Chiral molecule weak measurement device based on quantum entanglement light source

Abstract

The invention belongs to the technical field of biological chiral molecule detection, and discloses a quantum entanglement light source-based chiral molecule weak measurement device, which comprises a quantum entanglement light source light path for emitting a long-wave laser beam with a specific frequency and entanglement photon pairs; the polarization beam splitter is used for splitting the laser beam and splitting an entangled photon pair into two beams; the measuring light path is used for modulating one path of incident entangled photon pair to generate a pre-selection state, changing the spinning amount, modulating to generate a post-selection state and detecting the light intensity of a light spot in sequence; the entangled light source calibration light path is used for detecting the light intensity of the other light spot; the time-to-digital converter is connected with the measuring light path and the entangled light source calibration light path, outputs electric pulse signals according to received photons, completes counting according to the number of pulses, outputs results, detects light intensity according to the number of photons at upper and lower light spots, calculates optical rotation signals through the light intensity difference of the upper and lower light spots, and calculates the optical rotation of chiral molecules according to the optical rotation signals. The device and the method have the advantages of sample lossless, non-contact, repeatable and high-precision measurement.

Description

Technical Field

[0001] The present invention belongs to the technical field of biological chiral molecule detection, and relates to a chiral molecule weak measurement device based on a quantum entangled light source. Background Art

[0002] Chiral molecules are molecules with configurations whose mirror images are not identical and cannot overlap. Different types of chiral molecules perform distinct functions in organisms, making the identification of chiral molecules and the determination of chemical reaction parameters of great application value. Traditional chiral molecule identification methods (such as paper chromatography, ninhydrin, and isoelectric point methods) suffer from sample damage and low polarimeter measurement accuracy. Alternative methods (such as ultraviolet spectrophotometry and surface plasmon resonance) are costly or difficult to achieve high efficiency. In contrast, quantum weak measurement methods offer the advantages of higher precision, lower cost, and efficient real-time measurement. Combining the optical spin Hall effect and quantum entanglement technology, this method uses the optical rotation angle caused by the deflection of light in a solution of the chiral molecule to be measured as the measured quantity. Through a near-orthogonal polarization selective device, the measured quantity is weakly coupled to the measurement system, the measured quantity is amplified, and the lateral displacement of the light spot is measured to detect the spin chirality, type, and concentration of the chiral molecule. Quantum weak measurement methods offer lower cost while maintaining the same accuracy and enable real-time and efficient measurement.

[0003] The weak measurement method has the characteristics of high measurement sensitivity. According to the existing work (He Yonghong, Xu Yang, Shi Lixuan, Zhou Chongqi. A frequency domain quantum weak measurement biomolecule sensor and its measurement method [P]. Chinese patent: CN113758877A, 2021.12.07), the existing sensor can reach 10 -6 However, using a spectrometer to measure the central wavelength of different samples as a contrast indicator has certain limitations, because the resolution of the spectrometer is limited, and factors such as environmental disturbances and laser instability may cause spectrum measurement errors.

[0004] Therefore, methods based on optical weak measurement effects need to be further improved, including the introduction of new contrast indicators and the use of detection devices with higher resolution. Summary of the Invention

[0005] (1) Purpose of the invention

[0006] The purpose of the present invention is to provide a chiral molecular quantum weak measurement device based on a quantum entangled light source to reduce measurement errors.

[0007] (2) Technical solution

[0008] In order to solve the above technical problems, the present invention provides a chiral molecule weak measurement device based on a quantum entangled light source, including a quantum entangled light source optical path 6, a polarization beam splitter 8, a measurement optical path, an entangled light source calibration optical path and a time-to-digital converter 17; the quantum entangled light source optical path 6 emits a long-wave laser beam of a specific frequency containing entangled photon pairs; the polarization beam splitter 8 splits the laser beam emitted by the quantum entangled light source optical path 6, dividing the entangled photon pairs into two beams; the measurement optical path sequentially modulates one incident entangled photon pair to produce a pre-selected state, changes the spin amount, modulates to produce a post-selected state and detects the intensity of the light spot; the entangled light source calibration optical path is used to detect the intensity of the other light spot; the time-to-digital converter is connected to the measurement optical path and the entangled light source calibration optical path, outputs an electrical pulse signal according to the received photons, completes counting and outputs the result according to the number of pulses, detects the light intensity according to the number of photons at the upper and lower light spots, calculates the optical rotation signal through the light intensity difference between the upper and lower light spots, and calculates the optical rotation of the chiral molecule based on this.

