CN111189802A - Graphene characteristic-based gas sensor research method - Google Patents
Graphene characteristic-based gas sensor research method Download PDFInfo
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- CN111189802A CN111189802A CN202010206924.2A CN202010206924A CN111189802A CN 111189802 A CN111189802 A CN 111189802A CN 202010206924 A CN202010206924 A CN 202010206924A CN 111189802 A CN111189802 A CN 111189802A
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- G—PHYSICS
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- 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
- G01N21/41—Refractivity; Phase-affecting properties, e.g. optical path length
- G01N21/45—Refractivity; Phase-affecting properties, e.g. optical path length using interferometric methods; using Schlieren methods
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- G—PHYSICS
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- 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
- G01N21/41—Refractivity; Phase-affecting properties, e.g. optical path length
- G01N21/45—Refractivity; Phase-affecting properties, e.g. optical path length using interferometric methods; using Schlieren methods
- G01N2021/451—Refractivity; Phase-affecting properties, e.g. optical path length using interferometric methods; using Schlieren methods for determining the optical absorption
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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
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/41—Refractivity; Phase-affecting properties, e.g. optical path length
- G01N21/45—Refractivity; Phase-affecting properties, e.g. optical path length using interferometric methods; using Schlieren methods
- G01N2021/458—Refractivity; Phase-affecting properties, e.g. optical path length using interferometric methods; using Schlieren methods using interferential sensor, e.g. sensor fibre, possibly on optical waveguide
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Abstract
The invention discloses a graphene characteristic-based gas sensor research method, which comprises the following steps: step 1, stripping a coating layer of a single mode optical fiber (the diameter of a fiber core is 9 microns, the diameter of a cladding is 125 microns) by 2cm by using an optical fiber stripping clamp, wiping the coating layer by using alcohol, cutting the end face of the single mode optical fiber flat by using an optical fiber cutting knife, step 2, putting the single mode optical fiber with the end face cut flat and wiped in an optical fiber film coating machine, coating a layer of high-reflection film on the flat cut side, manufacturing microspheres by discharging the optical fiber through an optical fiber welding machine, and finally coating a layer of graphene on the optical fiber. The method has wide application in coal mine gas explosion, environmental pollution and the like.
Description
Technical Field
The invention relates to a graphene characteristic-based gas sensor research method.
Background
Along with the development of industrial and agricultural industries, tens of thousands of power plants and coal mines emit a large amount of toxic, flammable and explosive hazardous gases, so that the living environment of human beings is polluted in a large area, in addition, the gas explosion events of domestic coal mines occur occasionally, in order to reduce the hazards as much as possible, the gas in a special environment must be detected quickly, in real time and efficiently, and the optical fiber sensor has the advantages of small volume, light weight, electromagnetic interference resistance, corrosion resistance, suitability for severe environments, high responsiveness, high accuracy and the like, so that the rapid development is realized in recent years.
The optical fiber sensor can monitor temperature, strain, refractive index, micro displacement, magnetic field, gas concentration and the like on line in real time at present, has good responsivity, linearity and sensitivity, and brings great convenience to production and life of people.
In the conventional process, the gas to be determined cannot be accurately detected in real time, the anti-interference capability is weak, and the like.
Disclosure of Invention
The invention aims to provide a research method of a gas sensor based on graphene characteristics.
The invention is realized by the following technical scheme:
a graphene characteristic-based gas sensor research method comprises the following steps:
step 1, using an optical fiber stripper to strip off a coating layer of a single mode optical fiber (the diameter of a fiber core is 9 mu m, and the diameter of a cladding is 125 mu m) by 2cm, then wiping the coating layer with alcohol and cutting the end face of the coating layer flat by using an optical fiber cutter.
And 2, placing the single-mode optical fiber with the end face cut flat and wiped in an optical fiber coating machine, coating a layer of high-reflection film on one side of the cut flat, discharging the optical fiber by using an optical fiber fusion splicer to manufacture a microsphere, finally coating a layer of graphene on the optical fiber, wherein when light enters the optical fiber, part of the light of the fiber core can be leaked into the cladding to be transmitted when the light passes through the microsphere, the light passes through the right side of the microsphere and is coupled into the fiber core, the light in the cladding and the fiber core reaches the right end of the optical fiber and is reflected by the high-reflection film to continue to be transmitted, interference is formed when the light passes through the left end of the microsphere again, and the sensitivity of the sensor is improved through the.
The high-sensitivity optical fiber gas sensor based on the graphene characteristic is a reflective absorption spectrum sensor,、the intensity of the light reflected by the exit end face,、the light intensity entering the optical fiber is reflected by the high-reflection film interface, the four beams of reflected light reach the photoelectric detector to generate interference, and the output light intensity isCan be expressed as:
in the formula (I), the compound is shown in the specification,、-the intensity of the light reflected by the exit end face of the optical fiber;
,,,,,the intensity of the interference of the two incident light beams and the two reflected light beams.
