CN216208595U - Dual wavelength light source Raman spectrometer system - Google Patents

Abstract

The utility model discloses a dual-wavelength light source Raman spectrometer system, which comprises: the laser light source group is provided with laser light sources with two wavelengths, and the laser light sources with the two wavelengths respectively excite two material samples with different properties; the volume holographic transmission grating group comprises two independent volume holographic transmission gratings which respectively receive Raman scattered light generated after two samples are excited by light sources with two wavelengths; and different areas of the CCD detector receive the parallel light beams after the Raman scattered light from the two volume holographic transmission gratings is split. According to the multichannel Raman spectrometer for detecting the laser light sources with the two wavelengths, two samples with different types and properties can be detected by the same equipment through the dual-wavelength light source, and a plurality of samples can be simultaneously detected by the same type through multichannel arrangement, so that the multichannel Raman spectrometer is convenient and quick.

Description

Dual wavelength light source Raman spectrometer system

technical field

The utility model relates to the technical field of optical detection, in particular to a dual-wavelength light source Raman spectrometer system.

Background technique

Raman spectroscopy is that when a laser of a certain frequency is irradiated to the sample, the molecules of the substance and photons undergo energy conversion, so that the vibration of the chemical bonds between atoms in the molecules changes in different ways and degrees, and then scatters light of different frequencies, and the frequency changes. Depending on the characteristics of the scattering material, the chemical bonds between different types of atoms vibrate in a unique way, so scattered light with a specific difference in frequency from the incident light can be generated. The difference spectrum is called "Raman spectrum". A Raman spectrometer is an instrument that uses a laser to irradiate a sample, collects Raman scattered light for signal analysis, and obtains a Raman spectrum.

Raman spectrometer has a wide detection range (can detect light-transmitting gases, liquids and solids), short detection time (several seconds to minutes), small sample consumption, no damage to samples, rich spectral information and strong characteristics. , small size, remote detection, easy system maintenance and other advantages, is currently widely used in process analysis. The simultaneous detection of multiple materials and multiple channels can greatly improve the detection efficiency. Materials in different states sometimes need to use laser light sources of different wavelengths. In the prior art, although there are multi-channel Raman spectrometers that can detect samples of multiple materials at the same time, it is difficult to detect materials with different properties, such as a liquid and a gas, using a light source of one wavelength. , so in this case, two different Raman spectrometers are often required for detection.

Chinese patent application CN109085152A discloses a multi-channel fiber-optic gas Raman scattering measurement system. In this solution, a laser system, a Raman spectral imaging system, a 10-channel fiber coupling system, a measurement and control system, a 45-degree laser mirror, a laser focusing mirror and The laser collector is placed on the same optical platform. This scheme can realize the laser spontaneous vibration Raman spectral line imaging of gaseous species in the dynamic combustion field, and can realize the high-precision quantitative measurement of the mole fraction of gaseous species and the regional temperature in the dynamic combustion field. This prior art collects the Raman scattered light passing through the sample through a multi-channel fiber optic sensor, but can only be used for detection of a single wavelength light source.

In process analysis, such as the analysis of controlled materials in the refining process, it involves both gas and liquid. At present, different instruments are often used for analysis of different materials or materials of different shapes. etc., the gas phase material adopts gas chromatography and so on. Therefore, there is an urgent need for an instrument that can simultaneously detect two materials with different properties. A multi-channel Raman spectrometer based on a dual-wavelength laser light source can detect samples of different properties with the same device, and samples of the same property can also be detected at the same time. Detect multiple, convenient and fast.

The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person of ordinary skill in the art.

Utility model content

The purpose of this utility model is to provide a multi-channel Raman spectrometer system capable of detecting two wavelengths of laser light sources. The same device can detect two samples of different types and properties through the dual-wavelength light source, and through the multi-channel setting, The same type of samples can also be detected at the same time, which is convenient and quick.

In order to achieve the above purpose, the present utility model provides a dual-wavelength light source Raman spectrometer system, comprising: a laser light source group, which has laser light sources with two wavelengths, and the light sources with the two wavelengths excite two material samples with different properties respectively. ; Volume holographic transmission grating group, which includes two independent volume holographic transmission gratings, which respectively receive the Raman scattered light after two kinds of samples are excited by two wavelengths of light sources; CCD detector, whose different regions receive from the two volume holographic transmission gratings The Raman scattered light is split into a parallel beam.

