Detector for collecting surface enhanced Raman scattering spectrums by using multi-aperture angle parabolic mirror

Abstract

The invention discloses a detector for collecting surface enhanced Raman scattering spectrums by using a multi-aperture angle parabolic mirror, which maximizes the collection and transmission efficiency of Raman scattering signals through the optimized layout of a vertical light path channel, the parabolic mirror, a microporous structure and a conical structure. The parabolic mirror is used for efficiently collecting scattered light in a 2pi solid angle and reflecting the scattered light into parallel light beams, so that the signal intensity and the detection sensitivity are improved; and stray light interference is reduced and the signal-to-noise ratio is enhanced through the micropore structure and the conical design in the optical path channel. Besides, the separation of the laser space and the reflection space effectively avoids the path interference of laser and scattering signals, and the entrance slit of the optical fiber connector in the feedback space ensures the lossless transmission of the signals, so that the system has efficient light beam control and flexible modular expansion capability.

Description

Technical Field

[0001] The invention belongs to the field of spectrum analysis, and in particular relates to a detector for collecting surface enhanced Raman scattering spectra using a multi-aperture angular parabolic mirror. Background Art

[0002] In traditional SERS detection systems, signal collection efficiency and the stability of optical path control are often limited by multiple factors, especially laser beam scattering and path interference problems, which lead to signal energy loss and stray light interference during the detection process. This interference not only reduces the signal-to-noise ratio (SNR) of the system, but also affects the detection accuracy of the sample signal, resulting in insufficient sensitivity. In addition, the existing technology mostly uses high numerical aperture objectives for beam collection, but due to the limited collection range of the objective lens, it is usually difficult to cover a 2π solid angle, which means that part of the scattered light cannot be collected due to angle offset, resulting in the loss of Raman signals, thereby affecting the overall detection performance.

[0003] In addition, in traditional optical path design, the laser excitation path and the signal reflection path often interfere with each other, resulting in energy loss in the optical path and reduced signal purity; these problems are particularly prominent when detecting complex samples or weak signals. The presence of stray light further interferes with the transmission of effective signals, making the output results of the detection system not pure and reliable enough.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a detector for collecting surface enhanced Raman scattering spectra using a multi-aperture angular parabolic mirror, thereby solving the problems raised in the above-mentioned background technology.

[0006] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is:

[0007] A detector for collecting surface enhanced Raman scattering spectra using a multi-aperture angular parabolic mirror comprises: a cylinder, an optical path channel is installed in the vertical direction of the cylinder, a parabolic mirror for collecting SERS Raman scattered light within a 2π solid angle range and reflecting it into a parallel light beam is arranged above the inner wall of the optical path channel, a reflection space is arranged below the optical path channel, a laser space is arranged on one side of the optical path channel, a feedback space is arranged on one side of the inner wall of the reflection space, a microporous structure is arranged between the reflection space and the optical path channel, and the lower end of the optical path channel is a conical structure, an incident slit for installing an optical fiber connector is installed on one side of the feedback space, a substrate is arranged above the mounting cylinder, a laser for transmitting a laser beam to the optical path channel and the reflection space through the laser space is arranged on one side of the mounting cylinder, and the laser focuses the emitted laser to the focal position of the SERS substrate.

[0008] Optionally, the laser is a TEM00 mode laser with a wavelength of 785 nm and a power of 25 mW, which is used to excite SERS signals.

[0009] Optionally, a beam splitter, a variable focus lens and a liquid crystal phase modulator are provided inside the laser space, and a plurality of lasers are combined into optical paths through the beam splitter. The optical path channel is internally connected with a short-wave pass filter for filtering scattered light and non-target light waves in stray laser light and allowing only the excitation band to pass through.

[0010] Optionally, the variable focus lens is composed of a lens filled with liquid crystal material, wherein both sides of the lens filled with liquid crystal material are covered with transparent electrodes, and when in use, the orientation of the liquid crystal molecules is changed by applying an external voltage, thereby affecting the refractive index of the light beam passing through.

[0011] Optionally, an aperture objective lens for confocusing the excitation light emitted by the liquid crystal phase modulator on the substrate and the sample area is also provided on the inner wall of the optical path channel.

[0012] Optionally, an aspheric large-aperture objective lens for focusing the parallel light reflected by the parabolic mirror is arranged below the optical path channel, and a long-wave pass filter for filtering out Rayleigh scattering and allowing only Raman signals to pass through is arranged below the aspheric large-aperture objective lens. The light beam emitted by the long-wave pass filter will pass through the pinhole filter in the space to eliminate stray light and enter the reflection space.

