Phase sensing system and method based on weak measurement

Abstract

The invention provides a phase sensing system and method based on weak measurement, which can be applied to the field of quantum sensing. According to the system, a phase sensing module carries out phase modulation on pre-selected incident light according to a signal to be detected to obtain detection light; four post-selection modules respectively post-select four parts of light obtained by detecting the light; the detection module detects the first post-selection light, the second post-selection light, the third post-selection light and the fourth post-selection light respectively; the processing module calculates a first item according to the first light intensity and the fourth light intensity and / or the second light intensity and the third light intensity; calculating a second item according to the first light intensity and the second light intensity and / or the third light intensity and the fourth light intensity; processing the predetermined angle and a first ratio obtained according to the first item and the second item by using an arc tangent function to obtain a phase signal, and realizing wide dynamic range detection of the phase signal; and performing linear transformation on the phase signal to obtain the size of the to-be-detected signal, thereby realizing wide dynamic range detection of the to-be-detected signal.

Description

Technical Field

[0001] This invention relates to the field of quantum sensing, and more specifically, to a phase sensing system and method based on weak measurement. Background Technology

[0002] Since the spin Hall effect of photons was observed in experiments using the weak measurement method, the weak measurement method has received widespread attention in the field of quantum sensing because it can amplify signals.

[0003] In related technologies, adaptive strategies are employed to achieve real-time estimation of the weak measurement phase with a wide dynamic range, and the detected signal is recovered based on this phase. However, in practical applications, the control equipment and control accuracy required for adaptive strategies are limited by the scenario, making it difficult to fully realize the effectiveness of the wide dynamic range. Summary of the Invention

[0004] In view of this, the present invention provides a phase sensing system and method based on weak measurement.

[0005] According to one aspect of the present invention, a phase sensing system based on weak measurement is provided, comprising: a phase sensing module for performing phase modulation on the pre-selected incident light according to a test signal to obtain a detection light when the pre-selected incident light passes through the phase sensing module; and four post-selection modules for performing post-selection on a first portion, a second portion, a third portion, and a fourth portion of the light obtained from the detection light to obtain a first post-selected light, a second post-selected light, a third post-selected light, and a fourth post-selected light, wherein the angle between the post-selected state corresponding to the first portion, the post-selected state corresponding to the second portion, the post-selected state corresponding to the third portion, and the post-selected state corresponding to the fourth portion and a predetermined direction is ε. The angle between the predetermined direction and the pre-selected state corresponding to the pre-selected incident light is π / 2, and ε is the predetermined angle; the detection module is used to detect the first, second, third, and fourth post-selected lights respectively to obtain the first light intensity, second light intensity, third light intensity, and fourth light intensity; the processing module is used to calculate the first term based on the first light intensity and the fourth light intensity and / or the second light intensity and the third light intensity; calculate the second term based on the first light intensity and the second light intensity and / or the third light intensity and the fourth light intensity; process the predetermined angle and the first ratio obtained from the first term and the second term using the arctangent function to obtain the phase signal; and perform a linear transformation on the phase signal to obtain the magnitude of the signal to be measured.

[0006] According to an embodiment of the present invention, each post-selection module includes: a first quarter-wave plate and a polarizer, wherein the azimuth angle of the fast axis of the first quarter-wave plate is 45°, and the azimuth angles of the transmission axes of the four polarizers are ε, -ε, 90°+ε and 90°-ε, respectively.

[0007] According to an embodiment of the present invention, each post-selection module includes: a second quarter-wave plate, a half-wave plate, a third quarter-wave plate, a fourth quarter-wave plate, and a polarizer, wherein the azimuth angle of the fast axis of the second quarter-wave plate, the azimuth angle of the fast axis of the half-wave plate, and the azimuth angle of the fast axis of the third quarter-wave plate are equal, the azimuth angle of the fast axis of the fourth quarter-wave plate is 45°, and the azimuth angles of the transmission axes of the four polarizers are ε, -ε, 90°+ε, and 90°-ε, respectively.

[0008] According to an embodiment of the present invention, the processing module processes a predetermined angle and a first ratio obtained from the first term and the second term using an arctangent function to obtain a phase signal, including: processing the predetermined angle using a cotangent function to obtain an amplification factor; and processing a second ratio obtained from the amplification factor and the first ratio using an arctangent function to obtain the phase signal.

[0009] According to an embodiment of the present invention, the processing module is further configured to: when the phase signal is greater than 0 rad and less than 0.1 rad, obtain the phase signal based on a third ratio obtained based on the first ratio and the predetermined angle.

