CN204514811U - Portable laser raman spectrum sensing probe - Google Patents

Abstract

A portable laser Raman spectrum sensing probe, which includes an excitation optical path for laser excitation of a sample through an optical fiber, a Raman scattering receiving optical path and a variable object distance isolation tube, and an incident optical fiber, an optical fiber connector, and a beam expander Mirror, reflector, "long pass short reflection" cut-off filter, objective lens and sample holder, there are sample holder, objective lens, "long pass short reflection" cut-off filter, imaging lens, receiving optical fiber and optical fiber on the receiving optical path Connector. Its "long-pass short-reflection" cut-off filter is a "long-pass short-reflection" cut-off filter whose cut-off point is larger than the laser wavelength; at the same time, the objective lens, "long-pass short-reflection" cut-off filter, imaging lens and receiving The end face of the optical fiber is on the same optical axis and straight line; the variable distance of the variable object distance isolation cylinder is variable in steps, continuously variable and continuously variable in steps, and it also has a positioning device and a locking device to realize various forms of samples Portable laser Raman spectroscopy measurement analysis and on-site detection.

Description

Portable laser Raman spectroscopy sensor probe

technical field

The invention belongs to the field of optical analysis instruments, in particular to a portable laser Raman spectrum sensing probe.

Background technique

Since the Raman scattering phenomenon was discovered by the Indian physicist Raman in 1928, it has become more and more popular due to the remarkable characteristics of Raman spectroscopy, such as rich information, Raman shift is independent of the frequency of incident light, high analysis efficiency and less sample consumption. Widespread concern. In recent years, Raman spectroscopy can accurately detect the composition and content of substances, and has become an important research method in many fields such as chemical analysis, surface chemistry, mineralogy, semiconductor materials, and archaeology. The portable laser Raman spectrometer can quickly detect samples on-site and perform in-situ non-destructive testing and analysis on samples. Therefore, it is widely used in food and medicine testing, environmental protection testing, judicial identification, and explosives and drugs testing. At the beginning of this century, people proposed a portable laser Raman spectrometer based on near-infrared excitation. The sample holder, objective lens, reflector, cut-off filter, imaging lens, fiber optic connector and receiving optical path of the portable laser Raman excitation probe optical path The optical fiber is on the folded optical path. Because the light intensity of the Raman spectrum is very weak, it is very difficult to capture the Raman scattered light spots, so it is difficult to adjust the folded light path of the Raman excitation probe light path. In addition, the portable laser Raman spectrometer has a single function. Therefore, the popularization and application of portable laser Raman spectrometer is limited.

Contents of the invention

In view of the above situation, the purpose of this utility model is to provide a portable laser Raman spectrum sensing probe with compact structure, increased functions, improved adjustment efficiency and measurement stability, no need to invest in new equipment, and easy to popularize.

In order to achieve the above object, the portable laser Raman spectrum sensing probe of the utility model includes an excitation light path and a Raman scattering receiving light path for the laser to excite the sample through an optical fiber, and an incident optical fiber and an optical fiber connection are sequentially arranged on the excitation optical path for the laser optical fiber to excite the sample The Raman scattering receiving optical path is equipped with a sample holder, objective lens, and a "long pass short reflection" cut-off filter , imaging lens, optical fiber connector and receiving optical fiber. The "long-pass short-reflection" cut-off filter is a cut-off filter with a cut-off point greater than the wavelength of the laser that excites the sample. Laser reflection from sample. In the excitation light path, the "long pass short reflection" cut-off filter is adapted to the reflection light path, so that the laser beam is expanded by the optical fiber and the beam expander, reflected by the mirror, and then passed through the "long pass short reflection" cut-off filter Reflection, the incident laser light is reflected to the objective lens, and irradiated to the sample through the objective lens to excite Raman scattering. And the objective lens, the "long pass short reflection" cut-off filter, the imaging lens and the end face of the receiving optical fiber on the Raman scattering receiving optical path are placed on the same optical axis line. The reflector is installed on the three-dimensional adjustment frame, and the reflected light of the reflector is adjusted by the three-dimensional adjustment frame so that the laser light is irradiated on the sample, and the Raman scattered light of the sample is incident on the end face of the receiving fiber.

