Spectrum baseline calibration device and method based on time resolution

Abstract

The invention discloses a time resolution-based spectrum baseline calibration device and method, and the device comprises a cross flexible bearing uniaxial reflection galvanometer which is used for alternately generating measurement laser and reference laser from laser beams; the driving controller is used for controlling the cross flexible bearing uniaxial reflection galvanometer to periodically rotate; the detection assembly is used for alternately detecting the reference laser and the measurement laser after passing through the sample pool; and the processing assembly is used for processing output signals of the detection assembly, and the output signals comprise a first output signal corresponding to the reference laser and a second output signal corresponding to the measurement laser passing through the sample pool. The laser is divided into the measuring laser and the reference laser through the reflection galvanometer, so that the power change of the measuring laser and the reference laser caused by the change of a light splitting curve of the transmission-type optical element is prevented; reflection-type light splitting can ensure that the power change trends of the measurement laser and the reference laser are consistent, and the purpose of accurately calibrating a base line is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of laser spectrum measurement, and in particular relates to a spectrum baseline calibration device based on time resolution and a method thereof. Background Art

[0002] Spectroscopy mainly studies the interaction between light and matter. It has the characteristics of non-contact and non-damage to the measured object, and is typically used in astronomical observations, combustion diagnosis, satellite remote sensing, etc. It can be said that spectroscopy has become a powerful technical means for humans to explore the world.

[0003] However, since the collected spectral signals often contain baselines and noise, which greatly interfere with the retrieval and identification of spectral features, it is necessary to use preprocessing methods to eliminate the effects of these interferences. There are many methods for baseline measurement, such as frequency analysis, polynomial curve fitting, etc.

[0004] Frequency analysis considers the baseline to be a slowly changing low-frequency signal, and the spectral peak to be a relatively fast-changing high-frequency signal. The signal and the baseline are separated by different frequency characteristics. However, this method requires reasonable classification of low-frequency and high-frequency signals. Incorrect screening will lead to signal distortion.

[0005] Polynomial curve fitting adopts the least square fitting principle, and achieves the purpose of fitting the baseline based on the minimum mean square error of the fitting data points and the original data points. During fitting, the original data points where the absorption peak is located are shielded, and the remaining data points are used to fit the baseline using the internal extrapolation method, thereby separating the baseline from the measured signal. However, this method may have inaccurate fitting when dealing with irregular baselines.

[0006] The reference signal acquisition is to collect a spectrum without absorption as a reference signal. The reference signal is consistent with the test signal except that it does not contain absorption characteristics. The reference signal is then subtracted from the test signal to obtain the characteristic absorption spectrum. The reference signal acquisition method can overcome the baseline jitter caused by environmental interference such as light source fluctuations, and is very suitable for situations where the baseline is difficult to describe with a continuous function. Summary of the invention

[0007] In order to solve the above technical problems, the present invention proposes a spectral baseline calibration device and method based on time resolution, and the specific technical solution is as follows: On one hand, the present invention provides a spectral baseline calibration device based on time resolution, characterized in that it includes: Cross-flexure bearing single-axis reflective galvanometer, used to generate the laser beam alternately into measurement laser and reference laser; A driving controller, used for controlling the cross-flexible bearing uniaxial reflection galvanometer to rotate periodically; A detection component, used for alternately detecting the reference laser and the measurement laser after the measurement laser passes through the sample cell; A processing component is used to process the output signal of the detection component, wherein the output signal includes a first output signal corresponding to the reference laser and a second output signal corresponding to the measurement laser after passing through a sample cell.

[0008] The device as described above further comprises: A wavelength tunable laser is used to emit the laser beam and support the formation of a scanning spectrum line.

[0009] The device as described above further comprises the following: A reference laser light path adjustment component, used for adjusting the light path of the reference laser so that the reference laser can be detected by the detection component; The measuring laser light path adjustment component is used to adjust the light path of the measuring laser passing through the sample cell so that the measuring laser can be detected by the detection component.

