Terahertz-spectrum quantum weak measurement method and system, and application

Abstract

A terahertz-spectrum quantum weak measurement method and system, and application. The terahertz-spectrum quantum weak measurement method is applied to a terahertz-spectrum quantum weak measurement system (100). The measurement system (100) comprises a first polarizer (104), a second polarizer (105), a terahertz time-domain spectrum unit (101), a transmission end (102), a detection end (103) and a sample carrier (106). The terahertz quantum weak measurement method and system based on the quantum weak-value amplification effect can break through the trace detection limits of the current terahertz technology. A terahertz polarization state (a pre-selected state) is selected, a measured tiny change generates a "micro" disturbance for the terahertz polarization state, and strong measurement is then used to project a disturbed system state to a post-selected state, thereby establishing the terahertz quantum weak-measurement system. Since most chiral drugs have resonance absorbability in a terahertz waveband, high-sensitivity conformation recognition of chiral drugs by using a micro-variation in the optical rotation of chiral molecules as a weak coupling effect is facilitated.

Description

Terahertz spectroscopy quantum weak measurement methods, systems and applications Technical Field

[0001] The present invention relates to the field of terahertz technology, and in particular to a terahertz spectroscopy quantum weak measurement method, system and application. Background Art

[0002] The study of drug chirality is crucial in biomedical fields such as drug design and synthesis and protein structure determination, and is crucial for human health. Many chiral drugs exhibit distinct pharmacological, toxicological, and pharmacokinetic properties when interacting with proteins in living organisms. Identifying and testing drug chirality is imperative and extremely important.

[0003] Currently, the commonly used methods for identifying chiral molecules include chromatography (high-performance liquid chromatography, gas chromatography, and supercritical fluid chromatography), capillary electrophoresis (capillary zone electrophoresis and capillary electrochromatography), and spectroscopy (circular dichroism and Raman spectroscopy). These methods suffer from one or more of the following drawbacks: cumbersome operation, destructive testing, reliance on standards, significant limitations, and high limits of detection, making them less than ideal. Compared to other wavelengths such as visible light, terahertz (THz) electromagnetic waves (frequency 0.1-10 THz) exhibit strong sensitivity and fingerprint-like properties for low-frequency molecular vibrations. As a non-contact, label-free, and non-ionizing detection method, THz technology effectively detects molecular conformations and weak interactions, offering significant advantages and potential for conformational identification of chiral molecules. However, currently used THz time-domain spectroscopy techniques are mostly limited to spectral testing and qualitative analysis, making quantitative detection difficult and their sensitivity far from meeting requirements.

[0004] Therefore, a terahertz spectroscopy quantum weak measurement technology and system was established, which utilized the characteristic fingerprint property of the terahertz wave frequency band matching the energy level spacing caused by the vibration, rotation, and conformational changes of macromolecules, and the high sensitivity of quantum weak measurement to amplify the signal without amplifying the technical noise, thereby greatly improving the detection sensitivity of chiral molecules and meeting the needs of high-sensitivity conformational recognition of chiral drugs.

[0005] Summary of the Invention

[0006] In order to solve the current defect of insufficient sensitivity of chiral samples to be measured, the present invention proposes a terahertz spectroscopy quantum weak measurement method, system and application.

[0007] The technical solution adopted in the present invention is:

[0008] A terahertz spectroscopy quantum weak measurement method is applied to a terahertz spectroscopy quantum weak measurement system, the system comprising a first polarizer, a second polarizer, a terahertz time-domain spectroscopy unit, an emission end, a detection end, a sample carrier, and a terahertz spectroscopy quantum weak measurement calculation unit. The method comprises:

[0009] Pre-selection: the polarization state of the incident terahertz wave emitted by the terahertz time-domain spectroscopy unit through the transmitting end is selected by the first polarizer as the quantum pre-selected state;

[0010] Post-selection, the polarization state selected by the second polarizer is used as the quantum post-selected state;

[0011] Before measurement, the quantum pre-selected state and the quantum post-selected state are orthogonal to each other;

[0012] In the weak coupling effect, the sample to be tested is placed between the first polarizer and the second polarizer. After the terahertz wave interacts with the sample to be tested, the terahertz wave spectrum is measured by the terahertz time-domain spectroscopy unit after the terahertz wave is received by the detection end;

[0013] Construct a terahertz spectroscopy quantum weak measurement model, and calculate and select the change value β of the terahertz wave polarization state caused by the interaction between the terahertz wave and the sample to be measured;

[0014] The change value β of the terahertz wave polarization state reflects the measured quantity X of the sample to be measured.