[0009] Furthermore, the quantum entangled light source optical path 6 includes a laser 1, a half-wave plate 2, a two-color polarization beam splitter 3, a first confocal lens 41, a PPKTP crystal 5, a second confocal lens 42, and a long-wave pass filter 7 arranged in sequence along the optical path; the laser 1 is a pump laser, used to provide a high-energy narrow-band laser light source; the half-wave plate 2 is used to adjust the light intensity of the narrow-band laser light source; the two-color polarization beam splitter 3 is used to ensure that the output laser maintains stable polarization characteristics; the first confocal lens 41 is used to focus the light beam; the PPKTP crystal 5 is used to generate entangled photon pairs; the second confocal lens 42 is used to focus the light beam again and adjust the beam shape; the long-wave pass filter 7 allows a long-wave light source of a specific frequency to pass through, thereby improving the purity and stability of the entangled photon pairs.

[0010] Wherein, the PPKTP crystal 5 is a periodically poled potassium titanyl phosphate crystal.

[0011] Furthermore, the polarization beam splitter 8 is arranged on the light-emitting side of the long-wave pass filter 7 .

[0012] Furthermore, the measuring optical path includes a first collimator and a matching optical fiber 91, a third confocal lens 101, a first Glan laser polarizer 11, a cuvette 12 containing a solution of the chiral molecule to be measured, a prism 13 coated with a Ce:YIG magneto-optical film, a fourth confocal lens 102, a second Glan laser polarizer 14, and a first single-photon detector 15, which are arranged in sequence along the optical path direction; the first collimator and the matching optical fiber 91 are arranged on the reflective side of the polarization beam splitter 8 to transmit entangled photon pairs and reduce optical fiber loss; the third confocal lens 101 is used to focus the light beam; the first Glan laser polarizer 11 is used to modulate the incident entangled photon pairs to generate a pre-selected state, and vertically incident on the cuvette containing the chiral molecule to be measured. The cuvette 12 is filled with a solution of a chiral molecule to be measured; the cuvette 12 containing the solution of the chiral molecule to be measured uses the optical rotation of the chiral molecule solution to cause a change in the spin amount of the incident entangled photon pair; the prism 13 coated with a Ce:YIG magneto-optical film introduces the optical spin Hall effect to adjust the direction of the light path; the fourth confocal lens 102 focuses the light beam again; the second Glan laser polarizer 14 modulates the incident entangled photon pair to generate a post-selected state, and outputs the light source to the first single-photon detector 15 for analysis; the first single-photon detector 15 introduces the post-selected light beam into the receiving window of the single-photon counter, and the single-photon counter outputs an electrical pulse signal according to the number of photons received per unit time, and detects the light intensity through the electrical pulse signal per unit time.

[0013] Wherein, the Ce:YIG is cerium-doped yttrium iron garnet.

[0014] Furthermore, the entangled light source calibration optical path includes a second collimator and a matching optical fiber 92, and a second single-photon detector 16; the second collimator and the matching optical fiber 92 are arranged on the light-transmitting side of the polarization beam splitter 8, and are used to transmit entangled photon pairs to reduce optical fiber loss; the second single-photon detector 16 detects the light intensity of the light spot transmitted by the second collimator and the matching optical fiber 92.

