Hollow-core optical fiber micro-lens coupler and Raman analysis method and system based on hollow-core optical fiber micro-lens coupler

Abstract

The invention belongs to the field of Raman spectrum testing, and particularly discloses a hollow-core optical fiber micro-lens coupler and a Raman analysis method and system based on the hollow-core optical fiber micro-lens coupler. According to the application, the micro-lens array and the hollow-core optical fiber array are introduced, a single light source is split into multiple beams of exciting light, the multiple beams of exciting light are respectively coupled into the multiple hollow-core optical fibers, and each hollow-core optical fiber can be independently inserted into different holes of the microbial porous plate, so that multi-channel parallel detection is realized; by utilizing the Raman enhancement effect of the hollow-core optical fiber array, the interaction intensity of light and a microorganism culture solution is remarkably improved, so that the intensity of a Raman signal is greatly improved; by utilizing the special structure of the hollow-core optical fiber, efficient detection can be realized only by extracting a sample with a microliter-level volume, so that the consumption of the sample is remarkably reduced. Meanwhile, due to the high transmission efficiency of the hollow-core optical fiber and the rapid optical path coupling capability of the micro-lens array, the detection speed of the device is greatly improved.

Description

Technical Field

[0001] This application belongs to the field of Raman spectroscopy testing. More specifically, it relates to a hollow fiber microlens coupler, a Raman analysis method and system based on the same. Background Art

[0002] Microbial microplates are widely used in biological and medical research, especially in aspects such as microbial culture, drug screening, pathogen detection, etc. Traditional detection methods usually rely on chemical analysis (such as colorimetry, enzyme-linked immunosorbent assay ELISA) or fluorescence labeling techniques (such as fluorescence microscopy, flow cytometry). Although these methods can meet the detection requirements to a certain extent, they usually have problems such as low sensitivity, long detection time, and large reagent consumption. For example, chemical analysis methods often require complex sample pretreatment steps (such as staining, labeling, incubation, etc.), resulting in a long detection cycle; although fluorescence labeling techniques can provide high sensitivity, they rely on expensive fluorescent dyes and labeling reagents, and have limited detection ability for low-concentration samples. In addition, traditional methods usually can only detect single or a small number of samples, making it difficult to achieve high-throughput screening and unable to meet the requirements of modern biomedical research for rapid and dynamic monitoring. Traditional methods often need to take samples out of the microplate for offline analysis and cannot achieve online detection and real-time monitoring. Therefore, it is of great significance to develop a technology that can directly perform efficient, sensitive, and online detection of samples in microbial microplates.

[0003] Due to its advantages such as high sensitivity, non-destructive detection, and no need for labeling, Raman spectroscopy has become an ideal real-time detection technology. Combining Raman spectroscopy with microbial microplates can achieve online monitoring of microorganisms in the culture solution, and then analyze the metabolites or growth status of microorganisms in real time. However, due to the small pore size and complex structure of the microplate, how to efficiently couple the excitation light source into each pore and enhance the Raman signal has always been a technical problem in this field. Traditional fiber Raman spectroscopy technology usually uses solid-core fibers. In solid-core fibers, light mainly transmits in the core material, and the direct interaction volume with the sample is small, resulting in limited Raman signal intensity and difficult to meet the detection requirements of trace samples. In addition, traditional fiber coupling methods usually can only achieve single-point detection and cannot meet the requirements of high-throughput detection.

[0004] As a new type of optical fiber, the hollow core fiber (HCF) has an air core, and light propagates in the air, effectively reducing the nonlinear effect and transmission loss. The anti-resonant hollow core fiber (AR-HCF) further enhances the interaction between light and matter through special structural design, significantly improving the intensity of Raman scattering signals. In recent years, the application of AR-HCF in Raman spectroscopy has gradually attracted attention, and its excellent Raman gain effect provides a new solution for the rapid and highly sensitive detection of trace samples. However, there are still many technical obstacles in applying hollow core fibers to the detection of microbial microplates. First, the pore size of microbial microplates is small and the structure is complex. How to efficiently couple the excitation light source into each well and enhance the Raman signal is a technical difficulty. Second, the core diameter of the hollow core fiber is usually in the micron range. How to ensure that the sample liquid can be stably and uniformly filled into the hollow core fiber while avoiding air bubble residues and sample cross-contamination is also a problem that needs to be solved. In addition, the high-throughput detection of microbial microplates requires multi-channel parallel operation. How to design an efficient optical path system and signal acquisition system to achieve multi-channel synchronous detection is also a challenge that those skilled in the art need to overcome.