By usingAndreflecting light from the end faces of the optical fiber, representing the core and cladding of the optical fiber, respectivelyAndto the phase of the detector, respectivelyAndindicating light reflected by the highly reflective film interface and entering the fiberAndto the phase of the detector.
In equation (1), the coherence term can be expressed as:
in the formula (I), the compound is shown in the specification,、fiber end-face reflection of core and claddingAndthe phase reaching the detector is a constant related to the coupling coefficient of the fiber coupler and the optical power injected into the photodetector.
Preferably, light is emitted from a light source and enters an optical fiber through a 3dB coupler, the light is split and leaked to a cladding layer through the middle of a fiber core of an optical fiber microsphere and is transmitted partially in the fiber core, the transmitted light is reflected by a high-reflection film when reaching the right end of the optical fiber and is continuously transmitted in the optical fiber, the light is coupled to form interference when passing through the left end of the optical fiber microsphere again, the graphene adsorbs external gas molecules, the gas molecules can be adsorbed on the surface of the graphene to serve as an electron donor or an electron acceptor, electric doping is formed, the electrical conductivity and the dielectric constant of the graphene are changed, the optical refractive index of the graphene is further influenced, a frequency spectrum pattern of the gas change can be observed at a receiving end, and the sensitivity can actually.
According to the invention, based on the Michelson interference principle structure of graphene characteristics, when light enters an optical fiber, the light is reflected by a high-reflection film and reaches the left end of an optical fiber microsphere to form interference. Graphene has strong adsorption capacity on external gas molecules, so that detection of gas to be detected is realized
The invention has the beneficial effects that: the invention relates to a graphene characteristic optical fiber gas sensor based on the Michelson interference principle, which adopts the optical fiber microsphere coupling principle, can realize real-time detection of gas to be detected by plating a high-reflection film and coating graphene, and simultaneously realizes strong anti-interference capability and high sensitivity. The method has wide application in coal mine gas explosion, environmental pollution and the like.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a diagram of a structure of an optical fiber microsphere with graphene characteristics;
fig. 2 shows a highly sensitive optical fiber gas sensor device based on graphene characteristics.
Detailed Description
All of the features disclosed in this specification, or all of the steps in any method or process so disclosed, may be combined in any combination, except combinations of features and/or steps that are mutually exclusive.
Any feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.
In the description of the present invention, it is to be understood that the terms "one end", "the other end", "outside", "upper", "inside", "horizontal", "coaxial", "central", "end", "length", "outer end", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, should not be construed as limiting the present invention.
Further, in the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the present invention, unless otherwise explicitly specified or limited, the terms "disposed," "sleeved," "connected," "penetrating," "plugged," and the like are to be construed broadly, e.g., as a fixed connection, a detachable connection, or an integral part; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
As shown in fig. 1, a method for researching a gas sensor based on graphene characteristics includes the following steps:
step 1, using an optical fiber stripper to strip off a coating layer of a single mode optical fiber (the diameter of a fiber core is 9 mu m, and the diameter of a cladding is 125 mu m) by 2cm, then wiping the coating layer with alcohol and cutting the end face of the coating layer flat by using an optical fiber cutter.
And 2, placing the single-mode optical fiber with the end face cut flat and wiped in an optical fiber coating machine, coating a layer of high-reflection film on one side of the cut flat, discharging the optical fiber by using an optical fiber fusion splicer to manufacture a microsphere, and finally coating a layer of graphene on the optical fiber, wherein as shown in figure 1, when light enters the optical fiber, part of the light of the fiber core can be leaked into a cladding for propagation when the light passes through the microsphere, the light passes through the right side of the microsphere and is coupled into the fiber core, the light in the cladding and the fiber core reaches the right end of the optical fiber and is reflected by the high-reflection film to continue propagation, interference is formed when the light passes through the left end of the microsphere again, and the sensitivity of the sensor is improved through the adsorption.
The high-sensitivity optical fiber gas sensor based on the graphene characteristic is a reflective absorption spectrum sensor,、the intensity of the light reflected by the exit end face,、the light intensity entering the optical fiber is reflected by the high-reflection film interface, the four beams of reflected light reach the photoelectric detector to generate interference, and the output light intensity isCan be expressed as:
in the formula (I), the compound is shown in the specification,、-the intensity of the light reflected by the exit end face of the optical fiber;
,,,,,the intensity of the interference of the two incident light beams and the two reflected light beams.
By usingAndreflecting light from the end faces of the optical fiber, representing the core and cladding of the optical fiber, respectivelyAndto the phase of the detector, respectivelyAndindicating light reflected by the highly reflective film interface and entering the fiberAndto the phase of the detector.