[0015] During operation, the present application creatively adopts the method of selecting a terahertz polarization state (quantum pre-selected state), and the measured tiny change produces a "micro" perturbation on the terahertz wave polarization state, and then uses a strong measurement method to project the perturbed amount onto the quantum post-selected state, thereby establishing a terahertz quantum weak measurement system.

[0016] Preferably, the measured quantity X∝β, and the measured quantity X can be calculated from β through calibration; this facilitates the quantitative calculation of the measured quantity X and is beneficial to improving the measurement accuracy and sensitivity.

[0017] Preferably, when the terahertz wave acts on the sample to be measured, the quantum pre-selected state is π / 4 with the X direction, and the quantum post-selected state is 3π / 4-β with the X direction; utilizing the currently mature π / 4 and 3π / 4 polarization states facilitates measurement and debugging, which is beneficial to improving measurement accuracy and sensitivity.

[0018] Preferably, the terahertz spectroscopy quantum weak measurement model:

[0019] Among them, Aw is the quantum weak value, β is the polarization state change value of the terahertz wave, ImA w A w The imaginary part of the terahertz wave; G0 is the coupling strength between the terahertz wave and the sample under test; p is the photon momentum of the terahertz wave; δp is the change in the photon momentum of the terahertz wave; δλ is the wavelength shift of the terahertz wave; λ0 corresponds to the photon momentum p0, and Δλ is the spectral width.

[0020] Preferably, the terahertz wave interacts with the sample to be measured in a transmission mode or a metal grating-refraction mode, which facilitates weak coupling of the terahertz wave with respect to optical rotation (degree) and refractive index.

[0021] Preferably, when in transmission mode, the sample carrier is a sample cell, and the quantity to be measured X of the sample to be measured is the optical rotation b.

[0022] Preferably, when in the metal grating-refraction mode, the sample carrier is a prism coated with a metal grating, and the quantity to be measured X of the sample to be measured is the refractive index c.

[0023] The present invention also provides a terahertz spectroscopy quantum weak measurement system, comprising:

[0024] A first polarizer is disposed at the terahertz wave incident end of the terahertz time-domain spectroscopy unit to select the terahertz wave in the quantum pre-selected state;

[0025] The carrier to be tested is arranged between the first polarizer and the second polarizer so that the terahertz wave in the quantum pre-selected state is weakly coupled with the sample to be tested on the carrier to be tested;

[0026] The second polarizer is configured at the terahertz wave detection end of the terahertz time-domain spectroscopy unit to select the terahertz wave in the quantum post-selected state; before measurement, the quantum post-selected state and the quantum pre-selected state are orthogonal to each other;

[0027] a terahertz time-domain spectroscopy unit configured to emit, regulate, detect, and spectrally measure terahertz waves;

[0028] and a terahertz spectrum quantum weak measurement calculation unit, which is configured to select the terahertz wave polarization state change value and the measured value of the sample to be measured after calculating the terahertz spectrum quantum weak measurement model and the terahertz wave spectrum.

[0029] Preferably, the system further comprises:

[0030] The half-wave plate and the first focusing lens are arranged between the terahertz wave incident end and the first polarizer to adjust the intensity of the incident terahertz wave;

[0031] and a second focusing lens, which is arranged between the second polarizer and the terahertz wave detection end, for focusing detection.

[0032] Preferably, the carrier to be tested is a sample cell or a prism coated with a metal grating.