[0005] In summary, although the Raman spectroscopy technology based on hollow core fibers and the detection technology combining Raman spectroscopy and microbial microplates each have unique advantages, there are still many technical obstacles in how to organically combine these technologies to achieve high-throughput and highly sensitive on-line detection of microbial microplates. Summary of the Invention

[0006] Aiming at the defects of the prior art, the purpose of this application is to provide a hollow core fiber microlens coupler, a Raman analysis method and system based on it, aiming to solve the problem that the prior art cannot perform on-line detection of microbial microplates with high throughput and high sensitivity.

[0007] The first aspect of this application relates to a hollow core fiber microlens coupler, which sequentially includes along the optical path: a beam splitting element, a beam separation element, a microlens array and a hollow core fiber array, where The beam splitting element splits the beam of the excitation light source into multiple beams of excitation light. The multiple beams of excitation light are reflected by the beam separation element to the microlens array and are uniformly coupled into the hollow core fiber array through the microlens array, so that Raman scattering light is generated after the excitation light interacts with the microbial culture solution; The back-propagating Raman scattering light exits from the ports of the hollow core fiber array, is collimated by the microlens array and transmitted by the beam separation element in sequence to obtain enhanced Raman signals; The coupler further includes a hollow-core fiber sealing adapter, which is loaded and sealed with a microlens array and a hollow-core fiber array at both ends, and is equipped with a pump for pumping the microbial culture solution in the microbial microplate into the hollow-core fiber or discharging it from the hollow-core fiber.

[0008] Preferably, the multiple excitation light beams after beam splitting are arranged in a one-dimensional array, and the spacing between adjacent light beams is the same.

[0009] Preferably, the beam splitting element is a diffraction beam splitting element for realizing a one-dimensional light beam array with equally spaced and uniform spot energy distribution of adjacent light beams.

[0010] Preferably, the microlenses in the microlens array, the hollow-core fibers in the hollow-core fiber array, are consistent with the number, arrangement mode, and spacing of the multiple excitation light beams after beam splitting.

[0011] Preferably, the focal length of the microlenses in the microlens array ranges from 1 mm to 5 mm.

[0012] Preferably, the hollow-core fiber is a hollow-core anti-resonant fiber core with a diameter on the order of micrometers.

[0013] Preferably, a coupling lens is further included, which is located between the beam splitting element and the beam separation element for focusing the excitation light after beam splitting to the microlens array after being reflected by the beam separation element, and the beam splitting angle of the beam splitting element and the focal length of the coupling lens satisfy the following relationship:

[0014] Wherein, is the focal length of the coupling lens, is the beam splitting angle of the diffraction element, is the spacing between adjacent light beams after beam splitting.

[0015] Preferably, the following relationship is satisfied between the focal length of the microlenses in the microlens array and the mode field diameter of the hollow-core fiber:

[0016] Wherein, is the focal length of the microlens, is the mode field diameter of the hollow-core fiber, is the excitation light wavelength, is the spot size of the Gaussian light beam focused on the image plane after transmitting a specific distance, and the specific distance is the distance from the focus of the coupling lens to the microlens array.

[0017] The second aspect of the present application relates to a Raman analysis system based on a hollow-core fiber microlens coupler, including: an excitation light source, a hollow-core fiber microlens coupler as described in the first aspect, a focusing lens, and a spectrometer; The hollow-core fiber microlens coupler is used to couple the excitation light source into each well of the microbial microplate and form an enhanced Raman signal; A focusing lens is used to focus the enhanced Raman signal onto the slit of the spectrometer; A spectrometer is used to collect Raman scattered light and generate a Raman spectrogram.

