Terahertz technology detection and identification system and method

Abstract

The invention discloses a terahertz technology detection and identification system and method, and relates to the technical field of terahertz technology material detection.The system comprises a femtosecond laser amplifier, a strong field terahertz radiation generation assembly, an electro-optical sampling assembly and a computer, and the femtosecond laser amplifier is used for emitting femtosecond laser pulses; the strong-field terahertz radiation generation assembly is used for generating a strong-field terahertz radiation beam and combining the strong-field terahertz radiation beam with the detection laser after the strong-field terahertz radiation beam penetrates through the to-be-detected sample; the electro-optical sampling assembly is used for electro-optical sampling; and the computer judges whether the to-be-detected sample is a natural material or an artificial material. According to the invention, the self-developed strong-field terahertz time-domain spectroscopy technology is used for detection, and compared with a traditional radioactive ray detection method and weak-field terahertz radiation, the strong-field terahertz radiation has the advantages of high power, high penetrability, high signal-to-noise ratio and the like in addition to low photon energy and no damage characteristics; the subtle differences of different materials of the same material can be identified more accurately, and the accuracy of detecting and identifying the types of the materials is effectively improved.

Description

Technical Field

[0001] This application relates to the technical field of terahertz technology for material detection, and particularly to a terahertz technology detection and identification system and method. Background Technique

[0002] Currently, the detection and identification of object materials such as natural materials and artificial materials are common in various fields. Taking bone graft materials as an example, for patients with a large amount of bone loss, bone augmentation surgery is essential, and it is necessary to detect whether the bone graft material is a natural material or an artificial material. Terahertz (THz) technology is commonly used in applications such as information transmission, identification, and material detection, and has been less studied in the field of stomatology. Currently, most traditional terahertz sensing technologies use weak-field terahertz radiation, and have mature applications in fields such as skin detection, tumor examination, and biological cell detection due to their advantages of low damage characteristics, high sensitivity to water, and no ionizing radiation. However, the low terahertz radiation field strength will be interfered by the internal structure and environmental noise when distinguishing the subtle differences of the same material, resulting in poor identification effect and low detection accuracy.

[0003] Moreover, most of the existing terahertz devices on the market are constructed based on traditional photoconductive antennas. Limited by technical bottlenecks such as low average power and weak field strength of the transmitter, there are problems such as poor penetration ability, low thickness measurement resolution, and blurred imaging quality in the actual application process. In addition, the main way to obtain high-power strong-field terahertz electromagnetic pulse output currently depends on the interaction between femtosecond lasers and matter. Driven by ultra-short laser pulses, there are various ways to realize terahertz strong sources, including photoconductive antennas, plasma excitation, spin electron effects, and optical rectification. Among them, the optical rectification technology using nonlinear crystals has become an effective method for generating strong-field terahertz pulses due to its "three highs" characteristics of high efficiency, high beam quality, and high stability. As a nonlinear optical frequency conversion process, the terahertz pulses generated by optical rectification largely depend on the characteristics of the nonlinear optical crystals used in terms of electric field waveform, spectral distribution, and conversion efficiency. The emergence of the tilted wavefront technology can achieve efficient phase matching in crystals with high nonlinear coefficients, realizing the generation of terahertz pulses with microjoule energy and electric field strength of hundreds of kV / cm. It has currently become the key core technology for developing strong-field terahertz light sources of nonlinear crystals.

[0004] Currently, common nonlinear materials include organic crystals, semiconductors, and lithium niobate ferroelectric crystals, etc. Among them, although organic crystals have the highest efficiency, their damage threshold is low (usually about 20 mJ / cm 2) In the case of long-term exposure, crystal degradation will occur. The band gaps of semiconductor ZnTe and GaP are relatively low, and there is obvious photon and photon absorption at common wavelengths. The generation of free carriers increases the terahertz absorption, making it difficult to improve the efficiency, and it is difficult to break through 0.02%. Lithium niobate crystals have a large nonlinear coefficient, a high damage threshold, and good stability, making them the best choice for high-field terahertz light sources. Moreover, due to the large band gap of lithium niobate materials, there is no two-photon absorption when pumped with a titanium sapphire laser, and there is no three-photon absorption when pumped with a ytterbium laser, ensuring the generation efficiency and beam quality of high-energy high-field terahertz pulses.

[0005] In summary, to solve the problems of low precision and poor effect existing in the traditional detection technology for the field strength of weak terahertz radiation, the present application selects lithium niobate crystals to build a high-field terahertz time-domain spectroscopy system (SF-TDS). Based on the self-built high-field terahertz time-domain spectroscopy system, a near-infrared femtosecond laser pulse is used to pump the lithium niobate crystal. Under the condition of using the tilted wavefront technology to achieve phase matching, a high-field terahertz radiation with an electric field strength reaching 500 kV / cm is obtained. It has the advantages of higher power, stronger penetration, and higher system signal-to-noise ratio, and can be effectively used in scenarios such as bone detection, improving the ability to distinguish and identify different types of materials of the same material such as natural materials and artificial materials. The system uses the electro-optic sampling technology to detect the terahertz time-domain signal, collects the terahertz time-domain signal coupled with the complete information of the sample to be detected, and performs data processing on the time-domain signal through a backend device such as a computer to obtain the frequency-domain spectrum of the signal, and can accurately and efficiently complete the detection and identification task according to the requirements. In addition, for example, in bone graft materials, high-field terahertz radiation with different polarization states can also distinguish the integrity of crystal arrangement, and has the potential to cooperate with traditional electromagnetic radiation methods to achieve early screening of bone problems and efficient and accurate monitoring of the bone remodeling process after bone augmentation surgery. Summary of the Invention

[0006] The purpose of the present application is to provide a terahertz technology detection and identification system and method, which can effectively improve the accuracy of detecting and identifying natural materials and artificial materials.

[0007] To achieve the above purpose, the present application provides the following solutions:

[0008] In a first aspect, the present application provides a terahertz technology detection and identification system, and the terahertz technology detection and identification system includes a femtosecond laser amplifier, a high-field terahertz radiation generation component, an electro-optic sampling component, and a computer.

[0009] The femtosecond laser amplifier, the strong-field terahertz radiation generation component, and the electro-optic sampling component are arranged in sequence along the optical path transmission path. The femtosecond laser amplifier and the electro-optic sampling component are respectively connected to the computer; a sample to be measured is placed inside the strong-field terahertz radiation generation component.