[0010] According to an embodiment of the present invention, the processing module calculates the first item based on the first light intensity and the fourth light intensity and / or the second light intensity and the third light intensity, including: obtaining the first item based on the first difference between the first light intensity and the fourth light intensity; or, obtaining the first item based on the second difference between the second light intensity and the third light intensity; or, obtaining the first item based on the average value calculated based on the first difference and the second difference.

[0011] According to an embodiment of the present invention, the processing module calculates the second item based on the first light intensity and the second light intensity and / or the third light intensity and the fourth light intensity, including: obtaining the second item based on the third difference between the first light intensity and the second light intensity; or, obtaining the second item based on the fourth difference between the third light intensity and the fourth light intensity; or, obtaining the second item based on the average value calculated based on the third difference and the fourth difference.

[0012] According to an embodiment of the present invention, the phase sensing module described above includes at least one of the following: a waveplate, a liquid crystal display, and an optical fiber.

[0013] According to an embodiment of the present invention, the phase sensing system further includes: a beam splitting module for dividing the detection light into four parts to obtain the first part light, the second part light, the third part light, and the fourth part light; the detection module includes: a first detector, a second detector, a third detector, and a fourth detector; the first detector is used to detect the first post-selected light to obtain the first light intensity; the second detector is used to detect the second post-selected light to obtain the second light intensity; the third detector is used to detect the third post-selected light to obtain the third light intensity; and the fourth detector is used to detect the fourth post-selected light to obtain the fourth light intensity.

[0014] According to another aspect of the present invention, a phase sensing method based on weak measurement is provided, applied to the aforementioned phase sensing system based on weak measurement. The phase sensing method includes: a phase sensing module performing phase modulation on pre-selected incident light according to a signal to be measured to obtain detection light; and four post-selection modules performing post-selection on a first portion, a second portion, a third portion, and a fourth portion of light obtained from the detection light, respectively, to obtain a first post-selected light, a second post-selected light, a third post-selected light, and a fourth post-selected light, wherein the post-selected states corresponding to the first portion, the second portion, the third portion, and the fourth portion of light are respectively clamped to a predetermined direction. The angles are ε, -ε, π-ε, and π+ε, and the angle between the predetermined direction and the pre-selected state corresponding to the incident light after pre-selection is π / 2, where ε is the predetermined angle. The detection module detects the first, second, third, and fourth post-selected lights respectively, obtaining the first, second, third, and fourth light intensities. The processing module calculates the first term based on the first and fourth light intensities and / or the second and third light intensities. It calculates the second term based on the first and second light intensities and / or the third and fourth light intensities. The predetermined angle and the first ratio obtained from the first and second terms are processed using the arctangent function to obtain the phase signal. The phase signal is then linearly transformed to obtain the magnitude of the signal to be measured.

[0015] According to an embodiment of the present invention, by using four post-selection modules to perform post-selection on the first, second, third, and fourth portions of light obtained from the detection light, respectively, a first post-selected light, a second post-selected light, a third post-selected light, and a fourth post-selected light are obtained. The angles between the post-selected state corresponding to the first portion of light, the post-selected state corresponding to the second portion of light, the post-selected state corresponding to the third portion of light, and the post-selected state corresponding to the fourth portion of light and a predetermined direction are ε, -ε, π-ε, and π+ε, respectively. The angle between the predetermined direction and the pre-selected state corresponding to the incident light after pre-selection is π / 2. Then, a detection module is used to obtain the light corresponding to the four portions of light. After obtaining the first, second, third, and fourth light intensities, the processing module calculates the first term based on the first and fourth light intensities and / or the second and third light intensities; it then calculates the second term based on the same ratio. The phase signal is obtained by processing the predetermined angle and the first ratio obtained from the first and second terms using the arctangent function. Since the tangent function tan is continuous in the range of -π / 2 to π / 2, processing the predetermined angle and the first ratio obtained from the first and second terms using the arctangent function results in a continuous phase signal, thus enabling wide dynamic range detection of the phase signal. Subsequent linear transformation of the phase signal yields the magnitude of the signal to be measured, achieving wide dynamic range detection of the signal to be measured. Attached Figure Description

[0016] The above and other objects, features and advantages of the present invention will become clearer from the following description of embodiments of the invention with reference to the accompanying drawings.

[0017] Figure 1 A schematic diagram of a phase sensing system based on weak measurement according to an embodiment of the present invention is shown.

[0018] Figure 2 A schematic diagram of a phase sensing system based on weak measurement according to another embodiment of the present invention is shown.