[0010] In the device as described above, further, the measuring laser light path adjustment components are multiple groups, and each group of the measuring laser light path adjustment components is used to adjust the laser light path passing through the corresponding sample cell.

[0011] The device as described above, further, the reference laser light path adjustment component also includes a first off-axis parabolic reflector, which is used to focus the reference laser input to the first off-axis parabolic reflector; The measuring laser optical path adjustment component also includes a second off-axis parabolic reflector, which is used to focus the laser input to the second off-axis parabolic reflector.

[0012] In the device as described above, further, the detection component includes a pinhole aperture and a photodetector, the pinhole aperture is used to limit the size of the reference laser and the measurement laser input to the target surface of the photodetector in the detection component, and the photodetector is used to alternately detect the reference laser and the measurement laser.

[0013] In the device as described above, further, the measurement laser and the reference laser have the same frequency, and the frequency range is 1 Hz to 250 Hz.

[0014] In the device as described above, further, the drive controller controls the cross-flexure bearing uniaxial reflection galvanometer to periodically rotate within an angle range of ±10°.

[0015] Another aspect of the present invention provides a method for using the above-mentioned spectral baseline calibration device based on time resolution, comprising: The wavelength tunable laser is modulated to a first set frequency value, and the driving controller controls the cross-flexure bearing single-axis reflective galvanometer to rotate periodically at a second set frequency; The detection component detects the reference laser and the measurement laser passing through the sample cell alternately; The processing component obtains the output signal of the detection component, wherein the output signal includes a first output signal corresponding to the reference laser and a second output signal corresponding to the measurement laser passing through the sample pool; the first output signal is subtracted from the second output signal to correct the baseline disturbance generated during the spectral signal measurement process.

[0016] The method as described above, further, before the driving controller controls the cross-flexure bearing uniaxial reflection galvanometer to periodically rotate at a second set frequency, further comprises: Obtaining the center frequency of the absorption spectrum of the target detection material, and determining the frequency of the wavelength tunable laser as the first set frequency value; Obtain the response bandwidth of the detector and determine the second set frequency value under the premise that the collected signal is not distorted.

[0017] The advantages of the present invention are: (1) Compared with traditional mechanical bearings, the cross-flexure bearings used in the single-axis reflective galvanometer in this application eliminate errors caused by noise and lubrication, reduce component wear, and enable smoother and more precise motion.

[0018] (2) The present invention can solve the measurement error caused by laser power fluctuation in the wavelength tunable laser in the gas concentration measurement system. By real-time detection of the reference laser and the measurement laser, the baseline jitter can be effectively suppressed. In the spectroscopic process, reflective optics are used to eliminate the system error caused by the interference structure that may be formed by the transmission element, thereby achieving the purpose of improving the signal detection sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of a spectral baseline calibration device based on time resolution of the present invention.

[0020] Figure 2 In the embodiment of the present invention, a spectral baseline calibration device based on time resolution simultaneously detects a first output signal and a second output signal obtained when a light source is fixed in frequency.

[0021] Figure 3 The first output signal and the second output signal detected by the spectral baseline calibration device based on time resolution in the embodiment of the present invention are compared under the condition of light source frequency modulation.

[0022] Figure 4The figure is a flow chart of a spectral baseline calibration method based on time resolution in an embodiment of the present invention.

[0023] In the figure: 1. Wavelength tunable laser; 2. Cross-flexure bearing single-axis reflective galvanometer; 3. First plane reflector; 4. Second plane reflector; 5. Third plane reflector; 6. First off-axis parabolic reflector; 7. Fourth plane reflector; 8. Fifth plane reflector; 9. Sixth plane reflector; 10. Sample cell; 11. Second off-axis parabolic reflector; 12. Pinhole aperture; 13. Photodetector; 14. AD acquisition card; 15. Host computer; 16. Drive controller. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application. In the description of the embodiments of the present application, it should be understood that the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0025] Glossary: The cross-flexure bearing single-axis reflective galvanometer is mainly composed of a reflective galvanometer and a cross-flexure bearing. The reflective galvanometer is its key component, used to reflect the light beam, usually has a high-precision optical plane, can effectively reflect the incident light, and the surface quality of the reflective galvanometer (such as flatness, finish, etc.) will directly affect the quality of the light beam after reflection.

