Four-wavefront quantum weak measurement wavefront sensor and related wavefront restoration method

Abstract

The present invention discloses a four-wavefront quantum weak measurement wavefront sensor and a related wavefront restoration method. On the basis of the traditional quantum weak measurement wavefront sensor, a beam splitter is introduced. The intensity distribution of four beams of light can be measured simultaneously through one detection, which greatly reduces the measurement time. On this basis, the horizontal and vertical slope information of the wavefront can be obtained, thereby realizing real-time wavefront sensing. It can be applied to scenarios such as optical communication and astronomical observation that require real-time measurement of the wavefront.

Description

Technical Field

[0001] The present invention relates to the field of wavefront sensing and quantum weak measurement technology, and in particular to a four-wavefront quantum weak measurement wavefront sensor and a related wavefront restoration method. Background Art

[0002] Wavefront is an important physical quantity that can characterize the propagation characteristics of light. As an electromagnetic wave, light is affected by many factors such as processing errors and uneven medium distribution during its generation and propagation, which will cause the wavefront to deform, thereby affecting the imaging quality of the light beam. Wavefront sensing technology is a modern optical measurement technology that has emerged as the times require. It reconstructs and restores the wavefront phase by sampling, modulating and detecting the far-field light beam intensity distribution. It is widely used in astronomical observation, medical imaging, laser technology, optical communications and other fields. At present, wavefront sensing technology has various types with obvious characteristics, and different technical routes are suitable for different scenarios. Shearing interferometry wavefront sensing technology focuses on high-precision wavefront detection, Shack-Hartmann wavefront sensing technology is committed to real-time dynamic wavefront detection, and phase inversion wavefront sensing technology is suitable for quasi-static wavefront restoration. In addition, there are various other wavefront sensing technologies that use different technical solutions to achieve wavefront measurement in different application environments.

[0003] Quantum measurement is the core issue of the quantum mechanics interpretation system. According to different classification methods, quantum measurement can be divided into orthogonal measurement and non-orthogonal measurement, direct measurement and indirect measurement, or strong measurement and weak measurement. Among them, weak measurement has been a research hotspot in recent years. Weak measurement methods can amplify tiny physical effects and have been effectively used in the field of precision measurement of various physical quantities.

[0004] At present, a precision measurement technology such as quantum weak measurement has been used in the field of wavefront sensing. Please refer to the optical wavefront sensor disclosed in the Chinese Patent Application Publication Specification (Patent No.: ZL201920033899.5). Compared with traditional wavefront sensors, wavefront sensors based on quantum weak measurement technology have the characteristics of high resolution and high sensitivity. However, the optical wavefront sensor needs to perform multiple measurement operations to obtain the horizontal and vertical slope information of the wavefront respectively, which greatly increases the wavefront reconstruction time. Therefore, the optical wavefront sensor cannot perform high-speed real-time measurement, which limits the application scope of the sensor. Summary of the invention

[0005] The purpose of the present invention is to provide a four-wavefront quantum weak measurement wavefront sensor and a related wavefront restoration method, which does not require multiple operations and greatly reduces the measurement time. On this basis, the horizontal and vertical slope information of the wavefront can be obtained, thereby realizing real-time wavefront sensing.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] A four-wavefront quantum weak measurement wavefront sensor, comprising: a first polarization beam splitter, a first half-wave plate and a second half-wave plate, a first thin calcite crystal and a second thin calcite crystal, a first 1 / 4 wave plate and a second 1 / 4 wave plate, a second polarization beam splitter and an array photodetector; wherein:

[0008] After the incident light is polarized and split by the polarization beam splitter, horizontal polarized light and vertical polarized light are obtained; the horizontal polarized light is incident on the second polarization beam splitter through the first half-wave plate, the first thin calcite crystal and the first 1 / 4 wave plate in sequence; the vertical polarized light is incident on the second polarization beam splitter through the second half-wave plate, the second thin calcite crystal and the second 1 / 4 wave plate in sequence; the second polarization beam splitter projects the two incident beams of light respectively, and the generated four beams of light are incident on the array photodetector.

