A correlation imaging device based on high-order correlation light field and its control method

Abstract

The present invention belongs to the field of quantum communication technology, and in particular relates to a correlation imaging device based on a high-order correlation light field and a control method thereof. The correlation imaging device based on a high-order correlation light field includes a correlation photon source module, a photon beam amplification module, an imaging scanning module, and a photon detection module arranged along the propagation direction of the light path; the correlation photon source module is used to generate a correlation photon source; the photon beam amplification module is used to amplify the light source generated by the correlation photon source module; the imaging scanning module is used to scan the object in front of the reflector in the reference light path along the scanning light path, and the output light path of the imaging scanning module is divided into two paths; the photon detection module is used to receive light from the imaging scanning module for coincidence measurement and counting. The present invention utilizes two-photon composite detection to restore the spatial information of the object to be measured, realizing the separation of detection and imaging. It has the characteristics of non-locality and strong anti-interference ability, and has broad application prospects.

Description

Technical Field

[0001] The present invention belongs to the field of quantum communication technology, and in particular relates to a correlation imaging device based on a high-order correlation light field and a control method thereof. Background Art

[0002] Optical imaging is used in all aspects of production and life. Traditional optical imaging uses first-order correlations in light fields to obtain information about an object, as exemplified by applications such as microscopes and telescopes. With the development of quantum physics, the integration of quantum physics and imaging technology has given rise to an interdisciplinary field: quantum imaging, also known as correlation imaging. Correlation imaging uses higher-order correlations in light fields to obtain spatial or positional information about an object.

[0003] Correlation imaging splits the correlative light source into two paths, placing the target object in one path and capturing the image in the other. The photons used to create the image do not actually come into contact with the target object, making this a form of off-object imaging.

[0004] During the implementation process, the existing correlation imaging optical path is relatively complex and the device is large in size, which needs to be improved. Summary of the Invention

[0005] The purpose of the embodiments of the present invention is to provide a correlation imaging device based on a high-order correlation light field, aiming to solve the problems of the existing correlation imaging such as the complex optical path and large device size.

[0006] The embodiment of the present invention is implemented as follows: a correlation imaging device based on a high-order correlation light field, the correlation imaging device based on a high-order correlation light field includes a correlation photon source module, a photon beam amplification module, an imaging scanning module, and a photon detection module arranged along the propagation direction of the light path;

[0007] The associated photon source module is used to generate an associated photon source;

[0008] The photon beam amplification module is used to amplify the light source generated by the associated photon source module;

[0009] The imaging scanning module is used to scan the object in front of the reflector in the reference light path in the scanning light path. The light path of the imaging scanning module is divided into two paths, one path enters the scanning light path of the imaging scanning module, and the other path enters the reference light path of the imaging scanning module.

[0010] The photon detection module includes two receiving ends for receiving light from the imaging scanning module, and the photon detection module is used for coincidence measurement and counting.

[0011] Another object of an embodiment of the present invention is to provide a control method for a correlation imaging device based on a high-order correlation light field, which is applied to the correlation imaging device based on a high-order correlation light field described in an embodiment of the present invention. The control method for a correlation imaging device based on a high-order correlation light field comprises the following steps:

[0012] Start the associated photon source module and adjust it, and jointly rotate the long axis angles of the first quarter-wave plate and the first half-wave plate to output horizontally polarized laser light with stable phase and light intensity; adjust the positions of the first lens and the first lens so that the light input to the nonlinear crystal is a reduced, collimated laser light;

[0013] Adjust the positions of the third and fourth lenses so that the nonlinear crystal is located at the focus of the third lens, the distance between the third and fourth lenses is twice the focal length, and the distance between the front lens of the beam expander and the fourth lens is the sum of the two focal lengths;

[0014] Adjust the positions of the third polarization beam splitter and the reflector so that the distance between the third polarization beam splitter and the reflector is a set value, and adjust the long axis angle of the second quarter wave plate so that the output reflected horizontal polarized light reaches a maximum;

[0015] The position of the fifth lens is adjusted so that the focus is located at the first multimode optical fiber; the position and angle of the multimode optical fiber are adjusted to collect and couple into the single-photon detector. At the same time, the horizontally polarized photons in the associated photon source module of the other route are also collected as scanning single photons and coupled to another single-photon detector. Then, the signals generated by the two photons reach the coincidence counter for coincidence measurement and counting.