[0033] The present invention also proposes the application of the above-mentioned terahertz spectroscopy quantum weak measurement system in the high-sensitivity detection of chiral drugs.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. The terahertz (THz) quantum weak measurement technology proposed in this invention, based on the quantum weak value amplification effect, can break through the trace detection limit of current THz technology. A THz polarization state (preselected state) is selected, and small changes in the measured quantity produce a "micro" perturbation. Strong measurement is then used to project the perturbed system state onto the postselected state, thereby establishing a THz quantum weak measurement system. Most chiral drugs exhibit resonant absorption in the THz band, which is beneficial for utilizing small changes in the optical rotation of chiral molecules as weak coupling to achieve highly sensitive conformational recognition of chiral drugs.

[0036] 2. Establishing the theoretical basis of terahertz quantum weak measurement, namely the transfer function model of terahertz quantum weak value amplification effect, is the foundation and support of terahertz spectroscopy quantum weak measurement technology and system.

[0037] 3. Integrate terahertz time-domain spectroscopy technology and quantum weak measurement technology, build a quantum weak measurement system on the terahertz time-domain spectroscopy system, establish a transmission mode and a metal grating-refraction mode, which can greatly improve the detection accuracy of the optical rotation and refractive index of the material, and develop a new label-free terahertz trace detection technology.

[0038] 4. Compared with the currently commonly used terahertz time-domain spectroscopy technology, the terahertz spectroscopy quantum weak measurement technology and system involved in this invention is expected to improve its measurement sensitivity by 2-3 orders of magnitude. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The present invention is described in detail below with reference to the embodiments and accompanying drawings, in which:

[0040] Figure 1 is a block diagram of a terahertz spectroscopy quantum weak measurement system;

[0041] FIG2 is a flow chart of a terahertz spectroscopy quantum weak measurement method;

[0042] FIG3 is a schematic diagram of the mechanism of terahertz quantum weak value amplification effect;

[0043] Figure 4 shows the terahertz spectroscopy quantum weak measurement system in transmission mode;

[0044] Figure 5 shows the terahertz spectroscopy quantum weak measurement system in the metal grating-refraction mode;

[0045] FIG6 is a diagram showing the terahertz quantum weak measurement results of the terahertz spectroscopy quantum weak measurement system in a low-concentration glucose sample. DETAILED DESCRIPTION

[0046] To make the objectives, technical solutions, and advantages of the present invention more apparent, embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar components or components having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0047] The study of drug chirality is crucial in biomedical fields such as drug design and synthesis and protein structure determination, and is crucial for human health. Many chiral drugs exhibit distinct pharmacological, toxicological, and pharmacokinetic properties when interacting with proteins in living organisms. Identifying and testing drug chirality is imperative and extremely important.

[0048] Currently, the commonly used methods for identifying chiral molecules include chromatography (high-performance liquid chromatography, gas chromatography, and supercritical fluid chromatography), capillary electrophoresis (capillary zone electrophoresis and capillary electrochromatography), and spectroscopy (circular dichroism and Raman spectroscopy). These methods suffer from one or more of the following drawbacks: cumbersome operation, destructive testing, reliance on standards, significant limitations, and high limits of detection, making them less than ideal. Compared to other wavelengths such as visible light, terahertz (THz) electromagnetic waves (frequency 0.1-10 THz) exhibit strong sensitivity and fingerprint-like properties for low-frequency molecular vibrations. As a non-contact, label-free, and non-ionizing detection method, THz technology effectively detects molecular conformations and weak interactions, offering significant advantages and potential for conformational identification of chiral molecules. However, currently used THz time-domain spectroscopy techniques are mostly limited to spectral testing and qualitative analysis, making quantitative detection difficult and their sensitivity far from meeting requirements.

[0049] Therefore, this application discloses a terahertz spectroscopy quantum weak measurement method and system.

[0050] 1-6 , the system 100 includes a terahertz time-domain spectroscopy unit 101 configured for terahertz time-domain spectroscopy analysis;

[0051] The transmitting end 102 is configured to emit an incident terahertz wave;

[0052] The detection end 103 is configured to receive terahertz waves;

[0053] The first polarizer 104 is configured to be pre-selective, and the terahertz wave is selected to be in a quantum pre-selected state;

[0054] The second polarizer 105 is configured as a post-selection, through which the terahertz wave is selected to produce a quantum post-selection state.

