CN216285731U - Associated imaging device based on high-order associated light field - Google Patents
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Abstract
The utility model belongs to the technical field of quantum communication, and particularly relates to a high-order correlated light field-based correlated imaging device, which comprises a correlated photon source module, a photon beam amplification module, an imaging scanning module and a photon detection module, wherein the correlated photon source module, the photon beam amplification module, the imaging scanning module and the photon detection module are arranged along the propagation direction of a light path; the associated photon source module is used for generating an associated photon source; the photon beam amplifying module is used for amplifying the light source generated by the associated photon source module; the imaging scanning module is used for scanning an object in front of the reflecting mirror 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; the photon detection module is configured to receive light from the imaging scanning module for coincidence measurement counting. The utility model recovers the spatial information of the object to be detected by utilizing two-photon composite detection, realizes the separation of detection and imaging, has the characteristics of no localization, strong anti-interference capability and the like, and has wide application prospect.
Description
Technical Field
The utility model belongs to the technical field of quantum communication, and particularly relates to a high-order correlation light field-based correlation imaging device.
Background
Optical imaging is applied to the aspects of production and life. In the traditional optical imaging, object information is acquired by utilizing first-order correlation of a light field, and the traditional optical imaging is specifically applied to microscopes, telescopes and the like. With the development of quantum physics, the combination of quantum physics and imaging technology has led to a cross discipline, namely quantum imaging, also known as correlation imaging. Correlated imaging is the use of higher order correlation of a light field to obtain spatial or positional information of an object.
The correlated imaging divides the correlated light source into two paths, and the detected object is placed in one path, and the image is obtained in the other path. The photons for realizing imaging do not contact with the detection object, and the method belongs to an off-object imaging mode.
In the implementation process, the existing associated imaging light path is complex, the device size is large, and improvement is needed.
SUMMERY OF THE UTILITY MODEL
The embodiment of the utility model aims to provide a correlation imaging device based on a high-order correlation light field, and aims to solve the problems of complex light path and large device volume of the existing correlation imaging device.
The embodiment of the utility model is realized in such a way that the correlation imaging device based on the high-order correlation optical field comprises a correlation photon source module, a photon beam amplification module, an imaging scanning module and a photon detection module which are arranged along the propagation direction of a light path;
the associated photon source module is used for generating an associated photon source;
the photon beam amplifying module is used for amplifying the light source generated by the associated photon source module;
the imaging scanning module is used for scanning an object in front of the reflecting mirror in a reference light path out of 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;
the photon detection module comprises two receiving ends for receiving light from the imaging scanning module, and the photon detection module is used for coincidence measurement counting.
Preferentially, the associated photon source module comprises a laser, a first lens, a wave plate group, a first polarization beam splitter, a second lens and a nonlinear crystal which are sequentially arranged along the propagation direction of the light path;
the laser is used for pumping a light beam to provide an initial light beam for the whole device;
the first lens and the second lens are used for reducing and collimating the light beam before entering the nonlinear crystal;
the wave plate group is used for phase modulation of pump light;
the first polarization beam splitter is matched with the wave plate group and used for keeping the phase stability of the pump light and adjusting the intensity of the emergent light beam;
the nonlinear crystal is used for converting the pump light to obtain a required light beam.
Preferentially, the wave plate group comprises a first quarter wave plate and a first half wave plate which are sequentially arranged along the propagation direction of the light path; the long axis angles of the first quarter-wave plate and the first half-wave plate are adjustable so as to output horizontal polarization laser with stable phase and light intensity.
Preferentially, the photon beam amplification module comprises a 4f imaging system and a beam amplifier which are sequentially arranged along the propagation direction of the light path;
the 4f imaging system is used for reducing the phase distortion of single photons generated by the nonlinear crystal in the space transmission process and highly keeping the original association relation;
the focal length of the light beam amplifier is adjustable, the front focus of the light beam amplifier is coincided with the back focus of the 4f imaging system, and the light beam output by the light beam amplifier and the collimated light output by the associated photon source module form an amplification relation.
Preferably, the imaging system comprises a third lens and a fourth lens;
the third lens and the fourth lens have the same focal length, and two groups form a 4f imaging system.