Further, in the above technical solution, in the same Raman spectrometer, the laser light sources of the two wavelengths can be respectively provided with multiple light sources, and each light source corresponds to a different sampling point to form multi-channel detection.

Further, in the above technical solution, each channel in the multi-channel is unidirectionally connected to the incident optical fiber, the probe, the sample cell and the collection optical fiber in series.

Further, in the above technical solution, the Raman spectrometer may further include: an entrance slit, which receives the multi-channel Raman scattered light from the collection optical fiber; a relay lens, which receives the multi-channel Raman scattered light passing through the entrance slit, and Raman scattered light is sorted according to different excitation wavelengths.

Further, in the above technical solution, after sorting, Raman scattered light with different excitation wavelengths can respectively enter the corresponding volume holographic transmission grating.

Further, in the above technical solution, the two volume holographic transmission gratings may correspond to a single CCD detector.

Further, in the above technical solution, a collimating lens corresponding to the number of light sources is provided between the volume holographic transmission grating and the CCD detector, and the collimating lens receives the Raman scattered light from the volume holographic transmission grating and irradiates it in parallel. to different detection areas of the CCD detector.

Further, in the above technical solution, the laser light sources of the two wavelengths may be a 532 nm laser and a 785 nm laser, respectively; the two materials with different properties may be a gas and a liquid, respectively.

Further, in the above technical solution, the slit directions of the two volume holographic transmission gratings are perpendicular to the direction of the Raman scattered light from the front-end collimator, and the slits of the two volume holographic transmission gratings are parallel. This effectively prevents beam crossing.

Further, in the above technical solution, the CCD detector can be connected to a signal processing system for converting the photoelectric signal into a digital signal and acquiring the spectral spectrum of the Raman scattered light.

Compared with the prior art, the utility model has the following beneficial effects:

1) Using the Raman spectrometer system of the dual-wavelength light source of the present utility model, the material samples of the two properties can be simultaneously detected by using the light sources of the two wavelengths in the same equipment, and the dual-grating light splitting corresponds to the dual-wavelength light source, which expands the The range of detection objects of Raman spectrometer is more practical, and it can be used in the fields of chemical industry, petroleum refining, biomedicine, environmental monitoring and other fields that need to detect both gas phase and liquid phase materials at the same time;

2) Using the multi-channel system of the present invention, each sampling point can be excited by a light source, and the intensity of the light source can be adjusted according to the needs of each sampling point, thereby improving the detection sensitivity and detection accuracy;

3) The multi-channel system of the present utility model shares a CCD detector, which makes the Raman spectrometer system more compact, the instrument volume is smaller, and is more conducive to portability and the selection of the application site placement position;

4) By keeping the slits of the two independent volume holographic transmission gratings in a parallel state, and the slit directions of the two volume holographic transmission gratings are both perpendicular to the direction of the Raman scattered light entering through the front-end collimator, it can effectively It ensures that the split beams of the Raman scattered light obtained by different light sources can be irradiated in parallel on different detection areas of the CCD detector, avoiding beam crossing, enabling simultaneous detection of multiple channels and increasing detection efficiency;

5) The light source placement position of the present invention can be flexibly selected, because the longer the optical fiber, the more serious the attenuation of light, the optional light source placement position is conducive to controlling the length of the optical fiber, thereby increasing the detection capability.

The above description is only an overview of the technical solutions of the present invention, in order to be able to more clearly understand the technical means of the present invention and to implement it according to the content of the description, and to make the above and other purposes, technical features and advantages of the present invention more effective. It is easy to understand, one or more preferred embodiments are listed below and described in detail below with reference to the accompanying drawings.

Description of drawings

FIG. 1 is a schematic structural diagram of the dual-wavelength light source Raman spectrometer system of the present invention (for multi-channel setup).

FIG. 2 is a spectroscopic principle diagram of Embodiment 1 (four channels) of the dual-wavelength light source Raman spectrometer system of the present invention.

