A raman spectrum detection sample cell and a raman spectrum detection device

Abstract

The application relates to the field of Raman detection, and specifically provides a Raman spectrum sample cell and a Raman spectrum detection device. The sample cell comprises a sample cell body, and an incident optical fiber and an outgoing optical fiber are oppositely arranged on the inner wall of the sample cell body. The incident optical fiber and the outgoing optical fiber are fixedly arranged on the inner wall of the sample cell body. One end of the incident optical fiber and the optical fiber extends into the sample cell body, and the other end of the incident optical fiber and the optical fiber extends out of the sample cell body. The incident optical fiber and the outgoing optical fiber are both D-shaped optical fibers. The Raman spectrum detection device comprises the above sample cell, a laser and a spectrometer. In the application, the incident optical fiber and the outgoing optical fiber are directly in contact with the liquid to be detected, the distance between the optical field and the molecules to be detected is reduced, the interaction between the optical field and the molecules to be detected is stronger, the cross-sectional area of the D-shaped optical fiber is larger, more molecules in the liquid to be detected can be irradiated, the generated Raman signal is stronger, the signal-to-noise ratio of the Raman signal is improved, and the detection accuracy is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of Raman detection, in particular, to a Raman spectrum detection sample cell and a Raman spectrum detection device. BACKGROUND

[0002] Raman spectrum is widely used in substance detection and experimental characterization. Photons and molecules to be detected undergo inelastic collision, changing the frequency of scattered light. The change of the frequency of scattered light is related to the characteristic vibration of the molecules to be detected. That is, the frequency of the scattered light is shifted relative to the incident light. Different peak positions in the obtained scattered spectrum represent different scattered light frequencies, which correspond to the vibration modes inside the molecules to be detected. Different peak areas represent the content of the corresponding molecules. According to the decrease and increase of the frequency of scattered light, the spectrum is divided into Stokes line and anti-Stokes line. Usually, the intensity of Stokes line is much greater than that of anti-Stokes line, but the signal intensity of Stokes line is 2 to 3 orders of magnitude weaker than that of Rayleigh scattering. Therefore, it is very important to effectively detect the small Raman signal.

[0003] Compared with solid, the intensity of Raman signal is smaller because the molecules to be detected are uniformly dispersed in the solution, which makes it more difficult to detect liquid samples by Raman. The existing scheme detects the Raman signal generated by gas molecules by gasifying the liquid. The utility model patent with the name of "a sampling structure and a Raman spectrum and mass spectrum detection system" and the authorization announcement number of "CN 213600588 U" takes the liquid sample to be detected through the sampling tube, generates heat effect under the excitation of ultraviolet light, makes a part of the liquid gasify, generates liquid sample ions, enters the mass spectrometer from the flow path connected with the sampling tube, and realizes subsequent mass spectrum detection. The utility model patent with the name of "a liquid volatile Raman spectrum detection equipment" and the authorization announcement number of "CN 210604389 U" discloses a Raman spectrum detection equipment, which comprises a container fixing device, a Raman signal excitation and collection device and a Raman signal processing device. The container fixing device is used for fixing the liquid container to be detected, so that the bottle opening of the liquid container to be detected is slightly lower than the position of the Raman signal excitation and collection device. The Raman signal excitation and collection device collects the Raman signal of the liquid volatile to be detected, and transmits the collected Raman signal to the Raman signal processing device. Both of them detect the Raman signal of the liquid sample by volatile gas. The gas has stronger flowability, but the molecular weight of the gas is smaller, so the intensity of the Raman signal is smaller. That is, the liquid to be detected is volatilized, the gas volatilized is connected into the light path, and the Raman signal is detected. The gas molecules interacting with the light field are less, so the Raman signal is smaller.

[0004] In summary, in the existing liquid Raman spectrum detection device, the amount of molecules to be detected participating in the Raman scattering process is small, so the intensity of the Raman signal is small, which reduces the signal-to-noise ratio and leads to a decrease in detection accuracy. SUMMARY

[0005] The present application aims at providing a Raman spectrum detection sample cell and a Raman spectrum detection device to solve the problem that the amount of molecules involved in the Raman scattering process is small in the prior art Raman spectrum detection device for liquid, which reduces the Raman signal intensity and the signal-to-noise ratio, and thus reduces the detection accuracy.

