A microcavity vibrational spectrometer system and method for measuring intrinsic vibrational spectra of fine particulate matter

Abstract

The present application relates to fine particle sensing technology, and particularly relates to a microcavity vibration spectrum system and method for measuring inherent vibration spectrum of fine particles. The microcavity vibration spectrum system comprises an inherent vibration excitation light path unit and a microcavity detection light path unit; the inherent vibration excitation light path unit is sequentially provided with a pulsed light source, a vibrating mirror, an objective lens and a particle to be measured; and the microcavity detection light path unit is sequentially provided with a tunable laser light source, an adjustable attenuator, a polarization controller, a coupling optical waveguide, an optical microcavity, a photodetector and an oscilloscope. The present application can realize precise measurement of sound waves caused by particle vibration of mesoscale particles and biological particles with inherent vibration frequency in the sub-megahertz-gigahertz frequency range.

Description

Technical Field

[0001] This invention relates to fine particle sensing technology, specifically to a microcavity vibration spectrometer system and method for measuring the inherent vibration spectrum of fine particles. Background Technology

[0002] Objects of any scale possess inherent vibrations, ranging from chemical bonds, molecules, and quantum dots to macroscopic rocks and bridges. These objects possess a series of natural resonance frequencies, characteristic frequencies determined by their size, structure, and mechanical properties. Measuring the inherent vibrational spectrum of an object not only yields intrinsic properties such as its structure and mechanical properties (specifically including parameters like geometry, size, mass, and Young's modulus), but also holds promise for further inferring the object's species. Currently, vibrational spectrum measurements are primarily based on ultrasonic resonance spectrometers and optical vibrational spectrometers, which have become fundamental means of material characterization and identification. For example, Raman and infrared spectrometers specifically identify unique chemical bonds and molecular structures within molecules by detecting molecular vibrations; ultrasonic resonance spectrometers obtain the elastic tensor of a substance by measuring the vibrational spectrum of a single crystal particle. However, optical vibrational spectrometers are limited by the elastic scattering background, typically resolving vibrational frequencies in the high-frequency region above gigahertz; ultrasonic resonance spectrometers mainly rely on electrical ultrasonic transducers, and due to the inherent bandwidth and sensitivity limitations of the piezoelectric effect, they are usually used to detect particles in the low-frequency region below megahertz. Therefore, this field has long lacked vibrational spectrometer technology capable of covering microscopic and mesoscopic particles with natural frequencies in the megahertz-gigahertz range.

[0003] The natural frequencies of many micro- and nano-scale media particles (such as functional particles made of magnets, gold, and polymers) and biological cells (animal and plant cells, as well as fungi, bacteria, and viruses) typically lie in the tens of kilohertz to gigahertz range. Vibrational spectrum detection of particles within this spectral range is crucial for identifying their fine structures and provides a fingerprinting method for the regulation of particle geometry, structure, and function, which is of great significance for the fabrication, application, and development of the micro- and nano-scale fields. Furthermore, vibrational fingerprinting of biological particles is not only important for fundamental research in cell mechanics and pharmacology that relies on the analysis of cellular biomechanical properties, but its vibrational fingerprinting also holds promise for providing a method for rapid, label-free identification and detection of cell types and viability. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a microcavity vibration spectrometer system and method for measuring the inherent vibration spectrum of fine particulate matter. This invention enables precise measurement of acoustic waves induced by the vibrations of mesoscopic-scale particles and biological particles within the sub-megahertz to gigahertz frequency range.

[0005] In a first aspect, the present invention provides a microcavity vibration spectrometer system for measuring the intrinsic vibration spectrum of fine particulate matter, comprising an intrinsic vibration excitation optical path unit and a microcavity detection optical path unit; the intrinsic vibration excitation optical path unit is provided with a pulsed light source, a galvanometer, an objective lens and the particulate matter to be measured in sequence, and the microcavity detection optical path unit is provided with a tunable laser light source, an adjustable attenuator, a polarization controller, a coupling optical waveguide, the optical microcavity, a photodetector and an oscilloscope in sequence.

