuring the accuracy of the calibration of the quantum efficiency of the single-photon detector.

[0063] Among them, a suitable filter can be selected according to the type of laser pulse.

[0064] In one embodiment, the single-photon detector quantum efficiency calibration device also includes an optical platform, and the standard single-photon detector 4 is installed on the optical platform. The optical platform is also provided with at least one mounting position, and the mounting position is used to install the single-photon detector 200 to be tested; the optical platform can move relative to the photon collector 3 to switch the standard single-photon detector 4 or the single-photon detector 200 to be tested to the imaging point position of the photon collector 3.

[0065] In this embodiment, an optical platform is set up to install the standard single-photon detector 4 and the single-photon detector to be tested 200. The optical platform is set adjacent to the photon collector 3 and can move relative to the photon collector 3, so as to drive the standard single-photon detector 4 and the single-photon detector to be tested 200 to switch alternately to the imaging point position of the photon collector 3. The positions of the standard single-photon detector 4 and the single-photon detector to be tested 200 can be adjusted and restored without manual repositioning each time. It is simple and convenient to use, and the calibration efficiency is effectively improved.

[0066] Based on the single-photon detector quantum efficiency calibration device provided in the above embodiment, the present invention also provides a single-photon detector quantum efficiency calibration method, comprising the following steps:

[0067] Step S10, controlling the pulse excitation source to excite the single photon source to emit single photon radiation;

[0068] Step S20, controlling the standard single-photon detector to switch to the imaging point position of the photon collector, and obtaining the first photoelectron reading I1 of the standard single-photon detector;

[0069] Step S30, controlling the single-photon detector to be tested to switch to the imaging point position of the photon collector, and obtaining a second photoelectron reading I2 of the single-photon detector to be tested;

[0070] Step S40, controlling the pulse excitation source to excite a reference sample without a single photon source;

[0071] Step S50, controlling the standard single-photon detector to switch to the imaging point position of the photon collector, and obtaining a third photoelectron reading I3 of the standard single-photon detector;

[0072] Step S60, controlling the single-photon detector to be tested to switch to the imaging point position of the photon collector, and obtaining a fourth photoelectron reading I4 of the single-photon detector to be tested;

[0073] Step S70, calculating the quantum efficiency of the single-photon detector to be tested as: t =η s ×(I2-I4) / (I1-I3), where η s is the quantum efficiency of a standard single-photon detector.

[0074] The single-photon detector quantum efficiency calibration method of the present invention calibrates a single-photon detector of unknown quantum efficiency by using a single-photon source 2 as a standard calibration light source, and utilizes the single-photon characteristics of the single-photon source 2 to remove the single-photon detector quantum efficiency calibration error caused by the simultaneous emission of multiple photons, thereby achieving accurate calibration of the quantum efficiency of the single-photon detector with high calibration accuracy, thereby solving the defect in the prior art that the quantum efficiency of the single-photon detector cannot be calibrated with high accuracy.

[0075] On the other hand, when the single-photon detector 200 to be tested is a single-photon camera, the single-photon camera has multiple pixels. Based on the single-photon detector quantum efficiency calibration device provided in the above embodiment, the single-photon detector quantum efficiency calibration method of the present invention includes the following steps:

[0076] Step S100, controlling the single-photon camera to switch to the imaging point position of the photon collector, controlling the pulse excitation source to excite the single-photon source to emit single-photon radiation, and the single-photon radiation is imaged on the single-photon camera, so that the photoelectron reading of the corresponding imaging pixel point can be obtained;

[0077] Step S200, controlling the photon collector to change the imaging point position of the single photon radiation on the single photon camera by setting the path, and sequentially recording the positions of multiple imaging points, the number of pixels occupied by each imaging point, and the first average photoelectron reading I1 of the imaging pixel corresponding to each imaging point i , i = 1, 2, ..., n, where i represents the imaging point number and n is the number of imaging points;

[0078] Step S300, controlling the pulse excitation source to excite the reference sample without the single photon source, controlling the photon collector to change the imaging point position of the photon collector according to the set path, and sequentially recording the second average photoelectron reading I2 of the imaging pixel point corresponding to the imaging point position recorded in the case of the single photon source i ;

[0079] Step S400, controlling the standard single-photon detector to switch to the imaging point position of the photon collector, controlling the pulse excitation source to excite the single-photon source to emit single-photon radiation, and obtaining the fifth photoelectron reading I5 of the standard single-photon detector;

[0080] Step S500, controlling the pulse excitation source to excite the reference sample without the single photon source, and obtaining the sixth photoelectron reading I6 of the standard single photon detector;

[0081] Step S600, calculating the average quantum efficiency of each imaging pixel of the single-photon camera as: a =η s ×(I1 i -I2 i ) / (I5-I6), η s is the quantum efficiency of a standard single-photon detector.