[0006] To achieve the above object, the present application adopts the following technical solutions:

[0007] The present application provides a Raman spectrum detection sample cell, which comprises a sample cell body, the sample cell body is tubular, and an incident optical fiber and an outgoing optical fiber are oppositely arranged on the inner wall of the sample cell body, the incident optical fiber and the outgoing optical fiber are fixedly arranged on the inner wall of the sample cell body, one end of the incident optical fiber and the outgoing optical fiber extends into the sample cell body, the other end of the incident optical fiber and the outgoing optical fiber extends out of the sample cell body, the incident optical fiber and the outgoing optical fiber extend out of the same end of the sample cell body, and the incident optical fiber and the outgoing optical fiber are both D-shaped optical fibers.

[0008] Further, the cross sections of the incident optical fiber and the outgoing optical fiber are oppositely arranged and both face the central axis of the sample cell body.

[0009] Further, the D-shaped optical fiber is an optical fiber with a part of the cladding or the core removed, and the depth of the cross section of the D-shaped optical fiber is less than R / 2, where R is the radius of the cladding.

[0010] Further, the depth of the cross section of the incident optical fiber gradually increases from the incident end to the outgoing end, and the depth of the cross section of the outgoing optical fiber is the same as that of the incident optical fiber.

[0011] Further, the depth of the cross section of the incident optical fiber is greater than less than where R is the radius of the cladding and r is the radius of the core.

[0012] Further, a first nano array is fixedly arranged on the cross section of the incident optical fiber, the first nano array is formed by arranging an array of noble metal strips, and the arrangement pitch of the noble metal strips is 100-200 nm.

[0013] Further, noble metal nanoparticles are fixedly arranged on the cross section of the incident optical fiber, the size of the noble metal nanoparticles is 20-200 nm, and the pitch is 50-100 nm.

[0014] Further, the number of the outgoing optical fibers is greater than the number of the incident optical fibers, and the incident optical fibers and the outgoing optical fibers completely cover the inner wall of the sample cell body.

[0015] Further, the material of the first nano array and the noble metal nanoparticles is gold or silver.

[0016] A Raman spectrum detection device, comprising the sample cell, the laser, and the spectrometer.

[0017] Compared with the prior art, the sample cell and the detection device have the following beneficial effects: the incident optical fiber and the outgoing optical fiber are directly in contact with the liquid to be detected, which reduces the distance between the optical field and the molecules to be detected, and makes the interaction between the optical field and the molecules to be detected stronger. Meanwhile, the optical fiber is a D-shaped optical fiber, the cross section of the D-shaped optical fiber is provided with the optical field entering the liquid to be detected, the cross section area of the D-shaped optical fiber is larger, so that more molecules in the liquid to be detected can be irradiated, thereby making the generated Raman signal stronger. The optical field is reflected multiple times inside the sample cell, so that the optical field interacts with more molecules in the liquid to be detected, thereby further enhancing the strength of the generated Raman signal. Thus, the signal-to-noise ratio of the Raman signal is improved, and the detection accuracy is improved.

[0018] In addition, the device does not need to heat and vaporize the liquid to be detected, avoiding the movement of the Raman peak caused by the temperature change of the molecules to be detected due to heating, and the detection result is more accurate. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 A schematic view of a Raman spectrum detection sample cell provided by the present application is shown in the figure;

[0020] Figure 2 A schematic view of a D-shaped optical fiber in a Raman spectrum detection sample cell provided by the present application is shown in the figure;

[0021] Figure 3 A cross-sectional view of an incident optical fiber in a Raman spectrum detection sample cell provided by the present application is shown in the figure;

[0022] Figure 4 A schematic view of the cross section of an incident optical fiber in another Raman spectrum detection sample cell provided by the present application is shown in the figure;

[0023] Figure 5 A schematic view of an incident optical fiber and an outgoing optical fiber in another Raman spectrum detection sample cell provided by the present application is shown in the figure;

[0024] Figure 6 A schematic view of the cross section of an outgoing optical fiber in another Raman spectrum detection sample cell provided by the present application is shown in the figure.

