CN116990281B - Cavity-enhanced Raman detection device with high collection efficiency - Google Patents
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- 238000001069 Raman spectroscopy Methods 0.000 title claims abstract description 104
- 238000001514 detection method Methods 0.000 title claims abstract description 34
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- 239000005388 borosilicate glass Substances 0.000 claims description 3
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 claims description 3
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- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
- G01N21/65—Raman scattering
- G01N21/658—Raman scattering enhancement Raman, e.g. surface plasmons
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/01—Arrangements or apparatus for facilitating the optical investigation
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/01—Arrangements or apparatus for facilitating the optical investigation
- G01N2021/0106—General arrangement of respective parts
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Abstract
The invention provides a cavity enhanced Raman detection device with high collection efficiency, which utilizes a light source module to emit an excitation light beam to the reflecting surface of a spherical reflector, realizes multiple reflection through a pair of spherical reflectors to form a central converged reflection plane light, passes through a light passing window of a collection cavity, is converged at the focus of the parabolic reflector, a sample tube is placed at the focus, a sample to be detected is excited by the reflection plane light for multiple times to generate strong Raman scattering, wherein most scattered light is emitted from a signal collection hole after being collimated by the parabolic reflector, a small part of the scattered light continuously reflects in the collection cavity and then passes through the focus multiple times to act on the sample together with the reflection plane light, so that the signal intensity of the sample to be detected is further enhanced, and the emitted Raman signal light is filtered by a lens group and converged into an optical fiber to be analyzed and processed by a Raman spectrometer. The invention can improve the signal collection efficiency while exciting the sample for multiple times to generate strong Raman scattering, thereby realizing high-sensitivity detection of the sample.
Description
Technical Field
The invention relates to the technical field of Raman spectrum detection, in particular to a cavity enhanced Raman detection device with high collection efficiency.
Background
The Raman spectrum detection technology is a nondestructive detection technology with high sensitivity based on light scattering, and is widely applied to various fields such as chemical industry, material, environmental monitoring, biomedicine, medicine analysis, food safety and the like. With the increasing importance of the current society to the environmental pollution problem, the raman spectrum detection technology plays an important role in the field of environmental monitoring.
The Raman spectrum detection technology is a spectrum analysis method based on molecular vibration energy level. When excitation light is incident on the surface of a substance, most photons generate elastic Rayleigh scattering, the energy of scattered photons is the same as that of the incident photons, the tiny photons and molecules of the substance generate inelastic Raman scattering, the energy of the scattered photons changes, the energy change is related to the vibration energy level of the molecules of the substance, and the Raman spectrum of the substance can be obtained by measuring the wavelength or the energy change of the scattered light. The peaks in the raman spectrum correspond to specific vibrational modes of the molecule and can therefore be used for analysis of molecular structure and composition.
Compared with Rayleigh scattering, the Raman scattering signal is weak and is easily interfered by background noise, rayleigh scattering, fluorescence and the like. At present, the method for improving the sensitivity of Raman detection includes surface enhanced Raman scattering, resonance Raman scattering, cavity enhanced Raman scattering and other technologies.
The multiple reflection cavity Raman signal enhancement technology can well reflect excitation light for multiple times, improves the excitation light power intensity of the central area of the multiple reflection cavity, and further enhances the Raman scattering signal intensity, but the collection efficiency of the existing cavity enhanced Raman detection device on Raman scattering light is low, and the Raman scattering light cannot be collected in an omnibearing manner only by means of lateral collection through a lens, so that most of Raman scattering light is wasted in a collection stage.
Disclosure of Invention
In order to solve the technical problems, the invention provides a cavity enhanced Raman detection device with high collection efficiency, which is used for realizing high-efficiency collection of Raman scattered light and high-sensitivity detection of a sample while exciting the sample for multiple times to generate strong Raman scattering.
