CN113589426B - Hollow fiber, gas detection system and method - Google Patents
Hollow fiber, gas detection system and method Download PDFInfo
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- CN113589426B CN113589426B CN202111066785.9A CN202111066785A CN113589426B CN 113589426 B CN113589426 B CN 113589426B CN 202111066785 A CN202111066785 A CN 202111066785A CN 113589426 B CN113589426 B CN 113589426B
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- 238000005253 cladding Methods 0.000 claims abstract description 65
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Classifications
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/02—Optical fibres with cladding with or without a coating
- G02B6/02295—Microstructured optical fibre
- G02B6/02314—Plurality of longitudinal structures extending along optical fibre axis, e.g. holes
- G02B6/02319—Plurality of longitudinal structures extending along optical fibre axis, e.g. holes characterised by core or core-cladding interface features
- G02B6/02323—Core having lower refractive index than cladding, e.g. photonic band gap guiding
- G02B6/02328—Hollow or gas filled core
-
- 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
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N21/3504—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing gases, e.g. multi-gas analysis
-
- 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
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N21/3581—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light using far infrared light; using Terahertz radiation
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/02—Optical fibres with cladding with or without a coating
- G02B6/02295—Microstructured optical fibre
- G02B6/02314—Plurality of longitudinal structures extending along optical fibre axis, e.g. holes
- G02B6/02342—Plurality of longitudinal structures extending along optical fibre axis, e.g. holes characterised by cladding features, i.e. light confining region
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
Abstract
The invention provides a hollow fiber, a gas detection system and a method, wherein the gas detection system can comprise: the device comprises a terahertz wave generating device, a terahertz wave detecting device, a coupling device, a spectrum information processing device and a hollow optical fiber; terahertz wave generating means for generating terahertz waves to be incident into the coupling means; the coupling device is connected with one end of the hollow optical fiber and is used for respectively coupling the terahertz wave and the gas to be detected into the fiber core and the cladding of the hollow optical fiber so that the terahertz wave reacts with the gas to be detected penetrating into the fiber core from the cladding in the transmission process in the fiber core and is output from the other end of the fiber core; the terahertz wave detection device detects terahertz waves output from the fiber cores, and an absorption spectrum of the gas to be detected is obtained and sent to the spectrum information processing device; and the spectrum information processing device is used for obtaining an analysis result according to the absorption spectrum of the gas to be detected. According to the scheme, the volume of the gas detection system can be reduced, and the gas detection efficiency can be improved.
Description
Technical Field
The embodiment of the invention relates to the technical field of detection, in particular to a hollow fiber, a gas detection system and a gas detection method.
Background
In the prior art, methods for detecting gas components and the content of each gas component included in a mixed gas generally include colorimetry, chromatography, spectrophotometry, and the like. The gas components which can be detected by the existing detection method are single, and the detection system is large in volume.
Disclosure of Invention
The embodiment of the invention provides a hollow optical fiber, a gas detection system and a method, which can reduce the volume of the gas detection system and improve the gas detection efficiency.
In a first aspect, embodiments of the present invention provide a hollow fiber comprising: a core, a cladding surrounding an inner wall of the core, and a protective jacket outside the cladding; the inner wall comprises a plurality of vent holes.
Preferably, the core is hollow and is filled with dry air.
Preferably, the refractive index of the material used for the cladding is greater than 1.
Preferably, a plurality of organic structures are embedded in the cladding, and the material of the organic structures is thermoplastic organic polymer with low loss in the terahertz wave frequency band.
Preferably, the cross-sectional shape of the organic structure is at least one of a bar shape, a ring shape, and a circle shape; and/or the number of the groups of groups,
the material of the organic structure body is at least one of polyethylene, cycloolefin copolymer and polymer cycloaliphatic.
Preferably, gaps are formed between the plurality of organic structures embedded in the cladding layer, and the gaps in the cladding layer are communicated with the fiber cores through vent holes on the inner wall.
Preferably, one end of the hollow optical fiber includes a core entrance and a cladding entrance; the other end of the hollow optical fiber comprises a fiber core outlet.