[0009] A wavefront restoration method, comprising:

[0010] The intensity distribution of four beams of light is detected simultaneously using the aforementioned four-wavefront quantum weak measurement wavefront sensor;

[0011] The wavefront slope distribution is calculated by the light intensity distribution of four light beams;

[0012] Based on the wavefront slope distribution, the wavefront restoration algorithm is used to reconstruct the phase image of the wavefront to be measured.

[0013] It can be seen from the technical solution provided by the present invention that, on the basis of the traditional quantum weak measurement wavefront sensor, a beam splitter is introduced, and the intensity distribution of four beams of light can be measured simultaneously through one detection, which greatly reduces the measurement time. On this basis, the horizontal and vertical slope information of the wavefront can be obtained, so that the wavefront sensor has the ability of real-time measurement, and can be applied to scenarios such as optical communications and astronomical observations that require real-time measurement of the wavefront. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0015] Figure 1 A schematic diagram of a four-wavefront quantum weak measurement wavefront sensor provided by an embodiment of the present invention;

[0016] Figure 2 A schematic diagram of the light intensity detected by the array detector when Gaussian light is incident according to an embodiment of the present invention;

[0017] Figure 3 A schematic diagram of the light intensity detected by the array detector when Laguerre-Gaussian light is incident provided by an embodiment of the present invention;

[0018] Figure 4 A flow chart of a wavefront restoration method based on a four-wavefront quantum weak measurement wavefront sensor provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the protection scope of the present invention.

[0020] First, the terms that may be used in this article are explained as follows:

[0021] The terms "include", "comprises", "contains", "has" or other descriptions with similar semantics should be interpreted as non-exclusive inclusion. For example, including certain technical feature elements (such as raw materials, components, ingredients, carriers, dosage forms, materials, dimensions, parts, components, mechanisms, devices, steps, procedures, methods, reaction conditions, processing conditions, parameters, algorithms, signals, data, products or products, etc.) should be interpreted as including not only certain technical feature elements explicitly listed, but also other technical feature elements known in the art that are not explicitly listed.

[0022] The following is a detailed description of a four-wavefront quantum weak measurement wavefront sensor and a related wavefront restoration method provided by the present invention. The contents not described in detail in the embodiments of the present invention belong to the prior art known to professionals in the field. If no specific conditions are specified in the embodiments of the present invention, the conventional conditions in the field or the conditions recommended by the manufacturer are followed. The instruments used in the embodiments of the present invention, if the manufacturer is not specified, are all conventional products that can be purchased commercially.

[0023] Embodiment 1

[0024] like Figure 1As shown, a four-wavefront quantum weak measurement wavefront sensor mainly includes a first polarization beam splitter 1, a first half-wave plate 2 and a second half-wave plate 3, a first thin calcite crystal 4 and a second thin calcite crystal 5, a first 1 / 4 wave plate 6 and a second 1 / 4 wave plate 7, a second polarization beam splitter 8 and an array photodetector 9; the optical path structure can be described as: after the incident light is polarized and split by the polarization beam splitter 1, horizontal polarized light and vertical polarized light are obtained; the horizontal polarized light is sequentially incident on the second polarization beam splitter 8 through the first half-wave plate 2, the first thin calcite crystal 4 and the first 1 / 4 wave plate 6; the vertical polarized light is sequentially incident on the second polarization beam splitter 8 through the second half-wave plate 3, the second thin calcite crystal 5 and the second 1 / 4 wave plate 7; the second polarization beam splitter 8 projects the two incident beams respectively, and the generated four beams are incident on the array photodetector 9.

[0025] In the above optical path structure, the first polarization beam splitter 1 is mainly responsible for polarizing and splitting the incident light, the first half-wave plate 2 and the second half-wave plate 3 are mainly responsible for polarizing and selecting the light beam, the first thin calcite crystal 4 and the second thin calcite crystal 5 are mainly responsible for weak coupling of the light beam, and the second polarization beam splitter 8 is mainly responsible for post-selection of the light beam.