[0026] In the prior art, there is also a method for removing noise from the collected spectral signal and retaining the baseline, and a reference signal acquisition technology. The current reference signal acquisition technology is to simultaneously collect a spectrum without absorption as a reference signal. Except for not containing the absorption feature, the other conditions of the reference signal are consistent with the test signal. The reference signal is then subtracted from the test signal to obtain a characteristic absorption spectrum. The reference signal acquisition method can overcome the baseline jitter caused by environmental interference such as light source fluctuations, and is very suitable for situations where the baseline is difficult to describe with a continuous function.

[0027] The inventors have found that in the existing reference signal acquisition technology, the laser light source is divided into the measurement laser and the reference laser through an optical fiber splitter or a splitting element (including power splitting and polarization splitting). This method is very accurate for the measurement when using a non-tuned laser light source, but because the transmissive optical element is used as the splitting method, it is difficult to keep the splitting ratio of laser light sources of different frequencies constant, so it becomes inaccurate for the measurement when using a tunable laser light source.

[0028] In order to improve the accuracy of spectral baseline measurement, Figure 1 As shown, the present application discloses a spectral baseline calibration device based on time resolution, comprising: A cross-flexure bearing single-axis reflective galvanometer 2 is used to generate a measuring laser and a reference laser alternately from the laser beam; A driving controller 16, used for controlling the cross-flexure bearing uniaxial reflection galvanometer 2 to rotate periodically; A detection component, used for alternately detecting the reference laser and the measurement laser after the measurement laser passes through the sample cell 10; The processing component is used to process the output signal of the detection component, wherein the output signal includes a first output signal corresponding to the reference laser and a second output signal corresponding to the measurement laser after passing through the sample cell 10 .

[0029] The spectral baseline calibration device based on time resolution of the present invention is suitable for gas measurement in complex measurement environments where the light source power fluctuates irregularly, the ambient temperature changes, and optical interference is easily generated. Compared with the prior art, the present invention effectively solves the measurement error caused by the irregular fluctuation of laser power in the gas concentration measurement system. The same photodetector 13 detects the measurement laser and the reference laser generated by the split light, measures the absorption signal and the reference signal almost simultaneously, and calibrates the spectral baseline, thereby ensuring the synchronization of the two data sources, and can effectively suppress the problem of laser power fluctuation.

[0030] The present invention divides the laser into a measuring laser and a reference laser by a reflective galvanometer in a cross-flexible bearing single-axis reflective galvanometer 2, thereby preventing the power variation of the measuring laser and the reference laser caused by the variation of the spectral curve of the transmission optical element; the reflective spectroscopy can ensure that the power variation trend of the measuring laser and the reference laser is consistent, thereby achieving the purpose of accurately calibrating the baseline. Compared with traditional mechanical bearings, since the flexible element rigidly couples a single axis, the movement in the orthogonal direction is reduced. The cross-flexible bearing design has less wear, smaller positioning error, and higher repeatability.

[0031] The present invention takes into account the disadvantage of the existing spectroscope that produces two laser beams, and on this basis integrates the advantages of the reflective galvanometer in the cross-flexible bearing single-axis reflective galvanometer 2, and invents a reflective spectroscopic model. The device of the present invention has a simple structure, and a single beam of laser realizes the measurement of the absorption signal and the reference signal, so that the system measurement is not easily affected by external factors, and has high applicability; the reflective galvanometer in the cross-flexible bearing single-axis reflective galvanometer 2 is used to divide the laser emitted by the wavelength tunable laser 1 into a measurement laser and a reference laser. During the transmission and splitting process of the laser after the galvanometer, there is no complex interference structure caused by the transmission element, which eliminates the system error caused by complex interference; and unlike the optical fiber splitter / optical fiber coupler, there is no return loss, additional loss and insertion loss, which effectively improves the laser power utilization efficiency; the possible polarization loss is also consistent and fixed for the measurement laser and the reference laser, and the working performance is basically not affected by temperature changes, which is suitable for gas measurement.