[0010] The femtosecond laser amplifier is used to emit femtosecond laser pulses.

[0011] The strong-field terahertz radiation generation component is used to respectively generate a strong-field terahertz radiation beam for detecting and identifying the material category of the sample to be measured and a probe laser for electro-optic sampling detection based on the femtosecond laser pulse. After the strong-field terahertz radiation beam passes through the sample to be measured, it is combined with the probe laser to form a first combined laser, and is emitted to the electro-optic sampling component.

[0012] The electro-optic sampling component is used to perform electro-optic sampling on the first combined laser to obtain a first measurement signal, and transmit the first measurement signal to the computer.

[0013] The computer is used to draw a terahertz time-domain waveform diagram according to the first measurement signal, and obtain a first detection result of the sample to be measured according to the terahertz time-domain waveform diagram, so as to realize the function of strong-field terahertz time-domain spectroscopy detection; wherein, the first detection result is used to distinguish the material category of the sample to be measured, and the category includes natural materials and artificial materials.

[0014] Optionally, the strong-field terahertz radiation generation component includes a strong-field terahertz radiation sub-component.

[0015] The strong-field terahertz radiation sub-component includes a beam splitter, multiple mirrors, a chopper, a grating, a mirror, a convex lens, a half-wave plate, a convex lens, a lithium niobate crystal, a mirror, and two sets of off-axis parabolic mirrors arranged in sequence along the strong-field terahertz radiation beam transmission path; the sample to be measured is arranged between the two sets of off-axis parabolic mirrors.

[0016] Optionally, the strong-field terahertz radiation generation component further includes a probe laser sub-component.

[0017] The probe laser sub-component includes multiple mirrors, a half-wave plate, and a convex lens arranged in sequence along the probe laser transmission path.

[0018] Optionally, the electro-optic sampling component includes an electro-optic crystal, a mirror, a convex lens, a quarter-wave plate, a Wollaston prism, a balanced detector, and a lock-in amplifier arranged in sequence along the optical path transmission path. The output end of the balanced detector is connected to the input end of the lock-in amplifier, and the output end of the lock-in amplifier is connected to the input end of the computer.

[0019] Optionally, the electro-optic crystal is a zinc telluride crystal.

[0020] Optionally, the terahertz technology detection and identification system further includes a laser pumping generation component.

[0021] The laser pumping generation component is disposed between the femtosecond laser amplifier and the electro-optic sampling component, and the femtosecond laser amplifier, the laser pumping generation component, and the electro-optic sampling component are arranged in sequence along the optical path transmission path.

[0022] The laser pumping generation component is configured to generate pump laser based on the femtosecond laser pulse. The pump laser and the strong-field terahertz radiation beam are combined at the position of the sample to be measured to form a second combined laser. After the second combined laser transmits through the sample to be measured, it enters the electro-optic sampling component.

[0023] The electro-optic sampling component is further configured to perform electro-optic sampling on the second combined laser to obtain a second measurement signal, and transmit the second measurement signal to the computer.

[0024] The computer is further configured to obtain a second detection result of the sample to be measured according to the second measurement signal, and implement the function of laser pumping-strong-field terahertz detection.

[0025] Optionally, the laser pumping generation component includes a reflecting mirror, a beam splitter, a plurality of reflecting mirrors, a chopper, and a reflecting mirror arranged in sequence along the pump laser transmission path.

[0026] Optionally, the terahertz technology detection and identification system further includes a weak-field terahertz radiation generation component.

[0027] The weak-field terahertz radiation generation component is disposed between the femtosecond laser amplifier and the electro-optic sampling component, and the femtosecond laser amplifier, the weak-field terahertz radiation generation component, and the electro-optic sampling component are arranged in sequence along the optical path transmission path.

[0028] The weak-field terahertz radiation generation component is configured to generate a weak-field terahertz radiation beam based on the femtosecond laser pulse. The weak-field terahertz radiation beam and the strong-field terahertz radiation beam are combined at the position of the sample to be measured to form a third combined laser. After the third combined laser transmits through the sample to be measured, it enters the electro-optic sampling component.

[0029] The electro-optic sampling component is further configured to perform electro-optic sampling on the third combined laser to obtain a third measurement signal, and transmit the third measurement signal to the computer.

[0030] The computer is further configured to obtain a third detection result of the sample to be measured according to the third measurement signal, so as to implement the terahertz pump-terahertz detection function.

[0031] Optionally, the weak-field terahertz radiation generating component includes a reflecting mirror, a beam splitter, a plurality of reflecting mirrors, a chopper, a reflecting mirror, a half-wave plate, a zinc telluride crystal, and a reflecting mirror, which are arranged in sequence along the transmission path of the weak-field terahertz radiation beam.

[0032] In a second aspect, the present application provides a terahertz technology detection and identification method, which includes the following steps.

[0033] Obtain a detection and identification instruction and a sample to be measured.

[0034] According to the detection and identification instruction, use the terahertz technology detection and identification system described in the first aspect to detect the sample to be measured, and obtain a first detection result of the sample to be measured. The first detection result is used to distinguish the category of the material of the sample to be measured, and the category includes natural materials and artificial materials.

[0035] According to the specific embodiments provided by the present application, the present application has the following technical effects.

[0036] The present application provides a new terahertz technology detection and identification system and method. The system includes a femtosecond laser amplifier, a strong-field terahertz radiation generating component, an electro-optic sampling component, and a computer. After the femtosecond laser amplifier emits femtosecond laser pulses, a strong-field terahertz radiation beam for detecting and identifying the material category of the sample to be measured and a probe laser for electro-optic sampling detection are respectively generated under the action of the femtosecond laser pulses by the strong-field terahertz radiation generating component. Among them, after the strong-field terahertz radiation beam passes through the sample to be measured, it will be combined with the probe laser to form a first combined laser. The electro-optic sampling component performs electro-optic sampling on the first combined laser to obtain a first measurement signal. The computer draws a terahertz time-domain waveform diagram according to the first measurement signal, and obtains a first detection result of the sample to be measured according to the terahertz time-domain waveform diagram, which is used to determine and distinguish whether the category of the material of the sample to be measured belongs to natural materials or artificial materials. Compared with the traditional weak-field terahertz technology, the present application utilizes the strong-field terahertz time-domain spectroscopy detection function. The strong-field terahertz radiation used has the inherent advantages of low damage characteristics, high sensitivity to water, and no ionizing radiation of electromagnetic waves in the terahertz frequency band, and at the same time has the advantages of higher power, stronger penetration, and higher system signal-to-noise ratio. It can be effectively used for material detection of objects and improves the resolution and identification ability of different types of materials of the same material, such as natural materials and artificial materials.