Preferentially, the imaging scanning module comprises a second polarization beam splitter, a first optical filter and a reference light path;
the second polarization beam splitter is used for splitting a beam generated by the nonlinear crystal into a horizontally polarized transmitted beam and a vertically polarized reflected beam;
the first optical filter is positioned at the emergent end of the transmission light path of the second polarization beam splitter and is used for filtering non-single photon signals in the space light beam to complete the optical frequency filtering function, so that the signal-to-noise ratio is improved;
the reference light path is used for converting the vertical polarization reverse beam into a horizontal polarization beam after passing through an object and entering the photon detection module.
Preferably, the reference optical path includes a third polarization beam splitter, a second quarter wave plate, a mirror, a fifth lens, and a second filter;
the vertical polarization reflected light beam generated by the second polarization beam splitter enters the third polarization beam splitter and then is reflected to enter the second quarter-wave plate and the reflector, and the third polarization beam splitter is used for converting the vertical polarization reflected light beam passing through the second quarter-wave plate and the reflector into a horizontal polarization transmitted light beam to be emitted into a fifth lens and further to be emitted into the photon detection module;
the second quarter-wave plate and the reflector are used for converting the vertical polarization reflected beam into a horizontal polarization transmitted beam;
the fifth lens is used for emitting the collected light beam into the photon detection module;
the second optical filter is used for filtering non-single photon signals in the space light beams to complete the optical filtering function of optical frequency, so that the signal-to-noise ratio is improved.
Preferably, the photon detection module comprises a first multimode fiber, a first single-photon detector, a second multimode fiber, a second single-photon detector and a coincidence counter;
the first multimode fiber and the second multimode fiber have the same size and working wavelength, wherein the second multimode fiber is arranged on a displacement table and can be transversely scanned;
the first single-photon detector and the second single-photon detector respectively correspond to the first multimode optical fiber and the second multimode optical fiber and are used for receiving single photons, detecting photon information by utilizing a photoelectric conversion principle and transmitting the photon information to the coincidence counter;
the coincidence counter is used for coincidence counting.
Preferably, two end faces of the nonlinear crystal facing to the light propagation direction are coated with two layers of antireflection films, and the antireflection films have the functions of enhancing the transmittance of the light beam and corresponding to the wavelength of the mixed light beam.
The correlation imaging device based on the high-order correlation light field provided by the embodiment of the utility model recovers the spatial information of the object to be detected by utilizing two-photon composite detection, realizes the separation of detection and imaging, and is a non-localized imaging mode, namely, object-separated imaging. The utility model has the advantages of simple and convenient light path, high preparation efficiency of the correlated photon pair, small volume, light weight and easy movement, is easier to apply to the actual life compared with other correlated imaging devices, and has important significance for the field of quantum correlated imaging.
Drawings
FIG. 1 is a block diagram of a high-order correlation light field-based correlation imaging apparatus provided in the present invention;
FIG. 2 is a block diagram of an associated photon source module of the present invention;
FIG. 3 is a block diagram of a photon beam amplifying module according to the present invention;
FIG. 4 is a block diagram of an imaging scan module of the present invention;
FIG. 5 is a block diagram of a photon detection module of the present invention;
FIG. 6 is a graph of experimental data results of the present invention.
In the drawings: 1. an associated photon source module; 11. a laser; 12. a first lens; 13. a first quarter wave plate; 14. a first half wave plate; 15. a first polarizing beam splitter; 16. a second lens; 17. a nonlinear crystal; 2. a photon beam amplifying module; 21. a third lens; 22. a fourth lens; 23. a beam amplifier; 3. an imaging scanning module; 31. a second polarizing beam splitter; 32. a first optical filter; 33. a third polarization beam splitter; 34. a second quarter wave plate; 35. a mirror; 36. a fifth lens; 37. a second optical filter; 4 a photon detection module; 41. a first multimode optical fiber; 42. a second multimode optical fiber; 43. a first single photon detector; 44. a second single photon detector; 45. the coincidence counter.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the utility model and are not intended to limit the utility model.
Specific implementations of the present invention are described in detail below with reference to specific embodiments.
