High-sensitivity conjugate vortex interference system and method based on opposite reflection

Abstract

The invention provides a high-sensitivity conjugate vortex interference system and method based on opposite reflection. Belongs to the field of vortex interference and comprises a laser, a vortex phase plate, a first beam splitter prism, a second beam splitter prism, a third beam splitter prism, a fourth beam splitter prism, a first fixed reflector, a second fixed reflector, a third fixed reflector, a double-sided reflector and a camera. The method comprises the following steps: forming a pair of conjugate vortexes through a first beam splitter prism, wherein one beam of vortex light is reflected to a fourth beam splitter prism as an interference arm after passing through a first fixed reflector, a third beam splitter prism, a double-sided reflector and a third fixed reflector; the other beam of vortex light is reflected to a fourth beam splitter prism as a reference arm after passing through a second fixed reflector, a second beam splitter prism and a double-sided reflector; and the light is combined by a fourth beam splitter prism and is received by a camera to interfere with the light intensity. By means of the arrangement, under the same displacement, a larger rotation angle can be generated, and tiny displacement can be recognized more accurately.

Description

Technical Field

[0001] The present application relates to the field of vortex interference, and more particularly, to a highly sensitive conjugate vortex interference system and method based on retroreflection. Background Art

[0002] The interference method of a vortex interferometer mainly obtains the change in the interference arm length by observing the rotation direction and angle of the interference pattern: the interference arm is the object to be measured, and changes in its length, phase, or optical path will cause changes in the interference pattern. The reference arm provides a stable phase reference for comparison with the interference arm.

[0003] The existing interference methods mainly include the following two:

[0004] 1. Interference is performed using vortex light and spherical reference light, where the vortex light is the interference arm and the spherical wave is the reference arm. The change in the interference arm length is obtained by observing the rotation direction and angle of the interference pattern. That is, when the vortex light acts as the interference arm and interferes with the spherical reference light, the interference pattern will exhibit specific rotation characteristics. This rotation characteristic is related to the orbital angular momentum of the vortex light and the change in the interference arm length. By observing the rotation direction and angle of the interference pattern, the change in the interference arm length can be inferred. For example, if the interference pattern rotates clockwise by a certain angle, it means that the length of the interference arm has increased; conversely, if the interference pattern rotates counterclockwise, it means that the length of the interference arm has decreased.

[0005] 2. Interference is performed using a pair of conjugate vortex lights, where one vortex light is the interference arm and the other vortex light is the reference arm. The change in the interference arm length is obtained by observing the rotation direction and angle of the interference pattern.

[0006] In the measurement process of the existing vortex interferometer, only the length of the interference arm changes. Due to the limited change in the optical path, the sensitivity of the rotation angle of the interference pattern to the change in the arm length is also limited. The interferometer may not be able to accurately measure very small displacement changes, thus limiting its performance in some high-precision measurement or sensing applications. Summary of the Invention

[0007] The purpose of the present application is to provide a highly sensitive conjugate vortex interference system and method based on retroreflection. Under the same displacement, using conjugate vortices for interference can generate a larger rotation angle, enabling more precise measurement and identification of small displacements. This advantage makes conjugate vortex interference potentially valuable in applications requiring high-precision displacement measurement.

[0008] The present application is implemented as follows:

[0009] In a first aspect, the present application provides a highly sensitive conjugate vortex interference system based on retroreflection, including:

[0010] A laser, a vortex phase plate, a first beam splitting prism, a second beam splitting prism, a third beam splitting prism, a fourth beam splitting prism, a first fixed mirror, a second fixed mirror, a third fixed mirror, a double-sided mirror and a camera;

[0011] The pump light source generated by the laser passes through the vortex phase plate to generate vortex light with a topological charge number of l. After passing through the first beam splitting prism, a pair of conjugate vortices are formed. The transmitted light has a topological charge number of l, and the reflected light has a topological charge number of -l, which are used as the interference light and the reference light of the interferometer respectively; where

[0012] The vortex light with a topological charge number of l is transmitted by the third beam splitting prism after passing through the first fixed mirror, reflected by the movable double-sided mirror back to the third beam splitting prism, and then reflected by the third beam splitting prism and the third fixed mirror in sequence to the fourth beam splitting prism, serving as the interference arm; the double-sided mirror can move along the optical path;

[0013] The vortex light with a topological charge number of -l is reflected by the second fixed mirror, and then passes through the second beam splitting prism by transmission, is reflected by the double-sided mirror, and is reflected by the second beam splitting prism to the fourth beam splitting prism, serving as the reference arm;

[0014] The conjugate vortices are combined by the fourth beam splitting prism and the interference light intensity is received by the camera.

