CN113948971A - Quantum cascade laser, substance detection device and detection method thereof - Google Patents
Quantum cascade laser, substance detection device and detection method thereof Download PDFInfo
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- 239000000126 substance Substances 0.000 title claims abstract description 77
- 238000001514 detection method Methods 0.000 title claims abstract description 67
- 239000010931 gold Substances 0.000 claims abstract description 19
- 229910052737 gold Inorganic materials 0.000 claims abstract description 19
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims abstract description 18
- 238000012545 processing Methods 0.000 claims description 24
- 238000000034 method Methods 0.000 claims description 10
- 238000002310 reflectometry Methods 0.000 claims description 4
- 238000002834 transmittance Methods 0.000 claims description 2
- 238000010521 absorption reaction Methods 0.000 description 26
- 239000002360 explosive Substances 0.000 description 13
- WPYMKLBDIGXBTP-UHFFFAOYSA-N benzoic acid Chemical compound OC(=O)C1=CC=CC=C1 WPYMKLBDIGXBTP-UHFFFAOYSA-N 0.000 description 10
- 238000005516 engineering process Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 239000005711 Benzoic acid Substances 0.000 description 5
- 235000010233 benzoic acid Nutrition 0.000 description 5
- 239000004793 Polystyrene Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 229920002223 polystyrene Polymers 0.000 description 4
- 238000001228 spectrum Methods 0.000 description 4
- 238000000862 absorption spectrum Methods 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 3
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000001871 ion mobility spectroscopy Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 238000005033 Fourier transform infrared spectroscopy Methods 0.000 description 1
- 238000001069 Raman spectroscopy Methods 0.000 description 1
- 238000002835 absorbance Methods 0.000 description 1
- 238000004847 absorption spectroscopy Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
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- H01S5/00—Semiconductor lasers
- H01S5/40—Arrangement of two or more semiconductor lasers, not provided for in groups H01S5/02 - H01S5/30
- H01S5/4012—Beam combining, e.g. by the use of fibres, gratings, polarisers, prisms
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- 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
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- H01S5/00—Semiconductor lasers
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- H01S5/00—Semiconductor lasers
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Abstract
The invention provides a quantum cascade laser, which comprises N single-path quantum cascade lasers, a gold reflector and N-1 intermediate infrared wavelength beam combining sheets, wherein the N single-path quantum cascade lasers are connected with the gold reflector; the single-path quantum cascade laser is used for emitting laser, and the wavelength ranges of the laser emitted by each single-path quantum cascade laser are different; the gold reflector is used for reflecting the laser emitted by the corresponding single-path quantum cascade laser to obtain reflected laser; and the intermediate infrared wavelength beam combining sheet is used for transmitting the first laser, reflecting the second laser and combining the first laser and the second laser into coaxial light, the first laser comprises the reflected laser or the coaxial light combined by the previous intermediate infrared wavelength beam combining sheet, and the second laser comprises the laser emitted by the corresponding single-path quantum cascade laser. The invention also provides a substance detection device and a detection method thereof, which can accurately detect various substances.
Description
Technical Field
The invention relates to the technical field of laser remote sensing detection and the technical field of substance detection, in particular to a quantum cascade laser, a substance detection device and a detection method thereof.
Background
Since the 21 st century, many terrorist attacks have caused uneasiness in people around the world, and anti-terrorism has become one of the key concerns in various countries. How to detect explosives quickly and accurately becomes an important problem concerning national safety. With the emergence of new explosive varieties and the invention of new explosive technologies, the safety management problems caused by the new explosive varieties become more and more serious, and China, as a large population, has huge annual population flow, so that a rapid and accurate explosive detection system has very important values for transportation and national safety.