In a second aspect, an embodiment of the present invention provides a gas detection system, including a terahertz wave generating device, a terahertz wave detecting device, a coupling device, a spectral information processing device, and a hollow optical fiber as described in any one of the above;
the terahertz wave generating device is used for generating terahertz waves, and the generated terahertz waves are incident into the coupling device;
the coupling device is connected with one end of the hollow optical fiber and is used for respectively coupling the incident terahertz wave and the collected gas to be tested into the fiber core and the cladding of the hollow optical fiber so that the terahertz wave reacts with the gas to be tested permeated into the fiber core from the cladding in the transmission process in the fiber core and is output from the other end of the fiber core;
the terahertz wave detection device is used for detecting the terahertz waves output from the fiber core, obtaining the absorption spectrum of the gas to be detected, and sending the absorption spectrum of the gas to be detected to the spectrum information processing device;
the spectrum information processing device is used for obtaining an analysis result according to the absorption spectrum of the gas to be detected.
Preferably, the coupling device comprises an incident port for receiving terahertz waves and an air suction port for receiving the gas to be measured, wherein the incident port is communicated with the fiber core inlet of the hollow optical fiber, and the air suction port is communicated with the cladding inlet of the hollow optical fiber.
In a third aspect, an embodiment of the present invention provides a gas detection method based on any one of the above-mentioned gas detection systems, including:
generating terahertz waves by using a terahertz generating device, and enabling the generated terahertz waves to be incident into a coupling device;
coupling the terahertz wave and the gas to be measured into a fiber core and a cladding of the hollow optical fiber by using the coupling device respectively, so that the terahertz wave reacts with the gas to be measured penetrating into the fiber core from the cladding in the internal transmission process and is output from the other end of the fiber core;
detecting terahertz waves output from the fiber cores by using a terahertz wave detection device to obtain an absorption spectrum of the gas to be detected, and sending the absorption spectrum of the gas to be detected to the spectrum information processing device;
and obtaining an analysis result according to the absorption spectrum of the gas to be detected by utilizing the spectrum information processing device.
The embodiment of the invention provides a hollow optical fiber, a gas detection system and a method, wherein the hollow optical fiber is used as a reaction cavity of terahertz waves and gas to be detected, so that the terahertz waves can fully react with the gas to be detected in the transmission process of the hollow optical fiber, and the hollow optical fiber can be bent, therefore, even if the length of the hollow optical fiber is longer, the hollow optical fiber can occupy a smaller space through bending, and the volume of the gas detection system can be reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic view of a hollow fiber structure according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a gas detection system according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of another gas detection system according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a time delay line structure according to an embodiment of the present invention;
FIG. 5 is a flow chart of a gas detection method according to an embodiment of the present invention;
the reference numerals are:
1-a fiber core; 11-inner wall; 2-cladding; 21-structure; 3-protecting sleeve; 201-terahertz wave generating means; 202-a terahertz wave detection device; 203-coupling means; 204-a spectral information processing device; 205-hollow fiber; 206-a gas collection box; 207-a gas circulation pump; 208-an alarm unit; 209-a display; 2011-femtosecond laser; 2012—a beam splitter; 2013-a time delay line; 2014-polarization maintaining fiber; 2015-photoconductive antenna; 2021-photoconductive detection antenna; a1-pulse input; A2-A4-reflector; a5-pulse output port; a6-a roller guide rail.
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 of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in 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, and all other embodiments obtained by those skilled in the art without making any inventive effort based on the embodiments of the present invention are within the scope of protection of the present invention.
As described above, the method for detecting the gas components included in the mixed gas and the content of each gas component generally includes colorimetry, chromatography, spectrophotometry, and the like. Terahertz (THz for short) wave refers to electromagnetic wave with frequency of 0.1-10THz and wavelength of 0.03-3mm, the wave band is between microwave and far infrared, and the edge frequency spectrum area in traditional electronic and photonics research is also the transition area of classical macroscopic theory to quantum microscopic theory. The terahertz wave band is in the rotation frequency and vibration level range of most macromolecules, and the interaction of the terahertz wave and the substances can reflect the physical and chemical information of rich substances, so that the terahertz wave has great development prospect and application potential in the aspects of substance detection and identification. In recent years, along with the development of science and technology, terahertz waves have made important progress in the detection, identification, sensing and the like of harmful gases in the atmosphere. When the terahertz wave is used for detecting the gas component, the gas to be detected is generally filled into a spherical reaction cavity, and the terahertz wave and the gas to be detected react in the spherical reaction cavity. However, the reaction chamber has a larger volume, and the existing gas detection system has poor portability. Considering that terahertz wave can be transmitted in the hollow optical fiber, the terahertz wave can be freely bent and folded, if the gas to be detected can be filled in the hollow optical fiber, the terahertz wave reacts with the gas to be detected in the transmission process of the hollow optical fiber, namely, the hollow optical fiber is used as a reaction cavity, and when the length of the hollow optical fiber is the same as the diameter of the existing reaction cavity, the hollow optical fiber is bent, so that the volume of the reaction cavity can be reduced, the volume of a gas detection system is further reduced, and the portability of the gas detection system is improved.