[0055] Before measurement, the quantum post-selected state and the quantum pre-selected state are orthogonal to each other;

[0056] The sample carrier 106 is configured to carry the sample 10 to be tested between the first polarizer 104 and the second polarizer 105 to complete the weak coupling between the terahertz wave in the quantum pre-selected state and the sample to be tested;

[0057] The terahertz spectrum quantum weak measurement calculation unit 1011 is configured to select the terahertz wave polarization state change value and the measured value of the sample to be measured after calculating the terahertz spectrum quantum weak measurement model and the terahertz wave spectrum.

[0058] A terahertz spectroscopy quantum weak measurement method is applied to the above-mentioned terahertz spectroscopy quantum weak measurement system, the method comprising: S1, pre-selection, wherein the polarization state of the incident terahertz wave emitted by the terahertz time-domain spectroscopy unit through the transmitting end is selected by the first polarizer as the quantum pre-selected state; post-selection, wherein the polarization state of the terahertz wave is selected by the second polarizer as the quantum post-selected state; before measurement, the quantum pre-selected state and the quantum post-selected state are orthogonal to each other;

[0059] S2, weak coupling and spectral measurement, the sample to be measured is placed between the first polarizer and the second polarizer, after the terahertz wave interacts with the sample to be measured, the terahertz wave spectrum is measured after the terahertz wave is received by the detection end of the terahertz time domain spectroscopy unit;

[0060] S3, constructing a terahertz spectroscopy quantum weak measurement model, and calculating and selecting the terahertz wave polarization state change value β caused by the interaction between the terahertz wave and the sample to be measured;

[0061] S4. The terahertz wave polarization state change value β reflects the measured value X of the sample to be measured.

[0062] In some embodiments, when the terahertz wave interacts with the sample to be measured, the quantum pre-selected state is a terahertz wave that is π / 4 with the X direction, and the quantum post-selected state is a terahertz wave that is 3π / 4-β with the X direction; utilizing the currently mature π / 4 and 3π / 4 polarization states facilitates measurement debugging, which is beneficial to improving measurement accuracy and sensitivity.

[0063] In some embodiments, the quantum pre-selected state is a terahertz wave with an angle of θ with the X direction, and the quantum post-selected state is a terahertz wave with an angle of Where θ takes the value In this embodiment, the mechanism of the terahertz quantum weak value amplification effect is as follows: a terahertz photon system is used as the quantum system to be measured, the polarization state of the terahertz photon is selected as the physical quantity to be measured, and the momentum of the terahertz photon is selected as the indicator; its weak coupling effect refers to the fact that when the terahertz wave is transmitted in the sample, it is weakly absorbed, scattered, dispersed, or polarization rotated by the molecules to be measured; the terahertz spectrum change (broadening, frequency shift, etc.) can be characterized by the filtered out post-selected state and ultimately measured by a terahertz detector (balanced detector, spectrometer, power meter, etc.);

[0064] In this embodiment, the terahertz frequency domain transfer function model of quantum weak value amplification is: the mutually perpendicular terahertz wave polarization states are selected as mutually orthogonal quantum pre-selected states |ψ pre > and quantum postselected state |ψ post >; The optical activity of chiral molecules causes the polarization state of terahertz waves to rotate, that is, weak coupling. The weak coupling polarization state is expressed as |ψ'>; then the weak value is

[0065] In quantum weak measurement, the absolute value of the weak value is the amplification factor of the measured physical quantity; as shown in formula (1), when the pre-selected state and the post-selected state are nearly orthogonal, the coefficient can be much larger than 1. Therefore, according to the pre-selected state, post-selected state and weak coupling process, according to the terahertz emission wave expression and detection mechanism, according to the quantum weak measurement operator Criteria, derive weak value expressions and frequency domain transfer function models;