[0018] The third aspect of this application relates to a Raman analysis method based on the hollow-core fiber microlens coupler as described in the first aspect, including: S1. Inject rare gas into the hollow-core fiber until its internal channel is completely filled. After the gas stabilizes, obtain the background spectrum of the hollow-core fiber in the rare gas environment; S2. Extract the microbial culture solution in the microbial microplate into the hollow-core fiber until the liquid completely fills its internal channel. After the liquid stabilizes, obtain the Raman spectrum of the sample to be tested; S3. Subtract the Raman spectrum of the sample to be tested from the background spectrum of the hollow-core fiber in the rare gas environment, and then filter the obtained spectrum and remove the spectral baseline drift to obtain the pure Raman spectrogram of the microbial culture solution.

[0019] It can be understood that the beneficial effects of the above second aspect to the third aspect can be referred to the relevant descriptions in the first aspect above, and will not be elaborated here.

[0020] Generally speaking, compared with the prior art through the above technical solutions conceived in this application, the following beneficial effects are achieved: (1) This application introduces a microlens array (MLA) and a hollow-core fiber array, which splits a single light source into multiple beams of excitation light and couples them into multiple hollow-core fibers respectively. Each hollow-core fiber can be independently inserted into different wells of the microbial microplate, realizing multi-channel parallel detection. This design not only improves the detection efficiency, but also can monitor the growth state and metabolite changes of the microbial culture solution in real time, providing a powerful tool for biological and medical research.

[0021] (2) This application utilizes the Raman enhancement effect of the hollow-core fiber array to significantly increase the interaction intensity between light and the microbial culture solution, thereby greatly enhancing the intensity of the Raman signal and enabling high-sensitivity detection of low-concentration microbial culture solutions. This advantage has important application values in fields such as pathogen detection and drug screening.

[0022] (3) By utilizing the special structure of the hollow-core fiber, this application can achieve efficient detection by extracting only a microliter-level sample volume, significantly reducing the sample consumption. Meanwhile, the high transmission efficiency of the hollow-core fiber and the fast optical path coupling ability of the microlens array enable a substantial increase in the detection speed of this application, capable of completing high-throughput detection of multiple samples in a microplate in a short time. This advantage has broad application prospects in fields such as drug screening and environmental monitoring. Description of the Drawings

[0023] Figure 1 FIG. 1 is a schematic structural diagram of a Raman analysis system based on a hollow-core fiber microlens coupler provided by an embodiment of this application.

[0024] In all the drawings, the same reference numerals are used to represent the same elements or structures, where: 1 is a laser, 2 is a beam splitting element, 3 is a coupling lens L1, 4 is a beam separation element, 5 is a microlens array, 6 is a hollow-core fiber array, 7 is a hollow-core fiber sealing adapter, 8 is a microbial microplate, 9 is a long-pass filter, 10 is a focusing lens L2, and 11 is a spectrometer. Detailed Embodiments

[0025] In order to make the objectives, technical solutions, and advantages of this application clearer, the following further elaborates on this application in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0026] The embodiments of this application will be described below with reference to the drawings in the embodiments of this application.

[0027] As Figure 1 shown, this application provides a Raman analysis system based on a hollow-core fiber microlens coupler, and the Raman analysis system includes: a laser 1, a beam splitting element 2, a coupling lens L1 (3), a beam separation element 4, a microlens array 5, a hollow-core fiber array 6, a hollow-core fiber sealing adapter 7, a microbial microplate 8, a long-pass filter 9, a focusing lens L2 (10), and a spectrometer 11.