[0006] In this invention, the particulate matter to be tested can be an object of any shape, including but not limited to inorganic and organic particles, as well as biological particles such as cells and microorganisms; the optical microcavity can be any type, material, and shape, preferably including whispering-gallery microcavities, photonic crystal microcavities, Fabry-Perot cavities, etc., and optical microcavities fabricated by any process, preferably including on-chip integrated microdisk cavities, microring cavities, microbubble cavities, microspheres, etc. In this invention, the particulate matter to be tested is placed on the surface of the optical microcavity or on a solid substrate in contact with the optical microcavity. In this invention, the coupling waveguide can also be a micro / nano fiber, an integrated on-chip waveguide, or a prism, etc., a potential field coupling device.

[0007] Preferably, the oscilloscope includes a high-frequency oscilloscope and a low-speed oscilloscope. The low-speed oscilloscope is used to monitor the transmission spectrum of the microcavity optical mode, and the high-frequency oscilloscope is used to analyze the high-frequency vibration signal of the particles. The high-frequency oscilloscope and the photodetector are also equipped with a high-frequency amplifier.

[0008] Further preferably, the inherent vibration excitation optical path unit also includes a tunable attenuator, a reflector, a focusing lens, and a translation stage; used to adjust the intensity and spatial position of the pulse light, and to irradiate the fine particulate matter sensing area on the surface of the microcavity with the pulse light.

[0009] In a further preferred embodiment, the microcavity detection optical path unit also includes an erbium-doped fiber amplifier and a high-speed acquisition card; the erbium-doped fiber amplifier is used to amplify the optical signal, and the high-speed acquisition card is used for continuous acquisition of the optical signal.

[0010] Further preferably, the microcavity vibration spectrometer system also includes a particulate matter dilution atomization and microfluidic transport unit, which is used to dilute and atomize the solution of the particulate matter to be tested and transfer it to the surface of the optical microcavity through a gas microfluidic channel.

[0011] In a further preferred embodiment, the microcavity vibration spectrometer system also includes a laser frequency stabilization and mode-locking system, which is used to lock the laser frequency of the tuned single-frequency laser source within the optical mode to achieve long-term stable vibration detection.

[0012] In a further preferred embodiment, the microcavity vibration spectrometer system also includes a signal processing unit, which is used to detect the acoustic modulation signal and output time-domain and frequency-domain detection results.

[0013] Further preferably, the microcavity vibration spectrometer system also includes a signal amplification and noise processing unit; the acoustic wave modulation signal is amplified sequentially through a balanced detector, a high-pass filter, and a radio frequency amplifier. The balanced detector is also used to suppress common-mode noise, and the high-pass filter is set before and after the radio frequency amplifier to filter out low-frequency noise.

[0014] In a further preferred embodiment, the microcavity vibration spectrometer system also includes a pulsed laser spatial position scanning system; the pulsed laser spatial position scanning system is used together with the galvanometer and the electrically controlled three-dimensional translation stage to excite the particulate matter to be tested at any position of the three-dimensional sample, thereby realizing the imaging function.

[0015] Secondly, the method for measuring the inherent vibrational spectrum of fine particulate matter provided by the present invention includes the following steps:

[0016] 1) Place the particulate matter to be tested on the surface of the optical microcavity or on a solid substrate in contact with the optical microcavity;

[0017] 2) The laser from the pulsed light source irradiates the particulate matter under test, and the sound waves generated by the vibration of the particulate matter under test propagate to the region where the optical mode of the optical microcavity is located, causing the resonant frequency of the optical mode to shift.

[0018] 3) Single-frequency light is coupled through micro-nano optical waveguide-optical microcavity to excite optical modes. When the frequency of the single-frequency light is slightly detuned to the resonant frequency of the optical mode, the change in the mode resonant frequency caused by acoustic modulation is converted into a change in the intensity of transmitted light.

[0019] This invention solves the technical bottleneck by using electromagnetic pulse absorption to efficiently excite the inherent vibration modes of particulate matter, with a frequency range covering from sub-megahertz to over 10 GHz. It also achieves precise measurement of sound waves caused by particulate matter vibration through a highly sensitive optical microcavity ultrasonic sensor.