[0013] Optionally, a total internal reflection prism for refracting the light beam by 90 degrees is arranged in the reflection space, and a lens for focusing the light beam into the incident slit is arranged in the feedback space.

[0014] Optionally, the substrate is composed of a nanohole array made of gold or silver, and the nanoholes are used to excite surface plasmon resonance to enhance the local electromagnetic field and achieve amplification of Raman signals.

[0015] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art. Of course, any product implementing the present invention does not necessarily need to achieve all the advantages described below at the same time:

[0016] The collection and transmission efficiency of Raman scattering signals is maximized through the optimized layout of vertical optical path channels, parabolic mirrors, microporous structures, and conical structures. The parabolic mirror efficiently collects scattered light within a 2π solid angle and reflects it as a parallel beam, which improves signal strength and detection sensitivity; the microporous structure and conical design in the optical path channel reduce stray light interference and enhance the signal-to-noise ratio. In addition, the separation of the laser space and the reflection space effectively avoids path interference between the laser and the scattered signal, and the fiber optic connector incident slit in the feedback space ensures lossless transmission of the signal, giving the system efficient beam control and flexible modular expansion capabilities.

[0017] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described below are only some embodiments. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0019] In the figure:

[0020] Figure 1 is a schematic diagram of the cross-sectional structure of the detector;

[0021] Figure 2 is a schematic diagram of the base cross-section structure;

[0022] Figure 3 Schematic diagram of the cross-sectional structure of a variable focus lens.

[0023] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0024] 1. Cylinder; 2. Optical path; 3. Parabolic mirror; 4. Reflection space; 5. Laser space; 6. Feedback space; 7. Micropore structure; 8. Entrance slit; 9. Substrate; 10. Laser; 11. Beam splitter; 12. Variable focus lens; 13. Liquid crystal phase modulator; 14. Short wave pass filter; 15. Aperture objective lens; 16. Aspherical large aperture objective lens; 17. Total internal reflection prism; 18. Lens.

[0025] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but are intended to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0026] The present invention will now be described in further detail with reference to the accompanying drawings.

[0027] See also Figure 1-3 As shown, in this embodiment, a detector for collecting surface enhanced Raman scattering spectra using a multi-aperture angular parabola is provided, including a cylinder 1, an optical path channel 2 is installed in the vertical direction of the cylinder 1, a parabola 3 for collecting SERS Raman scattered light within a 2π solid angle range and reflecting it as a parallel light beam is arranged above the inner wall of the optical path channel 2, a reflection space 4 is arranged below the optical path channel 2, a laser space 5 is arranged on one side of the optical path channel 2, a feedback space 6 is arranged on one side of the inner wall of the reflection space 4, a microporous structure 7 is arranged between the reflection space 4 and the optical path channel 2, and the lower end of the optical path channel 2 is a conical structure, an incident slit 8 for installing an optical fiber connector is installed on one side of the feedback space 6, a substrate 9 is arranged above the mounting cylinder, and a laser 10 for transmitting a laser beam to the optical path channel 2 and the reflection space 4 through the laser space 5 is arranged on one side of the mounting cylinder, and the laser 10 focuses the emitted laser to the focal position of the SERS substrate 9.

[0028] Through the layout of the vertical optical path channel 2, the microporous structure 7 and the tapered lower end, the system can effectively guide the light beam transmission, avoid unnecessary reflection and scattering paths, thereby reducing light loss and improving the overall signal-to-noise ratio. The vertical arrangement of the optical path allows the laser beam and Raman scattered light to be transmitted smoothly, reducing the complexity of the optical path. The parabolic mirror 3 efficiently collects scattered light within a 2π solid angle and focuses it to reflect it as a parallel beam, ensuring that the maximum light energy is transmitted to the optical fiber and the detector end, greatly improving the sensitivity and detection efficiency of the SERS signal. In addition, the independent setting of the laser space 5 and the reflection space 4 avoids interference between the laser and scattered light paths, improving the stability of the system and the accuracy of measurement. The incident slit 8 in the feedback space 6 ensures that the Raman signal can be accurately coupled to the optical fiber, achieving lossless transmission of the signal, and supports modular integration with different spectrometers, improving the flexibility and scalability of the equipment in various detection applications.