As shown in fig. 1, a block diagram of a higher-order correlated light field-based correlation imaging apparatus provided in an embodiment of the present invention includes a correlated photon source module 1, a photon beam amplifying module 2, an imaging scanning module 3, and a photon detection module 4, which are arranged along a propagation direction of an optical path;
the associated photon source module 1 is used for generating an associated light source;
the photon beam amplifying module 2 is used for amplifying the light source generated by the associated photon source module 1;
the imaging scanning module 3 is used for scanning an object in front of the reflecting mirror in the reference light path out of 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;
the photon detection module 4 comprises two receiving ends for receiving light from the imaging scanning module 3, and the photon detection module 4 is used for coincidence measurement counting.
In the embodiment of the present invention, the associated photon source module 1 is controlled to generate a laser light source, and the embodiment of the present invention is described by taking the example of obtaining information of an object at 1m, the central wavelength of a light beam of the light source is 405nm, and a mixed light beam with the wavelengths of 405nm and 810nm is obtained after further processing by the associated photon source module 1. The photon beam amplifying module 2 performs amplification processing on 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 horizontal polarized light scanning light path and a vertical polarized light reference light path, so that the scanning light path can scan the object in the reference light path, namely, off-object imaging. The photon detection module 4 comprises two receiving ends, and can calculate the image of the object by receiving the light from the photon beam amplification module 2 and the imaging scanning module 3 through correlation calculation, so as to realize the off-object imaging. It should be noted that the process of the association calculation may be performed on other computer devices, and the apparatus provided in the embodiment of the present invention is mainly used for acquiring data, and of course, it is an optional specific implementation manner of the present invention to combine the operation function to the apparatus provided in the embodiment of the present invention.
The correlation imaging device based on the high-order correlation light field provided by the embodiment of the utility model recovers the spatial information of the object to be detected by utilizing two-photon composite detection, realizes the separation of detection and imaging, and is a non-localized imaging mode, namely, object-separated imaging. The utility model has the advantages of simple and convenient light path, high preparation efficiency of the correlated photon pair, small volume, light weight and easy movement, is easier to apply to the actual life compared with other correlated imaging devices, and has important significance for the field of quantum correlated imaging.
As shown in fig. 2, in an embodiment of the present invention, the associated photon source module 1 includes a laser 11, a first lens 12, wave plate sets 13 and 14, a first polarization beam splitter 15, a second lens 16, and a nonlinear crystal 17, which are sequentially arranged along a propagation direction of an optical path;
the laser 11 is used for pumping a light beam to provide an initial light beam for the whole device;
the first lens 12 and the second lens 16 are used for reducing and collimating the light beam before entering the nonlinear crystal 17;
the wave plate group is used for phase modulation of pump light;
the first polarization beam splitter 15 is matched with the wave plate group and used for adjusting the intensity of the emergent light beam while keeping the phase stability of the pump light;
the nonlinear crystal 17 is used to convert the pump light to obtain a beam having a wavelength of 810 nm.
In the embodiment of the present invention, the laser 11 may use a semiconductor continuous laser as a pump beam to provide an initial beam for the whole device. In one embodiment, the central wavelength of the light beam is 405nm, the spectral line width is less than 0.06nm, and the output power can reach 66 mW. The first lens 12 and the second lens 16 are lenses of different models, the working wavelength is 405nm, the focal length f of the first lens 12 is 100mm, and the focal length f of the second lens 16 is 50 mm. The nonlinear crystal 17 may employ PPKTP crystals (potassium titanyl phosphate crystals) for generating correlated photon pairs of orthogonal polarization. The nonlinear crystal 17 utilizes a spontaneous parametric down-conversion process to convert 405nm pump light incident on the crystal into 810nm light, and the light emitted by the nonlinear crystal 17 is a mixed light beam of 405nm and 810nm because the light path is a collinear light path. The length of the nonlinear crystal 17 is 5mm, two end faces of the nonlinear crystal 17 in the light propagation direction are plated with antireflection films with wavelengths of 405nm and 810nm, when the pump light intensity is 1mw, the generation rate of the associated photon pairs is 2500Hz/mw/s, and the brightness is high.