[0028] The laser 1 is used to excite the spontaneous Raman signal in the microbial culture solution. In this embodiment, a diode-pumped solid laser is preferably used, and its working wavelength is any wavelength in the ultraviolet-near infrared band, and typical values include but are not limited to 532 nm, 633 nm, 785 nm; the line width of the output excitation light is less than 0.003 nm, the output power is continuously adjustable in the range of 1 mW to 1500 mW, and the M² factor is less than 1.1, ensuring the high quality and stability of the laser beam. It should be noted that the diode-pumped solid laser is not the only option in this application, and other types of light sources (such as semiconductor lasers, fiber lasers, etc.), as long as they can meet the requirements of wavelength, line width, power, and beam quality, can be used as alternatives.

[0029] The beam splitting element 2 is used to split a single laser beam into a one-dimensional beam array and ensure that the spot energy of adjacent beams after splitting is evenly distributed and the angular interval is the same. In this embodiment, a diffraction beam splitting element is preferably used, and its material can be fused quartz, ZnSe, or optical plastic, and an antireflection film for the excitation light wavelength is coated on the surface to minimize the light energy loss. After being split by the diffraction beam splitting element, the spacing between adjacent beams can be calculated by the formula: , where is the focal length of the coupling lens L1, is the diffraction angle of the diffraction element for beam splitting. By reasonably designing the parameters of the diffraction beam splitting element, efficient beam splitting and uniform distribution of multiple excitation beams can be achieved, providing a basis for subsequent multi-channel detection.

[0030] The coupling lens L1 (3) is used to focus the excitation light, and the diameter of the focused spot can be calculated by the formula: , where is the excitation light wavelength, is the focal length of the coupling lens L1, is the diameter of the collimated light beam.

[0031] The beam separation element 4 is mainly used to separate the laser from the Raman scattered light and filter out most of the Rayleigh scattered light in the excitation optical path. In this embodiment, a dichroic mirror is preferably used, which can efficiently reflect the excitation light and transmit the Raman scattered light, realizing an equidistant and same-intensity one-dimensional array beam distribution. The laser is emitted by the laser, forms excitation light after passing through the diffraction beam splitting element and the coupling lens L1, enters the hollow fiber and interacts with the sample to generate Raman scattered light. The reflectivity of the dichroic mirror to the laser (Rayleigh scattered light) is not less than 98%, and the transmittance to the Raman scattered light with a longer wavelength is not less than 93%. In this application, the reflecting surface of the dichroic mirror must be placed at an angle of 45° to the laser incident direction. This angle design can not only maximize the separation of the laser from the Raman scattered light but also ensure that the placement angles of other optical elements (such as lenses, filters, etc.) in the optical path and the optical path transmission efficiency are not affected.

[0032] The microlens array 5 is composed of multiple short-focus microlenses (with a focal length range between 1 mm and 5 mm) and is arranged in a one-dimensional array. The number of microlenses is determined by the number of wells in the microbial microplate. Preferably, the surface of the microlens is coated with an optical antireflection film of 500 nm - 700 nm. In this embodiment, the microbial microplate is a 96-well plate. Correspondingly, the microlens array is composed of 96 microlenses. The focal length of each microlens is optimized to ensure that the laser beam can be efficiently focused into the hollow-core fiber, and the coupling efficiency of the excitation light entering each hollow-core fiber is not less than 80%. The interval between adjacent microlenses is determined by the interval between adjacent laser beams after being split by the diffraction splitting element, and usually remains consistent with the arrangement interval of the hollow-core fiber array to ensure that each laser beam can be accurately coupled into the corresponding hollow-core fiber. When the microlens array focuses the laser beam into the hollow-core fiber array, it is necessary to ensure that the spot size after being focused by the microlens array matches the mode field diameter (MFD) of the hollow-core fiber. The typical spot size range is 10 μm to 50 μm, and the specific value is optimized according to the MFD of the hollow-core fiber. The specific calculation steps are as follows: The spot size of the Gaussian beam after being focused by the coupling lens L1 is: , so the spot size after being focused by the microlens array should satisfy: , where is the focal length of the microlens array. By calculating through the formula, the size of is obtained, and the optical distance between the surface of the microlens array and the surface of the coupling lens L1 is controlled to be: , so as to ensure the best coupling efficiency. The specific distance is the distance from the rear focal point of the coupling lens L1 to the surface of the microlens array.