In order to achieve compact structure and increased functions, there are further measures.

The "long-pass short-reflection" cut-off filter is used not only for reflecting laser light, but also as a filter for filtering Rayleigh scattering lines and passing through Stokes Raman scattering spectral lines, which makes the probe compact in structure and realizes laser extraction. Portable measurement of Mann spectroscopy.

The isolation cylinder between the objective lens and the sample adopts a variable object distance isolation cylinder, and the variable distance of the variable object distance isolation cylinder is variable in steps, continuously variable and continuously variable in steps, and the steps can be changed to standard cover glass slice thickness and standard sample cell wall thickness. And it has a positioning device to ensure accurate and stable positioning. And it has a locking device to ensure that the object distance remains unchanged and the positioning is stable.

Because the thickness of the standard cover glass and the wall thickness of the standard sample cell are different but relatively close, the variable object distance isolation cylinder adopts different variable sleeves, one for positioning the object distance of the standard cover glass thickness, and one for positioning the standard sample cell Wall Thickness Object Distance.

Because the utility model adopts the variable object distance isolation cylinder and cooperates with the standard cover glass and the standard sample pool, it can be used to measure liquid samples, gel samples, powder samples, fine particle samples and biological samples, and can be used on-site detection.

Compared with the beneficial effects produced by the prior art, the utility model:

(1) Since the Raman scattering receiving optical path adopts optical elements on the same optical axis, the Raman scattering light passes through fewer optical surfaces, which reduces the loss of light intensity. Therefore, the detection sensitivity of the probe is improved.

(2) Since the Raman scattering receiving light path adopts optical elements on the same optical axis and straight line, it is simple and easy to adjust the Raman scattered light, and the intensity of the adjustment operation is reduced.

(3) Due to the use of the variable object distance isolation cylinder for positioning the object distance of the standard cover glass thickness and the object distance of the standard sample cell wall thickness, it is more convenient and quick to measure different samples.

(4) The structure is simple and compact, easy to manufacture, easy to carry, some test functions have been added, and the application range of the portable laser Raman spectrometer has been expanded, and no new equipment investment is required. The commercial prospect is good, and it is suitable for popularization and promotion.

Below in conjunction with accompanying drawing and embodiment the utility model is described further.

Description of drawings

Fig. 1 is a structural schematic diagram of a portable laser Raman spectrum sensing probe of the present invention.

Fig. 2 is the three-dimensional adjusting frame of the reflecting mirror M of the present invention.

Fig. 3 is a structural diagram of the variable object distance isolation cylinder of the present invention.

In Fig. 1: 1. Incident optical fiber F ₁ , 2, fiber optic connector J ₁ , 3, beam expander L ₁ , 4, mirror M, 5, "long pass short reflection" cut-off filter LF, 6, objective lens L ₂ , 7. Variable object distance isolation cylinder, 8. Sample and sample holder S, 9. Scattering imaging lens L ₃ , 10. Optical fiber connector J ₂ , 11. Receiving optical fiber F ₂ , 12. Optical element installation cassette, 13. Laser baffle.

In Fig. 2: 1, reflector lens, 2, screw, 3, spring fixing rod, 4, reflector mounting plate, 5, support plate, 6, steel ball, 7, spring, 8, support rod, 9, lens fixing pressure ring .

In Figure 3: 1. Objective lens barrel, 2. Positioning ring, 3. Locking screw, 4. Small through hole, 5. Variable object distance isolation sleeve, 6. Positioning pin, 7. Spring, 8. Small steel ball