The correlated photon source module 1 of the utility model prepares the correlated photon pair through the nonlinear crystal 17, the light path is simple and convenient, and the preparation efficiency of the correlated photon pair is high.
As shown in fig. 2, in one embodiment of the present invention, the wave plate set includes a first quarter-wave plate 13 and a first half-wave plate 14 sequentially arranged 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 light with stable phase and light intensity.
In the embodiment of the present invention, the working wavelengths of the first quarter-wave plate 13, the first half-wave plate 14 and the first polarization beam splitter 15 are all 405nm, the function of the wave plates is mainly used to adjust the polarization state of the light beam, and the first quarter-wave plate 13 and the first half-wave plate 14 are combined into a wave plate set, which can modulate the pump light to any phase. The wave plate group and the first polarization beam splitter 15 cooperate to adjust the intensity of the emergent light beam while maintaining the stable phase of the pump light. After the 405nm pump light passes through the first quarter wave plate 13, the first half wave plate 14 and the first polarization beam splitter 15, the horizontal polarized light with the phase-stable light intensity of 1mw is output.
The utility model adopts the combination of the quarter-wave plate, the half-wave plate and the polarization beam splitter, can obtain the horizontal polarization light phase of the photon beam, and can adjust the light intensity of the incident light of the photon beam.
As shown in fig. 3, in an embodiment of the present invention, the photon beam amplifying module 2 includes a 4f imaging system and a beam amplifier 23 sequentially arranged along the propagation direction of the optical path;
the 4f imaging system is used for reducing the phase distortion of single photons generated by the nonlinear crystal in the space transmission process and highly keeping the original association relation;
the focal length of the beam amplifier 23 is adjustable, the front focal point of the beam amplifier 23 coincides with the back focal point of the imaging system, and the beam output by the beam amplifier 23 and the collimated light output by the associated photon source module 1 form an amplifying relationship.
In the embodiment of the present invention, the photon beam amplifying module 2 includes an imaging system and a beam amplifier 23 sequentially arranged along the optical path direction 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, which carries the collimated light output at the beam waist of the nonlinear crystal 17 directly to the front focal point of the beam expander 23. The focal length of the beam amplifier 23 is adjustable, and the amplification factor is adjustable and can be amplified by 5-10 times. The front focal point of the beam amplifier 23 coincides with the back focal point of the imaging system, and the beam output by the beam amplifier 23 is in an amplified relationship with the collimated light output at the beam waist of the nonlinear crystal 17.
As shown in fig. 3, in one embodiment of the present invention, the imaging system includes a third lens 21 and a fourth lens 22;
the third lens 21 and the fourth lens 22 have the same focal length, and two groups form a 4f imaging system.
In the embodiment of the present invention, the third lens 21 and the fourth lens 22 are lenses of the same model, the operating wavelength is 810nm, and the focal length f of each 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, spaced by twice the focal length of the lenses, 100 mm. The nonlinear crystal 17 is located at the object point of the 4f imaging system, i.e. the third lens 21 is placed 50mm behind the nonlinear crystal 17. The third lens 21 and the fourth lens 22 directly carry collimated light output at the beam waist of the nonlinear crystal 17 to the focal point of the fourth lens 22 as a 4f system. And a 4f imaging system is set up to reduce the phase distortion of the single photon generated by the nonlinear crystal in the space transmission process, so that the single photon height keeps the original association relation.
The third lens 21 and the fourth lens 22 of the present invention have equal focal lengths, and the third lens 21 and the fourth lens 22 have a distance of twice the focal length. The third lens 21 and the fourth lens 22 form a 4f imaging system, and the phase distortion of emergent light of the nonlinear crystal 17 can be effectively reduced for the 4f system.
As shown in fig. 4, in an 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;
the second polarization beam splitter 31 is used for splitting the incident light beam into a horizontally polarized transmitted light beam and a vertically polarized reflected light beam;
the first optical filter 32 is located at the exit end of the transmission light path of the second polarization beam splitter 31, and is configured to receive and filter the horizontally polarized transmission light beam;
the reference optical path is used for converting the vertically polarized reverse beam into a horizontally polarized beam.
