Raman spectroscopy apparatus for cross-irradiation determination of trace samples

Abstract

This invention relates to a Raman spectroscopy apparatus for cross-irradiation determination of trace samples, comprising a spectrometer and a vacuum chamber connected to the spectrometer. The vacuum chamber contains a parallel optical path sleeve, a holding platform, a holding dish, a collecting lens, a focusing lens, and a concave lens. The inlet ends of multiple parallel optical path sleeves are connected to the spectrometer, converging the parallel laser output from the spectrometer at a single point through the various outlet ends of the parallel optical path sleeves, achieving cross-simultaneous irradiation of the sample and thus increasing the laser intensity at the convergence point. Compared with existing technologies, this invention significantly improves the sensitivity of existing Raman spectroscopy techniques for detecting trace samples, enhances the Raman signal, and features a simple structure, stable performance, and rapid and flexible operation, making it suitable for widespread application.

Description

Technical Field

[0001] This invention relates to the field of Raman spectroscopy, and in particular to a Raman spectroscopy apparatus for measuring trace samples by cross-irradiation. Background Technology

[0002] Raman spectroscopy is a spectroscopic technique developed based on the Raman scattering effect, which is based on the difference in energy between incident and scattered light. Since the energy difference between incident and scattered light depends on the molecular structure, it is often used to determine the molecular structure for qualitative analysis of substances.

[0003] Since the widespread use of laser light sources, Raman spectroscopy has developed rapidly, boasting advantages such as simple operation, no pretreatment required, and fast detection speed. However, it is also limited by the typically extremely weak Raman signal, which leads to a lack of ability to detect trace substances. Although it has been discovered in recent years that metal nanoparticles can enhance the Raman signal, using this method to detect trace substances negates the original advantages of Raman spectroscopy, such as simple operation and no pretreatment required.

[0004] CN108007921A provides a device for enhancing Raman spectral signals. This device can effectively control the amount of light flux to adjust the final output Raman spectrum. It enhances the Raman signal through multiple sets of condenser lenses and anti-reflection coatings. However, the focal length adjustment is difficult and requires a lot of manual adjustment, resulting in efficiency problems and difficulty in achieving light stability. In addition, it is suitable for the detection of large amounts of liquid samples but not for the detection of trace samples.

[0005] CN108717057A discloses a portable surface-enhanced Raman spectrometer and its measurement method. The method employs a Raman measurement optical path to generate a Raman signal; a white light optical path to obtain the microscopic morphology of the sample surface, thereby determining the focusing of the optical path; and by moving a three-dimensional translation stage, the sample surface is positioned precisely at the focal length of the microscope objective, ensuring clear imaging of the sample surface and maximizing laser focusing, thus obtaining the strongest Raman signal. However, this method is suitable for constant sample volumes, and may result in insufficient signal intensity for the analysis of trace samples.

[0006] Therefore, it is necessary to design a device that can enhance the Raman signal so that it can be applied to the detection of trace substances, thereby expanding the application range of Raman spectroscopy, and making it simple to design, easy to operate, and easy to promote in the market. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the existing technology by providing a Raman spectroscopy device for cross-irradiation measurement of trace samples. This device significantly improves the sensitivity of existing Raman spectroscopy technology for the detection of trace samples and enhances the Raman signal. At the same time, the device has a simple structure, stable performance, and fast and flexible operation, which is conducive to its widespread application.

[0008] The objective of this invention can be achieved through the following technical solutions:

[0009] The Raman spectroscopy apparatus for measuring trace samples by cross-irradiation in this invention includes a spectrometer and a vacuum chamber connected to the spectrometer. The vacuum chamber contains the following components:

[0010] A. Multiple parallel optical path sleeves: Their inlet ends are connected to the spectrometer, and the parallel laser output from the spectrometer is converged from the various outlet ends of the parallel optical path sleeves to a point, so as to achieve cross-simultaneous irradiation of the sample, thereby increasing the laser intensity at the convergence point.

[0011] B. Loading platform;

[0012] C. The container is placed on the container platform;

[0013] D. A collecting lens is positioned above the container.