[0037] After strong-field terahertz radiation irradiates the sample to be detected and takes effect, the system uses electro-optic sampling technology to detect and collect the terahertz time-domain signal. The time-domain signal contains the complete material information of the sample to be detected, and has a prominent amplification effect on the characteristics of bone samples compared with weak-field terahertz signals. After data processing of the time-domain signal by a backend device such as a computer to obtain the frequency-domain spectrum of the signal, analysis can be carried out according to requirements to improve the accuracy and efficiency of detection and identification tasks. This application can distinguish the subtle differences between natural materials and artificial materials that are essentially the same substance, and can accurately and reliably distinguish whether the sample to be detected is a natural material or an artificial material, which is beneficial to the development of material category detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0039] Figure 1 FIG. 9 is a schematic structural diagram of a terahertz technology detection and identification system provided in Embodiment 1 of the present application.

[0040] Figure 2 FIG. 13 is a comparison chart of the characteristics of strong and weak field terahertz sources provided in Embodiment 1 of the present application.

[0041] Figure 3 FIG. 17 is a schematic diagram of the time-domain waveform of the reference signal provided in Embodiment 1 of the present application.

[0042] Figure 4 FIG. 21 is a comparison chart of the time-domain waveforms of bone powder particles, dental bone powder, dental bone and the time-domain waveform of the reference signal provided in Embodiment 1 of the present application.

[0043] Figure 5 FIG. 25 is a schematic diagram of the frequency-domain waveform dependent on the angle of autologous bone block provided in Embodiment 1 of the present application.

[0044] Figure 6 FIG. 29 is a comparison chart of the frequency-domain waveforms of bone powder particles, dental bone powder, and dental bone provided in Embodiment 1 of the present application.

[0045] Figure 7 FIG. 33 is a flowchart of a terahertz technology detection and identification method provided in Embodiment 2 of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0046] The following will clearly and completely describe the technical solutions in the embodiments of the present application in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application.

[0047] At present, the detection and identification of natural materials and artificial materials are widely used. Taking bone graft materials as an example, with the increasing living standards of the people and the development of dental implant centralized procurement technology, the demand for oral dental implants has increased year by year. Patients with a large amount of alveolar bone resorption or severe atrophy need to undergo bone augmentation surgery before implantation. According to the different bone graft materials (whether bone substitutes are used, etc.) and the location of the recipient alveolar bone (upper / lower jawbone, etc.), the time required for bone remodeling is also different (4 to 6 months or even longer). First of all, at present, there is no research on the detection and identification of oral bone graft materials using terahertz technology. Traditional weak-field terahertz technology has low penetration and cannot accurately distinguish natural materials and artificial materials.

[0048] \At present, due to the insufficient discrimination of natural materials and artificial materials, low bone density resolution, unclear soft tissue structure imaging, the existence of ionizing radiation and an uncertain distortion rate, the traditional radiological examination method has limitations in the monitoring of bone remodeling after bone augmentation surgery. Due to the diversity of bone augmentation techniques and the lack of relevant research, it is difficult to accurately evaluate the accurate implant timing after bone augmentation at present. In clinical practice, doctors mostly judge the timing of the second surgery (implantation or second stage) based on their own experience, and the waiting time is preferably long rather than short, increasing the time cost of implant treatment. In summary, there is currently a lack of an efficient and accurate method to evaluate the bone remodeling process after bone augmentation. Therefore, it is crucial to provide a system and method that can distinguish natural materials and artificial materials and has high detection and identification accuracy.

[0049] Based on this, the present application aims to provide a new terahertz technology detection and identification system and method. Using terahertz spectroscopy imaging technology, terahertz spectroscopy imaging technology has the advantages of low photon energy, strong penetration ability, and high material discrimination ability. It can not only effectively improve the accuracy of detecting and identifying material categories, accurately distinguish natural materials and artificial materials, but also shorten the detection cycle, reduce the detection time cost, and solve the above technical problems existing in the traditional radiological examination method.

[0050] To make the above objects, features, and advantages of the present application more obvious and understandable, the following further details the present application in conjunction with the accompanying drawings and specific embodiments.

[0051] Embodiment 1

[0052] As Figure 1As shown in the figure, this embodiment proposes a new terahertz technology detection and identification system. The terahertz technology detection and identification system includes a femtosecond laser amplifier, a strong-field terahertz radiation generation component, an electro-optic sampling component, a computer, etc. Among them, the femtosecond laser amplifier, the strong-field terahertz radiation generation component, and the electro-optic sampling component are arranged in sequence along the optical path transmission path. The femtosecond laser amplifier and the electro-optic sampling component are respectively connected to the computer; a sample to be measured is placed inside the strong-field terahertz radiation generation component.

[0053] In this embodiment, the femtosecond laser amplifier is used to emit femtosecond laser pulses. The strong-field terahertz radiation generation component is used to generate, based on the femtosecond laser pulses, a strong-field terahertz radiation beam for detecting and identifying the material category of the sample to be measured and a probe laser for electro-optic sampling detection. After the strong-field terahertz radiation beam passes through the sample to be measured, it is combined with the probe laser to form a first combined laser, and is emitted to the electro-optic sampling component. The electro-optic sampling component is used to perform electro-optic sampling on the first combined laser to obtain a first measurement signal, and transmit the first measurement signal to the computer. The computer is used to draw a terahertz time-domain waveform diagram according to the first measurement signal, and obtain a first detection result of the sample to be measured according to the terahertz time-domain waveform diagram, realizing the function of strong-field terahertz time-domain spectroscopy detection; among them, the sample to be measured is a sample that can be penetrated by the terahertz radiation beam, and the first detection result is used to distinguish the material category of the sample to be measured, and the category includes natural materials and artificial materials.

[0054] In this embodiment, the strong-field terahertz radiation generation component includes a strong-field terahertz radiation sub-component. The strong-field terahertz radiation sub-component includes a beam splitter, multiple reflectors (five), a chopper, a grating, a reflector, a convex lens, a half-wave plate, a convex lens, a lithium niobate crystal, a reflector, and two sets of off-axis parabolic mirrors, etc., arranged in sequence along the strong-field terahertz radiation beam transmission path; the sample to be measured is arranged between the two sets of off-axis parabolic mirrors.