[0019] Figure 3 A flowchart of a phase sensing method based on weak measurement according to an embodiment of the present invention is shown. Detailed Implementation

[0020] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the invention. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the invention for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0021] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0022] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0023] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0024] Since the experimental observation of the spin Hall effect of photons using the weak measurement method, this method has gained widespread attention in the field of quantum sensing due to its ability to amplify signals. Researchers have successively achieved the sensing and measurement of physical quantities such as optical time delay, optical phase, sound field, temperature, and magnetic field. In these applications, the underlying technical principle can essentially be reduced to phase estimation methods based on weak measurement theory. Applying phase estimation methods based on weak measurement theory to practical scenarios requires considering two aspects: the frequency of the detected signal and the amplitude of the detected signal.

[0025] To address this issue, related technologies have proposed two weak measurement adaptive estimation systems: one based on light intensity detection and the other covering the entire phase range. The light intensity detection-based system, by introducing a reference phase, can estimate time-varying parameters with adjustable sensitivity and dynamic range. However, its effective range remains limited, failing to achieve real-time phase estimation over a wide dynamic range. The full-phase-range system employs an adaptive strategy to achieve real-time phase estimation over a wide dynamic range, recovering the detected signal from this phase. However, in practical applications, the control equipment and precision required for the adaptive strategy are limited by the scenario, hindering the full realization of its wide dynamic range effectiveness.

[0026] In view of this, the present invention provides a phase sensing system and method based on weak measurement, which can be applied to the field of quantum sensing.

[0027] Figure 1 A schematic diagram of a phase sensing system based on weak measurement according to an embodiment of the present invention is shown.

[0028] According to an embodiment of the present invention, before implementing the phase sensing method based on weak measurement, it is necessary to first build a phase sensing system based on weak measurement with a wide dynamic range.

[0029] like Figure 1 As shown, the phase sensing system based on weak measurement may include a phase sensing module 101, four post-selection modules 102, a detection module 103, and a processing module 104.

[0030] The phase sensing module 101 can be used to perform phase modulation on the pre-selected incident light according to the signal to be measured when the pre-selected incident light passes through the phase sensing module 101, so as to obtain the detection light.

[0031] The four post-selection modules 102 can be used to perform post-selection on the first, second, third, and fourth portions of light obtained from the detection light, respectively, to obtain a first post-selected light, a second post-selected light, a third post-selected light, and a fourth post-selected light. The angles between the post-selected state corresponding to the first portion of light, the post-selected state corresponding to the second portion of light, the post-selected state corresponding to the third portion of light, and the post-selected state corresponding to the fourth portion of light and a predetermined direction are ε, -ε, π-ε, and π+ε, respectively. The angle between the predetermined direction and the pre-selected state corresponding to the incident light after pre-selection is π / 2, where ε is the predetermined angle.

[0032] According to an embodiment of the present invention, in order to make the angles between the post-selection state corresponding to the first part of the light, the post-selection state corresponding to the second part of the light, the post-selection state corresponding to the third part of the light, and the post-selection state corresponding to the fourth part of the light and the predetermined direction respectively ε, -ε, π-ε, and π+ε, each post-selection module 102 may include at least one waveplate and a polarizer, and the azimuth angles of the transmission axes of the four polarizers may be predetermined angles ε, -ε, 90°+ε, and 90°-ε respectively.

[0033] It should be noted that using waveplates and polarizers to make the angles between the post-selection states corresponding to the first portion of light, the second portion of light, the third portion of light, and the fourth portion of light and the predetermined direction ε, -ε, π-ε, and π+ε, respectively, is merely an example. Any device structure that makes the angles between the post-selection states corresponding to the first portion of light, the second portion of light, the third portion of light, and the fourth portion of light and the predetermined direction ε, -ε, π-ε, and π+ε, respectively, can be used in the post-selection module of this invention, and is not limited thereto.

[0034] According to an embodiment of the present invention, the first portion of light, the second portion of light, the third portion of light, and the fourth portion of light each account for 1 / 4 of the detection light. The predetermined angle can be the post-selection angle.

[0035] According to an embodiment of the present invention, the predetermined angle ε is greater than 0 rad and much less than 1 rad.

[0036] For example, the azimuth angle of the transmission axis of the polarizer included in the post-selection module corresponding to the first post-selection light can be a predetermined angle ε, the azimuth angle of the transmission axis of the polarizer included in the post-selection module corresponding to the second post-selection light can be a predetermined angle -ε, the azimuth angle of the transmission axis of the polarizer included in the post-selection module corresponding to the third post-selection light can be 90°+ε, and the azimuth angle of the transmission axis of the polarizer included in the post-selection module corresponding to the fourth post-selection light can be 90°-ε.

[0037] For example, the first portion of light can sequentially pass through at least one waveplate and a polarizer, enabling the post-selection module 102 to perform post-selection on the first portion of light, resulting in the first post-selected light. Similarly, the post-selection process for the corresponding portion of light by the corresponding post-selection module can be obtained, which will not be elaborated here. The first, second, third, and fourth portions of light correspond one-to-one with the first, second, third, and fourth post-selected lights.