In order to achieve the above purpose, the invention adopts the following technical scheme:
a high collection efficiency cavity enhanced raman detection device comprising:
the light source module is used for emitting the shaped excitation light beam to the reflecting surface of the spherical reflecting mirror group;
The spherical reflector group is a pair of spherical reflectors with concave reflecting surfaces and arranged oppositely, the positions of the spherical reflectors are symmetrical by taking the focal point of the parabolic mirror as a symmetry center, the spherical reflectors are respectively arranged at two sides of the periphery of the parabolic mirror, the excitation light beam is received through the reflecting surface of one spherical reflector, the excitation light beam is continuously reflected between the two reflecting surfaces to form central converged reflected plane light, the reflected plane light can be totally injected into the parabolic mirror through two light-transmitting windows on the parabolic mirror, and the converging point is overlapped with the focal point of the parabolic mirror;
The Raman collection module comprises a parabolic mirror, a second plane mirror and a sample tube; the second plane mirror is detachably packaged at the open end of the parabolic mirror, an inner cavity formed by surrounding the second plane mirror and the parabolic mirror is used as a collecting cavity, and an opening is reserved on the mirror surface exposed in the parabolic mirror cavity and used as a signal collecting hole for emitting scattered light in the collecting cavity; two light-transmitting windows arranged on the parabolic mirror are symmetrically distributed by taking a focus as a symmetry center and are respectively opposite to the reflecting surface of the side spherical reflecting mirror; the sample tube is colorless and transparent, is perpendicular to the main shaft of the parabolic mirror and the central lines of the two spherical reflectors, passes through the focal point, is arranged on the parabolic mirror in a penetrating manner, and pipe orifices at two ends are exposed out of the collecting cavity and are respectively used for sample injection and sample discharge of a sample to be tested;
the lens group is used for filtering the Raman signal light emitted from the collecting cavity and converging the Raman signal light into the optical fiber;
and the Raman spectrometer is used for receiving the filtered Raman signal light through an optical fiber and analyzing and processing the filtered Raman signal light.
The structure of the invention is also characterized in that:
the signal collecting hole is positioned in the middle of the opening end of the parabolic mirror and is in a circular through hole shape, and the diameter ratio of the aperture to the opening end of the parabolic mirror is set to be 1:3 or more.
The light transmission window is in a structure of being wide from outside to inside and narrow from outside to inside along the wall thickness direction of the parabolic mirror, and is provided with an optical window sheet with high transmittance.
The transmittance of the optical window sheet is more than 95%, and the material types comprise magnesium fluoride, calcium fluoride and fused quartz.
The inner wall of the parabolic mirror is polished and coated, the substrate is made of aluminum, copper or stainless steel, and the coating is made of gold, silver, stainless steel or aluminum.
The light source module comprises an excitation light source, a first focusing lens and a first plane mirror, wherein the excitation light source emits an excitation light beam, the excitation light beam is focused by the first focusing lens, and the excitation light beam is reflected by the first plane mirror and then is emitted to the reflecting surface of one spherical reflecting mirror in the lens group.
The excitation light beam emitted by the light source module is narrow linewidth excitation light.
The sample tube is made of quartz, borosilicate glass and optical glass, and the sample to be measured comprises liquid and gas.
One end of the optical fiber is a signal collecting end and is aligned with the focus of the lens group, receives the Raman signal light focused by the lens group, and the other end of the optical fiber is a signal output end and is aligned with an incident slit of the Raman spectrometer.
The lens group is positioned at the periphery of the collecting cavity and is opposite to the second plane mirror, the lens group sequentially comprises a high-pass filter and a second focusing lens which are coaxially aligned with the main axis of the parabolic mirror at intervals along the emergent direction of the Raman signal light, rayleigh scattered light in the Raman signal light is filtered through the high-pass filter, the filtered Raman signal light is focused and sent into an optical fiber through the second focusing lens, and the signal collecting end of the optical fiber is aligned with the focus of the second focusing lens.
Compared with the prior art, the invention has the beneficial effects that:
Firstly, the loss of the Raman scattered light in the collecting stage can be avoided, and the high-efficiency collection of the Raman scattered light is realized:
The invention provides a collection cavity concept for the first time, a plane mirror is packaged at the opening end of the collection cavity by utilizing the characteristic that a parabolic mirror can collimate light rays, a collection cavity is formed by surrounding the plane mirror, the collection cavity is used for replacing a traditional lens to serve as a collection means of a cavity enhanced Raman detection device, a pair of spherical reflectors are arranged outside the collection cavity, a focus of the parabolic mirror is overlapped with a convergence point of reflected plane light formed between the pair of spherical reflectors, an excitation light beam forms central converged reflected plane light between the pair of spherical reflectors, excitation light power at the convergence point is increased, excitation intensity of Raman scattered light is improved, when the Raman scattered light at the convergence point, namely the focus of the parabolic mirror in the collection cavity, is scattered all around, the Raman scattered light is collimated into parallel light by the parabolic mirror, a part of parallel light is emitted through a signal collection hole on the plane mirror, and a part of parallel light is reflected by the plane mirror, returns according to an original light path and is collimated into parallel light by the parabolic mirror again and is emitted through the signal collection hole. The collection mode can realize high collection efficiency of the Raman scattered light, avoid loss of the Raman scattered light in a collection stage, and improve the sensitivity of the whole cavity enhanced Raman detection device;
secondly, the sensitivity and the efficiency of sample detection can be improved, and the detection of trace samples can be more efficiently realized:
According to the invention, the sample tube is integrated in the collecting cavity, the sample tube penetrates through the collecting cavity through the focal point of the parabolic mirror, and the sample to be tested is introduced into the sample tube and can be more concentrated near the focal point of the parabolic mirror, so that the trace sample can be more efficiently detected, and the sensitivity and the efficiency of the sample detection are improved.