[0029] In this embodiment, the laser 10 is a TEM00 mode laser 10 with a wavelength of 785nm and a power of 25mW, which is used to excite the SERS signal. A beam splitter 11, a variable focus lens 12 and a liquid crystal phase modulator 13 are arranged inside the laser space 5. Multiple lasers 10 merge the light path through the beam splitter 11, and the light path channel 2 is connected to a short-wave pass filter 14 for filtering scattered light and non-target light waves in the stray laser light and only allowing the excitation band to pass. The TEM00 mode laser 10 with a wavelength of 785nm and a power of 25mW provides a laser with high stability and high coherence for effectively exciting the SERS signal; the beam splitter 11 arranged in the laser space 5 can merge the light beams of multiple lasers 10 into the same light path, realizing the flexibility of multi-wavelength excitation to meet the detection requirements of complex samples. At the same time, the system integrates a variable focus lens 12 and a liquid crystal phase modulator 13, which can dynamically adjust the focal spot size and the beam phase, improve the excitation efficiency and adaptability to different samples. The short-wave filter 14 is used to filter out stray light and non-target wavelengths, allowing only specific wavelengths to pass through, thereby ensuring the purity of the excitation light and enhancing the accuracy of signal acquisition and detection sensitivity.

[0030] In this embodiment, the variable focus lens 12 is composed of a lens filled with liquid crystal material, wherein transparent electrodes are covered on both sides of the lens filled with liquid crystal material. When in use, the orientation of the liquid crystal molecules is changed by applying an external voltage, affecting the refractive index when the light beam passes through. By filling the variable focus lens 12 with liquid crystal material, the transparent electrodes on both sides of the lens change the arrangement direction of the liquid crystal molecules under the action of an applied voltage, thereby dynamically adjusting the refractive index. This design allows real-time control of the focal length and spot size of the light beam in different application scenarios, improving the adaptability of the system to samples of different sizes and shapes. Compared with traditional mechanical lenses, the adjustment of liquid crystal lenses is faster, more precise and free of mechanical wear, ensuring the stability of the system and the reliability of long-term operation. At the same time, this dynamic focusing function helps to optimize the shape of the light beam, further improving the excitation efficiency and the collection quality of the Raman signal.

[0031] In this embodiment, an aperture objective lens 15 is also provided on the inner wall of the optical path channel 2 for cofocusing the excitation light emitted by the liquid crystal phase modulator 13 on the substrate 9 and the sample area. By arranging the aperture objective lens 15 on the inner wall of the optical path channel 2, the excitation light adjusted by the liquid crystal phase modulator 13 is accurately cofocused on the SERS substrate 9 and the sample area. This structure ensures that the energy of the laser beam is concentrated on the target area, improves the excitation efficiency, and thus enhances the intensity of the SERS signal. In addition, the addition of the liquid crystal phase modulator 13 can dynamically adjust the phase of the light beam, and with the focusing ability of the aperture objective lens 15, the system can adapt to the shape and size of different samples, and improve the flexibility and accuracy of detection. This design optimizes the control and transmission of the light beam, which helps to achieve high-sensitivity and high-resolution SERS detection.

[0032] In this embodiment, a non-spherical large-aperture objective lens 16 for focusing the parallel light reflected by the parabola 3 is arranged below the optical path channel 2, and a long-wave pass filter 19 for filtering out Rayleigh scattering and allowing only Raman signals to pass is arranged below the non-spherical large-aperture objective lens 16. The beam emitted by the long-wave pass filter 19 will pass through the spatial pinhole filter to eliminate stray light and enter the reflection space 4. By arranging the non-spherical large-aperture objective lens 16 below the optical path channel 2, the parallel light beam reflected by the parabola 3 is accurately focused, thereby improving the efficiency of signal collection and the quality of light beam transmission. The non-spherical design can reduce optical aberrations, ensure that the focus of the excitation and scattered light is more accurate, and thus enhance the detection sensitivity of the SERS signal. The long-wave pass filter 19 arranged below the objective lens is used to effectively filter out Rayleigh scattering, allowing only the target Raman signal to pass, and ensuring the signal purity in the optical path. The residual stray light is further eliminated by the spatial pinhole filter to avoid interference from entering the reflection space 4, thereby improving the signal-to-noise ratio and measurement accuracy of the system.