[0016] The correlation imaging device based on a high-order correlated light field, provided by an embodiment of the present invention, utilizes two-photon composite detection to recover spatial information about the object being measured, achieving the separation of detection and imaging. This represents a non-localized imaging method, i.e., off-object imaging. The device features a simple and convenient optical path, high efficiency in preparing correlated photon pairs, and the advantages of being small, lightweight, and easy to move. Compared to other correlation imaging devices, it is more readily applicable in real life and has significant implications for the field of quantum correlation imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A structural block diagram of a correlation imaging device based on a high-order correlation light field provided by the present invention;

[0018] Figure 2 This is a structural diagram of the associated photon source module of the present invention;

[0019] Figure 3 This is a structural diagram of the photon beam amplification module of the present invention;

[0020] Figure 4 is a structural diagram of the imaging scanning module of the present invention;

[0021] Figure 5 is a structural diagram of the photon detection module of the present invention;

[0022] Figure 6 This is the experimental data result diagram of the present invention.

[0023] In the accompanying drawings: 1. Associated photon source module; 11. Laser; 12. First lens; 13. First quarter-wave plate; 14. First half-wave plate; 15. First polarization beam splitter; 16. Second lens; 17. Nonlinear crystal; 2. Photon beam amplification module; 21. Third lens; 22. Fourth lens; 23. Beam amplifier; 3. Imaging scanning module; 31. Second polarization beam splitter; 32. First filter; 33. Third polarization beam splitter; 34. Second quarter-wave plate; 35. Reflector; 36. Fifth lens; 37. Second filter; 4-photon detection module; 41. First multimode optical fiber; 42. Second multimode optical fiber; 43. First single-photon detector; 44. Second single-photon detector; 45. Coincidence counter. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0025] The specific implementation of the present invention is described in detail below with reference to specific embodiments.

[0026] like Figure 1 , which is a structural block diagram of a correlation imaging device based on a high-order correlation light field provided by an embodiment of the present invention, the correlation imaging device based on a high-order correlation light field includes a correlation photon source module 1, a photon beam amplification module 2, an imaging scanning module 3, and a photon detection module 4 arranged along the propagation direction of the light path;

[0027] The associated photon source module 1 is used to generate an associated light source;

[0028] The photon beam amplification module 2 is used to amplify the light source generated by the associated photon source module 1;

[0029] The imaging scanning module 3 is used to scan the object in front of the reflector in the reference light path in the scanning light path. The output light path of the imaging scanning module is divided into two paths, one path enters the scanning light path of the imaging scanning module 3, and the other path enters the reference light path of the imaging scanning module 3;

[0030] The photon detection module 4 includes two receiving ends for receiving light from the imaging scanning module 3 . The photon detection module 4 is used for coincidence measurement and counting.

[0031] In an embodiment of the present invention, the associated photon source module 1 is controlled to generate a laser light source. This embodiment of the present invention is explained using the example of obtaining information about an object 1 meter away. The central wavelength of the light source beam is 405 nm. After further processing by the associated photon source module 1, a mixed beam with wavelengths of 405 nm and 810 nm is obtained. The photon beam amplification module 2 amplifies the light beam generated by the light source to expand the imaging range of the light beam. The imaging scanning module 3 divides the light beam into a horizontally polarized light scanning path and a vertically polarized light reference path, thereby enabling the scanning path to scan an object in the reference path, i.e., imaging away from the object. The photon detection module 4 includes two receiving ends. By receiving light from the photon beam amplification module 2 and the imaging scanning module 3, the image of the object can be inferred through associated calculation, thereby achieving imaging away from the object. It should be noted that the associated calculation process can be performed on other computer devices. The device provided in the embodiment of the present invention is mainly used for data acquisition. Of course, incorporating computing functions into the device provided in the embodiment of the present invention is an optional specific implementation of the present invention.

[0032] The correlation imaging device based on a high-order correlated light field, provided by an embodiment of the present invention, utilizes two-photon composite detection to recover spatial information about the object being measured, achieving the separation of detection and imaging. This represents a non-localized imaging method, i.e., off-object imaging. The device features a simple and convenient optical path, high efficiency in preparing correlated photon pairs, and the advantages of being small, lightweight, and easy to move. Compared to other correlation imaging devices, it is more readily applicable in real life and has significant implications for the field of quantum correlation imaging.