[0032] In another embodiment, the device further comprises a wavelength tunable laser 1 for emitting the laser beam and supporting the formation of a scanning spectrum line.

[0033] In one embodiment, the device further comprises a reference laser optical path adjustment component and a measuring laser optical path adjustment component of the same specification, quantity and type. The reference laser optical path adjustment component is used to adjust the optical path of the reference laser so that the reference laser can be detected by the detection component; the measuring laser optical path adjustment component is used to adjust the optical path of the measuring laser passing through the sample cell 10 so that the measuring laser can be detected by the detection component.

[0034] In this embodiment, the specifications, quantity and type of the reference laser optical path adjustment component and the measuring laser optical path adjustment component are the same, ensuring that outside the absorption region, the baseline and noise in the second output signal are completely consistent with the baseline and noise of the first output signal portion formed by the reference optical path, that is, achieving the purpose of achieving nearly consistent characteristics of the two signals except for the absorption characteristics of the sample to be measured.

[0035] In one of the embodiments, the reference laser optical path adjustment component includes a first plane reflector 3, a second plane reflector 4, and a third plane reflector 5 arranged in sequence according to the optical path, and the light beam output to the reference laser optical path after passing through the cross-flexure bearing uniaxial reflection galvanometer 2 sequentially changes the optical path through the first plane reflector 3, the second plane reflector 4, and the third plane reflector 5. The light beam output to the reference laser optical path after passing through the cross-flexure bearing uniaxial reflection galvanometer 2 sequentially changes the optical path through the first plane reflector 3, the second plane reflector 4, and the third plane reflector 5.

[0036] Similarly, the measuring laser optical path adjustment component includes a fourth plane reflector 7, a fifth plane reflector 8 and a sixth plane reflector 9 arranged in sequence according to the optical path, and the light beam output to the measuring laser optical path after passing through the cross-flexure bearing uniaxial reflection galvanometer 2 changes the optical path in sequence through the fourth plane reflector 7, the fifth plane reflector 8 and the sixth plane reflector 9. The light beam output to the measuring laser optical path after passing through the cross-flexure bearing uniaxial reflection galvanometer 2 changes the optical path in sequence through the first plane reflector 3, the second plane reflector 4 and the third plane reflector 5.

[0037] In one of the embodiments, the reference laser optical path adjustment component further includes a first off-axis parabolic reflector 6, which is used to focus the reference laser input to the first off-axis parabolic reflector 6; The measuring laser optical path adjustment component further includes a second off-axis parabolic reflector 11 , which is used to focus the measuring laser input to the second off-axis parabolic reflector 11 .

[0038] In this embodiment, the arrangement of the plane reflector can be adapted to the layout of the components in the overall device by changing the optical path to adjust the optical path, and ensure that the final photodetector 13 can detect two lasers. The geometric shapes of the first off-axis parabolic reflector 6 and the second off-axis parabolic reflector 11 conform to the shape of a parabola rotated around an axis and then cut. According to the optical properties of the parabola, the light parallel to the axis of symmetry will converge at the focus after being reflected by the parabola, and will not produce spherical aberration and chromatic aberration.

[0039] In one embodiment, the measuring laser light path adjustment components are multiple groups, and each group of the measuring laser light path adjustment components is used to adjust the laser light path passing through the corresponding sample pool 10. This solution can realize multi-path detection. Within the amplitude range of the cross-flexure bearing single-axis reflection galvanometer 2, by setting multiple groups of measuring laser light path adjustment components, each group of measuring laser light path adjustment components is used to adjust the laser light path passing through the corresponding sample pool 10, and a reference signal can be used to simultaneously carry out the measurement of multiple gases. The device has a simple structure and good expandability, and there is no structure that is prone to interference when setting transmission elements in multiple light paths.