[0066] In this embodiment, first, the terahertz quantum weak value amplification effect mechanism is established: as shown in Figure 3, the Hamiltonian operator of quantum weak interaction is set to where g(t) is the coupling strength, which can be considered as a constant inside the sample and zero outside the sample, and Determined by the sample thickness L, absorption coefficient α(ω) and effective refractive index n(ω); is the momentum operator of the terahertz photon in the Z direction; is the polarization operator of the terahertz photon, and |H> and |V> are The two eigenstates of have eigenvalues ​​of ±1, that is, Represent the polarization states in the X and Y directions respectively. Select the terahertz polarization state that is π / 4 with the X direction as the pre-selected state of the terahertz photon, and the terahertz polarization state that is 3π / 4-β (β<<1, which is the polarization state change caused by the transmission of the terahertz wave in the object being measured) with the X direction as the post-selected state.

[0067] This gives the weak value

[0068] Because it is a weak coupling effect and β << 1, so is a very large amplification factor.

[0069] Secondly: The terahertz frequency-domain transfer function model of quantum weak value amplification; The coupling strength between the terahertz wave and the measured object is where x = νt (0 < x < L), ν is the propagation speed of the terahertz wave in the measured object, and L is the thickness of the measured object. When the terahertz wave advances x part in the sample, there is still L - x part that has not passed through; Let be the change per unit thickness in the sample, then The weak value is obtained by derivation

[0070] where the photon momentum h is the Planck constant, λ is the terahertz wavelength, v is the terahertz frequency, and c is the propagation speed of the terahertz wave in vacuum.

[0071] For G0p << 1 and β << 1

[0072] Its imaginary part

[0073] Compared with the extinction coefficient of the near-infrared optical polarizer, the extinction coefficient of the terahertz polarizer is poor, resulting in a large error in the selection after terahertz quantum weak measurement. Therefore, the imaginary part of the frequency-domain quantum weak measurement formula is preferably used as the weak value amplification part. From this, the change amount of the terahertz photon momentum p caused by the interaction is

[0074] From this, the wavelength shift amount is

[0075] Here the central wavelength λ0 corresponds to the photon momentum Δλ is the spectral width.

[0076] [[ID=4~2]]Therefore, by measuring the frequency shift amount of the terahertz spectrum, the small change β in the polarization state of the terahertz wave after passing through the measured sample can be deduced from the above formula, and the β value is determined by the small quantity to be measured of the measured sample.

[0077] In some embodiments, the terahertz time-domain spectroscopy unit 101 is connected between the transmitting end 102 and the detecting end 103 to form a basic terahertz time-domain spectroscopy system. The terahertz time-domain spectroscopy unit 101 specifically includes a femtosecond laser, a delay control, a photoconductive switch, an antenna, an electro-optic crystal, a Wollaston prism, a balanced detector, etc.;

[0078] The transmitting end 102 and the detecting end 103 have a terahertz wave transmission axis a. A terahertz half-wave plate 231, a first focusing lens 232, and a first polarizer 104 are arranged along the axis a between the transmitting end 102 and the detecting end 103 to perform pre-selection of terahertz quantum weak measurement.

[0079] The half-wave plate 231 is used to adjust the intensity of the terahertz light, and the first focusing lens 232 is used to focus the terahertz wave.

[0080] The second polarizer 105 is arranged between the first polarizer 104 and the detection end 103 along the axis a, and is configured as a post-selection for terahertz quantum weak measurement.

[0081] A second focusing lens 233 is disposed on the axis a between the second polarizer 105 and the detection end 103, for focusing the terahertz wave filtered out by the second polarizer and allowing it to enter the detection end 103. The terahertz wave entering the detection end enters the electro-optical crystal, Wollaston prism and balanced detector of the basic terahertz time-domain spectroscopy system, and the spectral measurement is completed using electro-optical sampling technology;

[0082] The sample carrier 106 is disposed between the first polarizer 104 and the second polarizer 105 and is used to carry the sample 10 to be measured, so that the terahertz wave is weakly coupled with the sample to be measured.