[0033] like Figure 2 As shown, in one embodiment of the present invention, the associated photon source module 1 includes a laser 11, a first lens 12, a wave plate group 13, 14, a first polarization beam splitter 15, a second lens 16 and a nonlinear crystal 17 arranged in sequence along the propagation direction of the light path;

[0034] The laser 11 is used for pumping light beam to provide the initial light beam for the entire device;

[0035] The first lens 12 and the second lens 16 are used to reduce and collimate the light beam before it enters the nonlinear crystal 17;

[0036] The wave plate group is used for phase modulation of the pump light;

[0037] The first polarization beam splitter 15 cooperates with the wave plate group to maintain the phase stability of the pump light while adjusting the intensity of the output light beam;

[0038] The nonlinear crystal 17 is used to convert the pump light to obtain a light beam with a wavelength of 810 nm.

[0039] In an embodiment of the present invention, the laser 11 can use a semiconductor continuous laser as a pump beam to provide an initial beam for the entire device. In a specific embodiment, the central wavelength of the light beam is 405nm, the spectral linewidth is less than 0.06nm, and the output power can reach 66mW. The first lens 12 and the second lens 16 are lenses of different models, with an operating wavelength of 405nm. The focal length f of the first lens 12 is 100mm, and the focal length f of the second lens 16 is 50mm. The nonlinear crystal 17 can use a PPKTP crystal (potassium titanyl phosphate crystal) to generate orthogonally polarized correlated photon pairs. The nonlinear crystal 17 uses the spontaneous parametric down-conversion process to convert the 405nm pump light incident on the crystal into 810nm light. Since the optical path is a collinear optical path, the light emitted by the nonlinear crystal 17 is a mixed beam of 405nm and 810nm. The nonlinear crystal 17 is 5 mm long and is coated with anti-reflection films with wavelengths of 405 nm and 810 nm on both end faces in the direction of light propagation. When the pump light intensity is 1 mW, the generation rate of correlated photon pairs is 2500 Hz / mw / s, which has high brightness.

[0040] The correlated photon source module 1 of the present invention prepares correlated photon pairs through the nonlinear crystal 17 , and the optical path is simple and convenient, and the efficiency of preparing correlated photon pairs is high.

[0041] like Figure 2 As shown, in one embodiment of the present invention, the wave plate group includes a first quarter wave plate 13 and a first half wave plate 14 arranged in sequence along the propagation direction of the optical path; the long axis angles of the first quarter wave plate 13 and the first half wave plate 14 are adjustable to output horizontally polarized laser with stable phase and light intensity.

[0042] In this embodiment of the present invention, the operating wavelength of the first quarter-wave plate 13, the first half-wave plate 14, and the first polarization beam splitter 15 are all 405 nm. The wave plates primarily function to adjust the polarization state of the light beam. The first quarter-wave plate 13 and the first half-wave plate 14 form a wave plate assembly that can modulate the pump light to any phase. The wave plate assembly, in conjunction with the first polarization beam splitter 15, can adjust the intensity of the output light beam while maintaining the phase stability of the pump light. After the 405 nm pump light passes through the first quarter-wave plate 13, the first half-wave plate 14, and the first polarization beam splitter 15, the output is horizontally polarized light with a phase-stable intensity of 1 mW.

[0043] The present invention adopts a combination of a quarter wave plate, a half wave plate and a polarization beam splitter to obtain the horizontal polarization light phase of a photon beam and to adjust the light intensity of the incident light of the photon beam.

[0044] like Figure 3As shown, in one embodiment of the present invention, the photon beam amplification module 2 includes a 4f imaging system and a beam amplifier 23 arranged in sequence along the propagation direction of the light path;

[0045] The 4f imaging system is used to reduce the phase distortion of single photons generated by nonlinear crystals during spatial propagation, and to highly maintain the original correlation relationship;

[0046] The focal length of the beam amplifier 23 is adjustable, and the front focus of the beam amplifier 23 coincides with the back focus of the imaging system. The light beam output by the beam amplifier 23 is in an amplifying relationship with the collimated light output by the associated photon source module 1 .