[0025] Figure legend: 1-sample cell body; 2-incident optical fiber; 3-outgoing optical fiber; 4-first nano array; 5-noble metal nanoparticles; 6-second nano array. DETAILED DESCRIPTION

[0026] In order to make the implementation process of the present application clearer, the following will be described in detail in combination with the drawings.

[0027] This invention provides a sample cell for Raman spectroscopy detection, such as... Figure 1 As shown, the sample cell includes a sample cell body 1, an incident optical fiber 2, and an exiting optical fiber 3. The sample cell body is tubular, and the incident optical fiber 2 and the exiting optical fiber 3 are disposed opposite each other on the inner wall of the sample cell body 1, and both the incident optical fiber 2 and the exiting optical fiber 3 are fixedly connected to the inner wall of the sample cell. One end of the incident optical fiber 2 extends into the sample cell, and the distance between this end of the incident optical fiber 2 and the inner edge of the sample cell is 0.1-0.3 mm, which serves to protect the incident optical fiber 2. The light field emitted from this end of the incident optical fiber 2 interacts with the sample to be tested and does not exit directly, thereby enhancing the interaction between the sample and the incident light and making the Raman scattering signal stronger; the other end of the incident optical fiber 2 extends out of the tube from the other end of the sample cell body and is used to connect with the incident optical path. Correspondingly, one end of the outgoing fiber 3 extends into the sample cell, and the distance between this end of the outgoing fiber 3 and the inner edge of the sample cell is 0.05-0.1 mm, which serves to protect the outgoing fiber 3. The outgoing fiber 3 can receive more Raman signals, thereby enhancing the intensity of the Raman signal transmitted in the Raman outgoing fiber, making the detected Raman scattering signal stronger. The other end extends out of the tube from the other end of the sample cell body 1 and is used to connect with the outgoing optical path. The incident fiber 2 and the outgoing fiber 3 extend from the same end of the sample cell body 1.

[0028] Preferably, the end of the sample cell body 1 extending from the incident optical fiber 2 and the outgoing optical fiber 3 is provided with a Y-shaped fork, leading out the incident optical fiber 2 and the outgoing optical fiber 3 respectively, and correspondingly providing interfaces for connection with the external optical path. The end of the sample cell body 1 away from the Y-shaped fork can be closed or open; when closed, the sample to be tested is injected or drawn into the sample cell body through the interface provided at the Y-shaped fork, that is, at least one of the two interfaces of the Y-shaped fork is detachably fixed; when open, this end is used to inject or draw in the liquid to be tested, and after the liquid to be tested enters, it is sealed with a metal cap. The material of the sample cell body 1 can be plastic, glass, metal, etc., as long as it does not react with the liquid to be tested; preferably, the material of the sample cell body 1 is glass, more specifically, the tubular part of the sample cell body 1 can be a capillary tube, so that the liquid to be tested can be drawn into the sample cell body by capillary effect; specifically, the inner diameter of the capillary tube is greater than 4R.

[0029] Both incident fiber 2 and outgoing fiber 3 are D-shaped fibers, such as Figure 2As shown, the D-shaped optical fiber is an optical fiber with a part of cladding or core removed, wherein the radius of the cladding is R, the radius of the core is r, and the depth of the cut is d, and d is less than R / 2. The optical fiber is a single-mode quartz optical fiber or a multi-mode quartz optical fiber; preferably, the optical fiber in the embodiment is a multi-mode quartz optical fiber because the radius of the core is larger and the contact area with the liquid to be measured at the cut surface is larger. The cut surfaces of the D-shaped incident optical fiber 2 and the D-shaped exit optical fiber 3 are oppositely arranged. The cut surface of the D-shaped optical fiber is closer to the light field at the center of the optical fiber, so that the surrounding substance is more likely to interact with the light field in the optical fiber. The incident optical fiber 2 is a D-shaped optical fiber, which reduces the distance between the incident laser in the Raman system and the molecules to be measured in the solution, and has a larger contact area, which enables more molecules to be measured to fully interact with the incident light, the Raman signals generated are superimposed on each other, and the intensity of the generated Raman signals is larger and easier to be detected. The exit optical fiber 3 is a D-shaped optical fiber, and the Raman signal is coupled into the exit optical fiber through the cut surface of the D-shaped optical fiber. The D-shaped optical fiber increases the receiving area of the Raman signal and improves the collection efficiency of the Raman signal. Therefore, the sample cell of the application can simultaneously enhance the intensity of the Raman signal from the aspects of generation and collection, thereby improving the signal-to-noise ratio of the Raman signal and improving the detection accuracy.