[0038] The detection module 103 can be used to detect the first post-selected light, the second post-selected light, the third post-selected light and the fourth post-selected light respectively, and obtain the first light intensity, the second light intensity, the third light intensity and the fourth light intensity.

[0039] According to an embodiment of the present invention, the first post-selected light, the second post-selected light, the third post-selected light, and the fourth post-selected light correspond one-to-one with the first light intensity, the second light intensity, the third light intensity, and the fourth light intensity.

[0040] The processing module 104 can be used to calculate a first term based on the first light intensity and the fourth light intensity and / or the second light intensity and the third light intensity; calculate a second term based on the first light intensity and the second light intensity and / or the third light intensity and the fourth light intensity; process a predetermined angle and a first ratio obtained from the first term and the second term using an arctangent function to obtain a phase signal; and perform a linear transformation on the phase signal to obtain the magnitude of the signal to be measured.

[0041] According to an embodiment of the present invention, since the tangent function tan is continuous in the range of -π / 2 to π / 2, the arctangent function is processed with a predetermined angle and a first ratio obtained from the first and second terms to obtain continuous phase signal data. Therefore, the scheme implemented by the present invention can achieve wide dynamic range detection of the phase signal. Specifically, in the phase signal... satisfy Under the condition of rad, the solution implemented by this invention has an approximately linear linear interval. Here, t represents time.

[0042] According to an embodiment of the present invention, by using four post-selection modules to perform post-selection on the first part of the light, the second part of the light, the third part of the light, and the fourth part of the light obtained from the detection light, respectively, a first post-selected light, a second post-selected light, a third post-selected light, and a fourth post-selected light are obtained. The angles between the post-selected state corresponding to the first part of the light, the post-selected state corresponding to the second part of the light, the post-selected state corresponding to the third part of the light, and the post-selected state corresponding to the fourth part of the light and a predetermined direction are ε, -ε, π-ε, and π+ε, respectively. The angle between the predetermined direction and the pre-selected state corresponding to the incident light after pre-selection is π / 2. Then, the first light intensity corresponding to each of the four parts of the light is obtained using a detection module. After obtaining the second, third, and fourth light intensities, the processing module calculates the first term based on the first and fourth light intensities and / or the second and third light intensities; it then calculates the second term based on the same ratio. The phase signal is obtained by processing the predetermined angle and the first ratio obtained from the first and second terms using the arctangent function. Since the tangent function tan is continuous in the range of -π / 2 to π / 2, the resulting phase signal is continuous. Therefore, wide dynamic range detection of the phase signal can be achieved without the need for an adaptive strategy. Subsequent linear transformation of the phase signal yields the magnitude of the signal under test, enabling wide dynamic range detection of the signal under test.

[0043] The following will be Figure 1 Based on the phase sensing system based on weak measurement shown, the system utilizes... Figure 2 The phase sensing system based on weak measurement according to the embodiments of the present invention will be further explained.

[0044] Figure 2 A schematic diagram of a phase sensing system based on weak measurement according to another embodiment of the present invention is shown.

[0045] like Figure 2 As shown, the phase sensing system based on weak measurement may include a phase sensing module 101, four post-selection modules 102, a detection module, a processing module 104, a pre-selection module 105, a beam splitter module, and a light source 107. The beam splitter module includes a first semi-transparent mirror 1061, a second semi-transparent mirror 1062, and a third semi-transparent mirror 1063. The detection module includes a first detector 1031, a second detector 1032, a third detector 1033, and a fourth detector 1034.

[0046] Light source 107 is used to generate and emit incident light.

[0047] The type of light source 107 can be selected according to the actual situation and is not limited here. For example, the light source 107 can be a laser, and the incident light emitted by the laser can be single-frequency light.

[0048] The pre-selection module 105 can be used to pre-select the incident light to obtain the pre-selected incident light.

[0049] For example, in the pre-selection process, the single-frequency light emitted by the laser can be modulated into a pre-selection state. , These are the horizontal polarization state and the vertical polarization state, respectively. Among them, the pre-selection state... This is the preselected state corresponding to the preselected incident light.

[0050] According to an embodiment of the present invention, the phase sensing process is the process by which the phase sensing module 101 modulates the phase of the pre-selected incident light according to the signal to be measured. During the phase sensing process, the phase signal... The interaction strength, as a weak measure, can be represented by a unitary transformation. It means that among them It is a polarization Stokes operator. It is the imaginary unit. It is an exponential function, where t is time. The polarization state after phase sensing can be written as... .

[0051] The phase sensing module 101 may include at least one of the following: a waveplate, a liquid crystal display, and an optical fiber.