[0033] The hollow-core fiber array 6 is composed of multiple hollow-core fibers and is arranged in a one-dimensional array. The interval between adjacent hollow-core fibers is determined by the interval between adjacent laser beams after being split by the diffraction splitting element, and its specific number is usually equal to the number of wells in the required microplate. In this embodiment, the microbial microplate is a 96-well plate. Correspondingly, the hollow-core fiber array is composed of 96 hollow-core fibers to ensure that the samples in each well can be independently detected. The hollow-core fiber satisfies low-loss transmission with a loss of <0.01 dB / m in the 500 nm - 700 nm band. Preferably, the hollow-core fiber is a hollow-core anti-resonant fiber, which is used to guide the laser and provides an ideal place for the interaction between the laser and the liquid (the generation of Raman scattered light of the microbial culture solution). Its transmission bandwidth covers the visible light to near-infrared band (300 nm - 1200 nm), and the core diameter is in the micron range, with a typical value of 10 μm - 100 μm.

[0034] The fiber optic sealing adapter 7 has a micro-lens array and a hollow fiber array loaded and sealed at both ends respectively, and is equipped with a pump for pumping the microbial culture solution in the microbial microplate 8 into the hollow fiber or discharging it from the hollow fiber. Specifically, it consists of components such as an adapter body, a flange, a sealing ring, screws, a fiber optic V-groove, an air inlet / outlet, a pressure gauge, a vacuum pump, and a pressure pump. The fiber optic sealing adapter with this structure belongs to the prior art and is used to achieve the sealed connection between the optical fiber and the external environment and the precise control of fluids. When in use, the gas in the adapter is pumped out by the vacuum pump to reduce the air pressure in the adapter, so that the liquid in the microbial microplate enters the hollow fiber; after the test is completed, an inert gas is filled into the adapter by the pressure pump to increase the air pressure in the adapter, so that the liquid to be tested in the hollow fiber is discharged. The air pressure in the adapter can be monitored in real time by the pressure gauge, and the air pressure adjustment range is from 0.01 MPa to 1 MPa to ensure the precise control of the liquid inflow and outflow.

[0035] The long-pass filter 9 is used to further filter out the residual Rayleigh scattered light in the Raman signal optical path. Its transmittance for Rayleigh scattered light does not exceed 0.1%, and its transmittance for Raman scattered light is not less than 93%. In this application, the mirror surface of the long-pass filter must be placed perpendicular to the laser incident direction. This angle design can minimize the transmittance of Rayleigh scattered light and ensure the efficient transmission of Raman scattered light. Other placement angles (such as tilting) will lead to a reduction in the filtering efficiency of Rayleigh scattered light and may even introduce additional optical path deviations, affecting the detection accuracy of Raman signals.

[0036] The focusing lens L2 (10) is used to focus the backward-collected Raman scattered light onto the slit of the spectrometer to ensure the efficient collection and detection of Raman signals.

[0037] The spectrometer 11 is the core component for collecting and analyzing the Raman scattered signals of the microbial culture solution. The spectral range of this spectrometer covers to and can completely capture the characteristic Raman peaks of the molecular vibration and rotation in the microbial culture solution. The optical system of the spectrometer adopts a high-precision grating and mirror design to ensure that its spectral resolution reaches , it is able to clearly distinguish adjacent Raman peaks. The slit width of the spectrometer supports continuous adjustment from 10 μm to 1000 μm. Users can flexibly adjust the slit width according to the sample concentration and signal intensity to optimize the light flux and resolution. In this embodiment, a high-performance back-illuminated CCD (Charge-Coupled Device) is preferably used, and its quantum efficiency exceeds 90% in the visible to near-infrared band (400 nm to 1000 nm), capable of efficiently capturing weak Raman scattering signals. In addition, the dark current of the CCD detector can be reduced to 0.001 electrons / pixel / second under the refrigeration condition of -60 °C, significantly improving the signal-to-noise ratio. The spectrometer supports integral time settings from 0.1 second to 300 seconds and is equipped with an automatic optimization function, which can dynamically adjust parameters according to the signal intensity to ensure the stability and reliability of the detection results.