[0015] Based on the first aspect, the included angles between the normal lines of the first fixed mirror and the second fixed mirror and the incident light are π / 8.

[0016] Based on the first aspect, the included angle between the normal line of the third fixed mirror and the incident light is π / 4.

[0017] In a second aspect, the present application provides a highly sensitive conjugate vortex interference method based on counter-reflection, which is applied to the above interference system. The method includes the following steps:

[0018] S1: Make the pump light source generated by the laser pass through the vortex phase plate to generate vortex light with a topological charge number of l. After passing through the first beam splitting prism, a pair of conjugate vortices are formed. The transmitted light has a topological charge number of l, and the reflected light has a topological charge number of -l, which are used as the interference light and the reference light of the interferometer respectively; where, the vortex light with a topological charge number of l is transmitted by the third beam splitting prism after passing through the first fixed mirror, reflected by the movable double-sided mirror back to the third beam splitting prism, and then reflected by the third beam splitting prism and the third fixed mirror in sequence to the fourth beam splitting prism, serving as the interference arm; the double-sided mirror can move along the optical path; the vortex light with a topological charge number of -l is reflected by the second fixed mirror, and then passes through the second beam splitting prism by transmission, is reflected by the double-sided mirror, and is reflected by the second beam splitting prism to the fourth beam splitting prism, serving as the reference arm; the conjugate vortices are combined by the fourth beam splitting prism and the interference light intensity is received by the camera;

[0019] S2: Move the dual-sided mirror along the optical path between the second beam splitter prism and the third beam splitter prism. If the dual-sided mirror moves a displacement of Δξ towards the second beam splitter prism, the interferometric arm length increases by 2Δξ, and the optical field relative to the initial state is expressed as: OAM l *exp(i2π / λ*2Δξ) = U(r)exp(ilθ + i4πΔξ / λ); the reference arm length decreases by 2Δξ, so the optical field is expressed as: OAM -l *exp(-i2π / λ*2Δξ) = U(r)exp(-ilθ - i4πΔξ / λ). If the dual-sided mirror moves a displacement of Δξ towards the third beam splitter prism, the interferometric arm length decreases by 2Δξ, and the optical field relative to the initial state is expressed as: OAM -l *exp(-i2π / λ*2Δξ) = U(r)exp(-ilθ - i4πΔξ / λ); the reference arm length increases by 2Δξ, so the optical field is expressed as: OAM l *exp(i2π / λ*2Δξ) = U(r)exp(ilθ + i4πΔξ / λ),

[0020] Therefore, when the dual-sided mirror moves a displacement of Δξ along the optical path between the second beam splitter prism and the third beam splitter prism, the interference light intensity distribution after beam combination received by the camera becomes:

[0021] Itot 1 ∝|U(r)exp(ilθ + i4πΔξ / λ) + U(r)exp(-ilθ - i4πΔξ / λ)| 2

[0022] = 2|U(r)| 2 [1 + cos(2lθ + 8πΔξ / λ)]

[0023] where, I tot1 represents the interference optical field intensity distribution after beam combination, the symbol ∝ represents a proportional relationship, U(r) represents the amplitude at the propagation cross-section, i is the imaginary unit, exp(ilθ) is the carried angular phase distribution and is related to the topological charge number l, r and θ are respectively the radial and azimuthal angles of the polar coordinates, and λ is the wavelength; it can be seen that at this time the rotation angle of the interference light intensity is Δφ = 4π / (λl)Δξ, and thus the displacement amount can be obtained:

[0024] Δξ = λl / (4π)*Δφ;

[0025] It can be seen from this that under the same displacement, the interference pattern of the conjugate vortex generates a larger rotation angle.

[0026] Based on the second aspect, it further includes:

[0027] Make the angles between the normal lines of the first fixed mirror and the second fixed mirror and the incident light be π / 8.

[0028] Based on the second aspect, it further includes:

[0029] Make the included angle between the normal of the third fixed mirror and the incident light be π / 4.