[0055] In this embodiment, the strong-field terahertz radiation generation component further includes a probe laser sub-component. The probe laser sub-component includes multiple reflectors (seven), a half-wave plate, and a convex lens, etc., arranged in sequence along the probe laser transmission path.

[0056] In this embodiment, the electro-optic sampling component includes an electro-optic crystal, a reflector, a convex lens, a quarter-wave plate, a Wollaston prism, a balanced detector, and a lock-in amplifier, etc., arranged in sequence along the optical path transmission path. The output end of the balanced detector is connected to the input end of the lock-in amplifier, and the output end of the lock-in amplifier is connected to the input end of the computer. Among them, the electro-optic crystal is preferably a zinc telluride crystal.

[0057] In this embodiment, the terahertz technology detection and identification system further includes a laser pumping generation component. The laser pumping generation component is disposed between the femtosecond laser amplifier and the electro-optic sampling component, and the femtosecond laser amplifier, the laser pumping generation component, and the electro-optic sampling component are arranged in sequence along the optical path transmission path. The laser pumping generation component is used to generate pump laser based on the femtosecond laser pulse. The pump laser and the strong-field terahertz radiation beam are combined at the position of the sample to be measured to form a second combined laser. After the second combined laser transmits through the sample to be measured, it enters the electro-optic sampling component. The electro-optic sampling component is further used to perform electro-optic sampling on the second combined laser to obtain a second measurement signal, and transmit the second measurement signal to the computer. The computer is further used to obtain a second detection result of the sample to be measured according to the second measurement signal, so as to realize the laser pumping-strong-field terahertz detection (OPTP) function.

[0058] In this embodiment, the laser pumping generation component includes a reflector, a beam splitter, multiple reflectors (four), a chopper, and a reflector, etc., which are arranged in sequence along the pump laser transmission path.

[0059] In this embodiment, the terahertz technology detection and identification system further includes a weak-field terahertz radiation generation component. The weak-field terahertz radiation generation component is disposed between the femtosecond laser amplifier and the electro-optic sampling component, and the femtosecond laser amplifier, the weak-field terahertz radiation generation component, and the electro-optic sampling component are arranged in sequence along the optical path transmission path. The weak-field terahertz radiation generation component is used to generate a weak-field terahertz radiation beam based on the femtosecond laser pulse. The weak-field terahertz radiation beam and the strong-field terahertz radiation beam are combined at the position of the sample to be measured to form a third combined laser. After the third combined laser transmits through the sample to be measured, it enters the electro-optic sampling component. The electro-optic sampling component is further used to perform electro-optic sampling on the third combined laser to obtain a third measurement signal, and transmit the third measurement signal to the computer. The computer is further used to obtain a third detection result of the sample to be measured according to the third measurement signal, so as to realize the terahertz pumping-terahertz detection (TPTP) function.

[0060] In this embodiment, the weak-field terahertz radiation generation component includes a reflector, a beam splitter, multiple reflectors (four), a chopper, a reflector, a half-wave plate, a zinc telluride crystal, and a reflector, etc., which are arranged in sequence along the weak-field terahertz radiation beam transmission path.

[0061] It should be noted that the number and layout positions of the reflectors in the strong-field terahertz radiation generation component, the laser pumping generation component, the weak-field terahertz radiation generation component, and the electro-optic sampling component in this embodiment are not completely fixed, depending on the design of the optical path transmission. The number and layout positions of the reflectors can be set according to the actual situation.

[0062] Such as Figure 2As shown in the figure, traditional terahertz sources (weak-field terahertz sources) mainly include electrical methods such as vacuum electron method and quantum cascade laser method, as well as optical methods such as photoconductive antenna method and optical rectification method. Although their cost is low and the equipment is simple, their energy is low, the penetration ability for hard tissues is weak (about 2 mm), and the peak power is low, so it is impossible to meet the requirement of monitoring the entire bone remodeling tissue. The strong-field terahertz source used in this application utilizes a near-infrared femtosecond laser to pump a lithium niobate crystal, and technologies such as using an inclined wavefront to achieve phase matching have advantages such as strong penetration ability, high efficiency, and high beam quality. This embodiment intends to optimize and improve the existing terahertz spectroscopy imaging technology, give full play to the advantages of strong penetration ability and high signal-to-noise ratio of the strong-field terahertz, and proposes a system integrated with a strong-field terahertz radiation generation component, a laser pumping generation component, and a traditional weak-field terahertz radiation generation component to meet the needs of different research scenarios and the identification of different natural and artificial materials, etc.

[0063] In this embodiment, the sample to be measured is taken as an example of a bone graft material for illustration. The detection and identification of bone graft materials mainly involve distinguishing autologous bone and bone substitutes. This embodiment is optimized for the research direction of oral bone tissue based on the self-built strong-field terahertz time-domain spectroscopy system. The system includes a femtosecond laser amplifier, preferably a titanium-sapphire femtosecond laser amplifier. The center wavelength of the titanium-sapphire femtosecond laser amplifier is 800 nm, the pulse width is 35 fs, the repetition frequency is 1 kHz, and the maximum output pump energy is about 7 mJ. Femtosecond laser pulses are generated by the titanium-sapphire femtosecond laser amplifier and are divided into a stronger pump beam and a weaker probe beam (beam splitting ratio 9:1) by a beam splitter. The pump beam is modulated by a delay line and a chopper and then focused on a lithium niobate crystal to reflect and generate a strong-field terahertz radiation beam. The strong-field terahertz radiation beam generated in this system is based on the inclined wavefront technology. Through the optical rectification effect of the lithium niobate crystal, a strong-field terahertz radiation beam with a single-pulse energy of several microjoules can be generated by this method.

[0064] In order to match the research on the nonlinear response characteristics of different natural and artificial materials under strong-field terahertz pumping, this embodiment intends to configure time-resolved multi-spectral detection capabilities for the strong-field terahertz radiation generation component, including weak-field terahertz detection and optical detection. Therefore, a weak-field terahertz radiation generation component and a laser pumping generation component are correspondingly set up to provide an experimental basis for subsequent imaging of natural and artificial materials and in-vivo bone remodeling tissue and the evaluation of the bone remodeling process. This embodiment realizes the functions of strong-field terahertz radiation beams with different powers and near-infrared 800-nm femtosecond pulse irradiation - weak-field terahertz detection. Its modified optical path is as Figure 1As shown, the thicker red optical path indicates that most of the laser energy pumps the lithium niobate crystal to generate a strong-field terahertz radiation beam based on the tilted wavefront technology. The remaining laser energy can be used to pump the zinc telluride crystal to generate a weak-field terahertz radiation beam for irradiating the sample to be measured and terahertz electro-optic sampling respectively.