[0047] In an embodiment of the present invention, the photon beam amplification module 2 includes an imaging system and a beam amplifier 23, which are sequentially arranged along the optical path of the spin single-photon beam generated by the associated photon source module 1. The nonlinear crystal 17 is located at the object point of the imaging system, and the imaging system directly transports the collimated light output from the beam waist of the nonlinear crystal 17 to the front focus of the beam amplifier 23. The focal length and magnification of the beam amplifier 23 are adjustable, and the magnification can be adjusted by 5-10 times. The front focus of the beam amplifier 23 coincides with the back focus of the imaging system, and the light beam output by the beam amplifier 23 is in an amplifying relationship with the collimated light output from the beam waist of the nonlinear crystal 17.

[0048] like Figure 3 As shown, in one embodiment of the present invention, the imaging system includes a third lens 21 and a fourth lens 22;

[0049] The third lens 21 and the fourth lens 22 have the same focal length, and the two lenses form a 4f imaging system.

[0050] In an embodiment of the present invention, the third lens 21 and the fourth lens 22 are lenses of the same model, with an operating wavelength of 810 nm, and the focal length f of the third lens 21 and the fourth lens 22 is 50 mm. The third lens 21 and the fourth lens 22 constitute a 4f imaging system, and the distance between the third lens 21 and the fourth lens 22 is twice the focal length of the lens, 100 mm. The nonlinear crystal 17 is located at the object point of the 4f imaging system, that is, the third lens 21 is placed 50 mm behind the nonlinear crystal 17. The third lens 21 and the fourth lens 22 act as a 4f system to directly transport the collimated light output from the waist of the nonlinear crystal 17 to the focus of the fourth lens 22. The 4f imaging system is constructed to reduce the phase distortion of single photons generated by the nonlinear crystal during spatial propagation, so that the single photons maintain their original correlation.

[0051] The third lens 21 and the fourth lens 22 of the present invention have equal focal lengths, and the distance between the third lens 21 and the fourth lens 22 is twice the focal length. The third lens 21 and the fourth lens 22 form a 4f imaging system, which can effectively reduce the phase distortion of the light emitted by the nonlinear crystal 17.

[0052] like Figure 4 As shown, in one embodiment of the present invention, the imaging scanning module 3 includes a second polarization beam splitter 31, a first filter 32 and a reference optical path;

[0053] The second polarization beam splitter 31 is used to split the incident light beam into a horizontally polarized transmitted light beam and a vertically polarized reflected light beam;

[0054] The first filter 32 is located at the output end of the transmission light path of the second polarization beam splitter 31, and is used to receive and filter the horizontally polarized transmission light beam;

[0055] The reference optical path is used to convert the vertically polarized reverse light beam into a horizontally polarized light beam.

[0056] In this embodiment of the present invention, the second polarization beam splitter 31 has an operating center wavelength of 810 nm. Its function is to separate a light beam perpendicularly incident on its end face into a horizontally polarized transmitted beam and a vertically polarized reflected beam. The first filter 32, located at the end of the transmission light path of the second polarization beam splitter 31, is used to receive and filter the horizontally polarized transmitted beam. This first filter 32 is a bandpass filter with an operating center wavelength of 800 nm and a full width at half maximum of 40 nm. It removes non-single-photon signals from the spatial beam, completing the optical frequency filtering function and improving the signal-to-noise ratio of the test system.

[0057] like Figure 4 As shown, in one embodiment of the present invention, the reference optical path includes a third polarization beam splitter 33, a second quarter-wave plate 34, a reflector 35, a fifth lens 36 and a second filter 37;

[0058] The vertically polarized reflected light beam generated by the second polarization beam splitter 31 enters the third polarization beam splitter 33 and is reflected into the second quarter-wave plate 34 and the reflector 35. The third polarization beam splitter 33 is used to convert the vertically polarized reflected light beam passing through the second quarter-wave plate 34 and the reflector 35 into a horizontally polarized transmitted light beam to be incident on the fifth lens 36 and then incident on the photon detection module 4.