[0020] The beneficial effects of the microcavity vibration spectrometer system and method for measuring the intrinsic vibration spectrum of fine particulate matter provided by this invention include the following: 1) Narrow electromagnetic pulses can achieve the co-excitation of intrinsic vibration modes of particles of different sizes and mixed particles, and the frequency excitation range depends on the width of the electromagnetic pulse. For example, using a pulsed laser with a pulse width of 100 picoseconds (or 200 ps or other pulse widths), intrinsic vibration modes in a bandwidth range from low frequency to 10 GHz can be excited. 2) Using an optical microcavity ultrasonic sensor, acoustic signals generated by all vibration modes of particles of different sizes and mixed particles can be detected simultaneously, with a detection bandwidth covering from low frequency to above 1 GHz. 3) Based on the microcavity vibration spectrometer, this invention can obtain information such as the geometry, size, mass, and Young's modulus of an object through the intrinsic vibration spectrum of the particle, and can further infer the composition and type of the object and biological particles through the vibration fingerprint of the material. 4) Based on the microcavity vibration spectrometer, this invention can perform rapid statistical analysis of particulate matter and can be used for particle screening analysis, etc. Attached Figure Description

[0021] To more clearly illustrate the embodiments of the present invention and the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the principle of the microcavity vibration spectrometer provided in an embodiment of the present invention.

[0023] Figure 2 This is a schematic diagram of the optical path structure of the microcavity vibration spectrometer provided in an embodiment of the present invention.

[0024] Figure 3 The image shows the time-domain and spectral signal results of the microcavity vibration spectrometer used in this embodiment of the invention for measuring the inherent vibration of fine particulate matter.

[0025] Figure 4 The image shows the spectral signal results of measuring the inherent vibrations of mixed microbial particles and organic particles using a microcavity vibration spectrometer provided in this embodiment of the invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the invention clearer, the technical solutions of the embodiments of the invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without creative effort are within the scope of protection of the invention.

[0027] The following is combined Figures 1-4 This invention describes a microcavity vibration spectrometer system and method for measuring the inherent vibration spectrum of fine particulate matter. This invention overcomes technical bottlenecks by utilizing electromagnetic pulse absorption to efficiently excite the high-frequency inherent vibrations of particulate matter, covering a frequency range from low frequencies to above 10 GHz. Furthermore, it achieves precise measurement of the acoustic waves induced by particulate matter vibration through a highly sensitive optical microcavity ultrasonic sensor.

[0028] The microcavity vibration spectrometer system for measuring the intrinsic vibration spectrum of fine particulate matter provided in this invention includes an intrinsic vibration excitation optical path unit and a microcavity detection optical path unit. The intrinsic vibration excitation optical path unit sequentially comprises a pulsed light source, a galvanometer, an objective lens, and the particulate matter to be measured. The microcavity detection optical path unit sequentially comprises a tunable laser light source, an adjustable attenuator, a polarization controller, a coupling waveguide, the optical microcavity, a photodetector, and an oscilloscope. According to this invention, the microcavity vibration spectrometer system for measuring the intrinsic vibration spectrum of fine particulate matter utilizes a short laser pulse to excite the intrinsic vibration of the particulate matter and uses an optical microcavity ultrasonic sensor to detect the vibration spectrum of the fine particulate matter. Based on the optical microcavity ultrasonic sensor and the intrinsic vibration excitation of the fine particulate matter, it is possible to measure the vibration spectrum of mesoscopic-scale particulate matter and biological particles with intrinsic vibration frequencies in the sub-megahertz to gigahertz frequency range.

[0029] The test particles can be objects of any shape, including but not limited to inorganic and organic particles, as well as biological particles such as cells and microorganisms. The optical microcavities can be of any type, material, and shape, including whispering-gallery microcavities, photonic crystal microcavities, Fabry-Perot cavities, and optical microcavities fabricated using any process, including on-chip integrated microdisk cavities, microring cavities, microbubble cavities, and microspheres. The test particles are placed on the surface of the optical microcavity or on a solid substrate in contact with it. The coupling waveguide can also be a micro / nano fiber, an integrated on-chip waveguide, or a prism, etc., for potential field coupling.