[0052] According to an embodiment of the present invention, the phase sensing module 101 may be composed of units capable of generating birefringent phase, such as waveplates, liquid crystal panels, and optical fibers. The phase sensing module 101 may include at least one of waveplates, liquid crystal panels, and optical fibers, but the present invention is not limited thereto; any unit capable of generating birefringent phase may be used in the phase sensing module of the present invention.

[0053] According to embodiments of the present invention, when the phase sensing module 101 includes a waveplate, it can sense a test signal in the form of light. When the phase sensing module 101 includes a liquid crystal panel, it can sense test signals in the form of temperature and electricity. When the phase sensing module 101 includes an optical fiber, it can sense test signals in the form of vibration and sound.

[0054] When the phase sensing module 101 includes a waveplate, a liquid crystal display, and an optical fiber, the phase sensing module 101 can be used to sense the signal to be measured in the form of light, temperature, electrical vibration, and sound.

[0055] According to an embodiment of the present invention, the beam splitting module can be used to divide the detection light into four parts to obtain a first part of light, a second part of light, a third part of light, and a fourth part of light.

[0056] For example, the first semi-transparent and semi-reflective mirror 1061 can partially reflect the detection light to obtain reflected light and transmitted light. The second semi-transparent and semi-reflective mirror 1062 can partially reflect the transmitted light to obtain a first part of the light and a second part of the light. The third semi-transparent and semi-reflective mirror 1063 can partially reflect the reflected light to obtain a third part of the light and a fourth part of the light.

[0057] According to an embodiment of the present invention, the detection light after phase sensing is divided into four equal parts, and the four parts of light are projected onto four preset post-selection states during the post-selection process.

[0058] According to an embodiment of the present invention, the pre-selected state and the post-selected states corresponding to the first, second, third, and fourth portions of light can all be represented on the equatorial plane of a Bloch sphere (i.e., the unit sphere for visualizing single-qubit quantum states). The pre-selected state is located on the positive x-axis, and the four post-selected states are nearly perpendicular to the pre-selected state. The angle between the post-selected state corresponding to the first portion of light and a predetermined direction (i.e., the direction indicated by the positive y-axis) is the post-selection angle, and the angle between the predetermined direction and the pre-selected state can be π / 2. The angles between the post-selected states corresponding to the first, second, third, and fourth portions of light and the positive y-axis are ε, -ε, π-ε, and π+ε, respectively.

[0059] Therefore, the angle between the post-selected state corresponding to the first part of the light and the post-selected state corresponding to the second part of the light is 2ε, and the angle between the post-selected state corresponding to the third part of the light and the post-selected state corresponding to the fourth part of the light is 2ε. The angle between the post-selected state corresponding to the first part of the light and the post-selected state corresponding to the third part of the light is π-2ε, and the angle between the post-selected state corresponding to the second part of the light and the post-selected state corresponding to the fourth part of the light is π. According to the orthogonal state relationship defined in the Bloch sphere, the post-selected state corresponding to the first part of the light and the post-selected state corresponding to the fourth part of the light are perpendicular. The angle between the post-selected state corresponding to the second part of the light and the post-selected state corresponding to the third part of the light is π. According to the orthogonal state relationship defined in the Bloch sphere, the post-selected state corresponding to the first part of the light and the post-selected state corresponding to the fourth part of the light are perpendicular.

[0060] The post-selection state corresponding to the first part of the light can be represented as: The post-selected state corresponding to the second part of the light can be represented as The post-selected state corresponding to the third part of the light can be represented as The post-selection state corresponding to the fourth part of the light can be represented as .

[0061] For example, each post-selection module 102 may include a first quarter-wave plate and a polarizer, wherein the azimuth angle of the fast axis of the first quarter-wave plate is 45°.

[0062] According to an embodiment of the present invention, each post-selection module 102 includes a first quarter-wave plate and a polarizer, wherein the azimuth angle of the fast axis of the first quarter-wave plate is 45°, and the azimuth angles of the transmission axes of the four polarizers are predetermined angles ε, -ε, 90°+ε, and 90°-ε, respectively, such that after the first part of light, the second part of light, the third part of light, and the fourth part of light pass through the four post-selection modules 102, the post-selection states corresponding to the first part of light, the second part of light, the third part of light, and the fourth part of light can be respectively... , , and This is so that subsequent wide dynamic range phase demodulation can be performed.

[0063] For example, each post-selection module 102 may sequentially include: a second quarter-wave plate, a half-wave plate, a third quarter-wave plate, a fourth quarter-wave plate, and a polarizer. The azimuth angles of the fast axis of the second quarter-wave plate, the half-wave plate, and the third quarter-wave plate are equal, while the azimuth angle of the fast axis of the fourth quarter-wave plate is 45°.