[0065] As Figure 1 shown, the femtosecond laser pulse emitted by the femtosecond laser amplifier is transmitted to the beam splitter and divided into pump light and probe light. Among them, the pump light has 90% of the laser energy and is used to pump the lithium niobate crystal to generate a strong-field terahertz radiation beam; the probe light has 10% of the laser energy and is used to generate weak-field terahertz detection and optical detection. Figure 1 A total of three delay lines are used. The delay line is essentially a one-dimensional translation stage, which can accurately control the moving position under the control of a computer. After installing a mirror on it, the optical path of the corresponding optical path can be adjusted.

[0066] The pump light split from the femtosecond laser pulse first passes through a chopper with a frequency synchronization of 500 Hz. The function of the chopper is to filter out high-frequency noise and improve the signal-to-noise ratio. The pump light then passes through a grating, and the function of the grating is to adjust the propagation direction of the laser and expand the beam. The two convex lenses after the grating are used to focus the pump laser and then transmit it into the lithium niobate crystal, whose function is to generate divergent terahertz radiation based on the optical rectification effect. The divergent terahertz radiation passes through two off-axis parabolic mirrors. The function of the first off-axis parabolic mirror is to collimate the terahertz radiation, and the function of the second off-axis parabolic mirror is to focus the terahertz wave at the sample to be measured. Then the terahertz wave diverging from the sample to be measured passes through two off-axis parabolic mirrors again. The function of the first off-axis parabolic mirror is to collimate the terahertz wave, and the function of the second off-axis parabolic mirror is to focus the terahertz wave at the zinc telluride crystal of the electro-optic sampling component. The electric field of the terahertz wave will change the refractive index of the electro-optic crystal, which is the basis for electro-optic sampling detection.

[0067] In this embodiment, the probe light passes through two beam splitters again and is respectively divided into three paths. The beam splitting ratios of these two beam splitters can be selected according to requirements. The first path of laser passes through a chopper with a synchronization of 500 Hz. The function of the chopper is to filter out high-frequency noise and improve the signal-to-noise ratio. Then it passes through the small hole at the back of the off-axis parabolic mirror and directly pumps the sample to be measured. This research method in which the pumping laser and the focused strong-field terahertz radiation beam act together on the sample to be measured is the laser pumping-strong-field terahertz detection function. The second path of laser passes through a chopper with a frequency of 500 Hz. The function of the chopper is to filter out high-frequency noise and improve the signal-to-noise ratio. Then it is pumped onto a zinc telluride crystal. The function of the zinc telluride crystal is different from that of the electro-optic crystal in the electro-optic sampling component and is used to generate a weak-field terahertz radiation beam. Subsequently, the weak-field terahertz radiation beam and the strong-field terahertz radiation beam act together on the sample to be measured. This is the terahertz pumping-terahertz detection function. The third path of laser is the laser for electro-optic sampling detection, that is, the probe laser. It passes through a convex lens. The function of the convex lens is to change the probe laser from collimated to focused. Combined with the electro-optic sampling component, the probe laser and the strong-field terahertz radiation beam are jointly focused on the zinc telluride crystal. Based on the electro-optic effect, the electric field of the strong-field terahertz radiation beam changes the refractive index of the electro-optic crystal. This change in the polarization state will change the polarization state of the third path of laser, from linear polarization to elliptical polarization close to linear polarization in shape. The third path of laser is collimated again by the convex lens. The function of the quarter-wave plate is to convert the elliptical polarization close to linear polarization into elliptical polarization close to circular polarization. The function of the Wollaston prism is to adjust and separate two orthogonal polarization components, and a balanced detector is used to collect the signals of the two orthogonal polarization states respectively. The function of the lock-in amplifier is to process and amplify the collected signals, and the terahertz time-domain waveform diagram is drawn through the graphic drawing software of the computer.

[0068] In this embodiment, a bone graft material is taken as an example, and the sample to be measured is a bone graft material. A sample holder is composed of two pieces of fused silica glass with a thickness of 1 mm, a through-hole diameter of 5 mm, and an intermediate spacer with a thickness of 2 mm. The sample to be measured is placed at the center of the through-hole diameter, and the time-domain waveforms of artificial bone powder, natural jaw bone powder, and natural jaw bone are respectively tested. A THz time-domain spectrometer is used, and the THz spot diameter of the THz time-domain spectrometer is 5 mm. The sample holder is used to confirm the THz focal position, obtain the time-domain waveform diagram of the reference signal, and locate the placement position of the sample holder. The second peak of the reference signal is generated after the reflection of the fused silica. The experimental process includes the following steps:

[0069] (1) Preparation of the sample for detection:

[0070] 11) Preparation of the bracket: To ensure that the sample thickness of the sample to be measured is uniform and flat, this embodiment designs a sample holder with a 3D-printed three-layer sandwich structure, with 1-mm-thick fused silica glass on both sides, an intermediate spacer thickness of 2 - 5 mm, and a central through-hole diameter of 5 - 10 mm. The sample to be measured is placed at the center position of the through-hole diameter.

[0071] 12) Sample preparation: Autologous bone was collected from the discarded bone tissue in the retromolar area generated during the extraction of wisdom teeth; the bone substitutes used were deproteinized bovine bone mineral (DBBM) artificial bone powder and artificial bone collagen, which are dominant in clinical applications.

[0072] 13) Sample treatment: Different natural and artificial material samples were classified. Autologous bone blocks and artificial bone collagen were cut according to the size of the sample holder. Autologous bone powder and artificial bone powder were evenly placed into the light-transmitting aperture until the internal space was completely filled and tightly adhered to the quartz glass.

[0073] (2) Acquisition and preprocessing of terahertz spectroscopic imaging data:

[0074] 21) Time-domain spectroscopic data acquisition: A terahertz time-domain spectroscopy system (TDS) was used to emit a series of short terahertz pulses, which passed through the sample to be measured and collected time-delay data and reflection / transmission signals. By scanning the optical delay line point by point, the terahertz time-domain spectroscopic data of the entire sample to be measured were collected.