[0030] Furthermore, the microcavity vibration spectrometer system for measuring the inherent vibration spectrum of fine particulate matter provided in this embodiment of the invention includes an oscilloscope comprising a high-frequency oscilloscope and a low-speed oscilloscope. The low-speed oscilloscope is used to monitor the transmission spectrum of the microcavity optical mode, and the high-frequency oscilloscope is used to analyze the high-frequency vibration signal of the particles. The high-frequency oscilloscope and the photodetector are also equipped with a high-frequency amplifier.

[0031] Furthermore, the microcavity vibration spectrometer system for measuring the intrinsic vibration spectrum of fine particulate matter provided in this embodiment of the invention further includes a tunable attenuator, a reflector, a focusing lens, and a translation stage in the intrinsic vibration excitation optical path unit; used to adjust the intensity and spatial position of the pulse light and to irradiate the fine particulate matter sensing area on the surface of the microcavity with the pulse light.

[0032] Furthermore, the microcavity vibration spectrometer system for measuring the inherent vibration spectrum of fine particulate matter provided in this embodiment of the invention further includes an erbium-doped fiber amplifier and a high-speed acquisition card in the microcavity detection optical path unit; the erbium-doped fiber amplifier is used to amplify the optical signal, and the high-speed acquisition card is used for continuous acquisition of the optical signal.

[0033] Furthermore, the microcavity vibration spectrometer system provided in this embodiment of the invention also includes a particulate matter dilution atomization and microfluidic transport unit, which is used to dilute and atomize the solution of the particulate matter to be tested and transfer it to the surface of the optical microcavity through a gas microfluidic channel.

[0034] Furthermore, the microcavity vibration spectrometer system provided in this embodiment of the invention also includes a laser frequency stabilization and mode-locking system, which is used to lock the laser frequency of the tuned single-frequency laser source within the optical mode to achieve long-term stable vibration detection.

[0035] Furthermore, the microcavity vibration spectrometer system provided in this embodiment of the invention also includes a signal processing unit, which is used to detect the acoustic modulation signal and output time-domain and frequency-domain detection results.

[0036] Furthermore, the microcavity vibration spectrometer system provided in this embodiment of the invention also includes a signal amplification and noise processing unit; the acoustic wave modulation signal is amplified sequentially through a balanced detector, a high-pass filter and a radio frequency amplifier, the balanced detector is also used to suppress common-mode noise, and the high-pass filter is set before and after the radio frequency amplifier to filter out low-frequency noise.

[0037] Furthermore, the microcavity vibration spectrometer system provided in this embodiment of the invention also includes a pulsed laser spatial position scanning system; the pulsed laser spatial position scanning system is used together with the galvanometer and the electrically controlled three-dimensional translation stage to excite the particulate matter to be tested at any position of the three-dimensional sample and realize the imaging function.

[0038] The method for measuring the inherent vibrational spectrum of fine particulate matter provided in this invention includes the following steps:

[0039] 1) Place the particulate matter to be tested on the surface of the optical microcavity or on a solid substrate in contact with the optical microcavity;

[0040] 2) The laser from the pulsed light source irradiates the particulate matter under test, and the sound waves generated by the vibration of the particulate matter under test propagate to the region where the optical mode of the optical microcavity is located, causing the resonant frequency of the optical mode to shift.

[0041] 3) Single-frequency light is coupled through micro-nano optical waveguide-optical microcavity to excite optical modes. When the frequency of the single-frequency light is slightly detuned to the resonant frequency of the optical mode, the change in the mode resonant frequency caused by acoustic modulation is converted into a change in the intensity of transmitted light.