[0064] According to an embodiment of the present invention, the first quarter-wave plate, the second quarter-wave plate, the third quarter-wave plate, and the fourth quarter-wave plate are all ordinary quarter-wave plates.

[0065] According to an embodiment of the present invention, each post-selection module includes: a second quarter-wave plate, a half-wave plate, a third quarter-wave plate, a fourth quarter-wave plate, and polarizers. The azimuth angles of the fast axis of the second quarter-wave plate, the half-wave plate, and the third quarter-wave plate are equal, the azimuth angle of the fast axis of the fourth quarter-wave plate is 45°, and the azimuth angles of the transmission axes of the four polarizers are predetermined angles ε, -ε, 90°+ε, and 90°-ε, respectively. This ensures that after the first part of the light, the second part of the light, the third part of the light, and the fourth part of the light pass through the four post-selection modules 102, the post-selection states corresponding to the first part of the light, the second part of the light, the third part of the light, and the fourth part of the light can be respectively... , , and This is so that subsequent wide dynamic range phase demodulation can be performed.

[0066] The first detector 1031 can be used to detect the first post-selected light to obtain the first light intensity. The second detector 1032 can be used to detect the second post-selected light to obtain the second light intensity. The third detector 1033 can be used to detect the third post-selected light to obtain the third light intensity. The fourth detector 1034 can be used to detect the fourth post-selected light to obtain the fourth light intensity.

[0067] According to an embodiment of the present invention, in light intensity detection, the light intensity of the quantum state projected onto the four-way selected state is detected, and the detection result can be expressed as follows: .in, This indicates that the post-selection operation corresponding to the j-th part of the light projects the evolved state of the system. In mathematics, it equals The conjugate transpose of . This is the number of the post-selection state corresponding to the j-th part of the light. =1,2,3,4 The initial light intensity is the single-frequency light.

[0068] According to an embodiment of the present invention, the processing module 104 can process the detected light intensity value and recover the phase signal corresponding to the signal to be measured based on the processed data.

[0069] According to an embodiment of the present invention, the processing module 104 may calculate the first item based on the first light intensity and the fourth light intensity and / or the second light intensity and the third light intensity, including: obtaining the first item based on the first difference between the first light intensity and the fourth light intensity; or obtaining the first item based on the second difference between the second light intensity and the third light intensity; or obtaining the first item based on the average value calculated based on the first difference and the second difference.

[0070] For example, the first term can be obtained according to formula (1). .

[0071] (1);

[0072] in, , , and The light intensities at time t are the first, second, third, and fourth light intensities, respectively.

[0073] According to an embodiment of the present invention, the processing module 104 may calculate the second term based on the first light intensity and the second light intensity and / or the third light intensity and the fourth light intensity, including: obtaining the second term based on the third difference between the first light intensity and the second light intensity; or, obtaining the second term based on the fourth difference between the third light intensity and the fourth light intensity; or, obtaining the second term based on the average value calculated based on the third difference and the fourth difference.

[0074] For example, the second term can be obtained according to formula (2). .

[0075] (2).

[0076] For example, the first ratio can be obtained from the first term and the second term according to formula (3).

[0077] (3);

[0078] in, This is the first ratio at time t.

[0079] According to formula (3), right High-sensitivity extraction was achieved, with an amplification factor of [value missing]. .

[0080] According to an embodiment of the present invention, for Further processing yields the phase signal.

[0081] According to an embodiment of the present invention, the processing module 104 processes a predetermined angle and a first ratio obtained from the first term and the second term using an arctangent function to obtain a phase signal, which may include: processing the predetermined angle using a cotangent function to obtain an amplification factor; and processing a second ratio obtained from the amplification factor and the first ratio using an arctangent function to obtain a phase signal.

[0082] For example, the phase signal can be obtained according to formula (4). This is the second ratio.

[0083] (4).

[0084] According to an embodiment of the present invention, since the tangent function tan is continuous in the range of -π / 2 to π / 2, the arctangent function processes the predetermined angle and the first ratio obtained according to the first term and the second term to obtain continuous phase signal data. Thus, the scheme implemented by the present invention can realize the detection of a wide dynamic range of phase signal.

[0085] According to an embodiment of the present invention, the processing module 104 can also be used to: obtain the phase signal based on a third ratio obtained based on a first ratio and a predetermined angle when the phase signal is greater than 0 rad and less than 0.1 rad.

[0086] According to an embodiment of the present invention, when the phase signal is greater than 0 rad and less than 0.1 rad, satisfy rad. In phase signal satisfy Under the condition of rad, the scheme implemented by the present invention has an approximately linear linear interval. At this time, the phase signal can be calculated according to formula (5). Where t represents time, This indicates the third ratio.