[0075] 22) Frequency-domain spectroscopic data acquisition: A terahertz frequency-domain spectroscopy system (FDS) was used to emit a continuous wave with a wide frequency range, which passed through the sample to be measured and collected the response data of the sample to the terahertz wave. By scanning the frequency points to be measured point by point, the terahertz frequency-domain spectroscopic data of the entire sample to be measured were collected.

[0076] 23) Imaging data acquisition: Based on the terahertz time-domain spectroscopic data and frequency-domain spectroscopic data obtained by point-by-point scanning in TDS and FDS, by performing a two-dimensional spatial scan on the sample to be measured, the spectroscopic data at different positions were measured, and different three-dimensional imaging maps were constructed using these data. These images can reveal the internal structural differences of bone tissue materials.

[0077] 24) Data noise reduction and preprocessing: Since the experimental data cannot be completed on the same day, and the thicknesses of different natural and artificial materials with different morphologies cannot be absolutely the same. Therefore, when comparing the time-domain waveforms of different samples to be measured, it is necessary to first normalize the experimental data using formula (1):

[0078]

[0079] where, E nor_sam represents the terahertz time-domain signal after normalization processing, E sam represents the terahertz time-domain signal, and E max_ref represents the reference signal.

[0080] (3) Data analysis and repeatability verification:

[0081] 31) Spectral analysis: Analyze the spectral data obtained from TDS and FDS, and perform operations such as Fourier transform (FT), inverse Fourier transform (IFT), filtering, and denoising on the terahertz spectral data using the signal processing toolboxes of software such as MATLAB, Python, or Origin Lab to identify specific absorption peaks and characteristic frequencies, etc. These characteristics are related to the chemical compositions and structures of different natural and artificial materials.

[0082] 32) Imaging analysis: Use the image processing toolboxes of software such as MATLAB, Python, or OriginLab to reconstruct the terahertz imaging data, and further process the imaging results using algorithms such as edge detection and region segmentation to quantitatively analyze the feature information extracted from the imaging data, focusing on structural differences such as the internal porosity and density distribution of the sample to be measured. These characteristics can distinguish different types of natural and artificial materials.

[0083] 33) Repeatability verification: Adjust the light source intensity, detector sensitivity, sample holder, and position of the light passing aperture of the high-field terahertz instrument according to the data analysis results to ensure the best signal-to-noise ratio and imaging quality. Establish and record the terahertz bands and related parameters such as frequency selection, pulse timing, and energy level of relevant natural and artificial materials to achieve the best resolution and contrast.

[0084] In this embodiment, for the detection and identification scenario of bone graft materials, a comparative experiment was conducted on autologous human jawbone and deproteinized bovine bone matrix artificial bone powder. The results showed that the absorption characteristics of autologous bone and artificial bone powder were significantly different, and the terahertz spectroscopy imaging technology could distinguish the two tissues of autologous bone and artificial bone powder. Figure 3 The schematic diagram of the time-domain waveform of the reference signal is shown. Figure 4 The comparison diagram of the time-domain waveforms of bone powder particles (artificial bone powder), dental bone powder (natural jawbone powder), dental bone (natural jawbone), and the time-domain waveform of the reference signal is shown. According to Figure 4 It can be intuitively seen that there is no obvious difference in the time-domain waveforms of the three samples to be measured, namely bone powder particles, dental bone powder, and dental bone. Figure 5 The schematic diagram of the angle-dependent frequency-domain waveform of the autologous bone block (dental bone) is shown. In this embodiment, the angle-dependent time-domain waveform of dental bone was obtained, and there was also no obvious difference. In this embodiment, the frequency-domain waveforms of bone powder particles (artificial bone powder), dental bone powder (natural jawbone powder), and dental bone (natural jawbone) were calculated, as Figure 6As shown, it can be seen that artificial bone powder and natural jawbone exhibit different absorption situations at 0.35 THz. When the frequency is lower than 0.35 THz, the absorption of artificial bone powder is less than that of natural jawbone; when the frequency is higher than 0.35 THz, the absorption of artificial bone powder is higher than that of natural jawbone. Thus, the two substances, autologous bone and artificial bone powder, can be distinguished. That is to say, the terahertz frequency-domain waveforms of autologous bone and artificial bone powder have a demarcation point at the frequency of 0.35 THz. When the frequency is lower than 0.35 THz, the transmittance of artificial bone powder is higher than that of autologous bone; when the frequency is higher than 0.35 THz, the transmittance of artificial bone powder is lower than that of autologous bone. In addition, the terahertz spectral characteristics of autologous bone are not related to the shape of bone tissue. Whether it is autologous bone block or autologous bone powder, their frequency-domain waveform characteristics are roughly the same, suggesting that the terahertz spectral characteristics of different materials may be independent of their shape.

[0085] In this embodiment, the femtosecond laser pulses generated by the femtosecond laser amplifier are split into two beams by a beam splitter. One of the beams with stronger energy is the pump light, which has 90% of the laser energy and is used to pump the lithium niobate crystal to generate a strong-field terahertz radiation beam; the beam with weaker energy is the probe light, which has 10% of the laser energy and is used to generate weak-field terahertz detection and optical detection. The pump light passes through a 500 Hz chopper to filter out high-frequency noise and improve the signal-to-noise ratio, and then passes through a grating to adjust the propagation direction and expand the beam. The pump laser passes through a convex lens and is focused into the lithium niobate crystal, interacts with it and generates divergent terahertz radiation. The lithium niobate crystal belongs to a nonlinear electro-optic crystal and generates terahertz radiation through the optical rectification effect. When the femtosecond laser pulse propagates in the lithium niobate crystal, the difference frequency effect of light with different frequency components inside the lithium niobate crystal will generate a low-frequency polarization electric field, thereby radiating terahertz radiation outward. The divergent terahertz radiation passes through two off-axis parabolic mirrors, which respectively complete collimation and focusing at the position of the sample to be measured. Then, the terahertz wave diverging from the sample to be measured passes through two off-axis parabolic mirrors again to achieve collimation and is focused on the zinc telluride crystal in the electro-optic sampling component, changing the refractive index of the electro-optic crystal, which serves as the basis for electro-optic sampling detection.