[0042] A schematic diagram of the microcavity vibration spectrometer system provided in this embodiment of the invention is shown below. Figure 1 As shown, the microcavity vibration spectrometer (system) mainly consists of a silica micro / nano fiber (approximately 1 micrometer in diameter) and a silica microsphere cavity (approximately 60 micrometers in diameter) coupling system. The fine particles to be tested are placed at any position on the surface of the microcavity. To excite the inherent vibration of the fine particles, a short-pulse light beam in free space (wavelength 532 nm, pulse width 200 picoseconds) is used to irradiate the particles. The sound waves generated by the particle vibration on the surface of the microcavity are transmitted to the region where the whispering-gallery microcavity optical mode is located, modulating the resonant frequency of the microcavity. To detect the acoustic modulation generated by the vibration, a single-frequency continuous light beam (wavelength 1550 nm) emitted from a tunable laser source is coupled into the optical microcavity mode through the micro / nano fiber. The frequency of this continuous light is adjusted to be near the maximum slope of the Lorentz line of the optical mode. The change in the resonant frequency caused by the sound wave can be converted into a change in the transmission power of the fiber. Therefore, the time-domain signal and the corresponding power spectrum signal of the particle can be directly read out by a high-frequency detector.

[0043] The optical path of the microcavity vibration spectrometer provided in the embodiments of the present invention is as follows: Figure 2 As shown, the optical path mainly includes a free-space excitation optical path and a microcavity probe optical path. The free-space excitation optical path mainly includes a pulsed light source, a galvanometer, and an objective lens. Optional components such as a tunable attenuator, a reflector, a focusing lens, and a translation stage can be added to adjust the pulsed light intensity and spatial position, illuminating the fine particle sensing area on the microcavity surface. The microcavity probe optical path mainly includes a tunable laser source, a tunable attenuator, a polarization controller, coupled micro / nano optical fibers, a silica microsphere cavity, a photodetector, and electrical high-frequency amplifiers and oscilloscopes. Optional components such as an erbium-doped fiber amplifier and a high-speed acquisition card can be added to amplify the optical signal and continuously acquire the signal, respectively. A low-speed oscilloscope is used to monitor the transmission spectrum of the microcavity optical mode, while a high-frequency oscilloscope is used to analyze the high-frequency vibration signals of the particles.

[0044] The vibrational spectrum results of standard polystyrene microsphere particles measured by the microcavity vibrational spectrometer provided in the embodiments of the present invention are as follows: Figure 3As shown. In the implementation example, black polystyrene microspheres with a radius of 2.8 micrometers are placed on the surface of the silica microsphere cavity. The polystyrene particles are irradiated with pulsed light with an energy density of 2 picojoules per square micrometer. The temporal vibration of the particles can be obtained by measuring the transmission power change of the fiber-microcavity coupling system using a photodetector (the temporal vibration signal of the particles is shown in the figure). Figure 2 -As shown on the left). Then, the vibrational power spectrum signal of the particles (the inherent vibration spectrum of the particles, as shown on the left) is obtained by directly taking the Fourier transform of the time-domain signal. Figure 2 (As shown on the right). By comparing the particle vibration spectrum characteristics obtained from theory or simulation, the number of modes corresponding to each intrinsic vibration mode in the experimental data can be inferred.

[0045] The vibrational spectrum results of the microcavity vibrational spectrometer used in the embodiments of the present invention for measuring the vibrational spectra of mixed microorganisms and organic particles are as follows: Figure 4 As shown, Figure 4 The spores of Aspergillus niger were shown respectively. Figure 4 -Above), Aspergillus niger spores and Aspergillus ( Figure 4 - (in the middle), Aspergillus niger spores and Aspergillus fungi, as well as polystyrene spheres ( Figure 4 (Below) Simultaneously excitation measurements yield the vibration spectrum. In this implementation, different types of biological particles are placed on the surface of a microcavity. Wide-field pulsed light with an energy density of less than 5 picojoules per square micrometer is applied to the particles. The temporal vibrations of all particles excited by the pulsed light can be obtained by measuring the transmission power change of the fiber-microcavity coupling system using a photodetector. Then, the vibration power spectrum signal of the particles is obtained by directly taking a Fourier transform of the time-domain signal. Selective excitation of the particles can be achieved by modulating the size and position of the pulsed light spot.

[0046] In the description of this invention, it should be understood that the terms "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings or specific embodiments, and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0047] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0048] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "coupling," "connection," and "fixation," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0049] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0050] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; 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; and these 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.

