High-sensitivity blood glucose noninvasive detection method and system based on polarization terahertz photoacoustic

Abstract

The invention belongs to the field of blood glucose detection, and relates to a high-sensitivity blood glucose noninvasive detection method and system based on polarized terahertz photoacoustic, which combines the advantages of terahertz wave band detection and photoacoustic detection, fully utilizes the chiral characteristics of glucose molecules, and adopts polarized terahertz photoacoustic to detect the blood glucose concentration. Polarization optical rotation change information is extracted through the time domain photoacoustic signal; by selecting the characteristic absorption wave band of glucose and utilizing the difference between glucose and other blood components in chiral characteristics, the influence of water and other high-concentration ions on terahertz signals is remarkably reduced, so that the selectivity and the anti-interference capability of blood glucose detection are effectively improved; terahertz non-ionizing radiation is adopted as an excitation source, no ionizing injury risk is caused to a human body, and the device is suitable for long-term repeated detection and is expected to be popularized and applied in wearable or bedside monitoring equipment.

Description

Technical Field

[0001] This invention belongs to the field of blood glucose detection, and in particular relates to a highly sensitive non-invasive blood glucose detection method and system based on polarized terahertz photoacoustics. Background Technology

[0002] Diabetes is widely recognized as one of the major chronic diseases threatening human life and health. To date, there is no cure for diabetes; clinical treatment primarily relies on a combination of medication, dietary control, and exercise therapy to achieve long-term management and control of blood glucose levels. Therefore, continuous, dynamic, and accurate monitoring of blood glucose levels in diabetic patients is a crucial aspect of diabetes prevention and treatment.

[0003] Currently, blood glucose testing methods can be broadly categorized into three types: invasive blood glucose monitoring, minimally invasive blood glucose monitoring, and non-invasive blood glucose monitoring. Invasive blood glucose testing typically involves obtaining a blood sample through finger-prick or venous blood collection, followed by testing using test strips, electrochemical sensors, or laboratory analytical instruments. While these methods are technically mature and widely used clinically, they require repeated skin punctures, leading to pain, risks of local infection, and poor patient compliance. Minimally invasive blood glucose monitoring reduces trauma to some extent, but still requires skin punctures or implanted devices, failing to fundamentally eliminate the discomfort and potential risks associated with trauma and foreign bodies. Non-invasive blood glucose monitoring, on the other hand, uses optical, electromagnetic wave, and acoustic methods to indirectly measure blood glucose parameters within the body, and its research and application are gradually becoming an important development direction in the field of blood glucose monitoring.

[0004] Among existing non-invasive detection methods, based on different detection mechanisms and physical means, they can be broadly categorized into several technical routes, including microwave detection, infrared spectroscopy detection, and photoacoustic detection. Photoacoustic non-invasive blood glucose monitoring methods, relying on the photoacoustic effect, possess advantages such as a high signal-to-noise ratio, excellent subcutaneous tissue penetration, and insensitivity to scattered light, demonstrating outstanding application potential among numerous non-invasive detection methods. Photoacoustic imaging and photoacoustic spectroscopy have gained widespread attention and application in the biomedical field, for example, for measuring blood oxygen saturation and analyzing parameters such as glucose concentration in body fluids and tissues.

[0005] On the other hand, terahertz electromagnetic waves have advantages such as no ionizing damage and distinct fingerprint spectral characteristics, making them equally promising for applications in the field of biomedical detection. Terahertz radiation can produce sensitive responses to a variety of biomolecules and their structural features, making it suitable for the detection and analysis of characteristic absorption spectra.

[0006] However, photoacoustic non-invasive blood glucose detection and terahertz non-invasive detection technologies still face many challenges in practical applications: Although photoacoustic detection has high sensitivity, its anti-interference ability is still insufficient in the complex tissue environment of the human body, making it difficult to stably and accurately separate blood glucose concentration changes; although terahertz waves have rich characteristic absorption spectra, water has a strong absorption effect on terahertz waves, which seriously limits the effective penetration depth and signal quality of terahertz in vivo detection; from the perspective of long-term diabetes management, existing detection methods cannot fully meet the needs of clinical and home scenarios in terms of continuous monitoring capability, real-time performance, portability, and comfort.