In equation (1), the coherence term can be expressed as:
in the formula (I), the compound is shown in the specification,、fiber end-face reflection of core and claddingAndthe phase reaching the detector is a constant related to the coupling coefficient of the fiber coupler and the optical power injected into the photodetector.
In a preferred embodiment of the present invention, as shown in fig. 2, light is emitted from a light source, enters an optical fiber through a 3dB coupler, is split and leaked to a cladding through the middle of a fiber core of an optical fiber microsphere, and is partially propagated in the fiber core, and when the transmitted light reaches the right end of the optical fiber, the transmitted light is reflected by a high-reflection film and is continuously propagated in the optical fiber, and is coupled to form interference again through the left end of the optical fiber microsphere, and the graphene adsorbs external gas molecules, so that the gas molecules can be adsorbed on the surface of the graphene to serve as an electron donor or an electron acceptor, and form electrical doping, which causes the electrical conductivity and the dielectric constant of the graphene to change, thereby affecting the optical refractive index thereof, and a spectrum pattern of the gas change can be observed at a receiving.
The high-sensitivity optical fiber gas sensing device based on the graphene characteristic can eliminate Fresnel reflection loss of the end face of an optical fiber, is compact in structure, easy to manufacture, high in coupling efficiency and high in sensitivity, and has application value in the fields of optical fiber coupling and sensing.
The specific mode of the invention is as follows:
(1) according to the requirements, the micro-sphere structures of the end faces of the optical fibers with different sizes are manufactured, and the high-reflection film with the best plating effect is selected.
(2) The single-mode optical fiber of the sensor structure with the graphene characteristics is connected with a broadband light source and a spectrum analyzer, and the light intensity of a receiving end in the spectrum analyzer is observed.
(3) And (3) researching the graphene with different coating processes, and judging the optimal coating effect by observing the light intensity of a receiving end in a spectrum analyzer.
The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that are not thought of through the inventive work should be included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope defined by the claims.
Claims (6)
1. A graphene characteristic-based gas sensor research method is characterized by comprising the following steps:
step 1, using an optical fiber stripper to strip off a coating layer of a single mode optical fiber (the diameter of a fiber core is 9 mu m, and the diameter of a cladding is 125 mu m) by 2cm, then wiping the coating layer with alcohol and cutting the end face of the coating layer flat by using an optical fiber cutter.
2. And 2, placing the single-mode optical fiber with the end face cut flat and wiped in an optical fiber coating machine, coating a layer of high-reflection film on one side of the cut flat, discharging the optical fiber by using an optical fiber fusion splicer to manufacture a microsphere, finally coating a layer of graphene on the optical fiber, wherein when light enters the optical fiber, part of the light of the fiber core can be leaked into the cladding to be transmitted when the light passes through the microsphere, the light passes through the right side of the microsphere and is coupled into the fiber core, the light in the cladding and the fiber core reaches the right end of the optical fiber and is reflected by the high-reflection film to continue to be transmitted, interference is formed when the light passes through the left end of the microsphere again, and the sensitivity of the sensor is improved through the.
3. The high-sensitivity optical fiber gas sensor based on the graphene characteristic is a reflective absorption spectrum sensor,、the intensity of the light reflected by the exit end face,、the light intensity entering the optical fiber is reflected by the high-reflection film interface, the four beams of reflected light reach the photoelectric detector to generate interference, and the output light intensity isCan be expressed as:
in the formula (I), the compound is shown in the specification,、-the intensity of the light reflected by the exit end face of the optical fiber;
4. By usingAndreflecting light from the end faces of the optical fiber, representing the core and cladding of the optical fiber, respectivelyAndto the phase of the detector, respectivelyAndindicating light reflected by the highly reflective film interface and entering the fiberAndto the phase of the detector.
5. In equation (1), the coherence term can be expressed as:
6. The graphene-based characteristic gas sensor research method according to claim 1, characterized in that: light is sent out from the light source and gets into the optic fibre through 3dB coupler, it leaks to propagate in the cladding through optic fibre microballon fibre core middle part split light, part propagates in the fibre core, it reflects back to continue to propagate in the optic fibre by the high anti-reflection coating when transmission light arrives the optic fibre right-hand member, the coupling forms the interference when once more passing through optic fibre microballon left end, graphite alkene adsorbs external gas molecule, can adsorb gas molecule and act as electron donor or acceptor on graphite alkene's surface, form the electricity and dope, lead to graphite alkene's conductivity and dielectric constant to change, and then influence its optical refractive index, can observe the frequency spectrum pattern of gas change at the receiving terminal.
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CN112362619A (en) * | 2020-11-12 | 2021-02-12 | 重庆理工大学 | Trace fluorine ion sensor and concentration detection device and method |
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