At present, explosive detection technologies adopted at home and abroad mainly include various spectral analysis technologies (FTIR), ion mobility spectrometry, raman spectroscopy, biosensing technologies and the like. The detection method is mainly divided into a contact type and a non-contact type. The ion mobility spectrometry technology is widely applied, but the detection speed is slow, and manpower and material resources are consumed. The laser absorption spectrum analysis technology based on the quantum cascade laser is used in the field of explosive detection and material detection, and has unique advantages: 1) some substances have different characteristic absorption peaks in an infrared band, and the characteristic absorption peaks are wider, while the quantum cascade laser has a wide gain spectrum of a middle and far infrared band, so that the component identification of different kinds of substances can be realized; 2) the quantum cascade laser has strong light intensity, high sensitivity and long detection distance; 3) the non-contact detection is used for preventing danger to detection personnel when harmful substances are detected; 4) the quantum cascade laser has wide tuning range, can cover a plurality of special absorption peak positions of explosives by combining the design of an external cavity light path and the like, is favorable for realizing accurate detection of the explosives, and avoids false detection caused by other chemical substances when a single absorption peak is detected.
Chinese patent application No. 201010583546.6 discloses a method for detecting trace gases by using direct absorption spectroscopy based on mid-infrared quantum cascade laser; the patent of application No. 20160415837.1 provides a hazardous chemical substance remote sensing detection device and method based on a wide tuning external cavity quantum cascade laser. However, the above methods all use a single laser as a light source, and realize substance detection in a certain waveband range, and cannot realize simultaneous detection in a large spectral range. However, there are several broad absorption peaks in some substance detection, different absorption peaks may be far apart, far exceeding the tuning range of a common laser, and false detection is easy to occur when a single absorption peak is used for detection.
In implementing the disclosed concept, the inventors found that there are at least the following problems in the related art: the single laser is a light source, the output wavelength range is limited, the material attribute is difficult to be accurately confirmed, and the condition of false detection is easy to occur.
Disclosure of Invention
To overcome at least one aspect of the above problems, the present disclosure provides a quantum cascade laser including:
n single-path quantum cascade lasers, a gold reflector and N-1 intermediate infrared wavelength beam combining sheets;
the single-path quantum cascade laser is used for emitting laser, and the wavelength ranges of the laser emitted by the single-path quantum cascade lasers are different;
the gold reflector is used for reflecting laser emitted by the corresponding single-path quantum cascade laser to obtain reflected laser;
the intermediate infrared wavelength beam combining sheet is used for transmitting first laser, reflecting second laser and combining the first laser and the second laser into coaxial light, the first laser comprises the coaxial light combined by the reflected laser or the previous intermediate infrared wavelength beam combining sheet, and the second laser comprises laser emitted by a corresponding single-path quantum cascade laser.
According to the embodiment of the disclosure, the mid-infrared wavelength beam combining sheet comprises a beam combining sheet dielectric film, the beam combining sheet dielectric film is transmissive to the first laser, and the transmissivity of the beam combining sheet dielectric film is greater than or equal to 90%; and reflecting the second laser, wherein the reflectivity is greater than or equal to 90%.
According to the embodiment of the disclosure, the external cavity of the single-path quantum cascade laser is a Littrow type external cavity.
According to the embodiment of the disclosure, the laser output by the single-channel external cavity quantum cascade laser is primary light.
According to an embodiment of the present disclosure, the display device further includes a visible light output device for outputting visible light.
According to the embodiment of the disclosure, the laser device further comprises a mid-infrared window sheet, wherein the mid-infrared window sheet is used for introducing the visible light into the coaxial light of the combined beam of the last mid-infrared wavelength combined beam sheet in the N-1 mid-infrared wavelength combined beam sheets and outputting third laser.
According to an embodiment of the present disclosure, the laser system further comprises a beam expander for expanding the beam of the third laser light.
The present disclosure also provides a substance detection device, comprising:
the system comprises a quantum cascade laser, a perforated off-axis parabolic mirror, a reflector, a low-temperature MCT detector and signal acquisition and processing equipment;
the quantum cascade laser is any one of the quantum cascade lasers;
the perforated off-axis parabolic mirror is used for passing third laser and converging fourth laser;
the reflector is used for reflecting the third laser carrying the information of the substance to be detected and outputting the fourth laser;
the low-temperature MCT detector is used for detecting and amplifying the converged signal of the fourth laser;
the signal acquisition and processing equipment is used for acquiring, analyzing and processing the signals.
