Dual-comb spectrometer and gas measurement system and method based on the spectrometer

Abstract

The present invention provides a dual-comb spectrometer and a gas measurement system and method based on the spectrometer. The spectrometer includes: a first femtosecond laser amplifier, a second femtosecond laser amplifier, and a signal light laser; a first pulse shaping module connected to the first femtosecond laser amplifier; a second pulse shaping module connected to the second femtosecond laser amplifier; and a dual-comb modulation module connected to the first pulse shaping module, the second pulse shaping module, and the signal light laser. The gas measurement system includes: a gas cell for containing the gas to be measured; a spectral detector and the dual-comb spectrometer disposed on opposite sides of the gas cell; and a data processing module connected to the spectral detector. The present invention can achieve rapid and accurate measurement of the gas to be measured.

Description

Technical Field

[0001] The present invention relates to the field of laser technology, and in particular, to a dual-comb spectrometer and a gas measurement system and method based on the spectrometer. Background Art

[0002] Monitoring and analyzing the performance of aero-engines is a necessary prerequisite for the manufacture and improvement of aero-engines. The combustion products of the engine are an important basis for analyzing and judging the engine performance and operating state. Therefore, the detection of the combustion gas products of aero-engines is particularly important for the design optimization of the engines.

[0003] The traditional measurement and analysis technology for pollutants emitted by aero-engines is the plug-in sampling analysis technology. This technology uses a sampling probe to collect the sample gas and transports the sample gas to different pollutant analysis instruments through a delivery pipe for detection. Among them, after the sample gas is taken out, it is first cooled to a suitable temperature and then kept warm to prevent heavier hydrocarbon compounds from condensing and adhering to the inner wall of the delivery pipe and changing the composition of the sample gas. At the same time, since the delivery pipe should be as short as possible to shorten the time for the sample gas to reach the analysis instrument. Common analysis instruments for gas pollutants include chemiluminescence analyzers, non-dispersive infrared analyzers, flame ionization detectors, etc. This traditional pollutant test system has a complex structure, the analysis instrument has a single function, cannot detect and analyze multiple pollutant components simultaneously, has a high measurement cost, and poor real-time performance.

[0004] In recent years, with the continuous development of optical measurement technologies and equipment, more and more optical equipment has been applied to the field of aero-engine measurement. Compared with traditional contact measurement means, laser spectroscopy measurement technology determines the type and content of substances by measuring the characteristic absorption spectrum or emission spectrum of gases, and has the characteristics of non-contact, large measurement range, high resolution, etc., which is very suitable for the measurement of pollutants in aero-engines.

[0005] Therefore, the present invention urgently needs to provide a solution for gas measurement based on laser spectroscopy measurement technology. Summary of the Invention

[0006] The purpose of the present invention is to provide a dual-comb spectrometer and a gas measurement system and method based on the spectrometer to achieve rapid and accurate measurement of different types of gases.

[0007] To achieve the above purpose, the present invention provides a dual-comb spectrometer, including:

[0008] A first femtosecond laser amplifier, a second femtosecond laser amplifier, and a signal light laser;

[0009] A first pulse shaping module connected to the first femtosecond laser amplifier;

[0010] A second pulse shaping module connected to the second femtosecond laser amplifier;

[0011] A dual-comb modulation module connected to the first pulse shaping module, the second pulse shaping module, and the signal light laser;

[0012] In a preferred embodiment of the present invention, the dual-comb modulation module includes:

[0013] A beam splitter connected to the signal light laser;

[0014] A first optical parametric amplifier connected to the first pulse shaping module and the beam splitter;

[0015] A second optical parametric amplifier connected to the second pulse shaping module and the beam splitter;

[0016] A combiner connected to the first optical parametric amplifier and the second optical parametric amplifier.

[0017] In a preferred embodiment of the present invention, the signal light laser is a mid-infrared continuous laser.

[0018] To achieve the above object, the present invention also provides a gas measurement system based on the foregoing dual-comb spectrometer, including:

[0019] A gas cell for containing the gas to be measured;

[0020] A spectral detector and the dual-comb spectrometer respectively disposed on opposite sides of the gas cell;

[0021] A data processing module connected to the spectral detector.

[0022] In a preferred embodiment of the present invention, the system further includes:

[0023] A gas sampling device connected to the gas cell through a delivery pipe.