In the present embodiment, the second polarization beam splitter 31 operates with a central wavelength of 810nm and functions to split the beam into a horizontally polarized transmitted beam and a vertically polarized reflected beam when the beam is incident perpendicularly on its end face. The first filter 32 is located at the end of the transmission optical path of the second polarization beam splitter 31, and is used for receiving and filtering the horizontally polarized transmission beam. The first optical filter 32 is a band-pass filter, the wavelength of the working center of the first optical filter is 800nm, the full width at half maximum is 40nm, and non-single photon signals in the spatial light beams are filtered out, so that the optical frequency filtering function is completed, and the signal-to-noise ratio of the test system is improved.
As shown in fig. 4, 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 mirror 35, a fifth lens 36, and a second filter 37;
the vertically polarized reflected light beam generated by the second polarization beam splitter 31 enters the third polarization beam splitter 33, and then is reflected by the second quarter wave plate 34 and the mirror 35, and the third polarization beam splitter 33 is configured to convert the vertically polarized reflected light beam passing through the second quarter wave plate 34 and the mirror 35 into a horizontally polarized transmitted light beam to be incident on the fifth lens 36, and then to be incident on the photon detection module 4;
the second quarter wave plate 34 and the reflector 35 are used for converting the vertically polarized reflected beam into a horizontally polarized transmitted beam;
the fifth lens 36 is used for emitting the collected light beam into the photon detection module 4;
the second optical filter 37 is used for filtering non-single photon signals in the spatial light beam to complete the optical frequency filtering function, so as to improve the signal-to-noise ratio.
In the embodiment of the present invention, the second filter 37 is located at the end of the reflected light path of the second polarization beam splitter 31, and receives the vertically polarized reflected light beam. The second optical filter 37 and the first optical filter 32 are bandpass filters of the same type, the wavelength of the working center of the bandpass filters is 800nm, the full width at half maximum is 40nm, non-single photon signals in the spatial light beams are filtered, the optical frequency filtering function is completed, and the signal-to-noise ratio of the test system is improved. The second quarter wave plate 34 operates at a wavelength of 810nm and converts the vertically polarized reflected beam into a horizontally polarized transmitted beam by rotating the angle of the long axis of the wave plate. The third polarization beam splitter 33 has a central wavelength of 810nm, and functions to convert the vertically polarized reflected beam passing through the second quarter-wave plate 34 and the mirror 35 into a horizontally polarized transmitted beam, and to emit the horizontally polarized transmitted beam into the fifth lens 36 and further into the multimode fiber. The fifth lens 36 has a focal length f of 35mm and functions to inject the collected light beams all into the multimode optical fiber.
As shown in fig. 5, in one embodiment of the present invention, the photon detection module 4 includes a first multimode fiber 41, a first single-photon detector 43, a second multimode fiber 42, a second single-photon detector 44, and a coincidence counter 45;
the first multimode fiber 41 and the second multimode fiber 42 have the same size and working wavelength, wherein the second multimode fiber 42 is mounted on a displacement table and can be scanned transversely;
the first single-photon detector 43 and the second single-photon detector 44 correspond to the first multimode fiber 41 and the second multimode fiber 42, respectively, and are configured to receive single photons, detect information of the photons by using a photoelectric conversion principle, and transmit the information to the coincidence counter 45;
the coincidence counter 45 is used for coincidence counting.
In the embodiment of the present invention, the spin single photon beam generated by the associated photon source module 1 enters the coincidence counter 45 through the beam amplification module, the second multimode fiber 42, and the second single photon detector 44; the other group enters the coincidence counter 45 through the first multimode fiber 41 and the first single-photon detector 43 after entering the imaging scanning module 3 through the beam amplification module. The first multimode fiber 41 and the second multimode fiber 42 are both 200um multimode fibers, the working wavelength is 810nm, and the second multimode fiber 42 is arranged on a displacement platform and can be scanned transversely. Meanwhile, the first single-photon detector 43 and the second single-photon detector 44 are configured to receive single photons, detect information of the photons by using a photoelectric conversion principle, and transmit the information to the coincidence counter 45. The first multimode fiber 41 is located at an imaging point imaged by the fifth lens 36, namely 35mm behind the fifth lens 36, and is used for improving the coupling efficiency of the first multimode fiber 41.