Detailed ways

As shown in accompanying drawing 1, a portable laser Raman spectrum sensing probe includes an incident optical fiber F ₁ , an optical fiber connector J ₁ , a beam expander L ₁ , a reflector M, and a "long-pass short-reflection" cut-off filter Film LF, objective lens L ₂ , variable object distance isolation cylinder, -sample and sample holder S, scattering imaging lens L ₃ , optical fiber connector J ₂ , receiving optical fiber F ₂ , optical element installation cassette and laser baffle. Optical fiber connector J ₁ , beam expander L ₁ , reflector M, "long pass short reflection" cut-off filter LF, objective lens L ₂ , scattering imaging lens L ₃ and optical fiber connector J ₂ are all fixedly mounted on the optical element installation , where the mirror M is installed on the three-dimensional adjustment frame inside the cassette; the variable object distance isolation cylinder, the sample holder S and the laser baffle are installed outside the optical element installation cassette. By adjusting the object distance of the variable object distance isolation cylinder to the thickness of the standard cover glass, the Raman spectrum of the substance on the standard cover glass can be measured; by adjusting the object distance of the variable object distance isolation cylinder to the thickness of the standard sample cell wall, the standard The Raman spectrum of the substance in the sample cell; therefore, it can be used to measure liquid samples, gel samples, powder samples, fine particle samples and biological samples, and realize the testing of various samples.

With reference to Figure 1, the incident fiber F ₁ is inserted into the fiber connector J ₁ , the receiving fiber F ₂ is inserted into the fiber connector J ₂ , the laser light is incident into the incident fiber F ₁ of the portable laser Raman excitation probe, and the laser beam is collimated through the beam expander L ₁ The straight expanded beam becomes a parallel beam, and the parallel laser beam is reflected by the mirror M to shoot the parallel laser light onto the "long-pass short-reflection" cut-off filter LF, because the "long-pass short-reflection" cut-off filter has a cut-off point greater than the wavelength of the laser that excites the sample Therefore, the "long-pass short-reflection" cut-off filter LF reflects the parallel laser light, and irradiates the sample S through the objective lens _L2 and the variable object distance isolation cylinder to produce Raman scattering and Rayleigh scattering, resulting in The Raman scattering and Rayleigh scattering light are incident on the "long pass short reflection" cut-off filter LF through the objective lens _L2 , because the Rayleigh scattering light wavelength is equal to the wavelength of the excitation laser, and the Rayleigh scattering light wavelength is shorter than the "long pass short reflection" The cut-off point of the "reverse" cut-off filter LF is small, and the "long-pass short-reflection" cut-off filter LF reflects the Rayleigh scattered light. The cut-off point of the sheet LF is large, so that the Stokes Raman scattered light passes through, and the Stokes Raman scattered light is irradiated to the incident end face of the receiving optical fiber _F2 through the scattering imaging lens _L3 , and is incident into the receiving optical fiber. Finally, It is transmitted to a spectrometer through an optical fiber to measure the Raman spectrum structure. The laser baffle blocks the emitted laser light when in use.

The three-dimensional adjustment frame of the reflecting mirror M shown in accompanying drawing 2. In conjunction with accompanying drawing 2, the three-dimensional adjustment frame of reflector M comprises support rod 8, and one end of support rod 8 is inserted on the low seat of cassette, and the other end of support rod 8 is screwed into support plate 5, and support plate 5 passes steel ball 6 and screw 2, and Corresponding to the spring 7 installed by the screw 2, the spring fixing rod 3 is connected and fixed with the reflector mounting plate 4, and the reflector lens 1 is installed in the reflector mounting plate 4, and is screwed and fixed on the reflector mounting plate 4 by the lens fixing pressure ring 9; The tops of the two screws 2 and the steel ball 6 are in the same plane as the reflector mounting plate 4. By adjusting the in and out of the two screws 2, the orientation of the reflective surface of the reflector 1 can be adjusted, so that the reflected laser light is irradiated on the sample S, and The Raman scattered light of the sample is incident on the end face of the receiving fiber _F2 for spectrometer measurement. After the mirror M three-dimensional adjustment frame is adjusted, it is glued and fixed.

The combination of the variable object distance isolation cylinder and the objective lens barrel shown in accompanying drawing 3. In conjunction with accompanying drawing 3, the variable object distance isolating tube 5 is installed on the objective lens barrel 1, and the variable object distance isolating sleeve can be freely adjusted in and out on the objective lens barrel, and the objective lens barrel has three symmetrical small holes equipped with springs 7 and small steel ball 8, there are three symmetrical small through holes 4 or concave ring structure in the variable object distance isolation sleeve, the object distance isolation sleeve is retracted, and the small steel top ball on the objective lens barrel is used to locate the standard cover glass thickness Object distance, no need to adjust the object distance for samples on the standard cover glass, lock the object distance to meet the portable requirements, convenient and fast testing. For sample testing of other container thicknesses, the distance between the object and the isolation sleeve can be adjusted freely to adapt to various sample tests. There is a positioning pin 6 on the objective lens barrel 1, and the variable object distance isolation sleeve 5 is fixedly connected with the positioning ring 2. When the object distance isolation sleeve 5 is pulled out to the positioning ring 2, it is blocked by the positioning pin 6 and stops at this position. For direct measurement of solid samples. The object distance isolating sleeve has a locking screw 3 or a locking nut to ensure that the object distance remains unchanged and the positioning is stable.