[0014] E. The focusing lens is positioned above the collecting lens;

[0015] F. A concave lens is positioned above the focusing lens to convert the scattered light collected and focused by the collecting lens and the focusing lens into parallel light that is input into the spectrometer.

[0016] Furthermore, the parallel light path sleeve is right-angled, and a 90° reflector is provided at the right angle of the parallel light path sleeve to achieve a 90° deflection of the parallel light.

[0017] Furthermore, the concave lens, focusing lens, and collecting lens are coaxial.

[0018] Furthermore, multiple parallel optical path sleeves are arranged symmetrically with the axes of the concave lens, focusing lens, and collecting lens as the axis of symmetry.

[0019] Furthermore, the output end of the parallel light path sleeve is equipped with a laser emission focusing device to converge and focus the parallel light onto the sample.

[0020] Furthermore, the laser emitting focusing device converges at the same point as the focal point of the collecting lens.

[0021] Furthermore, the Raman spectroscopy device for measuring trace samples by cross-irradiation also includes a vacuum pumping component.

[0022] Furthermore, the carrying platform is equipped with a microprocessor;

[0023] The holding platform is equipped with a horizontal displacement component and a first servo driver to realize the horizontal position adjustment of the holding dish;

[0024] The holding platform is equipped with a vertical lifting component and a second servo driver to realize the vertical position adjustment of the holding dish;

[0025] The microprocessor is electrically connected to the first servo driver and the second servo driver;

[0026] The microprocessor is electrically connected to an external human-computer interaction display.

[0027] Furthermore, the microprocessor is an ARM processor.

[0028] Furthermore, a photosensitive sensor is provided on the surface of the holding platform, and the photosensitive sensor is electrically connected to the microprocessor.

[0029] Furthermore, the concave lens, focusing lens, and collecting lens are all made of flint glass.

[0030] Furthermore, the sample amount applicable in this technical solution is 10mg to 20mg.

[0031] Compared with the prior art, the present invention has the following technical advantages:

[0032] 1. In this technical solution, the parallel optical path sleeve, the 90° reflector, and the laser emission focusing device constitute a multi-angle laser emission assembly. Multiple laser beams on both sides intersect at a certain angle to simultaneously irradiate the sample, which can increase the laser intensity at the intersection point. At the same time, simultaneous irradiation from both sides can also increase the scattering angle of the scattered light. As long as the collection ability of the scattered light is sufficient, a stronger Raman signal can be obtained.

[0033] 2. In this technical solution, lasers from both sides simultaneously irradiate the sample at a certain angle. The intersection of the lasers is both the focal point of the beam and the focal point of the collecting lens. By observing the size and shape of the laser spot on the holding platform, the focal point can be easily adjusted, and the sample can be accurately placed at the focal point.

[0034] 3. In this technical solution, the collecting lens, focusing lens, and concave lens constitute a large-aperture scattered light collecting component. The large-aperture double convex lens group can collect and focus more Raman scattered light, and transform the light into an extremely narrow parallel beam through the concave lens and project it into the spectrometer. These components are assembled into a fixed structure, without the use of optical fibers, and have an extremely short optical path, avoiding signal loss and impurity signals caused by optical fibers, thereby improving the sensitivity and accuracy of the measurement.

[0035] 4. In this technical solution, the vacuum chamber can eliminate the attenuation of light caused by gas disturbances and can also eliminate dust in the air, preventing dust from affecting the detection of trace samples.

[0036] 5. During use, the sample holder of this Raman spectroscopy device for trace samples is removable and cleanable. Multiple sample holders can be prepared to quickly complete the detection of batch samples. The whole device is simple and convenient to operate and can be widely used for the determination of various trace samples. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the Raman spectroscopy device for measuring trace samples by cross-irradiation in this invention.