[0015] Furthermore, the weak measurement process of chiral molecules is as follows: the chiral molecule solution to be measured is mixed with an optically inactive solvent, and solutions of the chiral molecule to be measured are prepared with different concentrations. They are dissolved by ultrasonic oscillation to obtain chiral molecule solutions of different concentrations, and then added to a cuvette and allowed to stand for three minutes. Next, the laser is turned on, and a light shield is used to block the two light spots that are finally received. The single-photon detector serves as the receiving end to record the light intensity, and the time-to-digital converter is used to convert the number of received photons into a pulse signal, and the counting is completed and the result is output based on the number of pulses. Using the light intensity difference between the two light spots, a contrast index is established to detect the optical rotation. Based on the optical rotation and the concentration of the solution, the specific optical rotation is calculated, and the type of chiral molecule to be measured is determined by looking up the corresponding biological parameter table.

[0016] Furthermore, before weak measurements of chiral molecules, the entangled light source calibration optical path is calibrated. The calibration process is as follows: in the dark state before turning on the laser, the single-photon detector is turned on and zeroed. The laser is turned on, and after the output laser stabilizes, the single-photon detector in the entangled light source calibration optical path detects the intensity difference between the upper and lower light spots. The polarization beam splitter is modulated to zero the intensity difference. Because the detection of one photon of an entangled photon pair instantly determines the state of the other entangled photon, this correlation completes the calibration of the measurement optical path.

[0017] When performing weak measurements of chiral molecules, the measuring device needs to be adjusted. The adjustment steps are as follows:

[0018] The first step is to adjust the optical path.

[0019] The laser satisfies the Gaussian distribution, and at the same time ensures the collimation of the light beam and keeps the light beam in a horizontal normal state; the optical axis of the half-wave plate ensures a small angle with the laser output light (the specific angle depends on the laser power), the half-wave plate bracket is close to the guide rail, and the bracket axis is adjusted to make the horizontal plane of the half-wave plate perpendicular to the propagation direction of the light beam; the optical axis of the first Glan laser polarizer is kept horizontal, the bracket is close to the guide rail, the 0 scale of the Glan laser polarizer turntable is aligned with the calibration line of the Glan laser polarizer mirror to ensure that the light beam is incident and emitted from the center of the Glan laser polarizer mirror; the cuvette bracket is close to the guide rail to ensure that the light beam passes through the middle position of the cuvette, and the horizontal plane of the cuvette is perpendicular to the propagation direction of the light beam; adjust the relative position of the Ce:YIG magneto-optical film medium and the prism, and at the same time It is placed on the vertical center axis of the high-precision rotating translation stage, and is kept at the center of the light beam when the Ce:YIG magneto-optical film medium rotates with the turntable; the angle of the prism is adjusted to near the Brewster angle through the high-precision rotating translation stage, and the angle is fixed; the lens bracket is close to the guide rail, the light beam passes through the center of the lens, and the lens plane is perpendicular to the propagation direction of the light beam; the optical axis of the second Glan laser polarizer is kept orthogonal to the optical axis of the first Glan laser polarizer, the bracket is close to the guide rail, and the 0 scale of the Glan laser polarizer turntable is aligned with the calibration line of the Glan laser polarizer mirror to ensure that the light beam is incident and emitted from the center of the Glan laser polarizer mirror; the detection interface of the single-photon detector is perpendicular to the propagation direction of the light beam, and the light beam is incident to the center position of the detection interface.

[0020] After completing the optical path adjustment, adjust the measuring device.

[0021] Fix the optical axes of the two Glan laser polarizers in an orthogonal position and record the turntable angle. Use a single-photon detector to detect the signal spot, count the number of pulses and output the result, fine-tune the front and back selection (i.e., the turntable angle of the Glan laser polarizer) until two spot signals appear, that is, light spin splitting occurs; fix other components in the optical path, replace the solution in the cuvette with chiral molecule solutions of different concentrations, read and record the light intensity difference when the spot splits at maximum polarization, repeat the experiment several times, and record the experimental results.

[0022] The first Glan laser polarizer is used to prepare the preselected state |ψ0>, whose optical axis is in the horizontal direction. The incident polarization state can be expressed as

[0023] The light beam passes through a chiral solution in a cuvette, introducing a small phase change α between the left and right circular polarization states.

[0024] At this time, the polarization state of the light beam can be expressed as Here α<<1 and β<<1.