In conjunction with accompanying drawing 3, another variable object distance isolating cylinder is positioned at the standard sample cell wall thickness object distance, and the variable object distance isolating cylinder is installed on the objective lens barrel, which has three symmetrical small holes on which springs and Small steel ball, the variable object distance isolation sleeve has a concave ring structure or three symmetrical small through holes, retract the object distance isolation sleeve, cooperate with the small steel top ball on the objective lens barrel to locate the object distance of the standard sample cell wall thickness, for The sample in the standard sample cell does not need to adjust the object distance, and the locked object distance meets the requirements of portability, which is convenient and fast for testing. For sample testing of other container thicknesses, the distance between the object and the isolation sleeve can be adjusted freely to adapt to various sample tests.

Claims (10)

1. a portable laser Raman spectrum sensing probe, is characterized in that it comprises the excitation optical path and the Raman scattering receiving optical path of laser light excitation sample through optical fiber, and the excitation optical path of described laser optical fiber excitation sample is provided with incident optical fiber, Optical fiber connector, beam expander, reflector, "long-pass short-reflection" cut-off filter, objective lens, object distance isolation tube and sample holder, the Raman scattering receiving optical path is provided with sample holder, object distance isolation Tube, objective lens, "long pass short return" cut-off filter, imaging lens, fiber optic connector and receiving fiber. 2. The portable laser Raman spectrum sensing probe according to claim 1, characterized in that the "long pass short reflection" cut-off filter is that the cut-off point is greater than the laser wavelength of the excitation sample, and the "long pass short reflection" cut-off filter The light sheet is adapted as a reflective light path to direct the incident laser light onto the sample. 3. The portable laser Raman spectrum sensor probe according to claim 1, characterized in that the laser light is reflected by the reflector after the beam expansion of the optical fiber and the beam expander, and then reflected by the "long pass and short return" cut-off filter, Excite Raman scattering through the objective lens onto the sample. 4. according to the described portable laser Raman spectrum sensing probe of claim 1 or 3, it is characterized in that reflector is installed on the three-dimensional adjusting frame, adjusts reflector reflected light by three-dimensional adjusting frame to make laser irradiation on the sample, and Make the sample Raman scattered light incident into the end face of the receiving fiber. 5. The portable laser Raman spectrum sensing probe according to claim 1, characterized in that the Raman scattering receiving optical path objective lens, "long pass short reflection" cut-off filter, imaging lens and receiving fiber end face are on the same optical axis in a straight line. 6. The portable laser Raman spectrum sensing probe according to claim 1, characterized in that the "long-pass short-reflection" cut-off filter is used both as a reflection laser and as a filter to remove Rayleigh scattering rays through the Stokes Filters for Slaman scattering spectral lines. 7. The portable laser Raman spectroscopy sensor probe according to claim 1, characterized in that the object distance isolation cylinder between the objective lens and the sample is a variable object distance isolation cylinder. 8. The portable laser Raman spectrum sensing probe according to claim 7, characterized in that the variable distance of the variable object distance isolation cylinder is variable in steps, continuously variable and continuously variable in steps, and the steps in steps Can be changed to standard cover glass thickness and standard sample cell wall thickness. 9. The portable laser Raman spectrum sensing probe according to claim 7 or 8, characterized in that the variable object distance isolation cylinder adopts different positioning object distance variable sleeves, one for positioning the standard cover glass thickness object distance , one is used to locate the object distance of the standard sample cell wall thickness. 10. The portable laser Raman spectroscopy probe according to claim 7, characterized in that the variable object distance isolation cylinder has a positioning device to ensure accurate positioning; a locking device to ensure constant object distance and stable positioning.