In an embodiment of the present invention, a coincidence counter 45 is used for the coincidence count. The principle is that a dual-channel input signal is adopted to respectively receive output signals from a first single-photon detector 43 and a second single-photon detector 44, each channel counts independently, parameters such as window time and delay time are set through a display screen main interface, pulses arrive in a set coincidence time window, and counting is carried out according to coincidence measurement results, namely the number of associated photon pairs.
The imaging scanning module 3 and the photon detection module 4 are matched with each other, and when the coincidence counter 45 in the photon detection module 4 collects the associated photon pair, the imaging scanning module 3 can collect the associated photon pair at a position of 1 m; the light path designed by the utility model can collect the associated photon pairs at 1m, and the imaging resolution at 1m can be very high.
In an embodiment of the present invention, two end faces of the nonlinear crystal 17 facing the light propagation direction are coated with antireflection films, which function to enhance the transmittance of the light beam and correspond to the wavelength of the mixed light beam.
In the embodiment of the utility model, two end faces of the nonlinear crystal 17 in the light propagation direction are coated with two layers of antireflection films with the wavelength thicknesses of 405nm and 810nm, and when the pump light intensity is 1mw, the generation rate of the associated photon pair is 2500Hz/mw/s, so that the nonlinear crystal has higher brightness.
An embodiment of the present invention further provides a control method for a higher-order correlation light field-based correlation imaging apparatus, which is applied to the higher-order correlation light field-based correlation imaging apparatus according to the embodiment of the present invention, and the control method for the higher-order correlation light field-based correlation imaging apparatus includes the following steps:
starting and adjusting the associated photon source module 1, and jointly rotating the long axis angles of the first quarter-wave plate 13 and the first half-wave plate 14 to output horizontal polarized laser with stable phase and light 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 reduced collimated laser light. After the collimated laser is emitted into the crystal, a horizontal polarization single photon and a vertical polarization single photon are generated in a correlation mode.
Adjusting the positions of the third lens 21 and the fourth lens 22 to enable the nonlinear crystal 17 to be located on the focus of the third lens 21, wherein the distance between the third lens 21 and the fourth lens 22 is 2 times of 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;
the positions of the second polarization beam splitter 31 and the third polarization beam splitter 33 are adjusted, the distance between the third polarization beam splitter 33 and the reflecting mirror 35 is a set value, and the long axis angle of the second quarter-wave plate 34 is adjusted, so that the output reflected horizontal polarized light reaches the maximum. The set value here is 1 m.
Adjusting the position of the fifth lens 36 to make the focal point at the first multimode fiber 41; the position and the angle of the multimode optical fiber are adjusted to collect and couple the multimode optical fiber into a single photon detector, meanwhile, horizontal polarization photons in the associated photon source module 1 serving as scanning single photons are also collected and coupled to another single photon detector, and then signals generated by the two paths of photons reach an coincidence counter 45 to carry out coincidence measurement counting.
Test data are recorded or derived as shown in the following table:
table 1: test data
In the embodiment of the utility model, a result graph obtained by scanning and imaging a 400um object 1m away is shown in fig. 6, the diameter of a scanning spot is larger than 5mm, and the imaging magnification of the actual object is 2 times. When a 400um object which is far away from 1m is imaged, the influence of the magnification factor is considered, and when 200um multimode fiber is used for scanning, the corresponding equivalent resolution is about 100 um.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the utility model, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (9)
1. A correlation imaging device based on a high-order correlation light field is characterized by comprising a correlation photon source module, a photon beam amplification module, an imaging scanning module and a photon detection module which are arranged along the propagation direction of a light path;
the associated photon source module is used for generating an associated photon source;
the photon beam amplifying module is used for amplifying the light source generated by the associated photon source module;
the imaging scanning module is used for scanning an object in front of the reflecting mirror in the reference light path out of 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, and the other path enters the reference light path of the imaging scanning module;
the photon detection module comprises two receiving ends for receiving light from the imaging scanning module, and the photon detection module is used for coincidence measurement counting.