[0040] In one embodiment, the detection component includes a pinhole aperture 12 and a photodetector 13, the pinhole aperture 12 is used to limit the size of the reference laser and the measurement laser input to the target surface of the photodetector 13 in the detection component, and the photodetector 13 is used to alternately detect the reference laser and the measurement laser.

[0041] In one embodiment, the frequency of the measuring laser and the reference laser is the same, and the frequency range is 1 Hz to 250 Hz. The rotation frequency in this range can match detectors with different response bandwidths and adapt to a wider range of application requirements. By detecting the first output signal and the second output signal of the tunable wavelength tunable laser 1 at different wavelengths, a spectral curve (such as Figure 3 To achieve the calibration of the spectral baseline. Figure 3 Middle 0.5cm -1 The reference laser and measurement laser measurement values ​​(absorption-free area) vary with the laser frequency (first set frequency value) within the range. In the specific case, the frequency of the periodic rotation of the cross-flexure bearing single-axis reflection galvanometer 2 can be selected from 1Hz, 10Hz, 50Hz, 80Hz, 100Hz, 165Hz, 200Hz, 250Hz. In one embodiment, the drive controller 16 controls the cross-flexible bearing uniaxial reflection galvanometer 2 to periodically rotate at a frequency ranging from 0.1 Hz to 250 Hz. The inherent vibrations of some devices can be avoided. In addition, slower frequencies are suitable for light beams with lower power. The light beam passes through the aperture for a longer time, which is convenient for peak finding. The drive controller 16 adjusts the frequency of time-division multiplexing of the measuring laser and the reference laser during the measurement process by changing the rotation frequency of the cross-flexible bearing reflection galvanometer. The cross-flexible bearing reflection galvanometer continuously changes the reflection angle of the laser generated by the wavelength tunable laser 1 at a fixed frequency in the range of 0.1 Hz to 250 Hz, so that the photodetector 13 obtains the first output signal almost at the same time as obtaining the second output signal.

[0042] It should be noted that a higher frequency requires a higher response bandwidth of the photodetector 13. Figure 2 If the absorption signal or the double peak value of the reference signal in the image has high and low changes, a photodetector 13 with a higher detection bandwidth should be used to avoid signal distortion caused by insufficient response of the photodetector 13. In the specific case, the frequency of the periodic rotation of the cross-flexure bearing single-axis reflection galvanometer 2 can be selected from 0.1Hz, 10Hz, 50Hz, 80Hz, 100Hz, 165Hz, 200Hz, and 250Hz. In one embodiment, the driving controller 16 controls the cross-flexible bearing uniaxial reflection galvanometer 2 to periodically rotate within an angle range of ±10°. The separation angle of the two light beams is relatively large, which is suitable for the placement of other optical elements. If the angle is too low, a very long transmission path is required to achieve a certain separation angle, which is not conducive to the conduct of the experiment. This angle can facilitate the conduct of the experiment while satisfying the placement of other optical elements. The cross-flexible bearing uniaxial reflection galvanometer 2 guides the laser light source directly to the reference laser light path at a certain reflection angle, and uses the photodetector 13 to measure the laser intensity in real time (equivalent to real-time measurement of the target laser power); similarly, the laser light source is guided to the measurement laser light path, so that after passing through the sample pool 10 to be tested, it is incident on the photodetector 13 to realize absorption signal measurement.

[0043] In one embodiment, the processing component includes a connected AD acquisition card 14 and a host computer 15, wherein the AD acquisition card 14 is used to acquire the signal detected by the photodetector 13, and the host computer 15 is used to process the signal data acquired by the AD acquisition card 14. The host computer 15 is also connected to the drive controller 16 and the controlled end of the wavelength tunable laser 1, and is used to input a first control signal for controlling the rotation frequency and / or swing angle of the cross-flexure bearing single-axis reflection galvanometer 2 to the drive controller 16 and a second control signal for inputting the laser frequency to the wavelength tunable laser 1.