[0030] The depths of cut d of the incident optical fiber 2 can be the same or different. The depths of cut d are easy to prepare when they are the same, and the depths of cut d are beneficial to the interaction between the incident light field and the molecules in the liquid to be measured when they are different. Figure 3 As shown, the depths of cut d are different, the depth of cut d near the incident light source is smaller than the depth of cut d far from the incident light source, and the depth of cut d gradually increases from small to large. Specifically, the minimum depth of cut d is The maximum depth of cut d is Wherein, R is the radius of the cladding, r is the radius of the core. The deeper the depth of the section d, the more the incident light field is emitted, and the stronger the intensity of the emitted incident light field from the end close to the light source to the end away from the light source, so that the to-be-measured liquid at different heights in the sample pool body 1 can be irradiated by the incident light field, thereby generating a Raman signal. If the depth of the section d is uniform and large, the intensity of the upper half of the transmitted light field is strong, and the light field intensity decays quickly, so that the lower half of the light field is very weak, and the to-be-measured liquid in the lower part cannot effectively participate in the generation of the Raman signal, so that the intensity of the generated Raman signal is small; if the depth of the section d is uniform and small, the intensity of the light field emitted at the section is weak, and the intensity of the light field emitted at the end face of the incident optical fiber 2 is strong, but the light emitting area at the end face is very small, and the strong incident light only interacts with the molecules in the to-be-measured liquid around the end face to generate a Raman signal, so that most of the molecules in the to-be-measured liquid do not generate a Raman signal, so that the Raman signal generated by the to-be-measured liquid as a whole is small. The depth of the section d changes from small to large, so that the incident light field is emitted on the section, so that the contact area between the incident light and the to-be-measured liquid is large, which can irradiate more molecules, so that the Raman signal generated by the to-be-measured liquid as a whole is strong, thereby improving the signal-to-noise ratio.

[0031] Preferably, in order to enhance the incident light and the to-be-measured liquid, a first nano array 4 is fixedly arranged on the section of the incident optical fiber 2, the first nano array 4 is a noble metal array, and the material is gold or silver, which can be prepared by electron beam evaporation and the like. As shown in the figure, Figure 4 The first nano array 4 is composed of an array of noble metal strips with nanometer size, the length of the noble metal strip is 300-800nm, the width is 50-200nm, and the height is 400-600nm. Under the irradiation of the incident light field in the optical fiber, the first nano array 4 generates surface plasmon effect, generates surface plasmon polariton, and the collective oscillation of free electrons, so that the light field is concentrated on the surface of the noble metal strip, and the local electric field intensity is enhanced, so that the interaction between the molecules in the to-be-measured liquid is enhanced, that is, the intensity of the incident light for the interaction of the to-be-measured molecules is improved, and the intensity of the Raman signal generated is stronger compared with the average dispersion of the light field in the entire section. At the same time, the noble metal strip generates resonance modes along the length direction and the height direction of the noble metal strip, the resonance mode along the length direction excites the to-be-measured liquid in the vertical direction (axial direction), and the resonance mode along the height direction excites the to-be-measured liquid in the horizontal direction (radial direction); so that as many molecules in the to-be-measured liquid as possible are irradiated in two spatial dimensions, thereby enabling more to-be-measured liquids to be irradiated to generate Raman signals.

[0032] In addition, the local strong electric field can gather the molecules in the liquid to be tested near the strong electric field, the resonance mode in the length direction can gather the molecules in the liquid to be tested at the two ends of the noble metal strip, and the resonance mode in the height direction can gather the molecules in the liquid to be tested at the bottom surface and the top surface of the noble metal strip; this can increase the density of the side molecules near the first nano array 4, so that the incident light can irradiate more test molecules, the test molecules generate Raman signals, and thus the Raman signals generated by the whole liquid to be tested are stronger.