The present disclosure also provides a substance detection method applied to the substance detection device as described above, including:
respectively emitting laser in different wavelength ranges by N single-path quantum cascade lasers, wherein the laser respectively irradiates a gold reflector or a mid-infrared wavelength beam combination sheet;
reflecting the laser emitted from the corresponding single-path quantum cascade laser through the gold reflector to obtain reflected laser;
transmitting a first laser through the intermediate infrared wavelength beam combining piece, reflecting a second laser, and combining the first laser and the second laser into coaxial light, wherein the first laser comprises the reflected laser or the coaxial light combined by the previous intermediate infrared wavelength beam combining piece, and the second laser comprises laser emitted by a corresponding single-path quantum cascade laser;
outputting visible light through a visible light output device;
reflecting the visible light and outputting third laser light through a mid-infrared window sheet;
transmitting the third laser to irradiate the surface of the substance to be detected through the perforated off-axis paraboloidal mirror, and converging the fourth laser;
reflecting the third laser carrying the information of the substance to be detected by a reflector, and outputting the fourth laser;
detecting and amplifying the converged signal of the fourth laser by a low-temperature MCT detector;
and acquiring, analyzing and processing the signals through signal acquisition and processing equipment.
According to an embodiment of the present disclosure, the beam of the third laser light is also expanded by a beam expander.
Based on the technical scheme, the method has the following beneficial effects:
the invention provides a quantum cascade laser, which comprises N single-path quantum cascade lasers, a gold reflector and N-1 intermediate infrared wavelength beam combining sheets; the single-path quantum cascade laser is used for emitting laser, and the wavelength ranges of the laser emitted by each single-path quantum cascade laser are different; the gold reflector is used for reflecting the laser emitted by the corresponding single-path quantum cascade laser to obtain reflected laser; and the intermediate infrared wavelength beam combining sheet is used for transmitting the first laser, reflecting the second laser and combining the first laser and the second laser into coaxial light, the first laser comprises the reflected laser or the coaxial light combined by the previous intermediate infrared wavelength beam combining sheet, and the second laser comprises the laser emitted by the corresponding single-path quantum cascade laser. The invention can output wide-range wave band by arranging a plurality of intermediate infrared wavelength beam combining sheets and a plurality of single-path quantum cascade lasers, and also provides a substance detection device and a detection method thereof, which can accurately detect the substance to be detected even if the characteristic absorption peak distribution of the substance is wide.
Drawings
For a more complete understanding of the present disclosure and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
fig. 1 is a graph of infrared absorption of explosive TNT;
fig. 2 is a schematic structural diagram of a quantum cascade laser of an embodiment of the disclosure;
FIG. 3 is a schematic structural diagram of a substance detection device according to an embodiment of the present disclosure;
FIG. 4 is a graph of the results of detecting benzoic acid using a substance detection method according to an embodiment of the present disclosure;
FIG. 5 is a graph of the results of detecting polystyrene using a substance detection method according to an embodiment of the present disclosure.
[ description of reference ]
1-gold reflector
2-mid-infrared wavelength beam combining sheet
3-visible light output device
4-mid-infrared window sheet
5-off-axis paraboloid mirror with hole
6-reflector
7-low temperature MCT detector
8-signal acquisition and processing equipment
9-single-path quantum cascade laser
Detailed Description
In order to make the objects, features and advantages of the present invention more obvious and understandable, the technical solutions in 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 only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The terms "comprises," "comprising," and the like, as used herein, specify the presence of stated features, steps, operations, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, or components.
All terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art unless otherwise defined. It is noted that the terms used herein should be interpreted as having a meaning that is consistent with the context of this specification and should not be interpreted in an idealized or overly formal sense.