[0086] In this embodiment, the zinc telluride crystal is an important device for detecting terahertz signals. The electro-optic sampling component mainly consists of an electro-optic crystal, a quarter-wave plate, a Wollaston prism, a balanced detector, a lock-in amplifier, etc. Among them, the electro-optic crystal can use the zinc telluride crystal. When the terahertz wave propagates to the zinc telluride crystal, the electric field of the terahertz wave will change the refractive index of the zinc telluride crystal, which in turn causes the linearly polarized probe light pulse to be modulated in the zinc telluride crystal, and then causes the probe laser to change from linear polarization to elliptical polarization. After the probe laser emitted from the electro-optic crystal enters the quarter-wave plate, the phase difference between the two polarization states of the elliptical polarization light changes. Then it enters the Wollaston prism, and the light in two orthogonal polarization directions exits at the separation angle of the prism and is received by the self-balanced detector. The difference in the intensities of the two polarization state lasers is proportional to the terahertz electric field. After being processed by a computer, the terahertz time-domain waveform diagram can be directly drawn.

[0087] The probe light is divided into three paths again after passing through two beam splitters. One of the laser beams passes through a 500 Hz chopper and directly pumps the sample to be measured through a small hole behind the off-axis parabolic mirror. This research method of the pump laser and the focused strong-field terahertz acting together at the sample to be measured is the laser pump-strong-field terahertz detection function. The second laser beam passes through a 500 Hz chopper and is pumped onto the zinc telluride crystal to generate a weak-field terahertz radiation beam, which then acts together with the strong-field terahertz radiation beam on the sample to be measured. This is the terahertz pump-terahertz detection function. The third laser beam is the laser for electro-optic sampling detection. It passes through a convex lens and is focused on the zinc telluride crystal together with the strong-field terahertz radiation beam. Based on the electro-optic effect, the electric field of the strong-field terahertz radiation beam changes the refractive index of the electro-optic crystal, thereby changing the polarization state of the third laser beam. The third laser beam is collimated again by the convex lens. The quarter-wave plate and the Wollaston prism are used to adjust the two orthogonal polarization components of the probe laser, and the balanced detector is used to collect them separately. After being processed by the lock-in amplifier, the terahertz time-domain waveform diagram is drawn in the self-written software of the computer. The computer can also control the movement of the delay line to change the optical path of the probe laser, which is used to map the electric field intensity of the terahertz wave at each moment and draw the shape of the terahertz pulse. Among them, the delay line in the optical path is essentially a one-dimensional translation stage. Two mirrors are placed on the one-dimensional translation stage. The computer can be used to control the delay line to move in two directions along a straight line. Therefore, the movement of the delay line can change the optical path of the corresponding laser. The delay line is equipped with a motor and a supporting control program. The movement of the delay line can be controlled by running the program on the computer.

[0088] In this embodiment, the lock-in amplifier is an electrical processing device at the backend. Its main function is to extract and amplify tiny signals hidden in the noise based on the coherence between the pump laser and the probe laser. The balanced detector is connected to the lock-in amplifier. The signal detected by the balanced detector is transmitted into the lock-in amplifier for processing, and then the processing result is transmitted to the control program of the computer to draw the terahertz time-domain waveform diagram for detecting and identifying the category of bone graft materials.

[0089] In this embodiment, when the first laser beam (i.e., the pump laser) and the strong-field terahertz radiation beam act on the sample to be measured together, the laser pumping-strong-field terahertz detection function can be realized; when the second laser beam (i.e., the weak-field terahertz radiation beam) and the strong-field terahertz radiation beam act together, the terahertz pumping-terahertz detection function can be realized. When there is only the strong-field terahertz radiation beam based on the third laser beam (i.e., the probe laser), the strong-field terahertz time-domain spectroscopy detection function can be realized. With a delay line, by controlling the delay line indirectly through the computer to control the movement of the mirror, the optical path of the probe laser can be changed, so that on the basis of the strong-field terahertz time-domain spectroscopy detection function, the function of mobile scanning can be realized. Integrating the above multiple detection functions in the same set of terahertz technology detection and identification system can be flexibly switched when conducting oral bone tissue research.

[0090] This embodiment fully considers the advantages of strong-field terahertz with strong penetration ability and high signal-to-noise ratio, and forms a system integrating multiple components and multiple detection modes such as strong-field terahertz radiation generation components, laser pumping generation components, and traditional weak-field terahertz radiation generation components. The combination of strong and weak makes up for each other's deficiencies, effectively improving the detection accuracy and detection efficiency, and meeting the needs of different research scenarios and the identification of different natural and artificial materials. Compared with the existing terahertz technology, in this application, using the strong-field terahertz time-domain spectroscopy detection function, after the strong-field terahertz radiation irradiates the sample to be detected and acts, the detected time-domain signal contains the complete material information of the sample to be detected, and has a prominent amplification effect on the characteristics of bone samples compared with weak-field terahertz signals. This application can distinguish the subtle differences between samples of different categories that are essentially the same substance, can accurately and reliably distinguish whether the sample to be measured belongs to natural materials or artificial materials, can effectively improve the accuracy and reliability of detecting the material category, and is conducive to the development of material category detection and identification.

[0091] Embodiment 2

[0092] As Figure 7 shown, this embodiment provides a terahertz technology detection and identification method, and this terahertz technology detection and identification method includes the following steps.

[0093] Step S1, obtain the detection and identification instruction and the sample to be measured.

[0094] Step S2: According to the detection and identification instruction, use the terahertz technology detection and identification system in Embodiment 1 to detect the sample to be tested, and obtain various corresponding detection results of the sample to be tested.

[0095] A terahertz technology detection and identification system and method provided by the present application emit femtosecond laser pulses through a femtosecond laser amplifier. Under the action of the femtosecond laser pulses, a strong-field terahertz radiation beam for detecting and identifying bone graft materials and a probe laser for electro-optic sampling detection are respectively generated by a strong-field terahertz radiation generation component. Among them, after the strong-field terahertz radiation beam passes through the sample to be tested, it will be combined with the probe laser to form a first combined laser. The electro-optic sampling component performs electro-optic sampling on the first combined laser to obtain a first measurement signal. The computer draws a terahertz time-domain waveform diagram according to the first measurement signal, and obtains a first detection result of the sample to be tested according to the terahertz time-domain waveform diagram, which is used to judge and distinguish whether the material category of the sample to be tested belongs to natural materials or artificial materials. Compared with the existing terahertz technology, the present application utilizes the strong-field terahertz time-domain spectroscopy detection function, combines the characteristic that the time-domain signal contains the complete material information of the sample to be detected, and the strong-field terahertz signal has a prominent effect on the material characteristics of bone samples, realizing the distinction of the subtle differences between different materials (natural materials and artificial materials) that are essentially the same substance. It can accurately and reliably distinguish whether the sample to be tested is natural material or artificial material, effectively improving the accuracy and reliability of detecting and identifying natural materials and artificial materials, and is conducive to the development of material category detection.