[0007] In summary, how to effectively suppress the influence of various interfering factors in complex physiological environments, give full play to the respective advantages of photoacoustic detection and terahertz detection, and achieve real-time, continuous, highly sensitive, and non-invasive detection of blood glucose concentration has become a key technical problem that urgently needs to be solved. Summary of the Invention

[0008] The main objective of this invention is to overcome the shortcomings and deficiencies of existing blood glucose detection technologies and provide a highly sensitive, non-invasive blood glucose detection method and system based on the polarization terahertz photoacoustic effect. Addressing the problems of traditional invasive and minimally invasive blood glucose monitoring requiring puncture for blood collection, being cumbersome, highly invasive, and having poor patient compliance, and the current situation where existing non-invasive detection technologies are insufficient to meet the needs of long-term dynamic clinical monitoring in terms of sensitivity, stability, and anti-interference capabilities, this invention constructs a novel polarization terahertz photoacoustic detection system to achieve real-time, continuous, non-invasive, and highly accurate measurement of blood glucose concentration in vivo.

[0009] This invention provides a high-sensitivity non-invasive blood glucose detection system based on polarized terahertz photoacoustics, the system comprising: Terahertz excitation module, used to generate terahertz pulse signals.

[0010] Specifically, the module includes a femtosecond laser, a collimating lens, a grating, a cylindrical mirror, and a parabolic mirror. The laser light generated by the femtosecond laser is collimated by the collimating lens, shaped by the grating and the cylindrical mirror, and then incident on a nonlinear crystal. Under phase-matching conditions, a broadband strong-field terahertz pulse is generated, and the parabolic mirror is used to focus the terahertz light spot. Specifically, the terahertz laser generates terahertz pulses with a frequency of 0.2–1.5 THz and a single pulse energy of 4 μJ, and the terahertz spot diameter is focused to 1.5 mm.

[0011] The terahertz control module includes a terahertz metamaterial polarizer and a terahertz metamaterial filter; the generated terahertz pulse is passed through the terahertz metamaterial polarizer again to change the terahertz polarization, and different frequency bands of terahertz are obtained through the metamaterial filter.

[0012] The photoacoustic signal receiving module is used to irradiate the target tissue in the sample cell with terahertz at different frequency bands, thereby exciting the photoacoustic effect in a local area and receiving and identifying the photoacoustic effect to obtain the photoacoustic signal.

[0013] Specifically, the module includes a sample cell, an acoustic impedance matching layer, an ultrasonic transducer, and a preamplifier; the target tissue in the sample cell is irradiated with terahertz waves of different frequency bands, thereby exciting a photoacoustic effect in a local area; the photoacoustic signal is received by the acoustic impedance and ultrasonic transducer, and amplified by the preamplifier.

[0014] The data acquisition and processing module collects photoacoustic signals through a filter using a data acquisition card and transmits them to a computer for processing. The acquired time-domain signal is deconvolved with the ultrasonic transducer response to obtain a more accurate time-domain photoacoustic signal. The horizontal axis of the obtained time-domain photoacoustic signal is multiplied by the speed of sound in the solution to reflect the data in terms of depth, further obtaining the sound pressure amplitude at different depths. The ratio of the initial sound pressure to the sound pressure after penetrating a certain depth in the solution is selected to obtain the optical rotation. Based on the relationship between blood glucose concentration and optical rotation in statistical data, a fitting is performed to obtain the blood glucose concentration in the target body.

[0015] This invention also provides a highly sensitive non-invasive blood glucose detection method based on polarized terahertz photoacoustics, the method comprising the following steps: Step 1: Generate a terahertz pulse signal; Specifically, the laser generated by the femtosecond laser is collimated by a collimating lens, shaped by a grating and cylindrical mirror, and then incident on a nonlinear crystal. Under phase-matching conditions, a broadband strong-field terahertz pulse is generated, and a parabolic mirror is used to focus the terahertz beam.

[0016] Step 2: The generated terahertz pulse is passed through a terahertz metamaterial polarizer to change its polarization state, and then through a metamaterial filter to obtain terahertz pulse signals of different frequency bands.