[0024] In a preferred embodiment of the present invention, the gas sampling device is a sampling probe.

[0025] In a preferred embodiment of the present invention, the gas cell is provided with a temperature control module and / or a pressure control module.

[0026] In a preferred embodiment of the present invention, the gas to be measured is an aeroengine pollutant.

[0027] To achieve the above object, the present invention also provides a gas measurement method based on the foregoing gas measurement system, including:

[0028] Two optical frequency combs are generated by the dual-comb spectrometer, and the two optical frequency combs are combined, and the combined dual-comb is passed through a gas cell containing the gas to be measured;

[0029] The absorption spectrum lines of the gas to be measured are detected by the spectral detector;

[0030] The absorption spectrum lines detected by the spectral detector are processed by the data processing module to obtain the components and content of the gas to be measured.

[0031] In a preferred embodiment of the present invention, the generation of two optical frequency combs by the dual-comb spectrometer and the combination of the two optical frequency combs include:

[0032] The power of two femtosecond laser beams is amplified by the first femtosecond laser amplifier and the second femtosecond laser amplifier respectively to obtain two amplified femtosecond laser pulses;

[0033] The two amplified femtosecond laser pulses are pulse-shaped by the first pulse shaping module and the second pulse shaping module respectively to obtain two shaped laser pulses, which are used as pump lights respectively;

[0034] Signal light is generated by the signal light laser;

[0035] The signal light is split by the dual-comb modulation module, and each split signal light is optically parametrically amplified with a pump light respectively to obtain two optical frequency combs, and the two optical frequency combs are combined.

[0036] By adopting the above technical solutions, the present invention has the following beneficial effects:

[0037] The dual-comb spectrometer provided by the present invention has a simple structure, and by generating two optical frequency combs and combining them, the spectral resolution can be improved. Based on the measurement system of the dual-comb spectrometer, since it only needs to be realized by using a dual-comb spectrometer, a spectral detector and a data processing module, the measurement system is greatly simplified, the cost is effectively reduced, and at the same time, it is convenient to realize a miniaturized and portable design; at the same time, the present invention realizes a full-static design, without the mechanical arm scanning in traditional spectral measurement, the single measurement time reaches the ms level, the measurement accuracy is in the order of hundreds of MHz, the comb tooth accuracy reaches kHz, and high-speed, high-precision and high-resolution measurement can be realized; in addition, the present invention can measure multiple gases at the same time and has great application prospects in the field of aero-engine pollutant measurement. Description of the Drawings

[0038] Figure 1 It is a structural block diagram of the dual-comb spectrometer according to Embodiment 1 of the present invention;

[0039] Figure 2Schematic diagram of the installation of a part of the components in the gas measurement system according to Embodiment 2 of the present invention;

[0040] Figure 3 Schematic diagram of the installation of another part of the components in the gas measurement system according to Embodiment 2 of the present invention;

[0041] Figure 4 Flow chart of the gas measurement method according to Embodiment 3 of the present invention. Detailed implementation manners

[0042] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0043] The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. The singular forms "a", "the" and "said" used in the present disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0044] Embodiment 1

[0045] This embodiment provides a dual-comb spectrometer, as Figure 1 shown. The spectrometer 1 includes: a first femtosecond laser amplifier 11, a second femtosecond laser amplifier 12, and a signal light laser 13; a first pulse shaping module 14 connected to the first femtosecond laser amplifier 11; a second pulse shaping module 15 connected to the second femtosecond laser amplifier 12; and a dual-comb modulation module 16 connected to the first pulse shaping module 14, the second pulse shaping module 15, and the signal light laser 13.

[0046] The functions of the above-mentioned respective components will be described in detail below: The first femtosecond laser amplifier 11 and the second femtosecond laser amplifier 12 are respectively used to amplify the power of two paths of femtosecond lasers to obtain two paths of amplified femtosecond laser pulses with high power; the first pulse shaping module 14 and the second pulse shaping module 15 are respectively used to perform pulse shaping on the two paths of amplified femtosecond laser pulses to obtain two paths of ultrashort shaped laser pulses with a duration of about one hundred femtoseconds and high power, which are used as pump light; the signal light laser 13 is used to generate signal light, and the signal light laser 13 is preferably a mid-infrared continuous laser, which is used to generate mid-infrared continuous laser as signal light. The dual optical comb modulation module 16 is used to split the signal light, and perform optical parametric amplification processing on each path of the split signal light and one path of pump light respectively, so as to obtain two optical combs, and combine the two optical combs.