Drawings
FIG. 1 is a schematic diagram of the structure of the present invention;
FIG. 2 is a schematic top view of a Raman collection module;
fig. 3 is a schematic diagram of a front view structure of the raman collection module;
FIG. 4 is a schematic side view of a Raman collection module;
Fig. 5 is a schematic diagram of the optical path reflection path within the collection chamber.
In the figure:
11 an excitation light source; a first focusing lens 12; 13 a first plane mirror;
2a spherical reflector;
31 parabolic mirror; 32 light-transmitting windows; 33 a second planar mirror; 34 sample tubes; 35 signal collection wells;
a 41 high pass filter; a second focusing lens 42;
5 optical fibers;
6 raman spectrometer.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions in the embodiments of the present invention will be clearly and completely described in the following in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1 to 5, the cavity-enhanced raman detection apparatus with high collection efficiency of the present embodiment includes:
the light source module is used for emitting the shaped excitation light beam to the reflecting surface of the spherical reflecting mirror group;
the spherical reflector group is a pair of spherical reflectors 2 with concave reflecting surfaces and arranged oppositely, the positions of the spherical reflectors 2 are symmetrical with the focus of the parabolic mirror 31 as a symmetry center, the spherical reflectors are respectively arranged at two sides of the periphery of the parabolic mirror 31, the excitation light beam is received through the reflecting surface of one spherical reflector 2, the excitation light beam is continuously reflected between the two reflecting surfaces to form central converged reflection plane light, the reflection plane light can be totally injected into the parabolic mirror 31 through two light-transmitting windows 32 on the parabolic mirror 31, and the convergence point is overlapped with the focus of the parabolic mirror 31;
The Raman collection module comprises a parabolic mirror 31, a second plane mirror 33 and a sample tube 34; the second plane mirror 33 is detachably packaged at the opening end of the parabolic mirror 31, and an inner cavity formed by the second plane mirror and the parabolic mirror 31 in a surrounding mode is used as a collecting cavity, and an opening is reserved on the mirror surface exposed out of the inner cavity of the parabolic mirror 31 and used as a signal collecting hole 35 for collecting the outgoing of scattered light in the cavity; two light-transmitting windows 32 arranged on the parabolic mirror 31 are symmetrically distributed by taking a focus as a symmetrical center and respectively opposite to the reflecting surface of the side spherical reflecting mirror 2; the sample tube 34 is colorless and transparent, is perpendicular to the main axis of the parabolic mirror 31 and the central lines of the two spherical reflectors 2, passes through the focal points, passes through the parabolic mirror 31, is exposed out of the collecting cavity at the two end orifices and is respectively used for sample injection and sample discharge of a sample to be tested, the sample to be tested in the tube at the focal point in the collecting cavity generates strong Raman scattering through multiple excitations of reflection plane light, part of the formed scattered light is directly emitted from the signal collecting hole 35, and the rest part of the scattered light is collimated into parallel light by the parabolic mirror 31 and then is emitted from the signal collecting hole 35, and the rest part of the scattered light is continuously reflected in the collecting cavity, passes through the focal points for multiple times and acts on the sample to be tested in the tube together with the reflection plane light, so that the signal intensity of the sample to be tested is further enhanced;
the lens group is used for filtering the Raman signal light emitted from the collecting cavity and converging the Raman signal light into the optical fiber 5;
the raman spectrometer 6 receives the filtered raman signal light through the optical fiber 5, and analyzes and processes the filtered raman signal light.