The present invention will be described in detail with reference to the drawings, wherein for convenience of illustration, the drawings showing the structure of the device are not enlarged partially according to the general scale, and the drawings are only examples, which should not limit the scope of the invention. In addition, the three-dimensional dimensions of length, width and depth should be included in the actual fabrication.
Fig. 1 is a graph of infrared absorption of explosive TNT. Some substances often have a plurality of wide absorption peaks, and different absorption peaks are far apart and far exceed the detection range of a common laser. As shown in FIG. 1, explosive TNT has strong broad-spectrum characteristic absorption peaks at positions of 6.5 μm, 7.4 μm, 9.2 μm and the like. The common laser spectrum testing means can only detect a certain peak or a specific position of a certain peak position, so that false detection is easy to occur, for example, the absorption of ethanol, ether and the like at a position of 7.4 μm often interferes with the detection of explosive TNT.
Fig. 2 is a schematic structural diagram of a quantum cascade laser according to an embodiment of the present disclosure. In order to accomplish the detection of substances having multiple absorption peaks in an ultra-wide range. As shown in fig. 2, the present invention provides a quantum cascade laser, including:
n single-path quantum cascade lasers 9, a gold reflector 1 and N-1 intermediate infrared wavelength beam combining sheets 2; the single-path quantum cascade laser 9 is used for emitting laser, and the wavelength ranges of the laser emitted by each single-path quantum cascade laser 9 are different; the gold reflector 1 is used for reflecting the laser emitted by the corresponding single-path quantum cascade laser 9 to obtain reflected laser; and the intermediate infrared wavelength beam combining piece 2 is used for transmitting the first laser, reflecting the second laser and combining the first laser and the second laser into coaxial light, the first laser comprises the reflected laser or the coaxial light combined by the previous intermediate infrared wavelength beam combining piece 2, and the second laser comprises the laser emitted by the corresponding single-path quantum cascade laser 9.
N is an integer, a plurality of single-path quantum cascade lasers 9 emit laser, the laser sequentially passes through a gold reflector 1 and a mid-infrared wavelength beam combining sheet 2, wave bands in different wavelength ranges emitted by the plurality of single-path quantum cascade lasers 9 are combined by a wavelength beam combining method, and finally the combined beam is coaxial light with a very wide wavelength range.
The quantum cascade laser of the embodiment is provided with the plurality of mid-infrared wavelength beam combining sheets 2 and the plurality of single-path quantum cascade lasers 9 by a wavelength beam combining method, can output a wide range of wave bands, and provides a basis for realizing accurate detection of various substances.
As an optional embodiment, the mid-infrared wavelength beam combining sheet 2 includes a beam combining sheet dielectric film, in wavelength beam combining, the selection of the beam combining sheet dielectric film is crucial, and the beam combining sheet dielectric film needs to have different transmittances and reflectivities for laser beams with different wavelengths to achieve the beam combining effect. In the embodiment, the beam combining piece dielectric film is transmitted to the first laser and has the transmissivity of more than or equal to 90%; and reflecting the second laser, wherein the reflectivity is greater than or equal to 90%.
As an alternative embodiment, the external cavity of the single-channel quantum cascade laser 9 is a Littrow-type external cavity, and the output laser is a primary light. The common Littrow type external cavity is divided into two types, zero-order light output and first-order light output, in the rotating process of the blazed grating, the angle of the zero-order light output can change along with the rotating angle change of the blazed grating, so that the external light path can not be fixed, the first-order light is selected as the output light to be beneficial to the adjustment of a subsequent light path, the laser energy of the first-order light is larger, and therefore the single-path quantum cascade laser 9 of the Littrow type external cavity with the first-order light output is beneficial to the light path expansion of the subsequent multi-beam laser combination.