[0047] Refer again to Figure 1 In this embodiment, the dual optical comb modulation module 16 specifically includes: a beam splitter 161 connected to the signal light laser 13; a first optical parametric amplifier 162 connected to one of the output ends of the first pulse shaping module 14 and the beam splitter 161; a second optical parametric amplifier 163 connected to the other output end of the second pulse shaping module 15 and the beam splitter 161; and a combiner 164 connected to the first optical parametric amplifier 162 and the second optical parametric amplifier 163.

[0048] The working principle of the dual optical comb modulation module 16 in this embodiment is as follows: First, the mid-infrared continuous laser output by the signal light laser 13 is split into two paths by the beam splitter 161, and the two paths of laser light respectively enter the first optical parametric amplifier 162 and the second optical parametric amplifier 163 as the signal light in the optical parametric process; then, the first optical parametric amplifier 162 performs optical parametric amplification processing on the shaped laser pulse output by the first pulse shaping module 14 and one of the split signal lights to obtain one optical comb, and at the same time, the second optical parametric amplifier 163 performs optical parametric amplification processing on the shaped laser pulse output by the second pulse shaping module 15 and the other split signal light to obtain another optical comb; finally, the combiner 164 combines the two generated optical combs.

[0049] The dual optical comb spectrometer 1 provided in this embodiment has a simple structure, and by generating and combining two optical combs, the spectral resolution can be improved.

[0050] Embodiment 2

[0051] This embodiment provides a gas measurement system based on the aforementioned dual optical comb spectrometer 1, in combination with Figures 2-3As shown in the figure, the system includes: a gas sampling device (such as a sampling probe 2); a gas cell 4 connected to the gas sampling device through a delivery pipeline 3; a dual-comb spectrometer 1 and a spectral detector 5 respectively disposed on opposite sides of the gas cell 4; and a data processing module 6 connected to the spectral detector 5.

[0052] For example, when the gas measurement system of this embodiment is used for measuring pollutants in an aero-engine, the process is as follows: First, the sampled probe 2 samples the post-combustion gas to be measured at the outlet of the combustion chamber flame tube 7, and the gas to be measured is transported to the gas cell 4 through the delivery pipeline 3. At the same time, the dual-comb spectrometer 1 generates two optical combs and combines the two optical combs, and the combined dual-comb passes through the gas cell 4 containing the gas to be measured. Then, the spectral detector 5 detects the absorption spectral lines of the gas to be measured. Finally, the data processing module 6 analyzes and processes the absorption spectral lines detected by the spectral detector 5 to obtain the composition of the gas to be measured and the content of each component.

[0053] The measurement system of this embodiment is realized only by using the dual-comb spectrometer 1, the spectral detector 5 and the data processing module 6. The system is greatly simplified, effectively reducing the cost, and at the same time facilitating the realization of a miniaturized and portable design. At the same time, a fully static design is realized, eliminating the need for mechanical arm scanning in traditional spectral measurements. The single measurement time reaches the millisecond level, the measurement accuracy is in the order of hundreds of MHz, and the comb tooth accuracy reaches kHz, enabling high-speed, high-precision, and high-resolution measurements. The present invention can simultaneously measure multiple gases and has great application prospects in the field of measuring pollutants in aero-engines.

[0054] Preferably, the gas cell 4 in this embodiment is cylindrical, and the dual-comb spectrometer 1 and the spectral detector 5 are respectively disposed on opposite sides of the cylindrical gas cell 4. In addition, a temperature control module 8 and / or a pressure control module 9 are provided on the gas cell 4 to facilitate the control of the temperature and pressure in the gas cell 4. A gas outlet 41 is also provided on the gas cell 4 to facilitate the discharge of the gas to be measured.

[0055] Embodiment 3

[0056] This embodiment provides a gas measurement method based on the aforementioned gas measurement system, as Figure 4 shown, the method specifically includes the following steps:

[0057] S1, generate two optical combs by the dual-comb spectrometer 1 provided in Embodiment 1 and combine the two optical combs, and make the combined dual-comb pass through the gas cell 4 containing the gas to be measured;

[0058] S2, detect the absorption spectral lines of the gas to be measured by the spectral detector 5;

[0059] S3. The data processing module 6 analyzes and processes the absorption spectral lines detected by the spectral detector 5 to obtain the composition components of the gas to be measured and the content of each composition component.