[0038] This application provides a Raman analysis method based on a hollow fiber microlens coupler, including: Step 1: Acquisition of background spectrum.

[0039] Inject rare gases (such as argon, helium, or neon) into the hollow fiber array through a gas injection device to ensure that the gas completely fills the internal channels of the hollow fiber. After the gas is stable, turn on the Raman spectrometer to obtain the background spectrum of the hollow fiber in the rare gas environment. The acquisition of the background spectrum helps to eliminate the interference of the fiber material and environmental gas on the Raman signal and provides a benchmark for the accurate analysis of the subsequent sample spectrum.

[0040] It should be noted that argon is preferably used in this application because argon has high chemical inertness, does not react chemically with the fiber material or the sample, and at the same time has a small Raman scattering cross-section, which can effectively reduce the background noise and improve the signal-to-noise ratio of the Raman signal. In addition, compared with other rare gases (such as helium, neon), argon has a lower cost and is easier to obtain, making it more suitable for large-scale applications. Therefore, argon is the preferred gas in this application.

[0041] Step 2: Acquisition of sample spectrum.

[0042] Use a vacuum pump to suck the microbial culture solution through the orifices of the porous plate and inject the liquid into the hollow fiber. To ensure that the liquid completely fills the internal channels of the hollow fiber, the liquid flow rate can be monitored in real time through a mass flow meter, and the liquid filling state can be judged in combination with the data of the pressure sensor. When the flow meter shows that the flow rate tends to be stable and the pressure sensor detects that the pressure reaches the preset threshold, it can be confirmed that the liquid has completely filled the hollow fiber. After the liquid is stable, turn on the Raman spectrometer to obtain the Raman spectrum of the sample to be measured. During this process, the microlens array evenly couples the excitation light source into each hollow fiber to ensure that the samples in each hole can obtain efficient Raman signal excitation.

[0043] Step 3: Sample Discharge and Optical Fiber Cleaning.

[0044] After the sample test is completed, use a pressure pump to completely discharge the liquid to be measured in the hollow optical fiber, and then inject anhydrous ethanol to clean the inside of the hollow optical fiber. The cleaning process is recommended to last for 5-10 minutes each time. After the cleaning is completed, it needs to be repeated at least 2 times to ensure that there is no residue of any pollutants inside the optical fiber, and to guarantee the reliability of the next detection and the accuracy of the data. After the rinsing is completed, use the pressure pump to discharge the anhydrous ethanol again, and introduce the inert gas argon to dry the inside of the optical fiber to ensure the cleanliness and reusability of the optical fiber.

[0045] Step 4: Spectrum Processing and Analysis.

[0046] Subtract the background spectrum obtained in Step 1 from the original spectrum of the sample to be measured obtained in Step 2 to eliminate background interference. Subsequently, perform smoothing processing on the spectral data (such as Savitzky-Golay filtering) to reduce noise, and use polynomial fitting or adaptive baseline correction methods to remove the spectral baseline drift. Finally, obtain the pure Raman spectrum of the microbial culture solution for further analysis of the metabolites, growth status, or other biochemical information of the microorganisms.

[0047] The entire optical path process experienced during the Raman spectrum detection of this application is specifically as follows: Stage 1: Laser Beam Splitting and Coupling.

[0048] The laser emits a laser with high stability and narrow linewidth. The laser is split into multiple beams of excitation light by a diffraction beam splitter element. The number of multiple beams of laser is determined by the number of holes in the microbial multi-well plate. For example, for a 96-well plate, it is usually split into 96 beams of excitation light. The split excitation light is focused to the image plane through the coupling lens L1, and is reflected by the dichroic mirror during this process. The dichroic mirror efficiently reflects the excitation light to the microlens array. The microlens array precisely focuses each beam of excitation light onto the end face of the hollow optical fiber and couples it into the hollow optical fiber array. The design of the microlens array ensures that the size of the focused spot matches the mode field diameter (MFD) of the hollow optical fiber, thereby achieving efficient coupling of the excitation light.