The signal collection aperture 35 is used to collect the exit of raman scattered light from the cavity. The optical path in the collection chamber is roughly divided into four parts as shown in fig. 4:
A part of the light is directly emitted from the signal collection hole 35;
a part of light is collimated once by the parabolic mirror 31 and then exits from the signal collecting hole 35;
A part of light is collimated by the parabolic mirror 31 twice and then exits from the signal collecting hole 35;
The rest part of light is continuously reflected in the collecting cavity, repeatedly passes through the focus and cannot exit.
The above-mentioned light path is further described in detail as follows:
The central convergent reflection plane light formed by multiple reflections of the pair of spherical reflectors 2 can increase the excitation light intensity and the excitation intensity of the raman scattered light in the area of the convergent point, but raman scattered signal light can be collected in each direction, and a large amount of signals can be wasted only by adopting the traditional mode of direct collection of lenses. Therefore, according to the characteristic of the parabolic mirror 31 that can collimate light, the embodiment adopts a collecting cavity formed by surrounding the parabolic mirror 31 and the second planar mirror 33 to collect, the focal point of the parabolic mirror 31 and the converging point of the reflected planar light are set to coincide, the excitation light at the focal point excites the sample to be measured in the sample tube 34, raman scattered light is generated, the raman scattered light is scattered all around, and the raman scattered light is collimated into parallel light by the parabolic mirror 31. Wherein:
A part of raman scattered light is directly emitted from the signal collection aperture 35;
a part of raman scattered light is collimated into parallel light by the parabolic mirror 31 once, and then emitted from the signal collection hole 35 and collected by the lens group;
A part of Raman scattered light is reflected by the second plane mirror 33 after being collimated once by the parabolic mirror 31, returns according to the original light path, passes through the focus of the parabolic mirror 31 again, is collimated twice by the parabolic mirror 31, forms parallel light, and then exits from the signal collecting hole 35 to be collected by the lens group;
After being collimated by the parabolic mirror 31, the rest of the raman scattered light returns to the focus through the reflection of the second plane mirror 33 according to the original light path, is collimated again by the parabolic mirror 31, returns to the focus again through the reflection original path of the second plane mirror 33, and repeatedly acts on the sample to be measured in the tube together with the reflected plane light.
The sample tube 34 passes through the focus, so that the sample to be detected in the tube can be more fully excited by the excitation light at the focus of the parabolic mirror 31, and the sample to be detected can be introduced in a short time by integrating the sample tube 34 in the collecting cavity, so that the sample introduction time is shortened, and the sample detection efficiency is improved. The two ends of the sample tube 34 are exposed outside the collecting cavity, are respectively used for sample injection and sample discharge of the sample to be tested, are respectively connected with an external sample injection pipeline and an external sample discharge pipeline, and are respectively provided with a switch valve.
In a specific implementation, the corresponding structural arrangement of the device also comprises:
The signal collecting hole 35 is located at the middle of the open end of the parabolic mirror 31 and is in a circular through hole shape. Theoretically, the optimal position of the signal collection aperture 35 should be centered at the open end of the parabolic mirror 31, and preferably be a circular aperture. In practice, therefore, the signal collection aperture 35 should be positioned as far as possible in the middle of the open end of the parabolic mirror 31 and should be nearly circular. In order to ensure that raman scattered light exiting from the signal collecting hole 35 is collected by the lens group as much as possible while ensuring an effective reflection area of the second plane mirror 33, therefore, in the present embodiment, the aperture of the signal collecting hole 35 is set to be identical to the filter lens size of the high-pass filter 41 in the lens group and to be set to be 1:3 or more in proportion to the diameter of the open end of the parabolic mirror 31, see fig. 4.
The light-transmitting window 32 has a structure that is wide from outside to inside and narrow from outside to inside along the wall thickness direction of the parabolic mirror 31, so as to ensure that the occupied area of the inner wall of the parabolic mirror 31 is as small as possible, ensure that the reflection area of the inner wall of the parabolic mirror 31 is as large as possible, ensure the highest reflection efficiency of the parabolic mirror 31, and is provided with an optical window sheet with high transmittance, wherein the transmittance of the optical window sheet is more than 95%, and the material types comprise magnesium fluoride, calcium fluoride and fused quartz, and can be correspondingly configured according to the wave bands of the excitation light source 11.