Specific implementations of the above concepts are described below.
Referring to fig. 1, an embodiment of the present invention provides a hollow fiber, including a core 1, a cladding 2 surrounding an inner wall 11 of the core 1, and a protective sheath 3 outside the cladding 2; the inner wall 11 comprises a plurality of ventilation holes.
In the embodiment of the invention, the fiber core is used for transmitting terahertz waves, gas to be detected can enter the hollow fiber through the cladding, then the gas to be detected permeates into the fiber core through the vent holes on the inner wall, and the gas to be detected permeated into the fiber core fully reacts with the gas to be detected along with the increase of the transmission distance of the terahertz waves in the fiber core and is output from the other end of the hollow fiber, so that the output terahertz waves can be detected by using a terahertz wave detection device, and the detection of the components of the gas to be detected is realized.
In one embodiment of the invention, the protective sleeve not only can protect the hollow optical fiber, but also can block the gas to be measured, so that the gas to be measured can be filled into the cladding without being dispersed outside the hollow optical fiber, and the gas to be measured can permeate into the fiber core through the vent holes on the inner wall of the fiber core under the action of pressure.
In one embodiment of the invention, when the terahertz wave is transmitted in the atmosphere environment, the terahertz wave is easily absorbed by the atmosphere due to the fact that the atmospheric environment is high in humidity and the like, so that in order to reduce the absorption of the terahertz wave by the atmosphere, the fiber core is filled with dry air, and when the terahertz wave is transmitted in the fiber core, the air in the fiber core is dry, so that compared with the air transmitted in the atmosphere environment, the amount of the terahertz wave transmitted in the fiber core can be reduced, the accuracy of the spectrum information of the terahertz wave detected by the terahertz wave detection device at the other end of the hollow optical fiber is high, and the accuracy of a detection result is further improved.
In one embodiment of the invention, the cladding has an equivalent refractive index that is greater than the refractive index within the core. In order to prevent the terahertz wave from leaking to the outside of the core during transmission, the terahertz wave can be localized inside the core by making the equivalent refractive index of the cladding larger than that of the core.
When the gas in the core is air, then the refractive index in the core is 1. Thus, the equivalent refractive index in the cladding needs to be greater than 1. I.e. the cladding material has an equivalent refractive index greater than 1.
In order to reduce the absorption of the terahertz waves by the cladding, the material of the cladding may be a thermoplastic organic polymer with low loss in the terahertz wave band, considering that the cladding also absorbs the terahertz waves.
In addition, considering that if the cladding is filled with the cladding material, that is, the gap between the inner wall of the core and the protective sheath is filled with the cladding material, not only the weight of the hollow optical fiber is large, but also the absorption of terahertz waves by more cladding material is large, in order to further reduce the absorption of terahertz waves by the cladding, in one embodiment of the present invention, the cladding 2 is embedded with a plurality of organic structures 21, and the material of the organic structures 21 is a thermoplastic organic polymer with low loss in the terahertz wave band.
Since the refractive index of the organic polymer is greater than 1, the equivalent refractive index in the cladding can be made greater than 1, that is, greater than the refractive index of air in the core, by embedding a plurality of organic structures in the cladding, so that the cladding can play a role in confining terahertz waves.
In one embodiment of the present invention, the material of the organic structure may be at least one of polyethylene, cyclic olefin copolymer, and polymer cycloaliphatic. For another example, polytetrafluoroethylene, polycarbonate, polystyrene, and the like are also possible.
In one embodiment of the present invention, the cross-sectional shape of the organic structure is at least one of a bar shape, a ring shape, and a circle shape. Referring to fig. 1, the organic structure is a structure with an elliptical ring embedded in a ring, wherein the diameter of the ring of the organic structure is the difference between the radius of the protecting sleeve and the radius of the fiber core, that is, one end of the ring contacts with the inner wall of the fiber core, and the other end of the ring contacts with the protecting sleeve, so that the ring can be fixed between the fiber core and the protecting sleeve. In addition, one end of the elliptical ring of the organic structure body is contacted with the inner wall of the circular ring, so that the elliptical ring is fixedly arranged.