[0083] Referring to FIG. 4 , in some embodiments, the sample to be tested is a chiral molecule, and the quantity to be measured X is the optical rotation b of the chiral molecule. In this case, the terahertz wave interacts with the sample to be tested in a transmission mode.

[0084] The sample carrier 106 is a sample pool 1061, and the sample 10 to be tested is placed in the sample pool 1061;

[0085] The terahertz wave in the quantum pre-selected state enters one side of the sample cell 1061 and is filtered out from the other side; the sample to be measured in the sample cell is weakly coupled with the terahertz wave in the quantum pre-selected state;

[0086] Referring to FIG. 5 , in some embodiments, the sample to be tested is a chiral molecule, and the quantity to be measured X is the refractive index c of the detected chiral molecule. In this case, the terahertz wave and the sample to be tested interact in a metal grating-refraction mode. The sample carrier 106 is a prism 1062 coated with a metal grating. In the metal grating-refraction mode, when the terahertz wave in the quantum preselected state is incident on the metal grating at any angle (determined by the position of the prism coated with the metal grating and the metal grating structure), a slight change in the refractive index of the sample to be tested will cause a change in the polarization state of the terahertz wave parallel to the metal grating, while the polarization state of the terahertz wave perpendicular to the metal grating is unaffected. Therefore, a slight change in the phase difference between the two is generated, completing the quantum weak coupling effect.

[0087] The terahertz wave in the quantum pre-selected state is weakly coupled to the sample to be measured, and the terahertz wave in the quantum post-selected state filtered out from the second polarizer 105 is 3π / 4-β; β is the change in the polarization state of the terahertz wave caused by the interaction between the terahertz wave and the sample to be measured.

[0088] Therefore, by measuring the frequency shift of the terahertz spectrum, the terahertz spectrum quantum weak measurement calculation unit 1011 can deduce the small change β in the polarization state of the terahertz wave after it passes through the sample under test from the above equations (1)-(8). In some embodiments, the measurement X can be calculated by calibrating it with the measurement X∝β;

[0089] In some embodiments, the terahertz spectroscopy quantum weak measurement calculation unit 1011 is built into the terahertz time-domain spectroscopy unit 101 ; in some embodiments, the terahertz spectroscopy quantum weak measurement calculation unit 1011 is connected to the terahertz time-domain spectroscopy unit 101 via wired and / or wireless communication.

[0090] In some embodiments, ultrapure water was used as the solvent to prepare low-concentration glucose solutions ranging from 0.01 mg / ml to 0.10 mg / ml, with a concentration gradient of 0.01 mg / ml. 60 μl of each concentration solution was dripped onto a double-sided polished JGS1 quartz plate with a diameter of 12 mm and a thickness of 1 mm. After natural air drying, the solution formed a biofilm. Terahertz signal testing was performed using the above system, and the results are shown in Figure 6. The red line in the figure is a test curve that combines the quantum weak measurement principle and terahertz time-domain spectroscopy technology. It shows that as the sample concentration increases, the time-domain signal peak-to-peak ratio (the peak-to-peak value of the transmission time-domain signal of the test sample / the peak-to-peak value of the transmission time-domain signal of the reference sample) gradually decreases. This is because as the number of glucose molecules gradually increases, its absorption of terahertz waves gradually increases; this demonstrates that the technology has the ability to detect low concentrations with high sensitivity. The blue line in the figure is a test curve based on traditional terahertz time-domain spectroscopy technology. Its trend remains almost unchanged as the sample concentration increases, indicating that this concentration range exceeds the detection limit of traditional terahertz time-domain spectroscopy technology. The above results verify the effectiveness and high sensitivity of terahertz spectroscopy quantum weak measurement technology and system.