[0060] Based on the specific structure of the dual-comb spectrometer 1 in Embodiment 1, step S1 is specifically implemented through the following steps:

[0061] S11. The first femtosecond laser amplifier 11 and the second femtosecond laser amplifier 12 respectively amplify the power of the two femtosecond lasers to obtain two amplified femtosecond laser pulses.

[0062] S12. The first pulse shaping module 14 and the second pulse shaping module 15 respectively perform pulse shaping on the two amplified femtosecond lasers to obtain two high-power ultrashort shaped laser pulses in the picosecond range as pump light.

[0063] S13. The signal light laser 13 generates signal light.

[0064] S14. The dual-comb modulation module 16 splits the signal light, and performs optical parametric amplification processing on each split signal light with a pump light respectively, thereby obtaining two optical combs and combining the two optical combs.

[0065] In this embodiment, by using the dual-comb spectrometer 1 for gas measurement, high-speed, high-precision, and high-resolution measurements can be achieved, and multiple gases can be measured simultaneously, which has great application prospects in the field of aero-engine pollutant measurement.

[0066] Although the specific implementation manners of the present invention have been described above, those skilled in the art should understand that this is only an example, and the protection scope of the present invention is defined by the appended claims. Without departing from the principles and essence of the present invention, those skilled in the art can make various changes or modifications to these implementation manners, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A dual-comb spectrometer, characterized in that, Comprising: A first femtosecond laser amplifier, a second femtosecond laser amplifier, and a signal light laser; A first pulse shaping module connected to the first femtosecond laser amplifier; A second pulse shaping module connected to the second femtosecond laser amplifier; A dual optical comb modulation module connected to the first pulse shaping module, the second pulse shaping module, and the signal light laser; The dual optical comb modulation module includes: A beam splitter connected to the signal light laser; A first optical parametric amplifier connected to the first pulse shaping module and the beam splitter; A second optical parametric amplifier connected to the second pulse shaping module and the beam splitter; A combiner connected to the first optical parametric amplifier and the second optical parametric amplifier.

2. The dual-comb spectrometer according to claim 1, wherein The signal light laser is a mid-infrared continuous laser.

3. A gas measurement system based on the dual-comb spectrometer according to any one of claims 1-2, characterized in that, Comprising: A gas cell for accommodating the gas to be measured; A spectral detector and the dual optical comb spectrometer respectively disposed on opposite sides of the gas cell; A data processing module connected to the spectral detector.

4. The gas measurement system according to claim 3, wherein The system further includes: A gas sampling device communicated with the gas cell through a delivery pipeline.

5. The gas measurement system according to claim 4, wherein The gas sampling device is a sampling probe.

6. The gas measurement system according to claim 3, wherein The gas cell is provided with a temperature control module and / or a pressure control module.

7. The gas measurement system according to claim 3, wherein The gas to be measured is an aero-engine pollutant.

8. A gas measurement method for the gas measurement system according to any one of claims 3-7, characterized in that, Comprising: Generating two optical combs through the dual optical comb spectrometer, combining the two optical combs, and passing the combined dual optical comb through a gas cell containing the gas to be measured; Detecting the absorption spectral lines of the gas to be measured through the spectral detector; Processing the absorption spectral lines detected by the spectral detector through the data processing module to obtain the composition and content of the gas to be measured.

9. The gas measurement method according to claim 8, wherein The generating two optical combs through the dual optical comb spectrometer and combining the two optical combs includes: Respectively power amplifying two femtosecond lasers through the first femtosecond laser amplifier and the second femtosecond laser amplifier to obtain two amplified femtosecond laser pulses; Respectively pulse shaping the two amplified femtosecond laser pulses through the first pulse shaping module and the second pulse shaping module to obtain two shaped laser pulses, respectively serving as pump lights; Generating signal light through the signal light laser; Splitting the signal light through the dual optical comb modulation module, respectively performing optical parametric amplification on each split signal light with a path of the pump light, thereby obtaining two optical combs, and combining the two optical combs.

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