[0026] The following is a detailed introduction to each part of the four-wavefront quantum weak measurement wavefront sensor.

[0027] 1. The first polarization beam splitter.

[0028] In the embodiment of the present invention, the optical axis of the first polarization beam splitter 1 is along the horizontal direction. After polarization and beam splitting, the horizontal polarized light obtained is recorded as |H>, and the vertical polarized light is recorded as |V>.

[0029] 2. The first half-wave plate and the second half-wave plate.

[0030] In the embodiment of the present invention, the angle between the optical axis 2 of the first half-wave plate and the vertical direction is 22.5°, and the angle between the optical axis of the second half-wave plate 3 and the vertical direction is -22.5°.

[0031] The first half-wave plate and the second half-wave plate are used to convert both the horizontal polarized light and the vertical polarized light into linear polarized light: |D>, completing the initial state preparation of the incident laser, which is expressed as: |Ψ>=|ψ> path |D>; where |ψ> path It is represented by the spatial complex amplitude of the laser to be measured (including the phase part and the amplitude part). The above process is a pre-selection process, in which the polarization direction of the light beam is rotated to the specified direction.

[0032] Those skilled in the art can understand that the two beams of light separated by the first polarization beam splitter are horizontally polarized light |H> and vertically polarized light |V>. Since the angles of the first half-wave plate and the second half-wave plate are different, as mentioned above, the angle between the optical axis 2 of the first half-wave plate and the vertical direction is 22.5°, so the horizontal polarized light |H> will be converted into linear polarized light |D>; the angle between the optical axis of the second half-wave plate 3 and the vertical direction is -22.5°, so the vertical polarized light |V> will be converted into linear polarized light |D>. It can be seen that after passing through the first half-wave plate and the second half-wave plate, the polarization of the horizontal polarized light |H> and the vertical polarized light |V> are the same, and both become |D>, so they can be combined for explanation.

[0033] 3. A first thin calcite crystal and a second thin calcite crystal.

[0034] In the embodiment of the present invention, the optical axis of the first thin calcite crystal 4 is located in a vertical plane, and the optical axis of the second thin calcite crystal 5 is located in a horizontal plane.

[0035] The first thin calcite crystal 4 and the second thin calcite crystal 5 are used to make the polarization of the incident light beam weakly coupled with the momentum of the photon.

[0036] When each thin calcite crystal causes the incident linearly polarized light to weakly couple with the photon momentum, the photon state evolution process can be expressed as:

[0037]

[0038] Among them, |Ψ′> represents the photon state after the incident linearly polarized light and the photon momentum are weakly coupled, represents the measurement pointer, k represents the photon momentum. For the first thin calcite crystal, the incident linearly polarized light is converted from the horizontally polarized light by the first half-wave plate. The photon momentum k is the photon horizontal momentum k. x For the second thin calcite crystal, the incident linearly polarized light is converted from vertically polarized light by the second half-wave plate, and the photon momentum k is the photon vertical momentum k y , g represents the coupling strength, represents Planck's constant, i represents the imaginary unit, t represents the evolution time, the symbol ≡ represents equality, |J> represents linearly polarized light, whose polarization direction is perpendicular to |D>.

[0039] Those skilled in the art will appreciate that the thickness of the thin calcite crystal can be reflected by the above photon state evolution expression, that is, only when the calcite crystal is thin can it satisfy

[0040] 4. The first 1 / 4 wave plate and the second 1 / 4 wave plate.

[0041] In the embodiment of the present invention, the angles between the optical axes of the first quarter wave plate 6 and the second quarter wave plate 7 and the vertical direction are both -45°.

[0042] 5. Second polarization beam splitter.

[0043] In the embodiment of the present invention, the optical axis of the second polarization beam splitter 8 is along the horizontal direction.