[0030] In a third aspect, the present application provides an electronic device, including:

[0031] A memory for storing one or more programs;

[0032] A processor;

[0033] When the one or more programs are executed by the processor, the above-mentioned method is implemented.

[0034] In a fourth aspect, the present application provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the above-mentioned method is implemented.

[0035] Compared with the prior art, the present application has at least the following advantages or beneficial effects:

[0036] 1. Using conjugate vortices for interference can make the change in the micro displacement be reflected in the rotation of the interference pattern, enabling more precise measurement and identification of the micro displacement and realizing micro displacement sensing.

[0037] 2. By forming an opposed reflection optical path through the second beam splitter prism, the third beam splitter prism, and the double-sided mirror, while the optical path of the interference arm changes, the optical path of the reflection arm generates an opposite change amount. Compared with the existing vortex interference system with only a single variable interference arm, the rotation angle is doubled, the sensitivity is higher, and it can be applied to high-precision displacement measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can also be obtained based on these drawings without creative efforts.

[0039] Figure 1 It is a schematic structural diagram of a high-sensitivity conjugate vortex interference system based on opposed reflection according to the present application;

[0040] Figure 2 It is a schematic structural diagram of an electronic device according to the present application;

[0041] ICON:

[0042] 1. Laser; 2. Vortex phase plate; 3. First beam splitting prism; 4. Second beam splitting prism; 5. Third beam splitting prism; 6. Fourth beam splitting prism; 7. First fixed mirror; 8. Second fixed mirror; 9. Third fixed mirror; 10. Double-sided mirror; 11. Camera; 12. Interference pattern; 13. Processor; 14. Memory; 15. Communication interface. Detailed implementation manners

[0043] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are some but not all of the embodiments of the present application. Usually, the components of the embodiments of the present application described and illustrated herein can be arranged and designed in various different configurations.

[0044] The following will describe in detail some implementation manners of the present application with reference to the accompanying drawings. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0045] Embodiment

[0046] Through long-term research and practice, the inventors found that during the measurement process of the existing vortex interferometer, only the length of the interference arm changes. Due to the limited change in the optical path, the sensitivity of the rotation angle of the interference pattern 12 to the change in the arm length is also limited. The interferometer may not be able to accurately measure very small displacement changes, thereby limiting its performance in some high-precision measurement or sensing applications.

[0047] In view of this, the embodiments of the present application provide a highly sensitive conjugate vortex interference system and method based on opposite reflection, which can more accurately measure and identify small displacements. This advantage makes conjugate vortex interference have potential application value in applications that require high-precision displacement measurement.

[0048] To facilitate the understanding of the technical solution, the following terms are explained:

[0049] Optical vortex (OV): A scalar beam with an angular distribution of the phase gradient at the propagation cross-section and a phase singularity at the center, having a helical wavefront and carrying orbital angular momentum (OAM).

[0050] Topological charge (TC): The ratio of the angular phase change amount to 2π when the azimuth angle at the propagation cross-section of the vortex beam changes by 2π.

[0051] Conjugate vortex: A pair of vortex beams with opposite topological charges.

[0052] Please refer to Figure 1 , the highly sensitive conjugate vortex interference system based on retroreflection includes:

[0053] Laser 1, vortex phase plate 2, first beam splitting prism 3, second beam splitting prism 4, third beam splitting prism 5, fourth beam splitting prism 6, first fixed mirror 7, second fixed mirror 8, third fixed mirror 9, double-sided mirror 10 and camera 11;

[0054] The pump light source generated by the laser 1 passes through the vortex phase plate 2 to generate vortex light with a topological charge number of l. After passing through the first beam splitting prism 3, a pair of conjugate vortices are formed. The transmitted light has a topological charge number of l, and the reflected light has a topological charge number of -l, which are used as the interference light and reference light of the interferometer respectively;

[0055] Specifically, the laser 1 outputs pump light, which is a high-intensity light source. The vortex phase plate 2 is a special optical element that can change the phase distribution of light. When light passes through it, its phase will change specifically according to the design of the vortex phase plate 2. The vortex light generated by the pump light source passing through the vortex phase plate 2 has l complete phase rotation cycles. The first beam splitting prism 3 is used to split the incident beam into two beams. These two beams not only have different directions, but also their vortex characteristics are conjugate, that is, they have opposite topological charge numbers. The transmitted light refers to the beam that continues to propagate in the original direction (or slightly changes direction but is not reflected) after passing through the first beam splitting prism 3. Here, the topological charge number of the transmitted light is l, indicating that its phase wavefront rotates around the optical axis by l complete cycles. The reflected light refers to the beam reflected by the beam splitting prism. Different from the transmitted light, the topological charge number of the reflected light is -l, indicating that the direction of its phase wavefront rotating around the optical axis is opposite to that of the transmitted light, that is, it rotates by -l complete cycles (or, if l is positive, the phase wavefront of the reflected light rotates clockwise, while the transmitted light rotates counterclockwise, and vice versa).