[0017] Step 3: Terahertz pulses irradiate the target tissue, thereby exciting a photoacoustic effect in a local area; the photoacoustic signal is received by an acoustic impedance transducer and an ultrasonic transducer, and then amplified by a preamplifier before being transmitted to a computer.

[0018] Because glucose in blood is chiral, the polarization of terahertz waves changes after traveling a certain distance. The photoacoustic signal is received by a preamplifier and a piezoelectric ultrasonic transducer, then filtered before being transmitted to a high-speed acquisition card, which transmits the acquired data to a computer.

[0019] Step 4: The data is processed in the computer. First, the acquired time-domain signal is deconvolved with the ultrasonic transducer response to obtain a more realistic and accurate time-domain photoacoustic signal. The horizontal axis of the obtained time-domain photoacoustic signal is multiplied by the speed of sound in the solution to reflect the data in terms of depth, so as to obtain the sound pressure amplitude at different depths. The ratio of the initial sound pressure and the sound pressure after penetrating a certain depth in the solution is selected to obtain the optical rotation. Based on the relationship between blood glucose concentration and optical rotation in the statistical data, a fitting is performed to obtain the blood glucose concentration in the target body. Finally, the detected blood glucose concentration is displayed in the computer.

[0020] The present invention has the following advantages over existing detection methods: 1. Achieve non-invasive, highly sensitive blood glucose detection This invention combines the advantages of terahertz band detection with photoacoustic detection, making full use of the chiral characteristics of glucose molecules. It uses polarized terahertz photoacoustic detection to detect blood glucose concentration and extracts information on polarization optical rotation changes through time-domain photoacoustic signals, thus achieving non-invasive and highly sensitive blood glucose detection.

[0021] 2. Strong anti-interference ability and good selectivity This invention significantly reduces the influence of water and other high-concentration ions on terahertz signals by selecting the characteristic absorption band of glucose and utilizing the differences in chiral properties between glucose and other blood components, thereby effectively improving the selectivity and anti-interference ability of blood glucose detection.

[0022] 3. Enables continuous real-time monitoring Leveraging the high signal-to-noise ratio of photoacoustic signals and a high-speed data acquisition and processing module, the method of this invention is suitable for continuous, real-time blood glucose monitoring, providing a technical foundation for clinical dynamic monitoring and home self-management, and helping to improve patient treatment adherence and quality of life.

[0023] 4. High safety and suitable for long-term use This invention uses terahertz non-ionizing radiation as the excitation source, which poses no risk of ionizing damage to the human body. It is suitable for long-term and repeated testing and is expected to be widely used in wearable or bedside monitoring devices.

[0024] In summary, the high-sensitivity non-invasive blood glucose detection method and system based on polarized terahertz photoacoustics proposed in this invention have significant advantages in terms of sensitivity, anti-interference ability, safety and real-time performance, providing a new technical approach for blood glucose monitoring in diabetes. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a framework diagram of a high-sensitivity non-invasive blood glucose detection system based on polarization terahertz photoacoustics proposed in this invention; Figure 2 This is a flowchart of a high-sensitivity non-invasive blood glucose detection method based on polarized terahertz photoacoustics proposed in this invention. Detailed Implementation

[0027] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0028] like Figure 1 As shown, this invention provides a high-sensitivity non-invasive blood glucose detection system based on polarized terahertz photoacoustics, the system comprising: Terahertz excitation module, used to generate terahertz pulse signals.

[0029] Specifically, the module includes a femtosecond laser, a collimating lens, a grating, a cylindrical mirror, and a parabolic mirror. The laser generated by the femtosecond laser is collimated by the collimating lens, shaped by the grating and the cylindrical mirror, and then incident on a nonlinear crystal. Under phase-matching conditions, a broadband strong-field terahertz pulse is generated, and the parabolic mirror is used to focus the terahertz light spot.

[0030] Specifically, the terahertz laser generates terahertz pulses with a frequency of 0.2–1.5 THz and a single pulse energy of 4 μJ, and the terahertz spot diameter is focused to 1.5 mm.