[0059] The second quarter wave plate 34 and the reflector 35 are used to convert the vertically polarized reflected light beam into a horizontally polarized transmitted light beam;

[0060] The fifth lens 36 is used to inject the collected light beam into the photon detection module 4;

[0061] The second filter 37 is used to filter out non-single-photon signals in the spatial light beam to complete the optical frequency filtering function, thereby improving the signal-to-noise ratio.

[0062] In an embodiment of the present invention, a second filter 37 is located at the end of the reflective light path of the second polarization beam splitter 31 and receives the vertically polarized reflected light beam. The second filter 37 and the first filter 32 are bandpass filters of the same model, with an operating center wavelength of 800 nm and a half-width at half maximum of 40 nm. They filter out non-single-photon signals in the spatial light beam, completing the optical frequency filtering function and improving the signal-to-noise ratio of the test system. The second quarter-wave plate 34 operates at a wavelength of 810 nm and converts the vertically polarized reflected light beam into a horizontally polarized transmitted light beam by rotating the long axis angle of the wave plate. The third polarization beam splitter 33 operates at a center wavelength of 810 nm and converts the vertically polarized reflected light beam after passing through the second quarter-wave plate 34 and the reflector 35 into a horizontally polarized transmitted light beam, which is then injected into the fifth lens 36 and then into the multimode optical fiber. The focal length f of the fifth lens 36 is 35 mm, and its function is to inject all collected light beams into the multimode optical fiber.

[0063] like Figure 5 As shown, in one embodiment of the present invention, the photon detection module 4 includes a first multimode optical fiber 41, a first single-photon detector 43, a second multimode optical fiber 42, a second single-photon detector 44 and a coincidence counter 45;

[0064] The first multimode optical fiber 41 and the second multimode optical fiber 42 have the same size and operating wavelength, wherein the second multimode optical fiber 42 is mounted on a translation stage and can be scanned laterally;

[0065] The first single-photon detector 43 and the second single-photon detector 44 correspond to the first multimode optical fiber 41 and the second multimode optical fiber 42 respectively, and are used to receive single photons, detect the photon information using the photoelectric conversion principle, and transmit the information to the coincidence counter 45;

[0066] The coincidence counter 45 is used for coincidence counting.

[0067] In an embodiment of the present invention, the spin single-photon beam generated by the associated photon source module 1 enters the coincidence counter 45 via the beam amplification module, the second multimode optical fiber 42, and the second single-photon detector 44; another group is emitted into the imaging scanning module 3 via the beam amplification module, and then enters the coincidence counter 45 via the first multimode optical fiber 41 and the first single-photon detector 43. The first multimode optical fiber 41 and the second multimode optical fiber 42 are both 200um multimode optical fibers with an operating wavelength of 810nm. The second multimode optical fiber 42 is mounted on a translation stage and can be scanned horizontally. At the same time, the first single-photon detector 43 and the second single-photon detector 44 are used to receive single photons, detect the information of the photons using the principle of photoelectric conversion, and transmit it to the coincidence counter 45. The first multimode optical fiber 41 is located at the image point of the fifth lens 36, that is, 35mm behind the fifth lens 36, to improve the coupling efficiency of the first multimode optical fiber 41.

[0068] In this embodiment of the present invention, the coincidence counter 45 is used for coincidence counting. The principle is to use a dual-channel input signal, receiving the output signals from the first single-photon detector 43 and the second single-photon detector 44 respectively. Each channel counts independently. Parameters such as the window time and delay time are set on the main display interface. The arrival of the pulse is detected within the set coincidence time window, and the number of correlated photon pairs is counted based on the coincidence measurement result.

[0069] The imaging scanning module 3 and the photon detection module 4 of the present invention cooperate with each other. When the coincidence counter 45 in the photon detection module 4 collects correlated photon pairs, it indicates that the imaging scanning module 3 can collect correlated photon pairs at 1m; the optical path designed by the present invention can not only collect correlated photon pairs at 1m, but also the imaging resolution at 1m can achieve a very high level.

[0070] In one embodiment of the present invention, the two end faces of the nonlinear crystal 17 facing the light propagation direction are coated with anti-reflection films, which function to enhance the transmittance of the light beam and correspond to the wavelength of the mixed light beam.