[0044] The device uses a driving controller 16 to control the rotation frequency of the cross-flexible bearing single-axis reflective galvanometer 2, so that the laser emitted by the wavelength tunable laser 1 is alternately and periodically modulated into a measuring laser and a reference laser; after the measuring laser is reflected by a plurality of plane reflectors in the measuring laser optical path adjustment component and enters the sample pool 10, it is focused on the photodetector 13 by the second off-axis parabolic mirror to detect the second output signal carrying the sample information in the sample pool 10; the reference laser is reflected by the plane reflector in the reference laser optical path adjustment component, and then focused on the sensor by the first off-axis parabolic mirror to measure the first output signal. The periodic time domain signal of the photodetector 13 is obtained through the AD acquisition card 14, and the first output signal and the second output signal are retrieved, and then the first output signal is subtracted from the second output signal, so as to correct the baseline disturbance caused by the optical power fluctuation in the process of spectral signal measurement and improve the accuracy of spectral measurement.

[0045] Based on the same application concept, Figure 4 As shown, the embodiment of the present application also proposes a spectral baseline calibration method based on time resolution, including: The wavelength tunable laser is modulated to a first set frequency value, and the driving controller controls the cross-flexure bearing single-axis reflective galvanometer to rotate periodically at a second set frequency; The detection component detects the reference laser and the measurement laser passing through the sample cell alternately; The processing component obtains the output signal of the detection component, wherein the output signal includes a first output signal corresponding to the reference laser and a second output signal corresponding to the measurement laser passing through the sample pool; the first output signal is subtracted from the second output signal to correct the baseline disturbance generated during the spectral signal measurement process.

[0046] Since the frequency of the wavelength tunable laser 1 is determined by the center frequency of the absorption spectrum, the scanning range is determined by the spectrum width, and the frequency of the spectrum scanning is determined by the single sampling time of the entire system, which cannot be faster than the single sampling time. The center frequency of the absorption spectrum can be queried according to existing databases, such as the HITRAN database.

[0047] In one embodiment, the wavelength tunable laser 1 is modulated to a first set frequency value so that its single scanning interval can cover the measured absorption spectrum range, and the driving controller 16 controls the cross-flexible bearing uniaxial reflection galvanometer 2 to rotate periodically at a second set frequency to match the detector bandwidth.

[0048] In one embodiment, the wavelength tunable laser 1 is modulated to a first set frequency value, and before the driving controller 16 controls the cross-flexure bearing uniaxial reflective galvanometer 2 to periodically rotate at a second set frequency, the process further includes: Obtaining the center frequency of the absorption spectrum of the target detection material, and determining the frequency of the wavelength tunable laser 1 as the first set frequency value; Obtain the response bandwidth of the detector and determine the second set frequency value under the premise that the collected signal is not distorted.

[0049] Taking a specific case as an example, we found that 7080.58cm -1 There is an isolated spectral line with high absorption intensity of water vapor molecules at 7080.58cm -1 As the center frequency, ±0.5cm -1 As the spectrum line scanning range (to ensure that the spectrum line is completely scanned and collected), that is, the first set frequency value is 7080.08cm -1 ~7081.08cm -1 The sampling points are spaced evenly within the range (e.g., wavelength tunable laser 1 is spaced every 0.05 cm -1 The reflection galvanometer uses the second set frequency value to alternately form reference laser and absorption laser, which are finally received by the detection signal. The selection of the second set frequency value is based on the principle of matching the detector response bandwidth. Specifically, the appropriate reflection galvanometer rotation frequency is selected according to the size of the detector bandwidth to ensure that Figure 2The ① peak and ② peak of the reference laser are equal and the ③ peak and ④ peak of the measuring laser are equal. On the contrary, if the ① peak and the ② peak or the ③ peak and the ④ peak are not equal, the second set frequency value should be appropriately reduced or the detector response bandwidth should be increased. Figure 2 The detection signal at the single first set frequency value is 5Hz, and the second set frequency value is 5Hz to match the 5kHz response bandwidth of the detector. In addition, to ensure the reliability of peak classification, the measurement laser intensity is slightly weaker than the reference laser.