[0031] The terahertz control module includes a terahertz metamaterial polarizer and a terahertz metamaterial filter; the generated terahertz pulse is passed through the terahertz metamaterial polarizer again to change the terahertz polarization, and different frequency bands of terahertz are obtained through the metamaterial filter.

[0032] The photoacoustic signal receiving module is used to irradiate the target tissue in the sample cell with terahertz at different frequency bands, thereby exciting the photoacoustic effect in a local area and receiving and identifying the photoacoustic signal to obtain the photoacoustic effect.

[0033] Specifically, the module includes a sample cell, an acoustic impedance matching layer, an ultrasonic transducer, and a preamplifier; the target tissue in the sample cell is irradiated with terahertz waves of different frequency bands, thereby exciting a photoacoustic effect in a local area; the photoacoustic signal is received by the acoustic impedance and ultrasonic transducer, and amplified by the preamplifier.

[0034] The data acquisition and processing module collects photoacoustic signals through a filter using a data acquisition card and transmits them to a computer for processing. The acquired time-domain signal is deconvolved with the ultrasonic transducer response to obtain a more accurate time-domain photoacoustic signal. The horizontal axis of the obtained time-domain photoacoustic signal is multiplied by the speed of sound in the solution to reflect the data in terms of depth, further obtaining the sound pressure amplitude at different depths. The ratio of the initial sound pressure to the sound pressure after penetrating a certain depth in the solution is selected to obtain the optical rotation. Based on the relationship between blood glucose concentration and optical rotation in statistical data, a fitting is performed to obtain the blood glucose concentration in the target body.

[0035] In the aforementioned high-sensitivity non-invasive blood glucose detection system, a femtosecond laser, after collimation and shaping, is incident on a nonlinear crystal in a linearly polarized state. Wavefront tilting technology is used to increase the terahertz pulse conversion efficiency, and a broadband terahertz pulse is obtained using optical rectification. The generated terahertz pulse signal is focused by a parabolic mirror and converted into circularly polarized terahertz pulses by a terahertz metamaterial polarizer. Therefore, the polarization state can be changed by switching the terahertz metamaterial polarizer, thus adapting to different human body conditions. The polarized terahertz pulse then passes through a terahertz metamaterial filter, and by switching the state of the metamaterial filter, signals in multiple frequency bands are obtained, used to extract blood glucose information in complex environments and remove interference from other blood components.

[0036] Because chiral molecules are optically active, the polarization state of polarized light changes after passing through them. According to Malus's law: , in The intensity of transmitted light passing through the sample. The intensity of the incident light. Let c be the optical rotation. After traveling the same distance, the change in optical rotation will differ due to variations in the concentration of chiral molecules in the sample, and the concentration c and optical rotation satisfy the following relationship: , in It is the specific rotation of chirality, which is related to wavelength and temperature. This represents the distance that polarized light travels through the sample. For the same chiral molecule, with constant incident light wavelength and temperature, after the incident light travels the same distance, the optical rotation increases with increasing chiral molecule concentration.

[0037] When a terahertz pulse irradiates a target tissue, the local area of ​​the tissue absorbs the terahertz energy, causing a momentary temperature rise and thermal expansion, thereby generating initial pressure and forming an ultrasonic signal, i.e., a photoacoustic signal. In time-domain photoacoustics, the pulse width of the excitation light is much shorter than the thermal relaxation time and the sound pressure relaxation time, satisfying both thermal and sound pressure constraints. Under these conditions, the generation of the photoacoustic signal can neglect the effects of thermal diffusion and sound pressure propagation within the excitation region, satisfying the photoacoustic equation, thus allowing the initial sound pressure to be obtained: , in For Grueneisen coefficient, The ratio of light energy to heat energy. The optical absorption coefficient, This refers to luminous flux.

[0038] Therefore, the relationship between sound pressure and light intensity can be obtained: , Therefore, a relationship similar to Malus's law can be obtained: , in This is the sound pressure after the sample is penetrated. The initial sound pressure generated by the incident light. Based on the initial sound pressure and the sound pressure after penetration (i.e., the optical path depth), the optical rotation of the solution is obtained. By selecting an appropriate path, the changes in optical rotation of solutions of different concentrations can be obtained, thus providing information on blood glucose concentration.