[0071] In the embodiment of the present invention, the nonlinear crystal 17 is coated with two layers of antireflection films with wavelength thicknesses of 405nm and 810nm on both end faces in the light propagation direction. When the pump light intensity is 1mw, the generation rate of correlated photon pairs is 2500Hz / mw / s, with high brightness.

[0072] One embodiment of the present invention further provides a control method for a correlation imaging device based on a high-order correlation light field, which is applied to the correlation imaging device based on a high-order correlation light field described in an embodiment of the present invention. The control method for the correlation imaging device based on a high-order correlation light field comprises the following steps:

[0073] The correlated photon source module 1 is activated and adjusted, and the long-axis angles of the first quarter-wave plate 13 and the first half-wave plate 14 are rotated in combination to output horizontally polarized laser light with stable phase and intensity. The positions of the first lens 12 and the first lens 12 are adjusted so that the light input to the nonlinear crystal 17 is a narrowed, collimated laser. When the collimated laser light enters the crystal, it produces correlated horizontally polarized single photons and vertically polarized single photons.

[0074] Adjust the positions of the third lens 21 and the fourth lens 22 so that the nonlinear crystal 17 is located at the focus of the third lens 21, the distance between the third lens 21 and the fourth lens 22 is twice the focal length, and the distance between the front lens of the beam expander and the fourth lens 22 is the sum of the two focal lengths;

[0075] Adjust the positions of the second polarization beam splitter 31 and the third polarization beam splitter 33 so that the distance between the third polarization beam splitter 33 and the reflector 35 is a set value. Adjust the long axis angle of the second quarter wave plate 34 so that the output reflected horizontal polarized light reaches the maximum. The set value here is 1m.

[0076] Adjust the position of the fifth lens 36 so that the focus is located at the first multimode optical fiber 41; adjust the position and angle of the multimode optical fiber to collect and couple into the single-photon detector. At the same time, the horizontally polarized photons in the associated photon source module 1 of the other route are also collected as scanning single photons and coupled to another single-photon detector. Then, the signals generated by the two photons reach the coincidence counter 45 for coincidence measurement and counting.

[0077] Record or export test data, as shown in the following table:

[0078] Table 1: Test data

[0079]

[0080]

[0081] In the embodiment of the present invention, the scanning imaging result of a 400um object at a distance of 1m is shown in FIG. Figure 6 As shown, the scanning spot diameter is greater than 5mm, and the actual object image is magnified by 2 times. When imaging a 400um object at a distance of 1m, taking into account the influence of the magnification factor, the corresponding equivalent resolution when scanning with a 200um multimode fiber is about 100um.