[0056] The vortex light with a topological charge number of l is transmitted by the third beam splitting prism 5 after passing through the first fixed mirror 7, reflected by the movable double-sided mirror 10 to the third beam splitting prism 5, and then reflected by the third beam splitting prism 5 and the third fixed mirror 9 to the fourth beam splitting prism 6 as the interference arm; the double-sided mirror 10 can move along the optical path;

[0057] The vortex light with a topological charge number of -l is reflected by the second fixed mirror 8, and successively passes through the second beam splitting prism 4 for transmission, reflection by the double-sided mirror 10, and reflection by the second beam splitting prism 4 to the fourth beam splitting prism 6 as the reference arm;

[0058] The conjugate vortices are combined by the fourth beam splitting prism 6 and the interference light intensity is received by the camera 11.

[0059] Specifically, the conjugate vortex light is combined at the fourth beam splitter prism 6 to generate an interference pattern. The interference pattern is captured by a camera 11 and the interference light intensity is recorded. The camera 11 can be a digital camera or any device capable of capturing light intensity distribution.

[0060] It should be understood that the distribution of a vortex light field with a topological charge of l can be expressed as:

[0061] OAM l =U(r)exp(ilθ)

[0062] Among them, U(r) represents the amplitude at the propagation cross section, exp(ilθ) is the angular phase distribution carried and is related to the topological charge number l, r, θ are the polar radius and azimuth angle of the polar coordinates, and i is an imaginary unit. Similarly, the distribution of a vortex light field with a topological charge number -l is:

[0063] OAM-l=U(r)exp(-ilθ)

[0064] Therefore, when a pair of conjugate vortices merge and interfere, the light intensity distribution of the interference pattern can be expressed as:

[0065] I tot ∝|OAM l +OAM -l | 2 =exp(-ilθ)

[0066] =2|U(r)| 2 [1+cos(2lθ)]

[0067] Among them, I tot1 represents the intensity distribution of the interference light field after beam combination, and the symbol ∝ represents a proportional relationship. It can be seen that the interference light intensity presents a "petal" shape distribution, and the number of "petals" is twice the topological charge.

[0068] In the present application, when the double-sided reflector 10 moves toward the beam splitting prism 2 by a displacement of Δξ, the interference arm length increases by 2Δξ, and the light field relative to the initial state can be expressed as:

[0069] OAM l *exp(i2π / λ*2Δξ)=U(r)exp(ilθ+i4πΔξ / λ),

[0070] The reference arm length is reduced by 2Δξ, so the light field is expressed as:

[0071] OAM -l *exp(-i2π / λ*2Δξ)=U(r)exp(-ilθ-i4πΔξ / λ),

[0072] At this time, the intensity distribution of the interference light after the combined beam received by the camera 11 becomes:

[0073] Itot 1 ∝|U(r)exp(ilθ + i4πΔξ / λ) + U(r)exp(-ilθ - i4πΔξ / λ)| 2

[0074] =2|U(r)| 2 [1 + cos(2lθ + 8πΔξ / λ)]

[0075] It can be seen that at this time, the rotation angle of the interference light intensity is Δφ = 4π / (λl)Δξ, and thus the displacement can be obtained as follows:

[0076] Δξ = λl / (4π) * Δφ

[0077] It can be seen that by forming an opposed reflection optical path through the second beam splitter prism 4, the third beam splitter prism 5, and the double-sided mirror 10, while changing the optical path of the interference arm, the optical path of the reflection arm generates an opposite change amount. Compared with the existing vortex interference system with only a single variable interference arm, the rotation angle is doubled, the sensitivity is higher, and it can be applied to high-precision displacement measurement. Using conjugate vortices for interference can make the change of small displacements be reflected in the rotation of the interference pattern, enabling more accurate measurement and identification of small displacements and realizing the sensing of small displacements.