[0049] Stage 2: Interaction between Excitation Light and Sample.

[0050] The excitation light propagates in the hollow optical fiber and interacts with the sample to be measured (microbial culture solution), generating a nonlinear effect. During this process, the wavelength of the excitation light changes, generating backscattered Raman light. The backscattered Raman light exits through the port of the hollow optical fiber, and its intensity is closely related to the molecular vibration and rotation characteristics of the sample.

[0051] Stage 3: Collection and Filtering of Raman Scattered Light.

[0052] After the backward Raman scattered light exits from the hollow-core fiber port, it is first collimated by a microlens array and then passes through a dichroic mirror. The dichroic mirror has a high transmittance (≥93%) for Raman scattered light and a high reflectance (≥98%) for Rayleigh scattered light, thus effectively separating the Raman signal from the Rayleigh scattered light. Subsequently, the Raman scattered light passes through a long-pass filter to further filter out the residual Rayleigh scattered light. The filtered Raman scattered light is focused by a focusing lens L2 onto the slit of the spectrometer to ensure efficient signal transmission.

[0053] Stage 4: Detection and analysis of Raman spectra.

[0054] The Raman scattered light entering the spectrometer is diffracted and dispersed by a high-precision grating and then detected by a back-illuminated CCD detector. The CCD detector has a high quantum efficiency (>90%) in the visible to near-infrared wavelength range (400nm - 1000nm) and supports an integration time setting from 0.1 second to 300 seconds, enabling efficient capture of weak Raman signals.

[0055] The detected Raman spectral data is processed by computer software, including steps such as background subtraction, smoothing, and baseline correction, and finally a Raman spectrogram of the microbial culture solution is obtained for further analysis of information such as the metabolites and growth status of microorganisms.

[0056] It should be understood that expressions such as "including" and "may include" that can be used in this application indicate the existence of the disclosed functions, operations, or components, and do not limit one or more additional functions, operations, and components. In this application, terms such as "including" and / or "having" can be interpreted as indicating a specific characteristic, number, operation, component, assembly, or a combination thereof, but cannot be interpreted as excluding the existence or possibility of addition of one or more other characteristics, numbers, operations, components, assemblies, or a combination thereof.

[0057] In addition, in this application, the expression "and / or" includes any and all combinations of the associated listed words. For example, the expression "A and / or B" can include A, can include B, or can include both A and B.

[0058] In the description of the embodiments of the present application, it should be noted that unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. Among them, "fixed connection" means that the two are connected and the relative positional relationship after connection remains unchanged. "Rotational connection" means that the two are connected and can rotate relative to each other after connection. "Sliding connection" means that the two are connected and can slide relative to each other after connection. The orientation terms mentioned in the embodiments of the present application, such as "top", "bottom", "inner", "outer", "left", "right", etc., are only references to the direction of the accompanying drawings. Therefore, the orientation terms used are for better and clearer explanation and understanding of the embodiments of the present application, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation on the embodiments of the present application.

[0059] In addition, in the embodiments of the present application, mathematical concepts such as symmetry, equality, parallelism, and perpendicularity are mentioned. These limitations are all in view of the current technological level, rather than absolute strict definitions in the mathematical sense, allowing for a small amount of deviation. Approximations to symmetry, equality, parallelism, perpendicularity, etc. are all acceptable. For example, when it is said that A is parallel to B, it means that A is parallel to B or approximately parallel to B, and the included angle between A and B can be between 0 degrees and 10 degrees. When it is said that A is perpendicular to B, it means that A is perpendicular to B or approximately perpendicular to B, and the included angle between A and B can be between 80 degrees and 100 degrees.