Claims

1. A microcavity vibration spectrometer system for measuring the inherent vibrational spectrum of fine particulate matter, characterized in that, The system includes an intrinsic vibration excitation optical path unit and a microcavity detection optical path unit. The intrinsic vibration excitation optical path unit is sequentially provided with a pulsed light source, a galvanometer, an objective lens, and the particle to be tested. The microcavity detection optical path unit is sequentially provided with a tunable laser light source, a tunable attenuator, a polarization controller, a coupling waveguide, an optical microcavity, a photodetector, and an oscilloscope. The particle to be tested is placed on the surface of the optical microcavity or on a substrate in contact with the optical microcavity. The intrinsic vibration excitation optical path unit also includes a tunable attenuator, a reflector, a focusing lens, and an electrically controlled three-dimensional translation stage. The tunable attenuator, reflector, focusing lens, and electrically controlled three-dimensional translation stage are used to adjust the intensity and spatial position of the pulsed light, irradiating the fine particle sensing area on the surface of the microcavity with the pulsed light. The microcavity vibration spectrometer system also includes a particle dilution atomization and microfluidic transport unit, which is used to dilute and atomize the solution of the particle to be tested and transfer it to the surface of the optical microcavity through a gas microfluidic channel.

2. The microcavity vibration spectrometer system according to claim 1, characterized in that, The oscilloscope includes a high-frequency oscilloscope and a low-speed oscilloscope. The low-speed oscilloscope is used to monitor the transmission spectrum of the microcavity optical mode, and the high-frequency oscilloscope is used to analyze the high-frequency vibration signal of the particles. A high-frequency amplifier is also provided between the high-frequency oscilloscope and the photodetector.

3. The microcavity vibration spectrometer system according to claim 1, characterized in that, The microcavity detection optical path unit also includes an erbium-doped fiber amplifier and a high-speed acquisition card; the erbium-doped fiber amplifier is used to amplify the optical signal, and the high-speed acquisition card is used for continuous acquisition of the optical signal.

4. The microcavity vibration spectrometer system according to claim 1, characterized in that, The microcavity vibration spectrometer system also includes a laser frequency stabilization and mode-locking system, which is used to lock the laser frequency of the tunable laser source within the optical mode to achieve long-term stable vibration detection.

5. The microcavity vibration spectrometer system according to claim 4, characterized in that, The microcavity vibration spectrometer system also includes a signal processing unit, which is used to detect the acoustic modulation signal and output the time-domain and frequency-domain detection results.

6. The microcavity vibration spectrometer system according to claim 5, characterized in that, The microcavity vibration spectrometer system also includes a signal amplification and noise processing unit; the acoustic wave modulation signal is amplified sequentially through a balanced detector, a high-pass filter and a radio frequency amplifier. The balanced detector is also used to suppress common-mode noise, and the high-pass filter is set before and after the radio frequency amplifier to filter out low-frequency noise.

7. The microcavity vibration spectrometer system according to claim 6, characterized in that, The microcavity vibration spectrometer system also includes a pulsed laser spatial position scanning system; the pulsed laser spatial position scanning system is used together with the galvanometer and the electrically controlled three-dimensional translation stage to excite the particulate matter to be tested at any position in three-dimensional space to achieve imaging function.

8. A method for measuring the inherent vibrational spectrum of fine particulate matter, characterized in that, Measurements are performed using the microcavity vibration spectrometer system according to any one of claims 1-7, including: 1) Place the particulate matter to be tested on the surface of the optical microcavity or on a solid substrate in contact with the optical microcavity; 2) The laser from the pulsed light source irradiates the particle to be tested, and the sound waves generated by the vibration of the particle to be tested propagate to the region where the optical mode of the optical microcavity is located, causing the resonant frequency of the optical mode to shift. 3) Single-frequency light is coupled through micro-nano optical waveguide-optical microcavity to excite optical modes. When the frequency of the single-frequency light is slightly detuned to the optical mode resonant frequency, the change in the mode resonant frequency caused by acoustic modulation is converted into a change in the intensity of transmitted light.

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