[0087] (5).

[0088] According to an embodiment of the present invention, the weak measurement-based phase sensing method corresponding to the weak measurement-based phase sensing system can be divided into three steps. Step 1: Construct a wide dynamic range quantum weak measurement-based phase sensing system. Step 2: Introduce the phase signal into the wide dynamic range quantum weak measurement-based phase sensing system. Step 3: Process the detected light intensity value to recover the phase signal to be measured.

[0089] The phase sensing system and method based on weak measurement provided in this invention can achieve real-time phase estimation with high sensitivity and wide dynamic range without the need for an adaptive strategy, further expanding the application prospects of quantum weak measurement technology.

[0090] Based on the aforementioned phase sensing system based on weak measurement, embodiments of the present invention also provide a phase sensing method based on weak measurement.

[0091] Figure 3 A flowchart of a phase sensing method based on weak measurement according to an embodiment of the present invention is shown.

[0092] Figure 3 The phase sensing method based on weak measurement shown can be applied to... Figure 1 and Figure 2 The phase sensing system shown is based on weak measurement.

[0093] like Figure 3 As shown, the phase sensing method based on weak measurement may include operations S301 to S304.

[0094] In operation S301, the phase of the previously selected incident light is modulated according to the signal to be measured to obtain the detection light.

[0095] In operation S302, the four post-selection modules perform post-selection on the first, second, third, and fourth portions of light obtained from the detection light, respectively, to obtain the first post-selected light, the second post-selected light, the third post-selected light, and the fourth post-selected light. The angles between the post-selected state corresponding to the first portion of light, the second portion of light, the third portion of light, and the fourth portion of light and the predetermined direction are ε, -ε, π-ε, and π+ε, respectively. The angle between the predetermined direction and the pre-selected state corresponding to the incident light after pre-selection is π / 2, where ε is the predetermined angle.

[0096] In operation S303, the detection module detects the first, second, third, and fourth post-selected light beams respectively, and obtains the first light intensity, second light intensity, third light intensity, and fourth light intensity.

[0097] In operation S304, the processing module calculates the first term based on the first light intensity and the fourth light intensity and / or the second light intensity and the third light intensity; calculates the second term based on the first light intensity and the second light intensity and / or the third light intensity and the fourth light intensity; processes the predetermined angle and the first ratio obtained from the first term and the second term using the arctangent function to obtain the phase signal; and performs a linear transformation on the phase signal to obtain the magnitude of the signal to be measured.

[0098] It should be noted that the phase sensing method based on weak measurement in the embodiments of the present invention corresponds to the phase sensing system based on weak measurement in the embodiments of the present invention. For a detailed description of the phase sensing method based on weak measurement, please refer to the phase sensing system based on weak measurement, which will not be repeated here.

[0099] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions. Those skilled in the art will understand that the features described in the various embodiments of the present invention can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in the present invention. In particular, the features described in the various embodiments of the present invention can be combined and / or combined in various ways without departing from the spirit and teachings of the present invention. All such combinations and / or pairings fall within the scope of this invention.

[0100] The embodiments of the present invention have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of the invention. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of the invention is defined by the appended embodiments and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of the invention, and all such substitutions and modifications should fall within the scope of the invention.

Claims

1. A phase sensing system based on weak measurement, characterized in that, include: The phase sensing module is used to perform phase modulation on the pre-selected incident light according to the signal to be measured to obtain the detection light; Four post-selection modules are used to perform post-selection on the first part of the light, the second part of the light, the third part of the light, and the fourth part of the light obtained from the detection light, respectively, to obtain the first post-selected light, the second post-selected light, the third post-selected light, and the fourth post-selected light. The angles between the post-selected state corresponding to the first part of the light, the post-selected state corresponding to the second part of the light, the post-selected state corresponding to the third part of the light, and the post-selected state corresponding to the fourth part of the light and the predetermined direction are ε, -ε, π-ε, and π+ε, respectively. The angle between the predetermined direction and the pre-selected state corresponding to the incident light after the pre-selection is π / 2, and ε is the predetermined angle. The detection module is used to detect the first post-selected light, the second post-selected light, the third post-selected light, and the fourth post-selected light respectively, and obtain the first light intensity, the second light intensity, the third light intensity, and the fourth light intensity. The processing module is used to calculate a first term based on the first light intensity and the fourth light intensity and / or the second light intensity and the third light intensity; calculate a second term based on the first light intensity and the second light intensity and / or the third light intensity and the fourth light intensity; process a predetermined angle and a first ratio obtained from the first term and the second term using an arctangent function to obtain a phase signal; and perform a linear transformation on the phase signal to obtain the magnitude of the signal to be measured.