[0044] Through the joint action of the first 1 / 4 wave plate, the second 1 / 4 wave plate and the second polarization beam splitter, the two beams of light emitted by the first thin calcite crystal and the second thin calcite crystal are projected respectively, so that each beam of light is transformed into two beams; when each beam of light is projected, it is projected onto the right-handed light projection base |R> and the left-handed light projection base |L> respectively, and the above process is a post-selection process.

[0045] 6. Array photodetector.

[0046] The four beams of light emitted by the second polarization beam splitter 8 are incident on the array photodetector, and the light intensity distribution of the four beams is received on the array photodetector. and like Figure 2 and Figure 3 As shown, the intensity distribution of Gaussian light and the intensity distribution of Laguerre-Gaussian light are shown respectively.

[0047] In the embodiment of the present invention, the array photodetector may be a CCD camera, a CMOS camera or an ICCD camera.

[0048] The above-mentioned solution provided by the embodiment of the present invention introduces a beam splitter on the basis of the traditional quantum weak measurement wavefront sensor. Through one detection, the intensity distribution of four beams of light can be measured simultaneously, and then the horizontal and vertical slope information of the wavefront can be obtained, so that the wavefront sensor has the ability of real-time measurement.

[0049] Embodiment 2

[0050] The embodiment of the present invention provides a wavefront restoration method, which is implemented based on the four-wavefront quantum weak measurement wavefront sensor provided in the above embodiment. Figure 4 As shown, the main steps include:

[0051] Step 1: Use the aforementioned four-wavefront quantum weak measurement wavefront sensor to simultaneously detect the light intensity distribution of four beams of light.

[0052] Step 2: Calculate the wavefront slope distribution through the light intensity distribution of the four light beams.

[0053] First, the horizontal momentum and vertical momentum of photons are calculated by the intensity distribution of four light beams. The calculation formula can be expressed as:

[0054]

[0055]

[0056] Among them, k x represents the horizontal momentum of the photon, k y represents the vertical momentum of the photon, represents the interaction strength, which is related to the thickness of the calcite crystal and the photon wavelength λ, g represents the coupling strength, which is proportional to the thickness of the calcite crystal, and t represents the evolution time; and Represents the light intensity distribution of four beams.

[0057] Then, using the photon horizontal momentum k x and the photon's vertical momentum k y Calculate the wavefront slope distribution, that is, multiply the horizontal momentum of the photon and the vertical momentum of the photon by a proportional coefficient Get the horizontal wavefront slope Vertical wavefront slope

[0058] Step 3: Based on the wavefront slope distribution, a wavefront restoration algorithm is used to reconstruct the phase diagram of the wavefront to be measured (ie, the phase part of the spatial complex amplitude of the laser to be measured).

[0059] The wavefront restoration algorithm includes the Hartmann wavefront restoration algorithm, such as: regional method, pattern method.

[0060] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A four-wavefront quantum weak measurement wavefront sensor, characterized in that: include: A first polarization beam splitter, a first half-wave plate and a second half-wave plate, a first thin calcite crystal and a second thin calcite crystal, a first 1 / 4 wave plate and a second 1 / 4 wave plate, a second polarization beam splitter and an array photodetector, wherein the optical axis of the first thin calcite crystal is located in a vertical plane, and the optical axis of the second thin calcite crystal is located in a horizontal plane; the first thin calcite crystal and the second thin calcite crystal are used to make the polarization of the incident light beam weakly coupled with the momentum of the photon; wherein: After the incident light is polarized and split by the first polarization beam splitter, horizontal polarized light and vertical polarized light are obtained; the horizontal polarized light is incident on the second polarization beam splitter through the first half-wave plate, the first thin calcite crystal and the first 1 / 4 wave plate in sequence; the vertical polarized light is incident on the second polarization beam splitter through the second half-wave plate, the second thin calcite crystal and the second 1 / 4 wave plate in sequence; the second polarization beam splitter projects the two incident beams of light respectively, and the generated four beams of light are incident on the array photodetector.