[0050] In summary, each time the wavelength tunable laser 1 moves to a first set frequency value, data acquisition is performed, and the 7080.08 cm -1 ~7081.08cm -1 All preset first set frequency values ​​are recorded and analyzed, and the single-point measurement laser signal and the reference laser signal under each first set frequency value are recorded and analyzed. Finally, the absorption spectrum minus the baseline effect is plotted with the first set frequency value as the horizontal axis and the ratio of the measurement laser signal to the reference laser signal as the vertical axis.

[0051] In the description of this specification, the description with reference to the terms "some embodiments" or "examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0052] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any technician in the relevant technical field, without departing from the scope of the technical solution of the present invention, makes any form of equivalent replacement or modification to the technical solution and technical content disclosed in the present invention, which does not depart from the content of the technical solution of the present invention and still falls within the protection scope of the present invention.

Claims

1. A spectral baseline calibration device based on time resolution, characterized in that: include: Cross-flexure bearing single-axis reflective galvanometer, used to generate the laser beam alternately into measurement laser and reference laser; A driving controller, used for controlling the cross-flexible bearing uniaxial reflection galvanometer to rotate periodically; A detection component, used for alternately detecting the reference laser and the measurement laser after the measurement laser passes through the sample cell; A processing component is used to process the output signal of the detection component, wherein the output signal includes a first output signal corresponding to the reference laser and a second output signal corresponding to the measurement laser after passing through a sample cell.

2. The device according to claim 1, characterized in that Also includes: A wavelength tunable laser is used to emit the laser beam and support the formation of a scanning spectrum line.

3. The device according to claim 1, characterized in that Also includes specifications of the same quantity type: A reference laser light path adjustment component, used for adjusting the light path of the reference laser so that the reference laser can be detected by the detection component; The measuring laser light path adjustment component is used to adjust the light path of the measuring laser passing through the sample cell so that the measuring laser can be detected by the detection component.

4. The device according to claim 3, characterized in that The measuring laser light path adjustment components are multiple groups, and each group of the measuring laser light path adjustment components is used to adjust the laser light path passing through the corresponding sample cell.

5. The device according to claim 3, characterized in that The reference laser optical path adjustment component comprises a first off-axis parabolic reflector, which is used to focus the reference laser input to the first off-axis parabolic reflector; The measuring laser optical path adjustment component further includes a second off-axis parabolic reflector for focusing the measuring laser input to the second off-axis parabolic reflector.

6. The device according to claim 1 or 5, characterized in that The detection component includes a pinhole aperture and a photodetector. The pinhole aperture is used to limit the size of the reference laser and the measurement laser input to the target surface of the photodetector in the detection component. The photodetector is used to alternately detect the reference laser and the measurement laser.

7. The device according to claim 1, characterized in that The frequency of the measuring laser and the reference laser is the same, and the frequency range is 1 Hz to 250 Hz.

8. The device according to claim 1, characterized in that The driving controller controls the cross-flexure bearing uniaxial reflection galvanometer to periodically rotate within an angle range of ±10°.

9. A method for using a time-resolved spectral baseline calibration device according to any one of claims 1 to 8, characterized in that: include: The wavelength tunable laser is modulated to a first set frequency value, and the driving controller controls the cross-flexure bearing single-axis reflective galvanometer to rotate periodically at a second set frequency; The detection component detects the reference laser and the measurement laser passing through the sample cell alternately; The processing component obtains the output signal of the detection component, wherein the output signal includes a first output signal corresponding to the reference laser and a second output signal corresponding to the measurement laser passing through the sample pool; the first output signal is subtracted from the second output signal to correct the baseline disturbance generated during the spectral signal measurement process.

10. The method according to claim 9, characterized in that Before the driving controller controls the cross-flexure bearing uniaxial reflection galvanometer to rotate periodically at a second set frequency, the method further includes: Obtaining the center frequency of the absorption spectrum of the target detection material, and determining the frequency of the wavelength tunable laser as the first set frequency value; Obtain the response bandwidth of the detector and determine the second set frequency value under the premise that the collected signal is not distorted.

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