As an optional embodiment, the quantum cascade laser further includes a visible light output device 3 and a mid-infrared window sheet 4, the visible light output device 3 is configured to output visible light, the mid-infrared window sheet 4 is configured to introduce the visible light into the coaxial light combined by the last mid-infrared wavelength combining sheet 2 of the N-1 mid-infrared wavelength combining sheets 2 and output third laser light, and by setting the visible light output device and the mid-infrared window sheet 4, the visible light can be introduced into the coaxial light combined as reference light, which provides convenience for subsequent tests.
As an optional embodiment, the quantum cascade laser further includes a beam expander, configured to expand a light beam of the third laser, and when the quantum cascade laser is closer to the substance to be detected, a light spot of the output laser is smaller, which may cause a loss of the obtained information of the substance to be detected, so that the beam expander may be configured to expand the light spot of the laser, so that the laser can be uniformly irradiated on the entire substance to be detected; when the quantum cascade laser has a certain distance from a substance to be detected, because the laser output by the laser generally has a divergence angle, when the quantum cascade laser has a certain distance, the laser irradiates a larger light spot on the substance to be detected, and at the moment, a beam expander is not needed.
In this embodiment, the divergence angle of the collimated and combined coaxial light of the lens of the quantum cascade laser is less than 5mrad, and the peak power is more than 150 mW. The power supply of the quantum cascade laser can realize random switching, and the power-on requirement of a plurality of paths of lasers is met.
The quantum cascade laser of this embodiment, through setting up a plurality of one way quantum cascade lasers 9, a plurality of intermediate infrared wavelength that can transmit first laser reflection second laser and close beam piece 2, still quote visible light simultaneously as the reference light, can realize having the detection of the material of a plurality of absorption peaks in super wide range, provide the basis for accomplishing the accurate detection to various materials.
Fig. 3 is a schematic structural diagram of a substance detection device according to an embodiment of the present disclosure. The present embodiment is the same as the above description of fig. 2 except for the following. As shown in fig. 3, the present disclosure also provides a substance detection device comprising:
the system comprises a quantum cascade laser, a perforated off-axis parabolic mirror 5, a reflector 6, a low-temperature MCT detector 7 and a signal acquisition and processing device 8. The quantum cascade laser is any one of the quantum cascade lasers described above, and the description of the quantum cascade laser specifically refers to the description of fig. 2, which is not repeated herein.
The off-axis parabolic mirror 5 with the hole is used for passing the third laser and converging the fourth laser; the reflector 6 is used for reflecting the third laser carrying the information of the substance to be detected and outputting fourth laser; the low-temperature MCT detector 7 is used for detecting and amplifying the converged signal of the fourth laser, and the low-temperature MCT detector 7 comprises a signal amplifier, so that even if the acquired signal is weak, the weak signal can be amplified through the signal amplifier, and the subsequent signal can be identified conveniently; the signal acquisition and processing equipment 8 is used for acquiring and analyzing and processing signals, the signal acquisition and processing equipment 8 comprises a data acquisition card and data processing equipment, the data acquisition card is used for acquiring signals, meanwhile, the data are transmitted into the data processing equipment for signal analysis and processing, the signals are subjected to noise reduction processing by using hardware filtering and digital lock phase methods, the background spectrum is scanned, the acquired signals are scanned, information such as the absorption spectrum and the absorption coefficient of the substance to be detected can be obtained, the components of the substance to be detected can be analyzed according to the information, and the data of the information are processed to obtain the information such as the concentration of the substance to be detected.
The substance detection device of the embodiment integrates laser emission and reception, realizes automatic acquisition of substance information, can detect common intermediate infrared wave bands, has a detection range of 4-12 microns, meets the requirement of detection of substances with a plurality of absorption peaks in an ultra-wide range, and realizes accurate detection of various substances.