[0025] The light beam is reflected on the surface of a prism coated with Ce:YIG magneto-optical film, and the optical spin Hall effect occurs. According to the relationship between the reflection angle spectrum and the electric field boundary distribution, the polarization state of the light evolves as follows: in, represents the spin evolution of the optical spin Hall effect, represents the change in polarization caused by reflection. represents the spin operator. δ represents the optical spin splitting distance. r p and r s denote the Fresnel reflection coefficients for horizontal and vertical polarization, respectively. The preselected state is prepared by the first Glan laser polarizer, and we can set represents the pre-selected state of the weak measurement system.

[0026] After the reflected beam is focused by the lens, the post-selection state is prepared by the second Glan laser polarizer, and the optical axis is vertical to produce a post-selection state.

[0027] At this time, the entire weak measurement system can be expressed as:

[0028] The shading plate receives two light spot signals, and the single-photon detector detects the light intensities of the two light spots, I1| α，β and I2| α，β , the contrast index is established using the intensity difference between the two spots, which is expressed as:

[0029]

[0030] in, and Represents the light intensity of the upper and lower light spots respectively; I0 represents the light intensity before post-selection; r p and r s represents the Fresnel reflection coefficient of horizontal polarization and vertical polarization respectively; ω is the laser frequency of the laser; δ represents the optical spin splitting distance; I t | α＝0,β＝0 =I1| α＝0,β＝0 +I2| α＝0,β＝0It represents the total intensity of the post-selected beam when there is no phase or amplitude change, which does not change in the subsequent process. The optical rotation α of the chiral molecule solution to be measured is calculated. Then according to the formula of specific optical rotation:

[0031] α=l·c·[α] D

[0032] Where c is the concentration of the chiral molecule solution in the cuvette, and l is the distance the laser passes through the chiral molecule solution in the cuvette. The specific optical rotation [α] of the chiral molecule can be obtained. D , thereby identifying the type of chiral molecule sample to be tested according to the corresponding biological parameter table.

[0033] (3) Beneficial effects

[0034] The chiral molecular quantum weak measurement device based on quantum entangled light source provided by the above technical solution has the following beneficial effects compared with the existing technology:

[0035] (1) The present invention adopts quantum weak measurement technology and utilizes quantum entangled light sources. By designing two optical paths for calibration and utilizing the correlation of entangled photon pairs, the calibration of the calibration optical path is completed, and the measurement optical path is also calibrated at the same time.

[0036] (2) This invention uses a single-photon detector to detect the light intensity difference, establishing a relationship between the intensity difference between the upper and lower light spots split by the optical spin Hall effect and the optical rotation signal. Compared to the commonly used contrast ratio method based on CCD detection of light spot displacement and spectrometer detection of central wavelength shift, the single-photon detector has a higher resolution, thereby improving measurement accuracy.

[0037] (3) The present invention utilizes entangled photon pairs to improve measurement accuracy. Entangled photon pairs provide strong correlation signals, which help distinguish small effects and thus improve measurement accuracy.

[0038] (4) The present invention is a chiral molecule measurement technology based on quantum weak measurement methods. It features non-destructive, non-contact, and repeatable measurement of samples. It is capable of high-precision measurement in the natural state of the sample and real-time monitoring and analysis of chiral molecule concentrations. This technology has important application value in a variety of fields, including biomedicine, life sciences, analytical chemistry, physics, and materials science. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a typical structure of a measurement system for differential linear molecular quantum weak measurement based on a quantum entangled light source as described in the present invention.

[0040] Figure 1In: 1. Laser, 2. Half-wave plate, 3. Two-color polarization beam splitter, 41. First confocal lens, 42. Second confocal lens, 5. PPKTP crystal, 6. Quantum entanglement light source generation device, 7. Long-wave pass filter, 8. Polarization beam splitter, 91. First collimator and supporting optical fiber, 92. Second collimator and supporting optical fiber, 101. Third confocal lens, 102. Fourth confocal lens, 11. First Glan laser polarizer, 12. Cuvette containing the solution of the chiral molecule to be measured, 13. Prism coated with Ce:YIG magneto-optical film, 14. Second Glan laser polarizer, 15. First single-photon detector, 16. Second single-photon detector, 17. Time-to-digital converter.