[0039] From the original photoacoustic signal and ultrasonic transducer impulse response The detected photoacoustic signal y(t) is obtained by convolution, and is expressed as: , To obtain a more realistic signal, the obtained signal needs to be deconvolved in the frequency domain to recover the photoacoustic signal that can be used as a depth function. This can be achieved through Fourier transform: , The resulting frequency-domain photoacoustic signal can be expressed as: , The processed frequency-domain photoacoustic signal is inversely Fourier transformed to obtain a more accurate time-domain photoacoustic signal. The time axis of this signal is then multiplied by the speed of sound in the solution to reflect the depth, allowing for the determination of sound pressure amplitude at different depths. This relationship allows the ratio of sound pressure values ​​at two points to reflect the different changes in optical rotation of solutions with different concentrations after traveling the same distance. Based on the statistical results, a model corresponding to optical rotation and concentration is established. This model simulates real-world scenarios for different populations and removes interference from other components by switching between different frequency bands.

[0040] like Figure 2 As shown, the present invention also provides a high-sensitivity non-invasive blood glucose detection method based on polarized terahertz photoacoustics, the method comprising the following steps: Step 1: Generate a terahertz pulse signal; Specifically, the laser generated by the femtosecond laser is collimated by a collimating lens, shaped by a grating and cylindrical mirror, and then incident on a nonlinear crystal. Under phase-matching conditions, a broadband strong-field terahertz pulse is generated, and a parabolic mirror is used to focus the terahertz beam.

[0041] Step 2: The generated terahertz pulse is passed through a terahertz metamaterial polarizer to change its polarization state, and then through a metamaterial filter to obtain terahertz pulse signals of different frequency bands.

[0042] Step 3: Terahertz pulses irradiate the target tissue, thereby exciting a photoacoustic effect in a local area; the photoacoustic signal is received by an acoustic impedance transducer and an ultrasonic transducer, and then amplified by a preamplifier before being transmitted to a computer.

[0043] Because glucose in blood is chiral, the polarization of terahertz waves changes after traveling a certain distance. The photoacoustic signal is received by a preamplifier and a piezoelectric ultrasonic transducer, then filtered before being transmitted to a high-speed acquisition card, which transmits the acquired data to a computer.

[0044] Step 4: The data is processed in the computer. First, the acquired time-domain signal is deconvolved with the ultrasonic transducer response to obtain a more realistic and accurate time-domain photoacoustic signal. The horizontal axis of the obtained time-domain photoacoustic signal is multiplied by the speed of sound in the solution to reflect the data in terms of depth, so as to obtain the sound pressure amplitude at different depths. The ratio of the initial sound pressure and the sound pressure after penetrating a certain depth in the solution is selected to obtain the optical rotation. Based on the relationship between blood glucose concentration and optical rotation in the statistical data, a fitting is performed to obtain the blood glucose concentration in the target body. Finally, the detected blood glucose concentration is displayed in the computer.

[0045] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0046] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0047] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0048] In the embodiments provided by this invention, it should be understood that the disclosed apparatus / terminal devices and methods can be implemented in other ways. For example, the apparatus / terminal device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0049] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0050] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0051] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A high-sensitivity non-invasive blood glucose detection system based on polarized terahertz photoacoustics, characterized in that, The system includes: Terahertz excitation module, used to generate terahertz pulse signals; The terahertz control module includes a terahertz metamaterial polarizer and a terahertz metamaterial filter; the generated terahertz pulse is passed through the terahertz metamaterial polarizer again to change the terahertz polarization, and different frequency bands of terahertz are obtained through the metamaterial filter; The photoacoustic signal receiving module is used to irradiate the target tissue in the sample cell with terahertz at different frequency bands, thereby exciting the photoacoustic effect in a local area and receiving and identifying the photoacoustic effect to obtain the photoacoustic signal. The data acquisition and processing module collects photoacoustic signals through a filter using a data acquisition card and transmits them to a computer for processing. The acquired time-domain signal is deconvolved with the ultrasonic transducer response to obtain a more accurate time-domain photoacoustic signal. The horizontal axis of the obtained time-domain photoacoustic signal is multiplied by the speed of sound in the solution to reflect the data in terms of depth, further obtaining the sound pressure amplitude at different depths. The ratio of the initial sound pressure to the sound pressure after penetrating a certain depth in the solution is selected to obtain the optical rotation. Based on the relationship between blood glucose concentration and optical rotation in statistical data, a fitting is performed to obtain the blood glucose concentration in the target body.