2. A four-wavefront quantum weak measurement wavefront sensor according to claim 1, characterized in that: The optical axis of the first polarization beam splitter is along the horizontal direction. After polarization and beam splitting, the horizontal polarized light obtained is recorded as |H>, and the vertical polarized light is recorded as |V>.

3. A four-wavefront quantum weak measurement wavefront sensor according to claim 1, characterized in that: The angle between the optical axis of the first half-wave plate and the vertical direction is 22.5°, and the angle between the optical axis of the second half-wave plate and the vertical direction is -22.5°; the horizontal polarized light and the vertical polarized light are both converted into linear polarized light by the first half-wave plate and the second half-wave plate: |D>, completing the initial state preparation of the incident laser, expressed as: |Ψ>=|ψ> path |D>; where |ψ> path Represented as the spatial complex amplitude of the laser to be measured.

4. A four-wavefront quantum weak measurement wavefront sensor according to claim 1, characterized in that: When each thin calcite crystal causes the incident linearly polarized light to weakly couple with the photon momentum, the photon state evolution process can be expressed as: Among them, |Ψ'> represents the photon state after the incident linearly polarized light and the photon momentum are weakly coupled, represents the measurement pointer, k represents the photon momentum. For the first thin calcite crystal, the incident linearly polarized light |D> is converted from the horizontally polarized light by the first half-wave plate, and the photon momentum k is the photon horizontal momentum k. x For the second thin calcite crystal, the incident linearly polarized light |D> is converted from vertically polarized light by the second half-wave plate, and the photon momentum k is the photon vertical momentum k y , g represents the coupling strength, represents Planck's constant, i represents the imaginary unit, t represents the evolution time, the symbol ≡ represents equality, |J> represents linearly polarized light, whose polarization direction is perpendicular to |D>; |ψ> path Represents the spatial complex amplitude of the laser to be measured.

5. A four-wavefront quantum weak measurement wavefront sensor according to claim 1, characterized in that: The angles between the optical axes of the first 1 / 4 wave plate and the second 1 / 4 wave plate and the vertical direction are both -45°.

6. A four-wavefront quantum weak measurement wavefront sensor according to claim 5, characterized in that: The optical axis of the second polarization beam splitter is along the horizontal direction; Through the joint action of the first 1 / 4 wave plate, the second 1 / 4 wave plate and the second polarization beam splitter, the two beams of light emitted by the first thin calcite crystal and the second thin calcite crystal are projected separately, so that each beam of light is transformed into two beams; when each beam of light is projected, it is projected onto the right-handed light projection base |R> and the left-handed light projection base |L> respectively.

7. A four-wavefront quantum weak measurement wavefront sensor according to claim 1, characterized in that: The array photodetector is a CCD camera, a CMOS camera or an ICCD camera.

8. A wavefront restoration method, characterized in that: include: Using the four-wavefront quantum weak measurement wavefront sensor described in any one of claims 1 to 7 to simultaneously detect the light intensity distribution of four beams of light; The wavefront slope distribution is calculated by the light intensity distribution of four light beams; Based on the wavefront slope distribution, the wavefront restoration algorithm is used to reconstruct the phase image of the wavefront to be measured.

9. A wavefront restoration method according to claim 8, characterized in that: The calculation of the wavefront slope distribution by the light intensity distribution of the four light beams comprises: The horizontal momentum and vertical momentum of photons are calculated by the intensity distribution of four light beams, which can be expressed as: Among them, k x represents the horizontal momentum of the photon, k y represents the vertical momentum of the photon, represents the interaction strength, g represents the coupling strength, t represents the evolution time, and λ represents the photon wavelength; and Represents the light intensity distribution of four beams; The horizontal momentum of the photon k x and the photon's vertical momentum k y Multiply by a proportional factor Get the horizontal wavefront slope Vertical wavefront slope 10. A wavefront restoration method according to claim 8 or 9, characterized in that: The wavefront restoration algorithm includes the Hartmann wavefront restoration algorithm.

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