[0082] In this embodiment, the single-photon source 2 is imaged on the single-photon camera 300, and the number of pixels occupied is between 1×1 and 4×4. First, the pulse excitation source 1 is used to excite the single-photon source 2 to emit light, and the pixel position occupied by the imaging point on the single-photon camera 300 is recorded, and the first average photoelectron reading of the imaging pixel is recorded; then the pulse excitation source 1 is used to excite the reference sample without the single-photon source, and the second average photoelectron reading of the imaging pixel at the same position as the previous step is recorded; thereafter, the pulse excitation source 1 is used to excite the single-photon source 2 to emit light and to excite the reference sample without the single-photon source, and the fifth reading and the sixth reading of the standard single-photon detector 4 are read respectively; the quantum efficiency of the standard single-photon detector 4 is known, so that the average quantum efficiency of the imaging pixel recorded above can be calculated. Finally, by moving the single-photon source 2 sample or controlling the scanning galvanometer 33 and other devices in the photon collector 3, the imaging point position of the single-photon source 2 sample on the single-photon camera 300 is adjusted, so as to calculate the quantum efficiency distribution of different areas of the photosensitive surface of the single-photon camera 300.

[0083] In a specific embodiment, the pulse excitation source 1 of the single-photon detector quantum efficiency calibration device is a femtosecond pulse laser, and the single-photon source 2 is a quantum dot single-photon source. The quantum dot single-photon source is a quantum dot solution sample placed on a glass slide and fully dispersed by a gel-spinning machine, which can be excited by the pulse laser through a photoexcitation process to produce radiation light with single-photon characteristics. The femtosecond pulse laser and the photon collector 3 are integrated into a multiphoton microscope, which also includes an ultrafast reflector, a laser scanning galvanometer, a dichroic mirror, and a microscope objective 31. After the femtosecond pulse laser is emitted from the femtosecond pulse laser, it is reflected by the above-mentioned optical lenses in turn, and then focused by the microscope objective 31 onto the surface of the quantum dot single-photon source sample.

[0084] The single-photon detector 200 to be tested may be a detector based on an avalanche diode or a photomultiplier tube, or may be a camera based on a CCD or CMOS that can image in weak light.

[0085] The photon collector 3 also includes a light-collecting scanning galvanometer, which is installed in the light-collecting optical path. The quantum dot single-photon fluorescence collected by the microscope objective 31 is focused on the light-collecting scanning galvanometer through a lens and reflected in a direction that forms a 90° angle with the original light-collecting optical path. The quantum dot single-photon source fluorescence reflected by the light-collecting scanning galvanometer is focused by another lens and received by the electro-photon detector 200 to be tested. The focused spot size of the quantum dot single-photon source is 0.1-10 microns.

[0086] The standard single-photon detector 4 with known quantum efficiency, the CCD camera to be calibrated and the single-photon detector 200 to be calibrated are installed on a repositionable optical platform, and the fluorescence generated by the quantum dot single-photon source is sequentially irradiated to the photosensitive surfaces of various single-photon detectors through the mobile optical platform. By controlling the signal waveform and voltage of the light-collecting scanning galvanometer, the fluorescence generated by the quantum dot single-photon source can be focused to different areas of the photosensitive surface of the single-photon detector.

[0087] In this embodiment, the single photon detector quantum efficiency calibration method includes the following steps:

[0088] First, a femtosecond pulse laser is used to excite the quantum dot single photon source sample, and the CCD camera is switched to the imaging point position. The waveform and voltage of the laser scanning galvanometer are controlled to scan the quantum dot distribution on the quantum dot single photon source sample, and the CCD camera is used to locate the appropriate monodisperse quantum dots.

[0089] Then, a standard single-photon detector with known quantum efficiency is switched to the imaging point position, and the photon flux entering the standard single-photon detector is converted by reading the photoelectron count of the standard single-photon detector;

[0090] Finally, the single-photon detector to be calibrated is switched to the imaging point position, the photoelectron count of the single-photon detector to be calibrated is read, and the quantum efficiency of the single-photon detector to be calibrated is calculated.