[0033] In this embodiment, a total internal reflection prism 17 for refracting the light beam 90 degrees is provided in the reflection space 4, and a lens 18 for focusing the light beam into the incident slit 8 is provided in the feedback space 6. By providing the total internal reflection prism 17 in the reflection space 4, a 90-degree refraction of the light beam path is achieved, the optical path layout of the system is optimized, making it more compact, and reducing the energy loss in the optical path. At the same time, the lens 18 configured in the feedback space 6 can accurately focus the filtered Raman signal onto the incident slit 8, ensuring that the signal is efficiently coupled to the optical fiber or detector. This design not only improves the space utilization of the system, but also enhances the transmission efficiency of the signal, reduces the stray light interference in the optical path, and ensures high-quality data acquisition.

[0034] In this embodiment, the substrate 9 is composed of a nanopore array composed of gold or silver, and the nanopores are used to excite surface plasmon resonance to enhance the local electromagnetic field and achieve amplification of the Raman signal. The SERS substrate 9 adopts a metal nanopore array structure to effectively excite surface plasmon resonance SPR, thereby enhancing the local electromagnetic field near the sample. This enhancement effect significantly amplifies the weak Raman signal and greatly improves the sensitivity of the detection system. The metal nanopore array can also provide more active areas, making it easier for sample molecules to adsorb on the surface, further improving the signal strength.

[0035] The experiment uses 785nm and 532nm wavelength lasers 10, both with a power of 25mW, to excite standard Raman samples rhodamine 6G and trace aniline solution to test the detection performance of the system; the SERS substrate 9 is composed of a metal nanohole array to enhance the signal; the concentrations of the samples are 1μM rhodamine 6G and 0.1ppm aniline. The experiment was carried out at room temperature of 25℃ and relative humidity of 40%, and the results were recorded and analyzed using a CCD spectrometer with a detection range of 400-1000nm. These conditions ensure the repeatability of the experiment and the accurate collection of Raman signals.

[0036] Experimental Example 1: In the experiment, the 785nm and 532nm lasers 10 are first started, the power is set to 25mW, and the light paths are merged through the beam splitter 11. After the stray light is removed by the short-wave filter 14, the laser beam is transmitted to the sample area; the CCD spectrometer is started and the detection range is calibrated to 400-1000nm. A 1μM Rhodamine 6G solution is dripped onto the nanoholes of the SERS substrate 9 to ensure that the sample is in contact with the substrate 9. Subsequently, single-wavelength excitation is performed using 785nm and 532nm lasers 10, respectively, and the light beams are focused by the liquid crystal phase modulator 13 and the variable focus lens 12, and the scattered light is collected using the parabolic mirror 3, and the signal intensity and signal-to-noise ratio are recorded. Finally, the sample is simultaneously excited through the dual-wavelength confocal path, the Raman spectrum is collected and recorded, and the signal intensity and signal-to-noise ratio under different excitation modes are analyzed and compared to verify the effect of dual-wavelength excitation on improving detection sensitivity. The experimental results are shown in Table 1:

[0037] Excitation wavelength sample Raman peak position cm-1 Raman signal intensity au Signal-to-Noise Ratio (SNR) 785nm Rhodamine 6G 1510 620 32 532nm Rhodamine 6G 1510 480 28 Dual wavelength confocal Rhodamine 6G 1510 890 40

[0038] In Example 1, the experimental results show that dual-wavelength confocal excitation significantly improves the Raman signal intensity from 620 a.u. and 480 a.u. to 890 a.u. compared to single-wavelength excitation, and improves the signal-to-noise ratio from 32 and 28 to 40, verifying the advantages of multi-wavelength excitation in improving detection sensitivity and reducing background noise, and is suitable for multi-component detection of complex samples.

[0039] Example 2: In the experiment, first enable the 785nm laser 10 to ensure that the laser beam enters the optical path channel 2 through the liquid crystal variable focus lens 12 and the short wave pass filter 14, and adjust the electrode voltage of the liquid crystal lens 18 to change the focal length to achieve dynamic regulation of the light beam. Prepare three types of samples: place rhodamine 6G powder as a solid sample on the SERS substrate 9, add 0.1ppm aniline solution as a liquid sample, and evenly distribute the nanoparticles on the surface of the substrate 9 as a particle sample. Use a conventional fixed-focus laser 10 to excite each sample and record the Raman signal intensity, then adjust the focal length of the liquid crystal lens 18 to excite the sample again, and record the spectral signal. Finally, by comparing the signal intensity under fixed focal length and variable focus excitation, analyze the adaptability of the liquid crystal lens 18 to different samples, and summarize its optimization effect and practical application value in the detection of samples of different morphologies. The experimental results are shown in Table 1:

[0040]

[0041] In Example 2, the liquid crystal variable focus lens significantly improves the signal intensity of samples of different forms by dynamically adjusting the focal length, such as increasing the signal intensity of solid samples from 620 a.u. to 740 a.u., liquid samples from 540 a.u. to 680 a.u., and particle samples from 430 a.u. to 620 a.u., which proves the role of liquid crystal lenses in optimizing beam focusing and enhancing system adaptability, and is suitable for the detection needs of diverse samples.