The cross-sectional shape of the organic structure shown in fig. 1 is a preferred embodiment of the present invention, and other shapes are also possible, so long as the function of the cladding in the hollow fiber can be satisfied.
In one embodiment of the present invention, a plurality of organic structures are uniformly disposed within the cladding layer, thereby well localizing the terahertz waves within the core.
In one embodiment of the present invention, because the organic structures have relatively poor air permeability, gaps are provided between the plurality of organic structures embedded in the cladding layer, and the gaps in the cladding layer are communicated with the fiber core through the air holes on the inner wall. So that the gas to be measured filled in the cladding can penetrate into the fiber core through the vent holes. For example, in fig. 1, a gap is left between two adjacent organic structures, and the gas to be measured filled in the gap can penetrate into the fiber core through the vent holes on the inner wall.
In one embodiment of the present invention, in order to be able to facilitate the hollow fiber to perform the function of the reaction chamber, one end of the hollow fiber includes a core entrance and a cladding entrance; the other end of the hollow optical fiber includes a core exit. In this way, the hollow fiber can receive the terahertz wave through the fiber core inlet, receive the gas to be detected through the cladding inlet, and then output the terahertz wave after reacting with the gas to be detected from the fiber core outlet at the other end of the hollow fiber.
In order to realize detection of a component of a gas to be detected by using the hollow fiber, referring to fig. 2, an embodiment of the present invention provides a gas detection system, including: terahertz wave generating means 201, terahertz wave detecting means 202, coupling means 203, spectral information processing means 204, and hollow optical fiber 205 as described in any of the above embodiments;
the terahertz wave generating device is used for generating terahertz waves, and the generated terahertz waves are incident into the coupling device;
the coupling device is connected with one end of the hollow optical fiber and is used for respectively coupling the incident terahertz wave and the collected gas to be tested into the fiber core and the cladding of the hollow optical fiber so that the terahertz wave reacts with the gas to be tested permeated into the fiber core from the cladding in the transmission process in the fiber core and is output from the other end of the fiber core;
the terahertz wave detection device is used for detecting the terahertz waves output from the fiber core, obtaining the absorption spectrum of the gas to be detected, and sending the absorption spectrum of the gas to be detected to the spectrum information processing device;
the spectrum information processing device is used for obtaining an analysis result according to the absorption spectrum of the gas to be detected.
In the embodiment of the invention, the hollow optical fiber can be bent and folded, and the hollow optical fiber is used as the reaction cavity of the terahertz wave and the gas to be detected, so that the reaction cavity has smaller volume and small occupied space, the volume of the gas detection system can be reduced, and the portability of the gas detection system is improved.
In one embodiment of the present invention, in order to ensure that the coupling process is not affected by each other when the terahertz wave and the gas to be measured are simultaneously coupled into the hollow optical fiber, the coupling device may include an incident port for receiving the terahertz wave and an air suction port for receiving the gas to be measured, the incident port being in communication with the core inlet of the hollow optical fiber, and the air suction port being in communication with the cladding inlet of the hollow optical fiber. In this way, the coupling device can receive terahertz waves from the incident port and couple the terahertz waves into the fiber core through the fiber core inlet of the hollow optical fiber, and the coupling device receives gas to be tested from the air suction port and couples the gas to be tested into the cladding through the cladding inlet of the hollow optical fiber, so that independent coupling of the terahertz waves and the gas to be tested can be realized, and mutual influence in the coupling process of the terahertz waves and the gas to be tested is reduced.
Next, each component in the gas detection system will be described by taking the gas detection gas shown in fig. 3 as an example.
First, the terahertz wave generating apparatus 201 may include a femtosecond laser 2011, a beam splitter 2012, a time delay line 2013, a polarization maintaining fiber 2014, and a photoconductive antenna 2015.
The laser pulse output by the femtosecond laser is divided into a pumping pulse and a detection pulse by a beam splitter. The pump pulse is incident on the photoconductive generating antenna through the polarization maintaining fiber to generate terahertz waves; the detection pulse is delayed by a time delay line and then is incident on the terahertz detection device through the polarization maintaining optical fiber.