[0060] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A hollow core fiber microlens coupler, characterized in that: The optical path includes: a beam splitter, a beam splitter, a microlens array, and a hollow-core optical fiber array, wherein: The beam splitting element splits the light beam of the excitation light source into multiple beams of excitation light, which are reflected to the microlens array by the beam splitting element and uniformly coupled into the hollow-core optical fiber array by the microlens array, so that the excitation light interacts with the microbial culture solution to generate Raman scattered light; The back-transmitted Raman scattered light is emitted from the port of the hollow-core fiber array, collimated by the microlens array and transmitted by the beam splitting element in sequence to obtain an enhanced Raman signal; The coupler also includes a hollow-core optical fiber sealing adapter, the two ends of which are respectively loaded with and sealed with a microlens array and a hollow-core optical fiber array, and is equipped with a pump for extracting the microbial culture liquid in the microbial porous plate into the hollow-core optical fiber or discharging it from the hollow-core optical fiber.

2. The coupler according to claim 1, characterized in that The multiple beams of excitation light after splitting are arranged in a one-dimensional array, and the spacing between adjacent beams is the same.

3. The coupler according to claim 2, characterized in that The beam splitter element is a diffraction beam splitter element, which is used to realize a one-dimensional beam array with equal spacing and uniform distribution of light spot energy of adjacent light beams.

4. The coupler according to claim 1, characterized in that The number, arrangement and spacing of the microlenses in the microlens array and the hollow-core optical fibers in the hollow-core optical fiber array are consistent with those of the multiple beams of excitation light after light splitting.

5. The coupler according to claim 1, characterized in that The focal length of the microlenses in the microlens array ranges from 1 mm to 5 mm.

6. The coupler according to claim 1, characterized in that Hollow core optical fiber is a hollow core anti-resonant optical fiber with a core diameter in the micron range.

7. The coupler according to claim 1, characterized in that It also includes a coupling lens, which is located between the beam splitting element and the beam separation element, and is used to focus the split excitation light onto the microlens array after being reflected by the beam separation element, and the beam splitting angle of the beam splitting element and the focal length of the coupling lens satisfy the following relationship: in, is the focal length of the coupling lens, is the angle of light splitting by the diffraction element, is the distance between adjacent light beams after splitting.

8. The coupler according to claim 7, characterized in that The focal length of the microlens in the microlens array and the mode field diameter of the hollow core optical fiber satisfy the following relationship: in, is the focal length of the microlens, is the mode field diameter of the hollow core fiber, is the excitation light wavelength, It is the spot size of the Gaussian beam focused on the image plane after being transmitted for a specific distance, and the specific distance is the distance from the focus of the coupling lens to the microlens array.

9. A Raman analysis system based on a hollow-core fiber microlens coupler, characterized in that: include: An excitation light source, a hollow-core fiber microlens coupler as claimed in any one of claims 1 to 8, a focusing lens and a spectrometer; The hollow-core optical fiber microlens coupler is used to couple the excitation light source into each well of the microbial multi-well plate and form an enhanced Raman signal; A focusing lens for focusing the enhanced Raman signal onto the slit of the spectrometer; A spectrometer is used to collect Raman scattered light and generate a Raman spectrum.

10. A Raman analysis method based on the hollow core fiber microlens coupler according to any one of claims 1 to 8, characterized in that: include: S1. Injecting a rare gas into the hollow-core optical fiber until the inner channel thereof is completely filled, and after the gas is stabilized, obtaining a background spectrum of the hollow-core optical fiber in a rare gas environment; S2. extracting the microbial culture liquid in the microbial porous plate into the hollow-core optical fiber until the liquid completely fills the internal channel thereof, and obtaining the Raman spectrum of the sample to be tested after the liquid is stabilized; S3. Subtract the background spectrum of the hollow-core optical fiber in a rare gas environment from the Raman spectrum of the sample to be tested, and then filter the obtained spectrum and remove the spectrum baseline drift to obtain a pure Raman spectrum of the microbial culture solution.

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