[0038] In the figure: 1-Spectrometer, 2-Vacuum chamber, 3-Concave lens, 4-Focusing lens, 5-Collecting lens, 6-90° reflector, 7-Parallel optical path sleeve, 8-Laser emission focusing device, 9-Sample container, 10-Container platform. Detailed Implementation

[0039] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0040] Example 1

[0041] In this embodiment, the Raman spectroscopy device for measuring trace samples by cross-irradiation includes a spectrometer 1 and a vacuum chamber 2 connected to the spectrometer 1. The vacuum chamber 2 is equipped with two parallel optical path sleeves 7, a holding platform 10, a holding dish 9, a collecting lens 5, a focusing lens 4, and a concave lens 3.

[0042] The inlet end of the parallel light path sleeve 7 is connected to the spectrometer 1, converging the parallel laser output from the spectrometer 1 to a single point through the various outlet ends of the parallel light path sleeve 7, achieving simultaneous cross-irradiation of the sample and thus increasing the laser intensity at the convergence point. The parallel light path sleeve 7 is right-angled, with a 90° reflecting mirror 6 at the right angle to achieve a 90° deflection of the parallel light. In specific implementation, the two parallel light path sleeves 7 are arranged symmetrically about the axis of the concave lens 3, the focusing lens 4, and the collecting lens 5. Each output end of the parallel light path sleeve 7 is equipped with a laser emission focusing device 8, which converges and focuses all the parallel light from the two parallel light path sleeves 7 onto a specific point on the sample. The convergence point of the parallel light from the laser emission focusing device 8 coincides with the focal point of the collecting lens 5. Specifically, the laser emission focusing device 8 is selected as a plano-concave lens with a diameter of 5 mm.

[0043] A carrying dish 9 is placed on the carrying platform 10; a collecting lens 5 is placed above the carrying dish 9; a focusing lens 4 is placed above the collecting lens 5; and a concave lens 3 is placed above the focusing lens 4. The collecting lens 5 and the focusing lens 4 collect and focus the scattered light onto the concave lens 3, converting it into parallel light that enters the spectrometer 1. In specific implementation, the concave lens 3, the focusing lens 4, and the collecting lens 5 are coaxial. The focusing lens 4 uses a large-aperture lens group, capable of focusing the parallel light collected and converted by the collecting lens onto the concave lens 3, where it is again converted into convergent parallel light and enters the spectrometer 1. The collecting lens 5 has a large surface area, capable of collecting Raman light scattered from the sample at large angles, and enabling scattered light from various angles to pass through the focusing lens 4 as parallel light. In specific selection, the diameter of the focusing lens 4 is 30 mm, and the diameter of the collecting lens 5 is 30 mm.

[0044] In terms of specific material selection, concave lens 3, focusing lens 4, and collecting lens 5 are all made of flint glass to increase the refractive index and reduce the loss of incident light and excitation light when passing through the hyperbola lens.

[0045] The Raman spectroscopy apparatus for measuring trace samples by cross-irradiation also includes a vacuum pumping component, which can evacuate the interior of the vacuum chamber 2 to eliminate the attenuation of light caused by gas disturbances and prevent dust from interfering with the detection results.

[0046] The holding platform is equipped with a microprocessor, a horizontal displacement component, and a first servo driver to adjust the horizontal position of the holding dish 9. The platform also includes a vertical lifting component and a second servo driver to adjust the vertical position of the holding dish 9. The microprocessor is electrically connected to the first and second servo drivers and to an external human-machine interface display. Specifically, an ARM processor is selected. A photosensitive sensor is mounted on the surface of the holding platform and electrically connected to the microprocessor to automatically adjust the height of the holding dish 9 to the height of the laser intersection point and position the sample at the focus point. Through the driving force of the horizontal displacement component, the vertical lifting component, and the servo drivers, the holding platform can automatically fine-tune its position in six directions: up, down, forward, backward, left, and right, ensuring that the sample on the holding dish is positioned at the intersection of the laser beams emitted from both sides of the multi-angle laser emission system. The horizontal displacement component can be implemented through a gear connection between a horizontal rack and pinion and the output of the servo driver, or through a horizontal lead screw and the servo driver. The lifting component can be implemented using a small lifting machine.

[0047] The following steps are used during operation:

[0048] 1. Evacuate vacuum chamber 2 to a vacuum state.