[0078] Preferably, the included angles between the normal lines of the first fixed mirror 7 and the second fixed mirror 8 and the incident light are π / 8.

[0079] Specifically, the included angles between the normal lines of the first fixed mirror 7 and the second fixed mirror 8 and the direction of the incident light are both π / 8 radians. Since π radians is equal to 180 degrees, π / 8 radians is equal to 22.5 degrees. That is to say, the incident light irradiates the surfaces of these two mirrors at an angle of 22.5 degrees.

[0080] Preferably, the included angle between the normal line of the third fixed mirror 9 and the incident light is π / 4.

[0081] Specifically, the included angle between the normal line of the third fixed mirror 9 and the direction of the incident light is π / 4 radians. Similarly, since π radians is equal to 180 degrees, π / 4 radians is equal to 45 degrees. Therefore, the incident light irradiates the surface of the third fixed mirror 9 at an angle of 45 degrees.

[0082] This application also provides a highly sensitive conjugate vortex interference method based on opposed reflection, which is applied to the above interference system. The method includes the following steps:

[0083] S1: Let the pump light source generated by the laser 1 pass through the vortex phase plate 2 to generate a vortex light with a topological charge number of l. After passing through the first beam splitting prism 3, a pair of conjugate vortices are formed. The topological charge number of the transmitted light is l, and the topological charge number of the reflected light is -l, which are used as the interference light and the reference light of the interferometer respectively. Among them, the vortex light with a topological charge number of l is transmitted through the third beam splitting prism 5 after passing through the first fixed mirror 7, reflected by the movable double-sided mirror 10 to the third beam splitting prism 5, and then reflected to the fourth beam splitting prism 6 through the third beam splitting prism 5 and the third fixed mirror 9 successively, serving as the interference arm. The double-sided mirror 10 can move along the optical path. The vortex light with a topological charge number of -l is reflected by the second fixed mirror 8, transmitted through the second beam splitting prism 4, reflected by the double-sided mirror 10, and reflected by the second beam splitting prism 4 to the fourth beam splitting prism 6, serving as the reference arm. The conjugate vortices are combined by the fourth beam splitting prism 6 and the interference light intensity is received by the camera 11.

[0084] Specifically, the pump light source generated by the laser 1 passes through the vortex phase plate 2 to generate a vortex light with a topological charge number of l. After passing through the first beam splitting prism 3, the vortex light is split into two beams: one is the transmitted light and the other is the reflected light. Due to the phase distribution characteristics of the vortex light, the transmitted light and the reflected light will have opposite topological charge numbers, that is, the topological charge number of the transmitted light is l, and the topological charge number of the reflected light is -l. These two beams of light are called conjugate vortices. The transmitted light and the reflected light (i.e., the conjugate vortices with opposite topological charge numbers) are used as the interference light and the reference light of the interferometer. The interference light (transmitted light) and the reference light (reflected light) meet and interfere in the interferometer to form an interference pattern. By analyzing the interference pattern, information about the phase distribution, topological charge number, etc. of the vortex light can be obtained.

[0085] S2: Move the double-sided mirror 10 along the optical path between the second beam splitting prism 4 and the third beam splitting prism 5. If the double-sided mirror 10 moves a displacement of Δξ towards the second beam splitting prism 4, the length of the interference arm increases by 2Δξ, and the optical field relative to the initial state is expressed as:

[0086] OAM l *exp(i2π / λ*2Δξ) = U(r)exp(ilθ + i4πΔξ / λ);

[0087] The length of the reference arm decreases by 2Δξ, so the optical field is expressed as:

[0088] OAM -l *exp(-i2π / λ*2Δξ) = U(r)exp(-ilθ - i4πΔξ / λ),

[0089] If the double-sided mirror 10 moves a displacement of Δξ towards the third beam splitting prism 5, the length of the interference arm decreases by 2Δξ, and the optical field relative to the initial state is expressed as:

[0090] OAM-l *exp(-i2π / λ*2Δξ) = U(r)exp(-ilθ - i4πΔξ / λ);

[0091] The reference arm length is increased by 2Δξ, so the optical field is expressed as:

[0092] OAM l *exp(i2π / λ*2Δξ) = U(r)exp(ilθ + i4πΔξ / λ),

[0093] Therefore, when the double-sided mirror 10 moves a displacement of Δξ along the optical path between the second beam splitter prism 4 and the third beam splitter prism 5, the interference light intensity distribution after beam combination received by the camera 11 becomes:

[0094] Itot 1 ∝|U(r)exp(ilθ + i4πΔξ / λ) + U(r)exp(-ilθ - i4πΔξ / λ)| 2

[0095] = 2|U(r)| 2 [1 + cos(2lθ + 8πΔξ / λ)]

[0096] where I tot1 represents the interference optical field intensity distribution after beam combination, the symbol ∝ represents a proportional relationship, U(r) represents the amplitude at the propagation cross-section, i is the imaginary unit, exp(ilθ) is the carried angular phase distribution and is related to the topological charge number l, r and θ are the radial and azimuthal angles of the polar coordinates respectively, and λ is the wavelength; it can be seen that at this time the rotation angle of the interference light intensity is Δφ = 4π / (λl)Δξ, and thus the displacement amount can be obtained:

[0097] Δξ = λl / (4π)*Δφ;

[0098] It can be seen from this that under the same displacement, the interference pattern 12 of the conjugate vortex generates a larger rotation angle.

[0099] In this application, a counter-reflection optical path is formed by the second beam splitter prism 4, the third beam splitter prism 5 and the double-sided mirror 10, so that while the optical path of the interference arm changes, the optical path of the reflection arm generates an opposite change amount. Compared with the existing vortex interference system with only a single variable interference arm, the rotation angle is doubled, the sensitivity is higher, and it can be applied to high-precision displacement measurement. Using conjugate vortices for interference can make the change of small displacements be reflected in the rotation of the interference pattern, and can measure and identify small displacements more accurately, realizing the sensing of small displacements.

[0100] Preferably, the included angles between the normal lines of the first fixed mirror 7 and the second fixed mirror 8 and the incident light are π / 8.

[0101] Specifically, the angles between the normal lines of the first fixed mirror 7 and the second fixed mirror 8 and the direction of the incident light are both π / 8 radians. Since π radians is equal to 180 degrees, π / 8 radians is equal to 22.5 degrees. That is to say, the incident light strikes the surfaces of these two mirrors at an angle of 22.5 degrees.

[0102] Preferably, the angle between the normal line of the third fixed mirror 9 and the incident light is π / 4.

[0103] Specifically, the angle between the normal line of the third fixed mirror 9 and the direction of the incident light is π / 4 radians. Similarly, since π radians is equal to 180 degrees, π / 4 radians is equal to 45 degrees. Therefore, the incident light strikes the surface of the third fixed mirror 9 at an angle of 45 degrees.

[0104] Please refer to Figure 2 , this application also provides an electronic device, including:

[0105] A memory 14 for storing one or more programs;

[0106] A processor 13; the memory 14 is connected to the processor 13 through a communication interface 15;

[0107] When the one or more programs are executed by the processor 13, all or part of the above methods are implemented.

[0108] In a fourth aspect, this application also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by the processor 13, all or part of the above methods are implemented.

[0109] For those skilled in the art, it is obvious that this application is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of this application, this application can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of this application is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in this application. Any reference signs in the claims should not be regarded as limiting the claimed rights.

Claims

1. A high-sensitivity conjugate vortex interferometry system based on counter-reflection, characterized in that: include: A laser, a vortex phase plate, a first beam splitting prism, a second beam splitting prism, a third beam splitting prism, a fourth beam splitting prism, a first fixed reflector, a second fixed reflector, a third fixed reflector, a double-sided reflector, and a camera; The pump light source generated by the laser passes through the vortex phase plate to generate vortex light with a topological charge of l, which passes through the first beam splitter prism to form a pair of conjugate vortices, the topological charge of the transmitted light is l, and the topological charge of the reflected light is -l, which serve as the interference light and reference light of the interferometer respectively; in The vortex light with a topological charge of l is transmitted by the third beam splitting prism after passing through the first fixed reflector, reflected back to the third beam splitting prism through the movable double-sided reflector, and then reflected to the fourth beam splitting prism through the third beam splitting prism and the third fixed reflector in sequence, as an interference arm; the double-sided reflector can move along the optical path; The vortex light with a topological charge of -1 is reflected by the second fixed reflector, and is sequentially transmitted through the second beam splitter prism, reflected by the double-sided reflector, and reflected by the second beam splitter prism to the fourth beam splitter prism as a reference arm; The conjugate vortices are combined by the fourth beam splitter prism and the interference light intensity is received by the camera.