[0096] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered that the scope described in this specification.

[0097] Specific examples are used in this article to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, based on the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A terahertz technology detection and identification system, characterized in that, The terahertz technology detection and identification system includes a femtosecond laser amplifier, a high-field terahertz radiation generation component, an electro-optic sampling component, and a computer; The femtosecond laser amplifier, the high-field terahertz radiation generation component, and the electro-optic sampling component are arranged in sequence along the optical path transmission path. The femtosecond laser amplifier and the electro-optic sampling component are respectively connected to the computer; A sample to be measured is placed inside the high-field terahertz radiation generation component; The femtosecond laser amplifier is used to emit femtosecond laser pulses; The high-field terahertz radiation generation component is used to generate a high-field terahertz radiation beam for detecting and identifying the material category of the sample to be measured and a probe laser for electro-optic sampling detection based on the femtosecond laser pulse. After the high-field terahertz radiation beam passes through the sample to be measured, it is combined with the probe laser to form a first combined laser, and is emitted to the electro-optic sampling component; The electro-optic sampling component is used to perform electro-optic sampling on the first combined laser to obtain a first measurement signal, and transmit the first measurement signal to the computer; The computer is used to draw a terahertz time-domain waveform diagram based on the first measurement signal, and obtain a first detection result of the sample to be measured according to the terahertz time-domain waveform diagram, realizing the function of high-field terahertz time-domain spectroscopy detection; Among them, the first detection result is used to distinguish the material category of the sample to be measured, and the category includes natural materials and artificial materials.

2. The terahertz technology detection and identification system according to claim 1, characterized in that, The high-field terahertz radiation generation component includes a high-field terahertz radiation sub-component; The high-field terahertz radiation sub-component includes a beam splitter, multiple reflectors, a chopper, a grating, a reflector, a convex lens, a half-wave plate, a convex lens, a lithium niobate crystal, a reflector, and two sets of off-axis parabolic mirrors arranged in sequence along the high-field terahertz radiation beam transmission path; The sample to be measured is arranged between the two sets of off-axis parabolic mirrors.

3. The terahertz technology detection and identification system according to claim 2, wherein The high-field terahertz radiation generation component further includes a probe laser sub-component; The probe laser sub-component includes multiple reflectors, a half-wave plate, and a convex lens arranged in sequence along the probe laser transmission path.

4. The terahertz technology detection and identification system according to claim 1, characterized in that, The electro-optic sampling component includes an electro-optic crystal, a reflector, a convex lens, a quarter-wave plate, a Wollaston prism, a balanced detector, and a lock-in amplifier arranged in sequence along the optical path transmission path. The output end of the balanced detector is connected to the input end of the lock-in amplifier, and the output end of the lock-in amplifier is connected to the input end of the computer.

5. The terahertz technology detection and identification system according to claim 4, wherein The electro-optic crystal is a zinc telluride crystal.

6. The terahertz technology detection and identification system according to claim 1, characterized in that, The terahertz technology detection and identification system further includes a laser pumping generation component; The laser pumping generation component is arranged between the femtosecond laser amplifier and the electro-optic sampling component, and the femtosecond laser amplifier, the laser pumping generation component, and the electro-optic sampling component are arranged in sequence along the optical path transmission path; The laser pumping generation component is used to generate pump laser based on the femtosecond laser pulse. The pump laser and the strong-field terahertz radiation beam are combined at the position of the sample to be measured to form a second combined laser. The second combined laser is transmitted through the sample to be measured and then enters the electro-optic sampling component; The electro-optic sampling component is further used to perform electro-optic sampling on the second combined laser to obtain a second measurement signal, and transmit the second measurement signal to the computer; The computer is further used to obtain a second detection result of the sample to be measured according to the second measurement signal, so as to realize the laser pumping-strong-field terahertz detection function.

7. The terahertz technology detection and identification system according to claim 6, characterized in that, The laser pumping generation component includes a reflecting mirror, a beam splitter, multiple reflecting mirrors, a chopper and a reflecting mirror arranged in sequence along the transmission path of the pump laser.

8. The terahertz technology detection and identification system according to claim 1, characterized in that, The terahertz technology detection and identification system further includes a weak-field terahertz radiation generation component; The weak-field terahertz radiation generation component is arranged between the femtosecond laser amplifier and the electro-optic sampling component, and the femtosecond laser amplifier, the weak-field terahertz radiation generation component and the electro-optic sampling component are arranged in sequence along the optical path transmission path; The weak-field terahertz radiation generation component is used to generate a weak-field terahertz radiation beam based on the femtosecond laser pulse. The weak-field terahertz radiation beam and the strong-field terahertz radiation beam are combined at the position of the sample to be measured to form a third combined laser. The third combined laser is transmitted through the sample to be measured and then enters the electro-optic sampling component; The electro-optic sampling component is further used to perform electro-optic sampling on the third combined laser to obtain a third measurement signal, and transmit the third measurement signal to the computer; The computer is further used to obtain a third detection result of the sample to be measured according to the third measurement signal, so as to realize the terahertz pumping-terahertz detection function.

9. The terahertz technology detection and identification system according to claim 8, wherein, The weak-field terahertz radiation generation component includes a reflecting mirror, a beam splitter, multiple reflecting mirrors, a chopper, a reflecting mirror, a half-wave plate, a zinc telluride crystal and a reflecting mirror arranged in sequence along the transmission path of the weak-field terahertz radiation beam.

10. A terahertz technology detection and identification method, characterized in that, The terahertz technology detection and identification method includes: Obtain a detection and identification instruction and a sample to be measured; According to the detection and identification instruction, use the terahertz technology detection and identification system described in any one of claims 1-9 to detect the sample to be measured, and obtain a first detection result of the sample to be measured. The first detection result is used to distinguish the category of the material of the sample to be measured, and the category includes natural materials and artificial materials.

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