Description of main reference signs:

1-laser source, 2-incident fiber, 3-probe, 4-sample cell, 5-collection fiber, 6-entry slit, 7-relay lens, 8-collimator, 9-volume holographic transmission grating, 9A - first volume holographic transmission grating, 9B- second volume holographic transmission grating, 10 - collimating lens, 11 - CCD detector, 12 - signal processing system.

Detailed ways

The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

Unless expressly stated otherwise, throughout the specification and claims, the term "comprising" or its conjugations such as "comprising" or "comprising" and the like will be understood to include the stated elements or components, and Other elements or other components are not excluded.

In this document, for convenience of description, spatially relative terms, such as "below", "below", "under", "above", "above", "over", etc., may be used to describe one element or feature with respect to another Relationship of elements or features in the drawings. It is to be understood that spatially relative terms are intended to encompass different orientations of items in use or operation in addition to the orientation depicted in the figures. For example, if the item in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the elements or features. Thus, the exemplary term "below" can encompass both an orientation of below and above. Items may also have other orientations (rotated 90 degrees or other orientations) and the spatially relative terms used herein should be interpreted accordingly.

In this document, the terms "first", "second" and the like are used to distinguish two different elements or parts, and are not used to limit a specific position or relative relationship. In other words, in some embodiments, the terms "first," "second," etc. are also interchangeable with each other.

The dual-wavelength light source Raman spectrometer system of the utility model adopts light sources with two wavelengths and a light source with one wavelength adopts multiple light sources to perform multi-channel detection. That is, in order to ensure the detection accuracy, one light source detects one sampling point, and one device uses multiple light sources to detect multiple sampling points. If the above conditions are met, double gratings are set in the spectrometer to be used after the two light sources excite the sample. For the spectroscopy of Raman scattered light, multiple light sources can be set for each light source, and one grating can support the spectroscopy of multiple light sources with the same wavelength, and the same CCD detector can select different pixel positions according to different light sources.

As shown in FIG. 1 , FIG. 1 takes a Raman spectrometer with dual wavelength light sources and six channels as an example for illustration. The Raman spectrometer in FIG. 1 may include a laser light source 1, an incident fiber 2, a probe 3, a sample cell 4, a collection fiber 5, an entrance slit 6, a relay lens 7, a collimator 8, and a first volume holographic transmission grating 9A , a second volume holographic transmission grating 9B, a collimating lens 10 , a CCD detector 11 and a signal processing system 12 .

Further as shown in FIG. 1 , six laser light sources 1 form a laser light source group, and the laser light source group has laser light sources with two wavelengths, and the two wavelength light sources excite material samples with two different properties respectively. Preferably, but not limitedly, the laser light sources of the two wavelengths can be a 532 nm laser and a 785 nm laser respectively; the two materials with different properties can be a gas and a liquid, respectively. Using these two wavelength light sources in the same Raman spectrometer to detect gas and liquid respectively can make the detection accuracy higher and the detection effect better.

Further as shown in Figure 1, a laser light source group composed of six laser light sources 1, an incident fiber group composed of six incident fibers 2, a probe group composed of six probes 3, a sample cell group composed of six sample cells 4, and six The collection fiber groups composed of the collection fibers 5 are in one-to-one correspondence and are connected in a unidirectional serial connection manner. The laser light emitted by laser light source 1 is transmitted to probe 3 through incident fiber 2 .