The inner wall of the parabolic mirror 31 is polished and coated, and the substrate is made of aluminum, copper or stainless steel; according to different excitation wavelengths, the plating materials can be selected from gold, silver, stainless steel or aluminum correspondingly. The second plane mirror 33 has a high reflectance, up to 95% or more.
The light source module comprises an excitation light source 11, a first focusing lens 12 and a first plane mirror 13, wherein the excitation light source 11 emits an excitation light beam, the excitation light beam is focused by the first focusing lens 12, and the excitation light beam is reflected by the first plane mirror 13 and then is emitted to the reflecting surface of one spherical reflecting mirror 2 in the lens group.
The excitation light beam emitted by the light source module is narrow linewidth excitation light.
The sample tube 34 is made of quartz, borosilicate glass and optical glass, and the sample to be measured includes liquid, gas and other substances which do not affect the detection light path.
The optical fiber 5 can be fixed by an optical fiber 5 clamp, one end is a signal collecting end and is aligned with the focus of the lens group, receives the Raman signal light focused by the lens group, and the other end is a signal output end and is aligned with an incident slit of the Raman spectrometer 6.
The lens group is located at the periphery of the collecting cavity and is opposite to the second plane mirror 33, and sequentially comprises a high-pass filter 41 and a second focusing lens 42 which are coaxially aligned with the main axis of the parabolic mirror 31 and are arranged at intervals along the emergent direction of the Raman signal light, the Rayleigh scattered light and other stray light in the Raman signal light are filtered through the high-pass filter 41, the filtered Raman signal light is focused and sent into the optical fiber 5 through the second focusing lens 42, and the signal collecting end of the optical fiber 5 is aligned with the focus of the second focusing lens 42.
The raman spectrometer 6 separates raman signal light of different wavelengths sent from the optical fiber 5 into different directions by internal grating light splitting, and the internal CCD further converts raman scattered light from an optical signal into an electrical signal, and generates a raman spectrum analysis chart after data processing.
The cavity enhanced Raman detection device with the structure combines the multiple reflection convergence capability of the excitation light of the multiple reflection cavity and the high signal collection efficiency capability of the parabolic mirror 31 cavity, and compared with the traditional lens collection mode, the collection mode of the collection cavity is adopted, the Raman signal detection intensity is greatly enhanced, the collection efficiency of the Raman scattered light is greatly improved, and the high-efficiency collection of the cavity enhanced Raman detection device is realized. The detection can be carried out according to the following steps:
step 1, turning on an excitation light source 11, and directing the shaped excitation light beam to the reflecting surface of one spherical reflecting mirror 2;
step 2, adjusting the positions and angles of the two spherical reflectors 2 to enable the received excitation light beams to form central convergent reflection plane light between the two reflection surfaces;
Step 3, a raman collection module is placed between the two spherical reflectors 2, and the position and the angle of a collection cavity are adjusted to enable the focus of the parabolic mirror 31 to coincide with the convergence point of the reflection plane light;
step 4, filling a sample to be tested into the sample tube 34;
Step 5, coaxially aligning a focus of the lens group and a signal collecting end of the optical fiber 5 with a signal collecting hole 35 of the collecting cavity, filtering and focusing Raman signal light emitted from the collecting cavity through the lens group, entering the signal collecting end of the optical fiber 5, and sending the Raman signal light into a Raman spectrometer 6 through the optical fiber 5;
And 6, after the raman spectrometer 6 splits the received raman signal light through the internal grating, converting the optical signal into an electric signal through the CCD, and generating a raman signal spectrum for detecting the information required by the sample to be detected.
While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: many changes, modifications, substitutions and variations may be made to the embodiments without departing from the spirit and principles of the invention, the scope of which is defined by the claims and their equivalents.