[0041] Figure 2 This is a relationship diagram between the difference in the number of pulses of two light spots recorded by the time-to-digital converter described in the experimental example of the present invention and the concentration of the sample artemisinin solution. DETAILED DESCRIPTION

[0042] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below with reference to the accompanying drawings and examples.

[0043] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or those recommended by the manufacturer. All reagents or instruments used, if the manufacturer is not specified, are commercially available conventional products.

[0044] Example 1:

[0045] This experimental example uses the drug ingredient artemisinin as an example.

[0046] Build a chiral molecule weak measurement device, such as Figure 1 As shown; prepare artemisinin solutions of different concentrations (the solvent is methanol) and perform system calibration. Fix the phase of the quantum weak meter and record the angle. Use a single-photon detector to detect the spot intensity signal, and process the detection signal through a time-to-digital converter. Fine-tune the front and back selection (i.e., the angle of the Glan laser polarizer) until light spin splitting occurs. Read and record the number of photons of the upper and lower spots at the time of maximum polarization of the light spot splitting. Replace the solution in the cuvette with the artemisinin solution to be tested, use a single-photon detector to detect the spot intensity signal, and process the detection signal of the single-photon detector through a time-to-digital converter. Read and record the number of photons of the upper and lower spots at the time of maximum polarization of the light spot splitting. Repeat the experiment several times and record the experimental results.

[0047] like Figure 2 As shown in the figure, for the pulse number difference corresponding to artemisinin solution (solvent is methanol) with a concentration range of 0 to 0.1 mg / ml, the artemisinin concentration is proportional to the recorded pulse number (the difference between the pulse numbers recorded by the two spots). Figure 2The solid line in the middle is the simulation result, and the small triangle is the experimental measurement value. It can be seen that within the measurement range, a slight change of 0.01 mg / ml in solution concentration can cause a difference in pulse counts of thousands, and the measurement sensitivity can reach 5.09×10 9 couts / rad. At the same time, the light intensity at the detection end is only 10 -11 w level, which largely avoids the influence of light on the sample. The variance of the single photon counter data under multiple groups of different light intensities was recorded, and the measurement accuracy was calculated to be 9.85×10 -8 rad.

[0048] Example 2:

[0049] In this experimental example, D-tryptophan, L-tryptophan, erythromycin, and penicillin samples were tested respectively.

[0050] Build a chiral molecule weak measurement device, such as Figure 1 As shown; configure D-tryptophan, L-tryptophan, erythromycin, and penicillin solutions (the solvent is methanol) of different concentrations and perform system calibration. Fix the phase of the quantum weak measurement instrument and record the angle. Use a single-photon detector to detect the spot intensity signal, and process the detection signal through a time-to-digital converter. Fine-tune the front and back selection (i.e., the angle of the Glan laser polarizer) until light spin splitting occurs. Read and record the number of photons of the upper and lower spots at the time of maximum polarization of the light spot splitting. Replace the solution in the cuvette with the D-tryptophan, L-tryptophan, erythromycin, and penicillin solutions to be tested in turn. Use a single-photon detector to detect the spot intensity signal, and process the detection signal of the single-photon detector through a time-to-digital converter. Read and record the number of photons of the upper and lower spots at the time of maximum polarization of the light spot splitting. Repeat the experiment several times and record the experimental results.

[0051] The difference in the pulse counts between the two recorded spots was used to calculate the corresponding spin-shift distance. Multiple measurements were then conducted and the results compared with theoretical values. Tests were conducted on sample solutions with concentrations ranging from 0 to 0.25 mg / ml (using methanol as the solvent). The average deviation between the measured spin-shift distance and the theoretical value was only 0.26%.

[0052] Table 1 is a table comparing the spot spin shift results obtained from the test of D-tryptophan, L-tryptophan, erythromycin, and penicillin solutions described in Experimental Example 2 of the present invention with the theoretical values.