The compact and miniaturized femtosecond laser is used as a pumping source, and the parameters can be as follows: the center wavelength is 1550nm, the pulse width is 80fs, the repetition frequency is 80MHz, and the maximum output power is 50mW. Ultrashort laser pulses output by the femtosecond laser can be processed by a beam splitter according to the following ratio of 1: the ratio 1 is divided into two beams, one beam is a pumping pulse, and the other beam is a detection pulse. When the pumping pulse is incident on the photoconductive generating antenna through the polarization maintaining fiber, because the single photon energy of the pumping pulse is larger than the energy gap width of the semiconductor material on the photoconductive antenna, electron hole pairs are generated on the surface of the semiconductor material, and under the action of externally applied 70V bias voltage, the electron hole pairs directionally move to form instantaneously-changed photo-generated current, and terahertz waves with the frequency range of 0.1-2.5THz are radiated outwards. The detection pulse is delayed by a time delay line and then is incident on the terahertz detection device 202 through the polarization maintaining fiber. Preferably, the photoconductive detection antenna 2021 may be selected as the terahertz detection device 202 because of its small size.
Fig. 4 is a schematic diagram of a time delay line according to an embodiment of the invention. In the figure, a broken line is a light path of a detection pulse, wherein A1 is a pulse input port, A2-A4 are reflectors, A5 is a pulse output port, A6 is a wheel slide guide rail, and the horizontal position of the reflector A3 can be adjusted by the wheel slide guide rail A6, so that the delay time length of the detection pulse is adjusted.
The time delay line needs to ensure that the phases of the detection pulse and the terahertz wave reach the photoconductive detection antenna are consistent.
Then, for the coupling device 203, the incident port thereof corresponds to the direction in which the terahertz wave is emitted from the photoconductive antenna 2015, and the emitted terahertz wave can directly enter into the coupling device through the incident port.
In order to be able to input the gas to be measured to the suction port of the coupling device 203, the gas detection system may further comprise a gas collection tank 206 for collecting the gas to be measured and a gas circulation pump 207, and then the gas to be measured in the gas collection tank is input to the suction port of the coupling device via the gas circulation pump.
The coupling device couples the terahertz wave into the fiber core through the fiber core inlet of the hollow fiber and into the cladding through the cladding inlet of the hollow fiber. The gas to be measured coupled into the cladding penetrates into the fiber core through the vent hole on the inner wall of the fiber core, and fully reacts with the gas to be measured along with the increase of the transmission distance of the terahertz wave, so that the gas to be measured is output at the other end of the hollow fiber.
Next, for the terahertz detection apparatus 202, the terahertz detection antenna 2021 detects terahertz wave radiation based on the photoconductive sampling principle, and when a detection pulse is incident on the photoconductive detection antenna, since the single photon energy of the ultrashort laser pulse is greater than the energy gap width of the semiconductor material, electron hole pairs are excited on the photoconductive surface, and under the action of no external electric field, the electron hole pairs randomly move and quickly recombine to annihilate. However, when the detection pulse and the terahertz wave radiation electric field exist at the same time, the electron hole pairs are driven by the terahertz wave radiation electric field to directionally move to form photo-generated current, and the magnitude of the photo-current is proportional to that of the terahertz wave radiation electric field, so that the terahertz wave output from the other end of the hollow optical fiber can be detected, and the absorption spectrum of the gas to be detected can be obtained.
Finally, for the spectrum information processing device 204, the positions and intensities of the spectrum absorption peaks of different gases in the terahertz wave frequency band can be obtained in advance as references, then the positions of the absorption peaks corresponding to the spectrums are analyzed according to the absorption spectrum of the gas to be detected obtained by the terahertz wave detection device, and then the positions of the absorption peaks corresponding to the referenced gas are compared, so that each gas component contained in the gas to be detected can be obtained, and the concentration of each gas component can be calculated according to the intensity of the absorption peak.
In one embodiment of the present invention, in order to obtain the detection result in time, the gas detection system may further include an alarm unit 208 and a display 209, and if the detected gas concentration exceeds the standard, the alarm unit is used to alarm, and each gas component detected in the gas to be detected and the corresponding concentration are displayed on the display, so as to realize digital presentation of data.