The present disclosure also provides a substance detection method applied to the substance detection device as described above, including:
emitting laser with different wavelength ranges to irradiate the gold reflecting mirror 1 or the mid-infrared wavelength beam combining sheet 2 through N single-path quantum cascade lasers 9 respectively; reflecting the laser emitted from the corresponding single-path quantum cascade laser 9 through the gold reflector 1 to obtain reflected laser; transmitting a first laser through the intermediate infrared wavelength beam combination sheet 2, reflecting a second laser, and combining the first laser and the second laser into a coaxial light, wherein the first laser comprises the reflected laser or the coaxial light combined by the previous intermediate infrared wavelength beam combination sheet 2, and the second laser comprises a laser emitted from a corresponding single-path quantum cascade laser 9; outputting visible light by the visible light output device 3; reflecting the visible light and outputting third laser light through the intermediate infrared window sheet 4; transmitting the third laser to irradiate the surface of the substance to be detected through the perforated off-axis paraboloidal mirror 5, and converging the fourth laser; reflecting the third laser carrying the information of the substance to be detected by a reflector 6, and outputting a fourth laser; detecting and amplifying the converged signal of the fourth laser by a low-temperature MCT detector 7; the signals are acquired and processed analytically by a signal acquisition and processing device 8.
The specific method of data processing is as follows:
fast Fourier transform is realized based on labview program, discrete Fourier transform of an input sequence is calculated, and the intensity value I of a stable echo signal can be obtained by locking the data after Fourier transform with the power frequency of the quantum cascade laser 90When the frequency is locked, instead of directly searching for an accurate frequency value corresponding to Fourier transform, a peak searching algorithm is performed near a target frequency (0.9f-1.1f) so as to lock the frequency, the digital phase lock reduces background noise, the final noise fluctuation is within 1%, and based on the Lambert-beer law, the direct relation is satisfied among the absorbance A, the gas absorption coefficient A, the gas concentration C and the effective absorption optical path L, and the specific formula is as follows:
scanning a background spectrum, then scanning the obtained signals to obtain information such as an absorption spectrum, an absorption coefficient and the like of a substance to be detected, analyzing components of the substance to be detected according to the information, and processing data of the information to obtain information such as concentration and the like of the substance to be detected, wherein the substance to be detected can be solid, liquid or gas; can be macromolecular substances or small molecular substances; it may be inorganic or organic.
As an optional embodiment, the beam of the third laser may be expanded by the beam expander, and when the quantum cascade laser 9 is closer to the substance to be measured, more comprehensive information of the substance to be measured may be obtained.
FIG. 4 is a graph of the results of detecting benzoic acid using a substance detection method according to an embodiment of the present disclosure; FIG. 5 is a graph of the results of detecting polystyrene using a substance detection method according to an embodiment of the present disclosure. In the present embodiment, since the substance to be measured is predicted, only a part of the single-pass quantum cascade laser 9 is turned on according to the distribution of the characteristic absorption peak of the substance to be measured. As shown in fig. 4 and 5, fig. 4 uses a substance detection method to detect benzoic acid, and as can be seen from fig. 4, the detection range of this example is 6.6-7.3 μm, and all characteristic absorption peaks of benzoic acid in the wavelength range of 6.7-7.2 μm are better detected, and the substance can be accurately confirmed to be benzoic acid from the positions and characteristics of the characteristic absorption peaks. FIG. 5 shows that the detection range of this example is 7.6-9, 3 μm, and all the characteristic absorption peaks of the polystyrene film in the wavelength range of 8.2-9.3 μm are better detected, and the material can be accurately confirmed to be the polystyrene film from the positions and characteristics of the characteristic absorption peaks, as can be seen from FIG. 4.
According to the substance detection method disclosed by the embodiment, laser with a wider wavelength range is output through a quantum cascade laser, the laser irradiates on a substance to be detected through the perforated off-axis parabolic mirror 5, is reflected through the reflector 6, and is converged to the perforated off-axis parabolic mirror 5, then converged to the low-temperature MCT detector 7, and finally transmitted to the signal acquisition and processing equipment 8, and specific information of the substance to be detected is finally obtained through data processing and analysis, so that the composition of the substance is judged, accurate detection of various substances is realized, and the problem of false detection possibly occurring during substance detection is solved.