[0049] 2. Place the sample to be tested onto the sample holder 9;

[0050] 3. Install the sample container 9 containing the sample onto the container platform 10;

[0051] 4. Turn on the light source of the spectrometer 1 so that multiple parallel laser beams pass through the parallel optical path sleeves 7 on both sides, pass through the 90° reflector 6, and are then focused by the laser emission focusing device 8 onto the sample container 9.

[0052] 5. First, adjust the loading platform 10 longitudinally to minimize the laser spot reflected on the surface of the sample container; then adjust the loading platform 9 laterally to position the sample on the sample container 8 at the point of minimum laser spot size.

[0053] 6. The scattered light is converted into parallel light by the collecting lens 5, and then focused onto the concave lens 3 by the focusing lens 4, and then converted into parallel light again to enter the spectrometer 1 to complete the spectral measurement.

[0054] Steps 4 through 6 are automated processes.

[0055] In practice, after the sample position is adjusted, the entire device can be placed in a dark environment to reduce the influence of other light signals on the detection.

[0056] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A Raman spectrometer for measuring trace samples by cross-irradiation, characterized in that, Includes a spectrometer (1) and a vacuum chamber (2) connected to the spectrometer (1), wherein the vacuum chamber (2) is provided with: Multiple parallel optical path sleeves (7) are connected to the spectrometer (1) at their inlet ends. The parallel laser output from the spectrometer (1) is converged from each outlet end of the parallel optical path sleeve (7) to a point, so as to achieve cross-simultaneous irradiation of the sample and thereby increase the laser intensity at the convergence point. Container platform (10); A container (9) is placed on the container platform (10); A collecting lens (5) is positioned above the container (9); A focusing lens (4) is positioned above the collecting lens (5); A concave lens (3) is positioned above the focusing lens (4) to convert the scattered light collected and focused by the collecting lens (5) and the focusing lens (4) into parallel light that is input into the spectrometer (1). The parallel light path sleeve (7) is right-angled, and a 90° reflector (6) is provided at the right angle of the parallel light path sleeve (7) to achieve a 90° turn of the parallel light. The concave lens (3), focusing lens (4), and collecting lens (5) are coaxial; The output end of the parallel light path sleeve (7) is equipped with a laser emission focusing device (8) to converge and focus the parallel light onto the sample; The laser emitting focusing device (8) converges at the same point as the focal point of the collecting lens (5) for parallel light; The container platform is equipped with a microprocessor; The loading platform is equipped with a horizontal displacement component and a first servo driver to realize the horizontal position adjustment of the loading dish (9); The holding platform is equipped with a vertical lifting component and a second servo driver to realize the vertical position adjustment of the holding dish (9); A photosensitive sensor is provided on the surface of the loading platform, and the photosensitive sensor is electrically connected to the microprocessor. The microprocessor is electrically connected to the first servo driver and the second servo driver; The microprocessor is electrically connected to an external human-computer interaction display. The container platform can automatically adjust its position in six directions—up, down, front, back, left, and right—through the horizontal displacement component and the vertical lifting component, so that the sample on the sample container (9) is at the intersection of the lasers emitted by the two sides of the multi-angle laser emission system.

2. The Raman spectroscopy apparatus for measuring trace samples by cross-irradiation according to claim 1, characterized in that, The surface of the holding platform is equipped with a photosensitive sensor, which is electrically connected to the microprocessor.

3. The Raman spectroscopy apparatus for measuring trace samples by cross-irradiation according to claim 1, characterized in that, Multiple parallel optical path sleeves (7) are arranged symmetrically with the axis of concave lens (3), focusing lens (4), and collecting lens (5) as the axis of symmetry.

4. The Raman spectroscopy apparatus for measuring trace samples by cross-irradiation according to claim 1, characterized in that, The Raman spectroscopy device for measuring trace samples by cross-irradiation also includes a vacuum pumping component.

5. The Raman spectroscopy apparatus for measuring trace samples by cross-irradiation according to claim 1, characterized in that, The concave lens (3), focusing lens (4), and collecting lens (5) are all made of flint glass.

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