Further as shown in FIG. 1 , the Raman scattered light collected by each collection fiber 5 enters the entrance slit 6, and the Raman scattered light from the multiple collection fibers is separately entered through the relay lens 7 according to its corresponding excitation wavelength. Corresponding collimator 8 . Since the present invention is in the same Raman spectrometer, the laser light sources of the two wavelengths are respectively provided with multiple light sources, that is, three of the six channels in FIG. 1 use lasers of the same wavelength (eg 532 nm), and the other three channels use another For a laser of one wavelength (eg 785nm), each light source corresponds to a different sampling point, forming multi-channel detection. The entrance slit 6 of the present invention receives the multi-channel Raman scattered light from the collection fiber group, and the relay lens 7 is used for receiving the multi-channel Raman scattered light passing through the entrance slit 6, and converts the Raman light according to different excitation wavelengths. The scattered light is sorted. Lights with different excitation wavelengths enter the corresponding volume holographic transmission gratings in sequence. For example, the Raman scattered light formed after the sample is excited by the laser with a wavelength of 532 nm enters the first volume holographic transmission grating 9A, and the Raman formed after the sample is excited by the laser with a wavelength of 785 nm. The scattered light enters the second volume holographic transmission grating 9B. The first volume holographic transmission grating 9A and the second volume holographic transmission grating 9B are two independent volume holographic transmission gratings, which can respectively receive Raman scattered light after two kinds of samples are excited by light sources with two wavelengths. The Raman scattered light is split by the volume holographic transmission grating and then enters the corresponding collimating lens 10, and is detected by the same CCD detector 11. Different regions of the CCD detector 11 receive the Raman scattered light from the two volume holographic transmission gratings and split the light. rear parallel beam. Further, the photoelectric signal is converted into a digital signal by the signal processing system 12 to obtain the required Raman spectrum.

In order to ensure that the multi-channel Raman scattered light can be incident on the CCD detector 11 in sequence after splitting, that is, to obtain parallel beams and avoid beam crossing, the present invention combines the first volume holographic transmission grating 9A and the second volume holographic transmission grating 9B. The slits are set in a parallel state, and the slit directions of the two volume holographic transmission gratings are both in a vertical state with the direction of the Raman scattered light entering through the collimator 8 . In this way, beam crossing can be effectively avoided. The parallel light beam further enters the collimating lens 10 between the volume holographic transmission grating and the CCD detector 11 corresponding to the number of light sources, and the collimating lens 10 receives the Raman scattered light from the volume holographic transmission grating and can be irradiated to the CCD in parallel Different detection areas of the detector 11 (see Figure 2).

By using the Raman spectrometer of the utility model, the material samples of the two properties can be detected simultaneously in the same equipment by using light sources of two wavelengths, and the double-grating light source corresponding to the double-wavelength light source can be used to expand the detection object of the Raman spectrometer. It can be used in chemical, petroleum refining, biomedicine, environmental monitoring and other fields that need to detect gas and liquid materials at the same time; each sampling point in the multi-channel selects a light source for excitation, and the intensity of the light source It can be adjusted according to the needs of each sampling point, so as to improve the detection sensitivity and detection accuracy; a CCD detector is shared by multiple channels, which makes the Raman spectrometer system of the present invention more compact, the instrument volume is smaller, and it is more conducive to portability and reliability. The selection of on-site placement positions is applied; using the Raman spectrometer of the present utility model, the beams of the Raman scattered light obtained by different light sources after being irradiated can be parallelly irradiated in different detection areas of the CCD detector, so that multiple channels can be detected at the same time, The detection efficiency is increased; the light source placement position of the utility model can be flexibly selected, because the longer the optical fiber, the more serious the attenuation of light, the optional light source placement position is beneficial to control the use length of the optical fiber, thereby increasing the detection capability.

Example 1

The four-channel Raman spectrometer is set up by the connection method shown in Figure 1, in which the Raman scattered light obtained by the irradiation of the two channels is finally projected on the CCD detector 11, and the corresponding pixel positions are [10, 45] and [60, 95]; the other two channels are the Raman scattered light obtained by the illumination of the 785nm light source and finally projected on the same CCD detector 11, and the corresponding pixel positions are [105, 140] and [155, 190] respectively.

Choice of two independent volume holographic transmission gratings:

532nm laser grating: Raman shift is set to 200～4000cm ^-1 , 532nm is converted to a frequency of 1/532nm=18796.99cm ^-1 , the range of Raman scattered light is [18796.99-4000,18796.99-200]cm ^-1 , conversion The wavelength is 537.7-675.8nm, the spectral range of the system is determined to be 530-670, and the center wavelength is 600nm. Considering the size of the system and the dispersion angle, the linear density of the grating is selected to be 600l/mm.

785nm laser grating: Raman shift is set to 250～3000cm ^-1 , 785nm is converted into a frequency of 1/785nm=12738.85cm ^-1 , the range of Raman scattered light is [12738.85-2800,12738.85-250]cm ^-1 , conversion The wavelength is 800.7-1026.8 nm, the spectral range of the system is determined to be 800-1000, and the center wavelength is 900 nm. Considering the size of the system and the dispersion angle, the linear density of the grating is selected to be 1200 l/mm.