2. A high-sensitivity conjugate vortex interferometry system based on counter-reflection according to claim 1, characterized in that: The angle between the normal lines of the first fixed reflector and the second fixed reflector and the incident light is pi / 8.

3. A high-sensitivity conjugate vortex interferometry system based on counter-reflection according to claim 2, characterized in that: The angle between the normal line of the third fixed reflector and the incident light is pi / 4.

4. A highly sensitive conjugate vortex interferometry method based on counter-reflection, characterized in that: Applied to the interference system of claim 1, the method comprises the following steps: S1: The pump light source generated by the laser passes through the vortex phase plate to generate vortex light with a topological charge of l, and a pair of conjugate vortices are formed through the first beam splitter prism, the topological charge of the transmitted light is l, and the topological charge of the reflected light is -l, which are respectively used as the interference light and reference light of the interferometer; wherein, the vortex light with a topological charge of l is transmitted by the third beam splitter prism after passing through the first fixed reflector, reflected back to the third beam splitter prism through the movable double-sided reflector, and reflected to the fourth beam splitter prism through the third beam splitter prism and the third fixed reflector in turn, as an interference arm; the double-sided reflector can move along the optical path; the vortex light with a topological charge of -l is reflected by the second fixed reflector, and is transmitted through the second beam splitter prism, reflected by the double-sided reflector, and reflected by the second beam splitter prism to the fourth beam splitter prism in turn, as a reference arm; the conjugate vortices are combined through the fourth beam splitter prism and the interference light intensity is received by the camera; S2: Move the double-sided reflector along the optical path between the second beam splitter prism and the third beam splitter prism. If the double-sided reflector moves toward the second beam splitter prism by a displacement of Δξ, the interference arm length increases by 2Δξ. The light field relative to the initial state is expressed as: OAM l *exp(i2π / λ*2Δξ)=U(r)exp(ilθ+i4πΔξ / λ); the reference arm length is reduced by 2Δξ, then the optical field is expressed as: OAM -l *exp(-i2π / λ*2Δξ)=U(r)exp(-ilθ-i4πΔξ / λ). If the double-sided reflector moves toward the third beam splitter prism by a displacement of Δξ, the interference arm length decreases by 2Δξ. The light field relative to the initial state is expressed as: OAM -l *exp(-i2π / λ*2Δξ)=U(r)exp(-ilθ-i4πΔξ / λ); the reference arm length increases by 2Δξ, then the optical field is expressed as: OAM l *exp(i2π / λ*2Δξ)=U(r)exp(il*+i4πΔξ / λ), Therefore, the double-sided reflector moves along the optical path between the second beam splitter prism and the third beam splitter prism by a displacement of Δξ, and the interference light intensity distribution after the combined beam received by the camera becomes: Itot1∝|U(r)exp(il*+i4πΔξ / λ)+U(r)exp(-il*-i4πΔξ / λ)| 2 =2|U(r)| 2 [1+cos(2l*+8πΔξ / λ)] Among them, I tot1 represents the intensity distribution of the interference light field after beam combination, the symbol ∝ represents a proportional relationship, U(r) represents the amplitude at the propagation cross section, and i is an imaginary unit. ex p(il*) is the angular phase distribution carried and is related to the topological charge number l. r, * are the polar diameter and azimuth of the polar coordinates, and λ is the wavelength. At this time, the rotation angle of the interference light intensity is Δφ=4π / (λl)Δξ, so the displacement is calculated: Δξ=λl / (4π)*Δφ; At the same displacement, the interference pattern of the conjugate vortex produces a larger rotation angle.

5. The high-sensitivity conjugate vortex interference method based on counter-reflection according to claim 4, characterized in that: Also includes: The angle between the normal lines of the first fixed reflector and the second fixed reflector and the incident light is pi / 8.

6. The high-sensitivity conjugate vortex interference method based on counter-reflection according to claim 5, characterized in that: Also includes: The angle between the normal line of the third fixed reflector and the incident light is pi / 4.

7. An electronic device, characterized in that: include: A memory for storing one or more programs; processor; When the one or more programs are executed by the processor, the method according to any one of claims 4 to 6 is implemented.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 4 to 6 is implemented.

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