[0053] Table 1

[0054] Sample name solvent Concentration (mg / ml) Theoretical value (μm) Experimental value 1(μm Experimental value 2(μm Experimental value 3(μm Experimental value 4(μm Experimental value 5(μm Experimental mean (μm Experimental bias D-Tryptophan Methanol 0.05 25.7 25.1 25.9 26.2 26.3 25.3 25.76 0.13％ D-Tryptophan Methanol 0.1 51.5 51.2 50.7 50.9 52.8 51.6 51.44 0.03％ D-Tryptophan Methanol 0.15 77.2 76.8 78.1 76.9 77.9 76.7 77.28 0.13％ D-Tryptophan Methanol 0.2 102.9 102.7 102.1 103.8 103.5 103.2 103.06 0.15％ D-Tryptophan Methanol 0.25 128.6 128.2 128.9 127.9 129.1 128.8 128.58 0.04％ L-Tryptophan Methanol 0.05 24.9 24.8 25.4 25.9 24.3 24.1 24.9 0.32％ L-Tryptophan Methanol 0.1 49.9 49.7 50.2 50.8 49.2 49.3 49.84 0.24％ L-Tryptophan Methanol 0.15 74.9 74.5 75.2 75 74.1 74.2 74.6 0.45％ L-Tryptophan Methanol 0.2 99.91701245 98.9 99.2 99 100.2 100.5 99.56 0.36％ L-Tryptophan Methanol 0.25 124.8 124.2 125.6 125.1 125.3 125.5 125.14 0.20％ Erythromycin Methanol 0.05 65.1 64.7 65.3 65.4 65.9 65.1 65.28 0.28％ Erythromycin Methanol 0.1 121.5 121.1 121.9 121.5 123.6 120.9 121.8 0.25％ Erythromycin Methanol 0.15 167.2 166.3 166.9 166.8 168.2 168.9 167.42 0.13％ Erythromycin Methanol 0.2 210.8 210.3 210.9 210.8 211.9 211.7 211.12 0.15％ Erythromycin Methanol 0.25 261.2 261.9 259.5 260.2 261.1 261.1 260.76 0.17％ artemisinin Methanol 0.05 60.2 63.2 58.3 61.2 60.5 59.8 60.6 0.66％ artemisinin Methanol 0.1 116 117.9 113.1 115.4 115.6 115 115.4 0.52％ artemisinin Methanol 0.15 161.7 164.5 162.1 159.8 163.7 160.4 162.1 0.25％ artemisinin Methanol 0.2 206.5 207.6 203.1 205.5 204.8 205.5 205.3 0.58％ artemisinin Methanol 0.25 256.1 257.1 254.2 254.6 252.2 256.4 254.9 0.47％

[0055] It can be seen from the above technical solution that the present invention has the following significant features:

[0056] 1. This invention splits entangled photon pairs into two paths: one for measurement and one for calibration. When one photon is detected, the state of the other entangled photon is instantly determined. After the calibration of the entangled light source calibration path is complete, the measurement path is also calibrated. This design reduces errors that may occur when directly calibrating the measurement path, such as device errors and spatial perturbations in the optical path.

[0057] 2. The present invention uses polarization-entangled photon pairs to significantly improve measurement accuracy, as entangled photon pairs statistically provide a stronger correlation signal, helping to distinguish small effects. By measuring the light intensity difference using a single-photon counter, a relationship is established between the intensity difference between the upper and lower light spots split by the optical spin Hall effect and the optical rotation signal. Compared to the commonly used methods of using CCD (charge-coupled device image sensor) to detect light spot displacement and spectrometers to detect central wavelength shift as contrast indicators, single-photon detectors have higher resolution, thereby improving measurement accuracy.