[0033] More preferably, the sizes of the noble metal strips can be the same or different; the arrangement interval of the noble metal strips is 100-200 nm; in this way, the coupling effect between adjacent noble metal strips can be generated, the coupling effect can make the space between adjacent noble metal strips have a stronger electric field, thereby increasing the contact area between the strong electric field and the liquid to be tested and enhancing the overall Raman signal intensity. The arrangement interval of the noble metal strips can be the same or different. Preferably, the arrangement interval of the noble metal strips is smaller at the position with a smaller cutting depth d and is larger at the position with a larger cutting depth d; the intensity of the incident light emitted at the position with a smaller cutting depth d is smaller, the smaller interval can enhance the coupling effect between adjacent noble metal strips, so that the electric field distribution area between adjacent noble metal strips is larger, the effective contact area between the incident light and the test molecules is larger, more test molecules are irradiated to generate Raman signals, and thus the overall Raman signal intensity is larger; correspondingly, the intensity of the incident light emitted at the position with a larger cutting depth d is larger, the larger interval makes the coupling effect between adjacent noble metal strips not too strong, and the too strong coupling effect can make the light field energy be localized in the local area, the light field energy on the side far from the light source is smaller, so that the interaction between the lower liquid to be tested and the incident light field is weaker, and the overall Raman signal is weakened.

[0034] The finally collected Raman signal intensity depends not only on the generation intensity of the Raman signal but also on the collection efficiency of the Raman signal by the exit optical fiber 3. The cutting depth d of the exit optical fiber 3 can be the same or different, and preferably, the cutting depth d of the exit optical fiber 3 is the same, which is convenient for preparation; more preferably, the cutting depth d is larger than The scattering light is more easily coupled into the exit optical fiber due to the small cutting depth d and the small distance between the scattering light and the core of the exit optical fiber 3, which ensures that the cutting surface is close enough to the center of the optical fiber, facilitates the coupling of the scattering light into the exit optical fiber, that is, facilitates the coupling of the scattering signal into the exit optical fiber 3, improves the collection efficiency of the Raman signal, and thus makes the Raman signal stronger and improves the signal-to-noise ratio. Further, the exit optical fiber 3 is fixedly provided with noble metal nanoparticles 5 on the cutting surface, and the material of the noble metal nanoparticles 5 is gold or silver; the surface electrons of the noble metal nanoparticles 5 resonate when the scattering light irradiates on the surface of the noble metal nanoparticles 5, the light field is localized on the surface of the noble metal nanoparticles 5, the noble metal nanoparticles 5 generate localized surface plasmon effect, and thus the Raman signal is more easily coupled into the inside of the exit optical fiber. The shape of the noble metal nanoparticles 5 is spherical, the projection area of the spherical shape in each direction is equal, and the scattering light in each direction can be received, so the collection efficiency of the scattering light is high.

[0035] The resonance wavelength of the noble metal nanoparticles 5 is closely related to the size and spacing of the noble metal nanoparticles. The size of the noble metal nanoparticles 5 is 20-200 nm, and the spacing is 50-100 nm. The size and spacing of the noble metal nanoparticles 5 are different, the size difference between adjacent noble metal nanoparticles 5 needs to be greater than 20 nm, and the number of noble metal nanoparticles 5 of different sizes is approximately equal. The greater the size difference between adjacent noble metal nanoparticles 5, the smaller the spacing, the smaller the difference, and the larger the spacing; the resonance frequencies of noble metal nanoparticles 5 of different sizes and spacings are different, which enables Raman scattering light of different wavelengths to be coupled into the exit optical fiber, that is, Raman scattering light with more or less frequency variables can be coupled into the exit optical fiber, improving the collection efficiency of the scattering light. The resonance wavelength difference between the noble metal nanoparticles 5 with larger size and the noble metal nanoparticles 5 with smaller size is large, the localized surface plasmon coupling between the noble metal nanoparticles 5 with larger size and the noble metal nanoparticles 5 with smaller size is strong, the resonance coupling between them is strong, a coupling mode along the central line direction is formed, the coupling mode has a large inclination angle with the cutting surface, and the normal component of the coupling mode is more easily coupled into the exit optical fiber 3; the resonance mode difference between the noble metal nanoparticles 5 with small size difference is small, the resonance wavelength between them is close, and the large spacing can reduce the localized surface plasmon coupling between them, so they do not easily affect each other, the half-peak width of two similar wavelengths is narrower, the resolution is higher, and the Raman detection result is more accurate. The noble metal nanoparticles 5 can be realized by electron beam evaporation coating technology.