Claims (7)
1. The cavity enhanced Raman detection device with high collection efficiency is characterized by comprising:
The light source module is used for emitting the shaped excitation light beam to the reflecting surface of the spherical reflecting mirror group and comprises an excitation light source (11), a first focusing lens (12) and a first plane mirror (13), wherein the excitation light source (11) emits the excitation light beam, the excitation light beam is focused by the first focusing lens (12), and the excitation light beam is reflected by the first plane mirror (13) and then is emitted to the reflecting surface of one spherical reflecting mirror (2) in the lens group;
The spherical reflector group is a pair of spherical reflectors (2) with concave reflecting surfaces and arranged oppositely, the positions of the spherical reflectors (2) are symmetrical with the focus of the parabolic mirror (31) as a symmetry center, the spherical reflectors are respectively arranged at two sides of the periphery of the parabolic mirror (31), the excitation light beam is received through the reflecting surface of one spherical reflector (2), the excitation light beam is continuously reflected between the two reflecting surfaces to form central converged reflecting plane light, and the reflecting plane light can be totally injected into the parabolic mirror (31) through two light-transmitting windows (32) on the parabolic mirror (31) and the converging point is coincident with the focus of the parabolic mirror (31);
The Raman collection module comprises a parabolic mirror (31), a second plane mirror (33) and a sample tube (34); the second plane mirror (33) is detachably packaged at the opening end of the parabolic mirror (31), an inner cavity formed by surrounding the second plane mirror and the parabolic mirror (31) is used as a collecting cavity, and an opening reserved on the mirror surface exposed out of the inner cavity of the parabolic mirror (31) is used as a signal collecting hole (35) for collecting the outgoing of scattered light in the cavity; two light-transmitting windows (32) arranged on the parabolic mirror (31) are symmetrically distributed by taking a focus as a symmetrical center and respectively opposite to the reflecting surface of the side spherical mirror (2); the sample tube (34) is colorless and transparent, is perpendicular to the main shaft of the parabolic mirror (31) and the central lines of the two spherical reflectors (2), passes through the focus, passes through the parabolic mirror (31), is exposed out of the collecting cavity at the two end orifices, is respectively used for sample injection and sample discharge of a sample to be tested, and is positioned in the collecting cavity, the sample to be tested in the tube at the focus generates strong Raman scattering through multiple excitation of reflected plane light, one part of the formed scattered light is directly emitted from the signal collecting hole (35), and the rest part of the scattered light is emitted from the signal collecting hole (35) after being collimated into parallel light by the parabolic mirror (31), and the rest part of the scattered light continuously reflects in the collecting cavity and jointly acts on the sample to be tested in the tube with the reflected plane light after passing through the focus for multiple times; the signal collecting hole (35) is positioned in the middle of the opening end of the parabolic mirror (31) and is in a circular through hole shape, and the diameter ratio of the aperture to the opening end of the parabolic mirror (31) is set to be 1:3 or more; the light transmission window (32) is in a structure with wide outside and narrow inside along the wall thickness direction of the parabolic mirror (31), and is provided with an optical window sheet with high transmittance;
The lens group is used for filtering the Raman signal light emitted from the collecting cavity and converging the Raman signal light into the optical fiber (5);
and the Raman spectrometer (6) is used for receiving the filtered Raman signal light through the optical fiber (5) and analyzing and processing the filtered Raman signal light.
2. The high collection efficiency cavity enhanced raman detection device of claim 1, wherein: the transmittance of the optical window sheet is more than 95%, and the material types comprise magnesium fluoride, calcium fluoride and fused quartz.
3. The high collection efficiency cavity enhanced raman detection device of claim 1, wherein: the inner wall of the parabolic mirror (31) is polished and coated, the substrate is made of aluminum, copper or stainless steel, and the coating is made of gold, silver, stainless steel or aluminum.
4. The high collection efficiency cavity enhanced raman detection device of claim 1, wherein: the excitation light beam emitted by the light source module is narrow linewidth excitation light.
5. The high collection efficiency cavity enhanced raman detection device of claim 1, wherein: the sample tube (34) is made of quartz, borosilicate glass and optical glass, and the sample to be measured comprises liquid and gas.
6. The high collection efficiency cavity enhanced raman detection device of claim 1, wherein: one end of the optical fiber (5) is a signal collecting end and is aligned with the focus of the lens group, receives the Raman signal light focused by the lens group, and the other end of the optical fiber is a signal output end and is aligned with an incident slit of the Raman spectrometer (6).
7. The high collection efficiency cavity enhanced raman detection device of claim 1 or 6, wherein: the lens group is positioned at the periphery of the collecting cavity and is opposite to the second plane mirror (33), the lens group sequentially comprises a high-pass filter (41) and a second focusing lens (42) which are coaxially aligned with the main axis of the parabolic mirror (31) and are arranged at intervals along the emergent direction of the Raman signal light, rayleigh scattered light in the Raman signal light is filtered through the high-pass filter (41), the filtered Raman signal light is focused and sent into the optical fiber (5) through the second focusing lens (42), and the signal collecting end of the optical fiber (5) is aligned with the focus of the second focusing lens (42).
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