[0058] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A chiral molecule weak measurement device based on quantum entangled light source, characterized in that: The invention comprises a quantum entangled light source optical path (6), a polarization beam splitter (8), a measurement optical path, an entangled light source calibration optical path and a time-to-digital converter (17); the quantum entangled light source optical path (6) emits a long-wave laser beam of a specific frequency containing an entangled photon pair; the polarization beam splitter (8) splits the laser beam emitted by the quantum entangled light source optical path (6) to divide the entangled photon pair into two beams; the measurement optical path sequentially modulates the incident entangled photon pair to produce a pre-selected state, a spin quantity change, a post-selected state and a light intensity detection light spot; the entangled light source calibration optical path is used to detect the light intensity of the other light spot; the time-to-digital converter connects the measurement optical path and the entangled light source calibration optical path, outputs an electrical pulse signal according to the received photons, completes counting and outputs the result according to the number of pulses, detects the light intensity according to the number of photons at the upper and lower light spots, calculates the optical rotation signal through the light intensity difference between the upper and lower light spots, and calculates the optical rotation of the chiral molecule accordingly.

2. The chiral molecule weak measurement device based on quantum entangled light source according to claim 1, characterized in that: The quantum entangled light source optical path (6) comprises a laser (1), a half-wave plate (2), a two-color polarization beam splitter (3), a first confocal lens (41), a PPKTP crystal (5), a second confocal lens (42), and a long-wave pass filter (7) arranged in sequence along the optical path; the laser (1) is a pump laser, used to provide a high-energy narrow-band laser light source; the half-wave plate (2) is used to adjust the light intensity of the narrow-band laser light source; the two-color polarization beam splitter (3) is used to ensure that the output laser maintains stable polarization characteristics; the first confocal lens (41) is used to focus the light beam; the PPKTP crystal (5) is used to generate entangled photon pairs; the second confocal lens (42) is used to focus the light beam again and adjust the shape of the light beam; the long-wave pass filter (7) allows a long-wave light source of a specific frequency to pass through, thereby improving the purity and stability of the entangled photon pairs.

3. The chiral molecule weak measurement device based on quantum entangled light source according to claim 2, characterized in that: The PPKTP crystal (5) is a periodically poled potassium titanyl phosphate crystal.

4. The chiral molecule weak measurement device based on quantum entangled light source according to claim 2, characterized in that: The polarization beam splitter (8) is arranged on the light-emitting side of the long-wave pass filter (7).

5. The chiral molecule weak measurement device based on quantum entangled light source according to claim 4, characterized in that: The measuring optical path comprises a first collimator and a matching optical fiber (91), a third confocal lens (101), a first Glan laser polarizer (11), a cuvette (12) containing a solution of a chiral molecule to be measured, a prism (13) coated with a Ce:YIG magneto-optical film, a fourth confocal lens (102), a second Glan laser polarizer (14), and a first single-photon detector (15), which are sequentially arranged along the optical path direction; the first collimator and the matching optical fiber (91) are arranged on the reflective side of the polarization beam splitter (8) for transmitting entangled photon pairs and reducing optical fiber loss; the third confocal lens (101) is used for focusing the light beam; the first Glan laser polarizer (11) is used for modulating the incident entangled photon pairs to generate a pre-selected state, and vertically incident on the cuvette containing the chiral molecule to be measured. A cuvette (12) containing a molecular solution; the cuvette (12) containing a chiral molecular solution to be measured uses the optical activity of the chiral molecular solution to cause a change in the spin amount of an incident entangled photon pair; a prism (13) coated with a Ce:YIG magneto-optical film introduces an optical spin Hall effect to adjust the direction of the light path; a fourth confocal lens (102) focuses the light beam again; a second Glan laser polarizer (14) modulates the incident entangled photon pair to generate a post-selected state, and outputs the light source to a first single-photon detector (15) for analysis; the first single-photon detector (15) introduces the post-selected light beam into a receiving window of a single-photon counter, and the single-photon counter outputs an electrical pulse signal according to the number of photons received per unit time, and detects light intensity through the electrical pulse signal per unit time.

6. The chiral molecule weak measurement device based on quantum entangled light source according to claim 5, characterized in that: The Ce:YIG is cerium-doped yttrium iron garnet.

7. The chiral molecule weak measurement device based on quantum entangled light source according to claim 5, characterized in that: The entangled light source calibration optical path includes a second collimator and a matching optical fiber (92), and a second single-photon detector (16); the second collimator and the matching optical fiber (92) are arranged on the light-transmitting side of the polarization beam splitter 8, and are used to transmit entangled photon pairs to reduce optical fiber loss; the second single-photon detector (16) detects the light intensity of the light spot transmitted by the second collimator and the matching optical fiber (92).