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A correlation imaging device based on high-order correlation light field, characterized in that: The correlation imaging device based on the high-order correlation light field includes a correlation photon source module, a photon beam amplification module, an imaging scanning module and a photon detection module arranged along the propagation direction of the light path; The associated photon source module is used to generate an associated photon source; The photon beam amplification module is used to amplify the light source generated by the associated photon source module; The imaging scanning module is used to scan the object in front of the reflector in the reference light path out of the scanning light path, and the output light path of the imaging scanning module is divided into two paths, one path enters the scanning light path of the imaging scanning module, and the other path enters the reference light path of the imaging scanning module; The photon detection module includes two receiving ends for receiving light from the imaging scanning module, and the photon detection module is used for coincidence measurement and counting; The imaging scanning module includes a second polarization beam splitter, a first filter and a reference optical path; The second polarization beam splitter is used to separate the light beam generated by the nonlinear crystal into a horizontally polarized transmitted light beam and a vertically polarized reflected light beam; The first filter is located at the output end of the transmission light path of the second polarization beam splitter, and is used to filter out non-single-photon signals in the spatial light beam to complete the optical frequency filtering function, thereby improving the signal-to-noise ratio; The reference optical path is used to convert the vertically polarized reverse light beam into a horizontally polarized light beam after passing through the object and then enter the photon detection module; The reference optical path includes a third polarization beam splitter, a second quarter wave plate, a reflector, a fifth lens and a second filter; The vertically polarized reflected light beam generated by the second polarization beam splitter enters the third polarization beam splitter and is reflected into the second quarter-wave plate and the reflector. The third polarization beam splitter is used to convert the vertically polarized reflected light beam passing through the second quarter-wave plate and the reflector into a horizontally polarized transmitted light beam to be incident on the fifth lens and then incident on the photon detection module. The second quarter wave plate and the reflector are used to convert the vertically polarized reflected light beam into a horizontally polarized transmitted light beam; The fifth lens is used to inject the collected light beam into the photon detection module; The second filter is used to filter out non-single-photon signals in the spatial light beam to complete the optical frequency filtering function, thereby improving the signal-to-noise ratio; The associated photon source module includes a laser, a first lens, a wave plate group, a first polarization beam splitter, a second lens and a nonlinear crystal arranged in sequence along the propagation direction of the light path; The laser is used for pumping light beam to provide the initial light beam for the entire device; The first lens and the second lens are used to reduce and collimate the light beam before it enters the nonlinear crystal; The wave plate group is used for phase modulation of the pump light; The first polarization beam splitter cooperates with the wave plate group to maintain the phase stability of the pump light while adjusting the intensity of the output light beam; The nonlinear crystal is used to convert the pump light to obtain the desired light beam; The wave plate group includes a first quarter wave plate and a first half wave plate arranged in sequence along the propagation direction of the optical path; the long axis angles of the first quarter wave plate and the first half wave plate are adjustable to output horizontally polarized laser light with stable phase and light intensity; The photon beam amplification module includes a 4f imaging system and a beam amplifier arranged in sequence along the propagation direction of the light path; The 4f imaging system is used to reduce the phase distortion of single photons generated by nonlinear crystals during spatial propagation, and to highly maintain the original correlation relationship; The focal length of the beam amplifier is adjustable, and the front focus of the beam amplifier coincides with the back focus of the 4f imaging system. The light beam output by the beam amplifier is in an amplifying relationship with the collimated light output by the associated photon source module. The imaging system includes a third lens and a fourth lens; The third lens and the fourth lens have the same focal length, and the two lenses form a 4f imaging system.

2. The correlation imaging device based on high-order correlation light field according to claim 1, characterized in that: The photon detection module includes a first multimode optical fiber, a first single-photon detector, a second multimode optical fiber, a second single-photon detector and a coincidence counter; The first multimode optical fiber and the second multimode optical fiber have the same size and operating wavelength, wherein the second multimode optical fiber is mounted on a translation stage and can be scanned laterally; The first single-photon detector and the second single-photon detector correspond to the first multimode optical fiber and the second multimode optical fiber, respectively, and are used to receive single photons, detect the information of the photons using the principle of photoelectric conversion, and transmit the information to the coincidence counter; The coincidence counter is used for coincidence counting.

3. The correlation imaging device based on high-order correlation light field according to claim 1, characterized in that: The two end faces of the nonlinear crystal facing the light propagation direction are plated with two layers of anti-reflection films, which function to enhance the transmittance of the light beam and correspond to the wavelength of the mixed light beam.

4. A control method for a correlation imaging device based on a high-order correlation light field, applied to the correlation imaging device based on a high-order correlation light field according to any one of claims 1 to 3, characterized in that: The control method of the correlation imaging device based on the high-order correlation light field comprises the following steps: Start the associated photon source module and adjust it, and jointly rotate the long axis angles of the first quarter-wave plate and the first half-wave plate to output horizontally polarized laser light with stable phase and light intensity; adjust the positions of the first lens and the first lens so that the light input to the nonlinear crystal is a reduced, collimated laser light; Adjust the positions of the third and fourth lenses so that the nonlinear crystal is located at the focus of the third lens, the distance between the third and fourth lenses is twice the focal length, and the distance between the front lens of the beam expander and the fourth lens is the sum of the two focal lengths; Adjust the position of the third polarization beam splitter and the reflector so that the distance between the third polarization beam splitter and the reflector is a set value, and adjust the long axis angle of the second quarter wave plate so that the output reflected horizontal polarized light reaches a maximum; The position of the fifth lens is adjusted so that the focus is located at the first multimode optical fiber; the position and angle of the multimode optical fiber are adjusted to collect and couple into the single-photon detector. At the same time, the horizontally polarized photons in the associated photon source module of the other route are also collected as scanning single photons and coupled to another single-photon detector. Then, the signals generated by the two photons reach the coincidence counter for coincidence measurement and counting.

Images