[0036] Further, the number of exit optical fibers 3 is greater than that of incident optical fibers, and the number ratio of exit optical fibers 3 to incident optical fibers 2 is greater than 2, so that the scattering light in each direction can be coupled into the exit optical fiber 3, the collection efficiency is high, and the Raman signal can be detected. Preferably, as shown in FIG. 1, the number of exit optical fibers 3 is equal to the number of incident optical fibers 2, and the number ratio of exit optical fibers 3 to incident optical fibers 2 is equal to 1, so that the scattering light in each direction can be coupled into the exit optical fiber 3, the collection efficiency is high, and the Raman signal can be detected. Figure 5As shown, the profile normal lines of the plurality of exit fibers 3 all pass through the center axis of the sample cell body 1, that is, the incident fiber 2 and the exit fiber 3 are oppositely arranged, the exit fiber 3 and the incident fiber 2 contact each other, and the inner wall of the sample cell body 1 is completely covered, so that the light field can be localized in the sample cell body, the light field transmits in the to-be-measured liquid multiple times, is superimposed multiple times, and the interaction between the light and the to-be-measured molecules is enhanced.

[0037] As shown in the figure, Figure 6 As shown, the second nano array 6 is arranged at the connection of the two exit fibers 3, the material of the second nano array 6 is gold or silver, the second nano array 6 is composed of a long side parallel to the length direction of the first nano array 4 and a short side perpendicular to the long side, the length of the short side is less than that of the long side, one end of the short side contacts one end of the long side, and the short side points to the center of the fiber, that is, the contact forms a backwardly arranged "L" shape structure. The second nano array 6 can be realized by electron beam evaporation coating technology. The "L" shape structure produces surface plasmon effect under the irradiation of the light field, and surface plasmon polariton effect is produced. The length direction of the long side is the same as that of the first nano array 4, so the vibration modes of the two are the same, so it is easier to collect the corresponding mode components. The short side is close to the noble metal nanoparticles 5 arranged in the middle region, and the coupling effect between the local surface plasmon and the surface plasmon polariton is produced between them. The coupling between the "one-dimensional" mode and the "zero-dimensional" mode makes the local characteristics of the electric field stronger, so that the light field on the "L" shape structure is localized at the end of the short side away from the long side, and is transferred to the middle region closer to the fiber core position, so as to more easily enter the inside of the exit fiber. In addition, the electric field intensity at the second nano array 6 is stronger, so that the exit coupling is easier. The distance between the light field at the connection and the exit fiber is large, and the scattered light is difficult to enter the inside of the fiber core of the exit fiber 3. The arrangement of the second nano array 6 enables the light field irradiated on the connection with poor coupling effect to be coupled into the exit fiber 3, thereby improving the strength of the detected Raman signal.

[0038] The first nano array 4, the noble metal nanoparticles 5, and the second nano array 6 all reflect light, which can enhance the local effect of the light field, increase the number of times of transmission of the light field in the to-be-measured liquid, enhance the interaction between the light and the to-be-measured molecules after multiple superimpositions, improve the generation and collection efficiency of the Raman signal, so that the strength of the Raman signal is larger and the signal-to-noise ratio is larger.

[0039] In application, the Raman spectrum detection sample cell can be used in any Raman detection system, the laser irradiating the sample to be detected is introduced into the incident optical fiber 2, that is, the incident optical fiber 2 is connected into the incident light path; similarly, the interface for collecting scattered light is connected with the exit optical fiber 3, and the exit optical fiber 3 is connected into the light path. The liquid to be detected is injected (or sucked by capillary effect) into the sample cell body 1, specifically, it can be injected at the two interfaces of the Y-shaped bifurcation (when the lower side is closed), or it can be sucked or injected by capillary effect through the tubular end away from the Y-shaped bifurcation. The sample cell of the present application enhances the Raman signal from the aspects of generation and collection of the Raman signal, so that the intensity of the Raman signal is increased, thereby improving the signal-to-noise ratio and improving the accuracy of Raman signal detection.