8. The chiral molecule weak measurement device based on quantum entangled light source according to claim 7, characterized in that: The weak measurement process of chiral molecules is as follows: first, solutions of the chiral molecules to be measured with different concentrations are prepared and poured into a cuvette (12); then, the laser (1) is turned on, and the two light spots finally received are shielded by a light shield; the first single-photon detector (15) and the second single-photon detector (16) serve as receiving ends to record the light intensity, and the time-to-digital converter (17) is used to convert the number of received photons into a pulse signal, and the counting is completed and the result is output according to the number of pulses; the light intensity difference between the two light spots is used to establish a contrast index to detect the optical rotation; the specific optical rotation is calculated according to the optical rotation and the concentration of the chiral molecule solution, and the type of the chiral molecule to be measured is determined by looking up the corresponding biological parameter table.

9. The chiral molecule weak measurement device based on quantum entangled light source according to claim 8, characterized in that: Before the weak measurement of chiral molecules, the entangled light source calibration optical path is calibrated. The calibration process is as follows: in a dark environment, firstly, the first single-photon detector (15) and the second single-photon detector (16) are zeroed, and then the laser (1) is started. When the laser output is stable, the second single-photon detector (16) in the entangled light source calibration optical path is turned on to determine the light intensity difference between the upper and lower light spots; by adjusting the polarization beam splitter (8), the light intensity difference is made zero, and the calibration of the entangled light source calibration optical path is completed.

10. The chiral molecule weak measurement device based on quantum entangled light source according to claim 9, characterized in that: The process of using the intensity difference between the two light spots to establish a contrast index to detect optical rotation is as follows: The first Glan laser polarizer is used to prepare the preselected state |ψ0>, whose optical axis is in the horizontal direction; the incident polarization state is expressed as The light beam passes through the chiral solution in the cuvette, introducing a small phase change α between the left and right circular polarization states; the polarization state of the light beam at this time is expressed as: Among them, α<<1 and β<<1; The light beam is reflected on the surface of a prism coated with a Ce:YIG magneto-optical film, and the optical spin Hall effect occurs. According to the relationship between the reflection angle spectrum and the electric field boundary distribution, the polarization state of the light evolves as follows: in, represents the spin evolution of the optical spin Hall effect, represents the polarization change caused by reflection; represents the spin operator; δ represents the light spin splitting distance, r p and r s represent the Fresnel reflection coefficients of horizontal polarization and vertical polarization respectively; the front selection state is prepared by the first Glan laser polarizer, setting represents the pre-selected state of the weak measurement system; After the reflected beam is focused by the lens, the post-selection state is prepared by the second Glan laser polarizer, and the optical axis is vertical to produce a post-selection state. The entire weak measurement system is expressed as: The shading plate receives two light spot signals, and the single photon detector detects the light intensity I of the two light spots. 1|α，β and I 2|α，β , the contrast index is established using the intensity difference between the two spots, which is expressed as: in, and Represents the light intensity of the upper and lower light spots respectively; I0 represents the light intensity before post-selection; r p and r s represents the Fresnel reflection coefficient of horizontal polarization and vertical polarization respectively; ω is the laser frequency of the laser; δ represents the optical spin splitting distance; I t | α＝0，β＝0 =I1| α＝0，β＝0 +I2| α＝0，β＝0 It represents the total intensity of the post-selected beam when there is no phase or amplitude change, which does not change in the subsequent process; the optical rotation α of the chiral molecule solution to be measured is calculated, and then according to the formula of specific optical rotation: α＝l·c[α] D Where c is the concentration of the chiral molecule solution to be measured in the cuvette, l is the distance the laser passes through the chiral molecule solution in the cuvette; the specific optical rotation [α] of the chiral molecule is obtained. D , and identify the type of the chiral molecule sample to be tested by looking up the corresponding biological parameter table.

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