[0091] The method for measuring the uniformity of the quantum efficiency of a single-photon detector of this embodiment includes the following steps:

[0092] After measuring the photon flux entering the standard single-photon detector, switch to the single-photon detector to be calibrated. By controlling the signal voltage and waveform of the light-collecting scanning galvanometer, the quantum dot fluorescence is focused on different areas of the single-photon detector. The readings of the single-photon detector are recorded, and the quantum efficiency uniformity of different areas of the single-photon detector's photosensitive surface can be calculated.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A single-photon detector quantum efficiency calibration device, characterized in that: include: A pulse excitation source, used for generating an excitation pulse; A single photon source, which can emit single photon radiation with a specific wavelength under the stimulation of the excitation pulse; A photon collector, including a microscope objective lens, for receiving the single photon radiation and forming an image; A standard single-photon detector is used to be alternately placed at the imaging point position of the photon collector with the single-photon detector to be tested, so that the single-photon radiation can irradiate the photosensitive surfaces of the standard single-photon detector and the single-photon detector to be tested respectively, and the single-photon detection quantum efficiency of the standard single-photon detector is calibrated; the pulse width generated by the pulse excitation source is smaller than the energy level transition relaxation time of the single-photon source; the non-bunching characteristics of the single-photon source are determined by HBT experiment.

2. The single-photon detector quantum efficiency calibration device according to claim 1, characterized in that: The pulse excitation source can generate one or more of electric pulses, magnetic pulses, electromagnetic wave pulses, acoustic pulses, and high-energy particle pulses.

3. The single-photon detector quantum efficiency calibration device according to claim 1, characterized in that: The single-photon source is one of a quantum dot single-photon source, a color center single-photon source, a single-atom single-photon source, a single-molecule single-photon source, a single-ion single-photon source, an atomic ensemble single-photon source, a two-dimensional material single-photon source, and a carbon nanotube single-photon source.

4. The single-photon detector quantum efficiency calibration device according to claim 1, characterized in that: The photon collector further comprises a reflector and a scanning galvanometer. In the optical path of the photon collector, the reflector and the scanning galvanometer are located on a side of the microscope objective lens away from the single photon source. The scanning galvanometer is used to adjust the imaging point position.

5. The single photon detector quantum efficiency calibration device according to claim 1, characterized in that: The photon collector further comprises a filter. In the optical path of the photon collector, the filter is arranged on a side of the microscope objective lens away from the single photon source, and the filter is used to filter out scattered laser radiation.

6. The single-photon detector quantum efficiency calibration device according to any one of claims 1 to 5, characterized in that: The single-photon detector quantum efficiency calibration device also includes an optical platform, the standard single-photon detector is installed on the optical platform, and the optical platform is also provided with at least one mounting position, which is used to install the single-photon detector to be tested; the optical platform can move relative to the photon collector to switch the standard single-photon detector or the single-photon detector to be tested to the imaging point position of the photon collector.

7. A single-photon detector quantum efficiency calibration method, based on the single-photon detector quantum efficiency calibration device according to any one of claims 1 to 6, characterized in that: The single photon detector quantum efficiency calibration method comprises the following steps: Controlling the pulse excitation source to excite the single photon source to emit single photon radiation; Controlling the standard single-photon detector to switch to the imaging point position of the photon collector to obtain the first photoelectron reading of the standard single-photon detector; Controlling the single-photon detector to be tested to switch to the imaging point position of the photon collector to obtain a second photoelectron reading of the single-photon detector to be tested; Controlling the pulse excitation source to excite a reference sample without a single photon source; Controlling the standard single-photon detector to switch to the imaging point position of the photon collector to obtain the third photoelectron reading of the standard single-photon detector; Controlling the single-photon detector to be tested to switch to the imaging point position of the photon collector to obtain the fourth photoelectron reading of the single-photon detector to be tested; Calculate the quantum efficiency of the single-photon detector under test.

8. A single-photon detector quantum efficiency calibration method, based on the single-photon detector quantum efficiency calibration device according to any one of claims 1 to 6, characterized in that: The single-photon detector to be tested is a single-photon camera, and the single-photon camera has a plurality of pixel points; The single photon detector quantum efficiency calibration method comprises the following steps: Control the single-photon camera to switch to the imaging point position of the photon collector, control the pulse excitation source to excite the single-photon source to emit single-photon radiation, the single-photon radiation is imaged on the single-photon camera, and the photoelectron reading of the corresponding imaging pixel point can be obtained; Controlling the photon collector to change the imaging point position of the single photon radiation on the single photon camera in a set path, and sequentially recording the positions of multiple imaging points, the number of pixels occupied by each imaging point, and the first average photoelectron reading of the imaging pixel corresponding to each imaging point; Controlling the pulse excitation source to excite a reference sample without a single photon source, controlling the photon collector to change the imaging point position of the photon collector according to the set path, and sequentially recording the second average photoelectron readings of the imaging pixel points corresponding to the recorded multiple imaging point positions; Controlling the standard single-photon detector to switch to the imaging point position of the photon collector, controlling the pulse excitation source to excite the single-photon source to emit single-photon radiation, and obtaining the fifth photoelectron reading of the standard single-photon detector; Controlling the pulse excitation source to excite a reference sample without a single photon source to obtain a sixth photoelectron reading of a standard single photon detector; Calculate the average quantum efficiency of each imaging pixel of the single-photon camera.

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