It should be noted that the substance detection method portion in the embodiment of the present disclosure corresponds to the substance detection device portion in the embodiment of the present disclosure, and the description of the substance detection method portion specifically refers to the substance detection device portion, and is not repeated herein.
In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A quantum cascade laser, comprising:
n single-path quantum cascade lasers, a gold reflector and N-1 intermediate infrared wavelength beam combining sheets;
the single-path quantum cascade laser is used for emitting laser, and the wavelength ranges of the laser emitted by the single-path quantum cascade lasers are different;
the gold reflector is used for reflecting laser emitted by the corresponding single-path quantum cascade laser to obtain reflected laser;
the intermediate infrared wavelength beam combining sheet is used for transmitting first laser, reflecting second laser and combining the first laser and the second laser into coaxial light, the first laser comprises the coaxial light combined by the reflected laser or the previous intermediate infrared wavelength beam combining sheet, and the second laser comprises laser emitted by a corresponding single-path quantum cascade laser.
2. The quantum cascade laser of claim 1, wherein the mid-infrared wavelength beam combining sheet comprises a beam combining sheet dielectric film, the beam combining sheet dielectric film being transmissive to the first laser light and having a transmittance of greater than or equal to 90%; and reflecting the second laser, wherein the reflectivity is greater than or equal to 90%.
3. The quantum cascade laser of claim 1, wherein the external cavity of the single-pass quantum cascade laser is a Littrow-type external cavity.
4. The quantum cascade laser of claim 3, wherein the laser light output by the single-channel external cavity quantum cascade laser is primary light.
5. The quantum cascade laser of claim 1, further comprising a visible light output device for outputting visible light.
6. The quantum cascade laser of claim 5, further comprising an intermediate infrared window slice, wherein the intermediate infrared window slice is configured to introduce the visible light into the coaxial light of the last intermediate infrared wavelength beam combining slice of the N-1 intermediate infrared wavelength beam combining slices and output a third laser.
7. The quantum cascade laser of claim 6, further comprising a beam expander to expand the beam of the third laser.
8. A substance detection device, comprising:
the system comprises a quantum cascade laser, a perforated off-axis parabolic mirror, a reflector, a low-temperature MCT detector and signal acquisition and processing equipment;
the quantum cascade laser is the quantum cascade laser as set forth in any one of claims 1 to 7;
the perforated off-axis parabolic mirror is used for passing third laser and converging fourth laser;
the reflector is used for reflecting the third laser carrying the information of the substance to be detected and outputting the fourth laser;
the low-temperature MCT detector is used for detecting and amplifying the converged signal of the fourth laser;
the signal acquisition and processing equipment is used for acquiring, analyzing and processing the signals.
9. A substance detection method applied to the substance detection device according to claim 8, comprising:
respectively emitting laser in different wavelength ranges by N single-path quantum cascade lasers, wherein the laser respectively irradiates a gold reflector or a mid-infrared wavelength beam combination sheet;
reflecting the laser emitted from the corresponding single-path quantum cascade laser through the gold reflector to obtain reflected laser;
transmitting a first laser through the intermediate infrared wavelength beam combining piece, reflecting a second laser, and combining the first laser and the second laser into coaxial light, wherein the first laser comprises the reflected laser or the coaxial light combined by the previous intermediate infrared wavelength beam combining piece, and the second laser comprises laser emitted by a corresponding single-path quantum cascade laser;
outputting visible light through a visible light output device;
reflecting the visible light and outputting third laser light through a mid-infrared window sheet;
transmitting the third laser to irradiate the surface of the substance to be detected through the perforated off-axis paraboloidal mirror, and converging the fourth laser;
reflecting the third laser carrying the information of the substance to be detected by a reflector, and outputting the fourth laser;
detecting and amplifying the converged signal of the fourth laser by a low-temperature MCT detector;
and acquiring, analyzing and processing the signals through signal acquisition and processing equipment.
10. The substance detecting method according to claim 9, wherein a beam of the third laser light is also expanded by a beam expander.
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