[0040] The present application also discloses a Raman spectrum detection device, which comprises the above-mentioned Raman spectrum detection sample cell, a laser and a spectrometer. The laser is a 532nm or 633nm single-wavelength laser or a variable-wavelength laser; the spectrometer can be any spectrometer capable of distinguishing the detection waveband, including collimating mirrors, gratings, focusing mirrors, optical filters and the like; the specific structure can be the structure in the application with the title of "Raman system" and the authorization announcement number of "CN 205941369 U". The incident light path and the exit light path can also be the optical path disclosed in the application with the title of "Raman spectrum liquid detection method based on laser frequency multiplication and double hollow-core optical fiber" and the application publication number of "CN 106645080 A". Figure 1 The disclosed optical path.

[0041] The above is only the preferred embodiment of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A Raman spectroscopic sample cell, the sample cell comprising a sample cell body, the sample cell body being tubular, characterised in that, The inner wall of the sample cell body is oppositely provided with an incident optical fiber and an outgoing optical fiber, the incident optical fiber and the outgoing optical fiber are fixedly arranged on the inner wall of the sample cell body, one end of the incident optical fiber and the outgoing optical fiber extends into the sample cell body, the other end of the incident optical fiber and the outgoing optical fiber extends out of the sample cell body, the incident optical fiber and the outgoing optical fiber extend out of the same end of the sample cell body, the incident optical fiber and the outgoing optical fiber are both D-shaped optical fibers; the D-shaped optical fiber is an optical fiber with a part of cladding or core removed, the cross sections of the incident optical fiber and the outgoing optical fiber are oppositely arranged and both face the central axis of the sample cell body; the cross section depth of the incident optical fiber is greater than , and less than , wherein R is the radius of the cladding, and r is the radius of the core; the end of the incident optical fiber is 0.1-0.3 mm away from the bottom of the sample cell, and the end of the outgoing optical fiber is 0.05-0.1 mm away from the bottom of the sample cell; The cross section of the incident fiber is fixedly provided with a first nano array formed by an array of noble metal strips, the arrangement interval of the noble metal strips being 100-200 nm; the cross section of the incident fiber is fixedly provided with noble metal nanoparticles, the size of the noble metal nanoparticles being 20-200 nm and the interval being 50-100 nm; the number of the incident fibers is greater than that of the incident fibers, the incident fibers and the incident fibers completely covering the inner wall of the sample cell body, the material of the first nano array and the noble metal nanoparticles being gold or silver; Two connection parts of the incident fibers are provided with a second nano array, the material of the second nano array being gold or silver, the second nano array being fixedly connected by a long side parallel to the length direction of the first nano array and a short side perpendicular to the long side, the length of the short side being less than that of the long side, one end of the short side being in contact with one end of the long side, the short side pointing to the center of the incident fiber, the contact part forming a backward "L" shaped structure; the short side is closer to the noble metal nanoparticles arranged in the middle region, and the coupling effect of localized surface plasmons and surface plasmonic polaritons is generated between them, the coupling between the "one-dimensional" mode and the "zero-dimensional" mode makes the local characteristics of the electric field stronger, and the light field on the "L" shaped structure is localized at one end of the short side away from the long side and transferred to the middle region closer to the fiber core position, so as to more easily enter the inside of the incident fiber.

2. The Raman spectroscopic sample cell of claim 1, wherein, The cross section of the incident fiber is fixedly provided with a first nano array formed by an array of noble metal strips, the arrangement interval of the noble metal strips being 100-200 nm; the cross section of the incident fiber is fixedly provided with noble metal nanoparticles, the size of the noble metal nanoparticles being 20-200 nm and the interval being 50-100 nm; the number of the incident fibers is greater than that of the incident fibers, the incident fibers and the incident fibers completely covering the inner wall of the sample cell body, the material of the first nano array and the noble metal nanoparticles being gold or silver; 3. A Raman spectroscopic probe apparatus, characterized by, The device comprises the sample cell of any one of claims 1-2, further comprising a laser and a spectrometer.

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