2. The high-sensitivity non-invasive blood glucose detection system based on polarized terahertz photoacoustics according to claim 1, wherein the terahertz excitation module includes a femtosecond laser, a collimating lens, a grating, a cylindrical mirror, and a parabolic mirror. The laser generated by the femtosecond laser is collimated by the collimating lens, shaped by the grating and the cylindrical mirror, and then incident on a nonlinear crystal to generate a broadband strong-field terahertz pulse under phase-matching conditions. The parabolic mirror is used to focus the terahertz light spot.

3. The high-sensitivity non-invasive blood glucose detection system based on polarized terahertz photoacoustics according to claim 2, wherein the terahertz laser generates terahertz pulses with a frequency of 0.2–1.5 THz and a single pulse energy of 4 μJ.

4. The high-sensitivity non-invasive blood glucose detection system based on polarized terahertz photoacoustics according to claim 1, wherein the diameter of the terahertz light spot is 1.5 mm.

5. The high-sensitivity non-invasive blood glucose detection system based on polarized terahertz photoacoustics according to claim 1, wherein the photoacoustic signal receiving module includes a sample cell, an acoustic impedance matching layer, an ultrasonic transducer, and a preamplifier; the target tissue in the sample cell is irradiated with terahertz waves of different frequency bands, thereby exciting the photoacoustic effect in a local area; the photoacoustic signal is received by the acoustic impedance and ultrasonic transducer, and amplified by the preamplifier.

6. A highly sensitive non-invasive blood glucose detection method based on polarized terahertz photoacoustics, characterized in that, The method includes the following steps: Step 1: Generate a terahertz pulse signal; Step 2: The generated terahertz pulse is passed through a terahertz metamaterial polarizer to change its polarization state, and then passed through a metamaterial filter to obtain terahertz pulse signals of different frequency bands. Step 3: Terahertz pulses irradiate the target tissue, thereby exciting a photoacoustic effect in a local area; the photoacoustic signal is received by an acoustic impedance transducer and an ultrasonic transducer, and then amplified by a preamplifier before being transmitted to a computer. Step 4: The data is processed in the computer. First, the acquired time-domain signal is deconvolved with the ultrasonic transducer response to obtain a more realistic and accurate time-domain photoacoustic signal. The time on the horizontal axis of the obtained time-domain photoacoustic signal is multiplied by the sound velocity in the solution to reflect the data on the depth, so as to obtain the sound pressure amplitude at different depths. The ratio of the initial sound pressure and the sound pressure after penetrating a certain depth in the solution is selected to obtain the optical rotation. Based on the relationship between blood glucose concentration and optical rotation in the statistical data, fitting is performed to obtain the blood glucose concentration in the target body.

7. The high-sensitivity non-invasive blood glucose detection method based on polarized terahertz photoacoustics according to claim 6, the method further includes displaying the detected blood glucose concentration in a computer.

8. The high-sensitivity non-invasive blood glucose detection method based on polarized terahertz photoacoustics according to claim 6, wherein step 1 specifically involves the following steps: the laser generated by the femtosecond laser is collimated by a collimating lens, shaped by a grating and a cylindrical mirror, and then incident on a nonlinear crystal to generate a broadband strong-field terahertz pulse under phase-matching conditions, and the terahertz light spot is focused using a parabolic mirror.

9. The high-sensitivity non-invasive blood glucose detection method based on polarized terahertz photoacoustics according to claim 8, wherein the terahertz laser generates terahertz pulses with a frequency of 0.2–1.5 THz and a single pulse energy of 4 μJ.

10. The high-sensitivity non-invasive blood glucose detection method based on polarized terahertz photoacoustics according to claim 8, wherein the diameter of the terahertz light spot is 1.5 mm.

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