Referring to fig. 5, an embodiment of the present invention further provides a gas detection method based on any one of the above-mentioned gas detection systems, including:
step 501: generating terahertz waves by using a terahertz generating device, and enabling the generated terahertz waves to be incident into a coupling device;
step 502: coupling the terahertz wave and the gas to be measured into a fiber core and a cladding of the hollow optical fiber by using the coupling device respectively, so that the terahertz wave reacts with the gas to be measured penetrating into the fiber core from the cladding in the transmission process in the fiber core and is output from the other end of the fiber core;
step 503: detecting terahertz waves output from the fiber cores by using a terahertz wave detection device to obtain an absorption spectrum of the gas to be detected, and sending the absorption spectrum of the gas to be detected to the spectrum information processing device;
step 504: and obtaining an analysis result according to the absorption spectrum of the gas to be detected by utilizing the spectrum information processing device.
In the embodiment of the invention, the method can be used for detecting various gas components and concentrations, and effectively improving the gas detection efficiency.
It is noted that relational terms such as first and second, and the like, are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one …" does not exclude the presence of additional identical elements in a process, method, article or apparatus that comprises the element.
Those of ordinary skill in the art will appreciate that: all or part of the steps for implementing the above method embodiments may be implemented by hardware related to program instructions, and the foregoing program may be stored in a computer readable storage medium, where the program, when executed, performs steps including the above method embodiments; and the aforementioned storage medium includes: various media in which program code may be stored, such as ROM, RAM, magnetic or optical disks.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (3)
1. The gas detection system is characterized by comprising a terahertz wave generating device, a terahertz wave detecting device, a coupling device, a spectrum information processing device and a hollow optical fiber; the hollow optical fiber comprises a fiber core, a cladding surrounding the inner wall of the fiber core and a protective sleeve outside the cladding;
the terahertz wave generating device is used for generating terahertz waves, and the generated terahertz waves are incident into the coupling device; the cladding is internally embedded with a plurality of organic structures, gaps are arranged among the plurality of organic structures embedded in the cladding, and the gaps in the cladding are communicated with the fiber cores through vent holes on the inner wall; one end of the hollow optical fiber comprises a fiber core inlet and a cladding inlet; the other end of the hollow optical fiber comprises a fiber core outlet; the coupling device comprises an incident port for receiving terahertz waves and an air suction port for receiving gas to be detected, wherein the incident port is communicated with a fiber core inlet of the hollow optical fiber, and the air suction port is communicated with a cladding inlet of the hollow optical fiber;
the coupling device is connected with one end of the hollow optical fiber and is used for respectively coupling the incident terahertz wave and the collected gas to be tested into the fiber core and the cladding of the hollow optical fiber so that the terahertz wave reacts with the gas to be tested permeated into the fiber core from the cladding in the transmission process in the fiber core and is output from the other end of the fiber core;
the terahertz wave detection device is used for detecting the terahertz waves output from the fiber core, obtaining the absorption spectrum of the gas to be detected, and sending the absorption spectrum of the gas to be detected to the spectrum information processing device;
the spectrum information processing device is used for obtaining an analysis result according to the absorption spectrum of the gas to be detected;
the fiber core is hollow and is filled with dry air; the refractive index of the material adopted by the cladding is greater than 1; the material of the organic structure body is thermoplastic organic polymer with low loss in terahertz wave frequency band; the plurality of organic structures are uniformly disposed within the cladding layer to localize the terahertz waves within the core.
2. A gas detection system according to claim 1, wherein,
the cross section of the organic structure body is at least one of strip, ring and round; and/or the number of the groups of groups,
the material of the organic structure body is at least one of polyethylene, cycloolefin copolymer and polymer cycloaliphatic.
3. A gas detection method based on the gas detection system according to any one of the preceding claims 1-2, characterized by comprising:
generating terahertz waves by using a terahertz generating device, and enabling the generated terahertz waves to be incident into a coupling device;
coupling the terahertz wave and the gas to be measured into a fiber core and a cladding of the hollow optical fiber by using the coupling device respectively, so that the terahertz wave reacts with the gas to be measured penetrating into the fiber core from the cladding in the transmission process in the fiber core and is output from the other end of the fiber core;
detecting terahertz waves output from the fiber cores by using a terahertz wave detection device to obtain an absorption spectrum of the gas to be detected, and sending the absorption spectrum of the gas to be detected to the spectrum information processing device;
and obtaining an analysis result according to the absorption spectrum of the gas to be detected by utilizing the spectrum information processing device.
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