2. The phase sensing system according to claim 1, characterized in that, Each post-selection module includes: a first quarter-wave plate and polarizers, wherein the azimuth angle of the fast axis of the first quarter-wave plate is 45°, and the azimuth angles of the transmission axes of the four polarizers are ε, -ε, 90°+ε and 90°-ε, respectively.

3. The phase sensing system according to claim 1, characterized in that, Each post-selection module includes: a second quarter-wave plate, a half-wave plate, a third quarter-wave plate, a fourth quarter-wave plate, and polarizers. The azimuth angles of the fast axis of the second quarter-wave plate, the fast axis of the half-wave plate, and the fast axis of the third quarter-wave plate are equal. The azimuth angle of the fast axis of the fourth quarter-wave plate is 45°. The azimuth angles of the transmission axes of the four polarizers are ε, -ε, 90°+ε, and 90°-ε, respectively.

4. The phase sensing system according to any one of claims 1 to 3, characterized in that, The processing module uses the arctangent function to process the predetermined angle and the first ratio obtained from the first and second terms to obtain the phase signal, which includes: The predetermined angle is processed using the cotangent function to obtain the magnification factor; The phase signal is obtained by processing the second ratio obtained from the amplification factor and the first ratio using the arctangent function.

5. The phase sensing system according to any one of claims 1 to 3, characterized in that, The processing module is also used for: When the phase signal is greater than 0 rad and less than 0.1 rad, the phase signal is obtained according to a third ratio based on the first ratio and the predetermined angle.

6. The phase sensing system according to any one of claims 1 to 3, characterized in that, The processing module calculates the first item based on the first light intensity and the fourth light intensity and / or the second light intensity and the third light intensity, including: The first item is obtained based on the first difference between the first light intensity and the fourth light intensity; Alternatively, the first item can be obtained based on the second difference between the second light intensity and the third light intensity; Alternatively, the first item can be obtained based on the average value calculated from the first difference and the second difference.

7. The phase sensing system according to any one of claims 1 to 3, characterized in that, The processing module calculates the second item based on the first light intensity and the second light intensity and / or the third light intensity and the fourth light intensity, including: The second item is obtained based on the third difference between the first light intensity and the second light intensity; Alternatively, the second item can be obtained based on the fourth difference between the third light intensity and the fourth light intensity; Alternatively, the second item can be obtained based on the average value calculated from the third difference and the fourth difference.

8. The phase sensing system according to any one of claims 1 to 3, characterized in that, The phase sensing module includes at least one of the following: a waveplate, a liquid crystal display, and an optical fiber.

9. The phase sensing system according to any one of claims 1 to 3, characterized in that, Also includes: The beam splitting module is used to divide the detection light into four parts to obtain the first part of light, the second part of light, the third part of light, and the fourth part of light; The detection module includes: a first detector, a second detector, a third detector, and a fourth detector; The first detector is used to detect the first post-selected light to obtain the first light intensity; The second detector is used to detect the second post-selected light to obtain the second light intensity; The third detector is used to detect the third post-selective light to obtain the third light intensity; The fourth detector is used to detect the fourth post-selective light to obtain the fourth light intensity.

10. A phase sensing method based on weak measurement, characterized in that, The phase sensing method, applicable to any one of claims 1 to 9 based on weak measurement, comprises: The phase sensing module modulates the phase of the pre-selected incident light according to the signal to be measured to obtain the detection light. Four post-selection modules perform post-selection on the first, second, third, and fourth portions of light obtained from the detection light, respectively, to obtain the first post-selected light, the second post-selected light, the third post-selected light, and the fourth post-selected light. The angles between the post-selected state corresponding to the first portion of light, the post-selected state corresponding to the second portion of light, the post-selected state corresponding to the third portion of light, and the post-selected state corresponding to the fourth portion of light and the predetermined direction are ε, -ε, π-ε, and π+ε, respectively. The angle between the predetermined direction and the pre-selected state corresponding to the incident light after pre-selection is π / 2, where ε is the predetermined angle. The detection module detects the first post-selected light, the second post-selected light, the third post-selected light, and the fourth post-selected light respectively, and obtains the first light intensity, the second light intensity, the third light intensity, and the fourth light intensity. The processing module calculates the first term based on the first light intensity and the fourth light intensity and / or the second light intensity and the third light intensity; calculates the second term based on the first light intensity and the second light intensity and / or the third light intensity and the fourth light intensity; processes the predetermined angle and the first ratio obtained from the first term and the second term using the arctangent function to obtain the phase signal; and performs a linear transformation on the phase signal to obtain the magnitude of the signal to be measured.

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