[0091] The above description is only part of the implementation methods of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A terahertz spectroscopy quantum weak measurement method, characterized in that: Applied to a terahertz spectroscopy quantum weak measurement system, the system includes a first polarizer, a second polarizer, a terahertz time-domain spectroscopy unit, a transmitter, a detector, a sample carrier and a terahertz spectroscopy quantum weak measurement calculation unit, the method includes: Pre-selection: the first polarizer selects the polarization state of the terahertz wave as the quantum pre-selected state; Post-selection, the second polarizer selects the polarization state of the terahertz wave as the quantum post-selected state; Before measurement, the quantum post-selected state and the quantum pre-selected state are orthogonal to each other; Weak coupling and spectral measurement: the terahertz wave is weakly coupled with the sample to be tested on the sample carrier and then received by the detection end, and the terahertz wave spectrum is measured by the terahertz time-domain spectroscopy unit; Construct a quantum weak measurement model for terahertz spectroscopy and select the change value of the polarization state of terahertz waves after calculation; The terahertz wave polarization state change value reflects the measured value of the sample to be measured.

2. The terahertz spectroscopy quantum weak measurement method according to claim 1, characterized in that: When the terahertz wave is weakly coupled with the sample to be tested, the quantum pre-selected state of the terahertz wave is 3π / 4 with the X direction, and the quantum post-selected state is 3π / 4-β with the X direction, where β is the change value of the polarization state of the terahertz wave in the post-selection.

3. The terahertz spectroscopy quantum weak measurement method according to claim 2, characterized in that: Terahertz spectroscopy quantum weak measurement model: Among them, A w is the quantum weak value, β is the change value of the polarization state of the terahertz wave, ImA w A w The imaginary part of the terahertz wave; G0 is the coupling strength between the terahertz wave and the sample under test; p is the photon momentum of the terahertz wave; δp is the change in the photon momentum of the terahertz wave; δλ is the wavelength shift of the terahertz wave; λ0 corresponds to the photon momentum p0, and Δλ is the spectrum width.

4. The terahertz spectroscopy quantum weak measurement method according to claim 1, characterized in that: The weak coupling action mode between the terahertz wave and the sample to be measured adopts a transmission mode or a metal grating-refraction mode.

5. The terahertz spectroscopy quantum weak measurement method according to claim 4, characterized in that: When in transmission mode, the sample carrier is a sample cell, and the quantity to be measured of the sample to be measured is optical rotation.

6. The terahertz spectroscopy quantum weak measurement method according to claim 4, characterized in that: When in the metal grating-refraction mode, the sample carrier is a prism coated with a metal grating, and the measured value of the sample to be measured is the refractive index.

7. Terahertz spectroscopy quantum weak measurement system, characterized in that: include: A first polarizer, used for pre-selection, is arranged at the terahertz wave incident end of the terahertz time-domain spectroscopy unit to select the quantum pre-selected state of the terahertz wave; The sample carrier is used to carry the sample to be measured and is arranged between the first polarizer and the second polarizer so that during measurement, the terahertz wave is weakly coupled with the sample to be measured on the sample carrier; The second polarizer is used for post-selection and is arranged at the terahertz wave detection end of the terahertz time-domain spectroscopy unit to select the quantum post-selected state of the terahertz wave; before measurement, the quantum post-selected state and the quantum pre-selected state are orthogonal to each other; A terahertz time-domain spectroscopy unit is configured to emit, regulate, detect, and spectrally measure terahertz waves; and a terahertz spectrum quantum weak measurement calculation unit, which is configured to select the terahertz wave polarization state change value and the measured value of the sample to be measured after calculating the terahertz spectrum quantum weak measurement model and the terahertz wave spectrum.

8. A terahertz spectroscopy quantum weak measurement system according to claim 7, characterized in that: The system further comprises: The half-wave plate and the first focusing lens are arranged between the terahertz wave incident end and the first polarizer to adjust the intensity of the incident terahertz wave for front selection; and a second focusing lens, which is arranged between the second polarizing plate and the terahertz wave detection end, to focus the terahertz wave for detection.

9. A terahertz spectroscopy quantum weak measurement system according to claim 7, characterized in that: The sample carrier is a sample pool or a prism coated with a metal grating.

10. Application of the terahertz spectroscopy quantum weak measurement system according to any one of claims 7 to 9 in high-sensitivity detection of chiral drugs.

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