Choice of CCD detectors:

The detector selects 1650 × 200 active pixels (16 × 16 μm pixel size), the light is imaged on the detector through the optical system through the slit, the image of one spectral channel is scattered on the detector by 2 pixel widths, and the interval between the two spectral channels is one pixel. pixel, then the number of spectral channels is 1650/3=550, for a 785nm light source, the resolution is (1000-800)/550=0.36nm, which is converted into a frequency of 4.44cm ^-1 ; for a 532nm light source, the resolution is (670- 530)/550=0.25 nm, which is 6.95 cm ⁻¹ when converted into a wave number.

The light splitting principle of this embodiment is shown in FIG. 2 . In this embodiment, the slits of two independent volume holographic transmission gratings are set to be parallel, and the slit directions of the two volume holographic transmission gratings are the same as those of the front-end collimator. The direction of the incoming Raman scattered light is in a vertical state, so as to ensure that the light beam hitting the CCD detector is a parallel light beam in a certain order.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise form disclosed, and obviously many changes and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described for the purpose of explaining certain principles of the invention and its practical applications, to thereby enable those skilled in the art to make and utilize various exemplary embodiments of the invention and various Different choices and changes. Any simple modifications, equivalent changes and modifications made to the above exemplary embodiments should fall within the protection scope of the present invention.

Claims (10)

1. a dual-wavelength light source Raman spectrometer system, is characterized in that, comprises: A laser light source group, which has laser light sources with two wavelengths, and the light sources with the two wavelengths respectively excite two material samples with different properties; A volume holographic transmission grating group, comprising two independent volume holographic transmission gratings, respectively receiving Raman scattered light after the two kinds of samples are excited by the light sources of the two wavelengths; The different regions of the CCD detector receive the split parallel beams of the Raman scattered light from the two volume holographic transmission gratings. 2. The dual-wavelength light source Raman spectrometer system according to claim 1, wherein, in the same Raman spectrometer, the laser light sources of the two wavelengths are respectively provided with a plurality of light sources, and each light source corresponds to a different light source. Sampling points to form multi-channel detection. 3 . The dual-wavelength light source Raman spectrometer system according to claim 2 , wherein each channel in the multi-channel is connected in series with an incident fiber, a probe, a sample cell and a collection fiber in a unidirectional series. 4 . 4. The dual-wavelength light source Raman spectrometer system according to claim 3, wherein the Raman spectrometer further comprises: an entrance slit that receives the multi-path Raman scattered light from the collection fiber; a relay lens that receives the multiplexed Raman scattered light through the entrance slit and sorts the Raman scattered light according to different excitation wavelengths. 5 . The dual-wavelength light source Raman spectrometer system according to claim 4 , wherein the sorted Raman scattered light with different excitation wavelengths respectively enters the corresponding volume holographic transmission grating. 6 . 6 . The dual-wavelength light source Raman spectrometer system according to claim 5 , wherein two of the volume holographic transmission gratings correspond to one of the CCD detectors. 7 . 7. The dual-wavelength light source Raman spectrometer system according to claim 6, wherein a collimating lens corresponding to the number of light sources is provided between the volume holographic transmission grating and the CCD detector, the collimating lens The Raman scattered light from the volume holographic transmission grating is received and irradiated in parallel to different detection areas of the CCD detector. 8. The dual-wavelength light source Raman spectrometer system according to claim 1, wherein the laser light sources of the two wavelengths are respectively a 532nm laser and a 785nm laser; the materials of the two different properties are respectively a gas and a liquid . 9. The dual-wavelength light source Raman spectrometer system according to claim 1, wherein the slit directions of the two volume holographic transmission gratings are perpendicular to the direction of the Raman scattered light from the front-end collimator, and the two The slits of each of the volume holographic transmission gratings are parallel. 10 . The dual-wavelength light source Raman spectrometer system according to claim 1 , wherein the CCD detector is connected to a signal processing system for converting photoelectric signals into digital signals and acquiring the spectrum of the Raman scattered light. 11 . Spectrum.

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