2. The correlation imaging device based on the higher-order correlation light field according to claim 1, wherein the correlation photon source module comprises a laser, a first lens, a wave plate group, a first polarization beam splitter, a second lens and a nonlinear crystal, which are arranged in sequence along the propagation direction of the light path;
the laser is used for pumping a light beam to provide an initial light beam for the whole device;
the first lens and the second lens are used for reducing and collimating the light beam before entering the nonlinear crystal;
the wave plate group is used for phase modulation of pump light;
the first polarization beam splitter is matched with the wave plate group and used for keeping the phase stability of the pump light and adjusting the intensity of the emergent light beam;
the nonlinear crystal is used for converting the pump light to obtain a required light beam.
3. The correlation imaging device based on the higher-order correlation light field according to claim 2, wherein the wave plate group comprises a first quarter wave plate and a first half wave plate which are 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 so as to output horizontal polarization laser with stable phase and light intensity.
4. The correlation imaging device based on the higher-order correlation light field according to claim 1, wherein the photon beam amplifying module comprises a 4f imaging system and a beam amplifier which are arranged in sequence along the propagation direction of the light path;
the 4f imaging system is used for reducing the phase distortion of single photons generated by the nonlinear crystal in the space transmission process and highly keeping the original association relation;
the focal length of the light beam amplifier is adjustable, the front focus of the light beam amplifier is coincided with the back focus of the 4f imaging system, and the light beam output by the light beam amplifier and the collimated light output by the associated photon source module form an amplification relation.
5. The higher-order correlated light field based correlated imaging device according to claim 4, wherein said imaging system comprises a third lens and a fourth lens;
the third lens and the fourth lens have the same focal length, and two groups form a 4f imaging system.
6. The correlation imaging device based on the higher-order correlation light field according to claim 1, wherein the imaging scanning module comprises a second polarization beam splitter, a first filter and a reference light path;
the second polarization beam splitter is used for splitting a beam generated by the nonlinear crystal into a horizontally polarized transmitted beam and a vertically polarized reflected beam;
the first optical filter is positioned at the emergent end of the transmission light path of the second polarization beam splitter and is used for filtering non-single photon signals in the space light beam to complete the optical frequency filtering function, so that the signal-to-noise ratio is improved;
the reference light path is used for converting the vertical polarization reverse beam into a horizontal polarization beam after passing through an object and entering the photon detection module.
7. The correlation imaging device based on the higher-order correlation light field according to claim 6, wherein the reference light path comprises a third polarization beam splitter, a second quarter wave plate, a mirror, a fifth lens and a second filter;
the vertical polarization reflected light beam generated by the second polarization beam splitter enters the third polarization beam splitter and then is reflected to enter the second quarter-wave plate and the reflector, and the third polarization beam splitter is used for converting the vertical polarization reflected light beam passing through the second quarter-wave plate and the reflector into a horizontal polarization transmitted light beam to be emitted into a fifth lens and further to be emitted into the photon detection module;
the second quarter-wave plate and the reflector are used for converting the vertical polarization reflected beam into a horizontal polarization transmitted beam;
the fifth lens is used for emitting the collected light beam into the photon detection module;
the second optical filter is used for filtering non-single photon signals in the space light beams to complete the optical filtering function of optical frequency, so that the signal-to-noise ratio is improved.
8. The higher-order correlated light field based correlated imaging device according to claim 1, wherein said photon detection module comprises a first multimode fiber, a first single photon detector, a second multimode fiber, a second single photon detector and a coincidence counter;
the first multimode fiber and the second multimode fiber have the same size and working wavelength, wherein the second multimode fiber is arranged on a displacement table and can be transversely scanned;
the first single-photon detector and the second single-photon detector respectively correspond to the first multimode optical fiber and the second multimode optical fiber and are used for receiving single photons, detecting photon information by utilizing a photoelectric conversion principle and transmitting the photon information to the coincidence counter;
the coincidence counter is used for coincidence counting.
9. The correlation imaging device based on the higher-order correlation optical field according to claim 2, wherein two end faces of the nonlinear crystal facing to the light propagation direction are coated with two layers of antireflection films, and the antireflection films are used for enhancing the transmittance of the light beam and correspond to the wavelength of the mixed light beam.
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