[0042] The present invention is not limited to the above-mentioned embodiments. Anyone should be aware that any structural changes made under the enlightenment of the present invention, and any technical solutions that are the same or similar to the present invention, fall within the protection scope of the present invention. The technology, shape, and structural parts not described in detail in the present invention are all well-known technologies.

Claims

1. A detector for collecting surface enhanced Raman scattering spectra using a multi-aperture angular parabolic mirror, characterized in that: include: A cylinder (1) is provided with an optical path channel (2) installed in a vertical direction on the cylinder (1); a parabolic mirror (3) is provided above the inner wall of the optical path channel (2) for collecting SERS Raman scattered light within a 2π solid angle range and reflecting it into a parallel light beam; a reflection space (4) is provided below the optical path channel (2); a laser space (5) is provided on one side of the optical path channel (2); a feedback space (6) is provided on one side of the inner wall of the reflection space (4); the reflection space (4) and the optical path channel are connected to each other. A microporous structure (7) is arranged between the optical path channel (2), and the lower end of the optical path channel (2) is a conical structure. An incident slit (8) for installing an optical fiber connector is installed on one side of the feedback space (6). A base (9) is arranged above the mounting tube. A laser (10) is arranged on one side of the mounting tube for transmitting a laser beam to the optical path channel (2) and the reflection space (4) through the laser space (5). The laser (10) focuses the emitted laser to the focal position of the SERS substrate (9).

2. A detector for collecting surface enhanced Raman scattering spectra using a multi-aperture angular parabolic mirror according to claim 1, characterized in that: The laser (10) is a TEM00 mode laser (10) with a wavelength of 785 nm and a power of 25 mW, and is used to excite SERS signals.

3. The detector for collecting surface enhanced Raman scattering spectra using a multi-aperture angular parabolic mirror according to claim 1, characterized in that: A beam splitter (11) and a variable focus lens (12) and a liquid crystal phase modulator (13) are arranged inside the laser space (5); a plurality of lasers (10) are combined into optical paths through the beam splitter (11); and a short-wave filter (14) is connected inside the optical path channel (2) and is used to filter scattered light and non-target light waves in stray laser light and only allow the excitation band to pass through.

4. The detector for collecting surface enhanced Raman scattering spectra using a multi-aperture angular parabolic mirror according to claim 1, characterized in that: The variable focus lens (12) is composed of a lens filled with liquid crystal material, wherein both sides of the lens filled with liquid crystal material are covered with transparent electrodes, and when in use, the orientation of the liquid crystal molecules is changed by applying an external voltage, thereby affecting the refractive index of the light beam passing through.

5. The detector for collecting surface enhanced Raman scattering spectra using a multi-aperture angular parabolic mirror according to claim 1, characterized in that: An aperture objective lens (15) for co-focusing the excitation light emitted by the liquid crystal phase modulator (13) on the substrate (9) and the sample area is also provided on the inner wall of the optical path channel (2).

6. The detector for collecting surface enhanced Raman scattering spectra using a multi-aperture angular parabolic mirror according to claim 1, characterized in that: An aspheric large-aperture objective lens (16) for focusing the parallel light reflected by the parabolic mirror (3) is arranged below the optical path channel (2); a long-wave pass filter (19) for filtering out Rayleigh scattering and allowing only Raman signals to pass is arranged below the aspheric large-aperture objective lens (16); the line beam emitted by the long-wave pass filter (19) passes through the pinhole filter in the space to eliminate stray light and enter the reflection space (4).

7. The detector for collecting surface enhanced Raman scattering spectra using a multi-aperture angular parabolic mirror according to claim 1, characterized in that: A total internal reflection prism (17) for refracting the light beam by 90 degrees is arranged in the reflection space (4), and a lens (18) for focusing the light beam into the incident slit (8) is arranged in the feedback space (6).

8. The detector for collecting surface enhanced Raman scattering spectra using a multi-aperture angular parabolic mirror according to claim 1, characterized in that: The substrate (9) is composed of a nanopore array made of gold or silver, and the nanopores are used to excite surface plasma resonance to enhance the local electromagnetic field and achieve amplification of Raman signals.

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