An anti-jamming ultra-high time resolution laser diagnostic method and device

Abstract

An anti-interference ultra-high time-resolution laser diagnostic method and device, belonging to the field of laser diagnostic technology, utilizes an ultra-high-speed wavelength modulation device with a GHz bandwidth to achieve GHz-level wavelength modulation of the laser output light, thereby improving the time resolution of laser diagnostics from the existing hundreds of kHz level to the GHz level, reaching the nanosecond level of detection. It can accurately capture the rapid evolution process of combustion and explosion flow fields at the nanosecond to microsecond scale, filling the technological gap in ultra-high-speed detection of nanosecond-level combustion and explosion flow fields. By mixing and filtering to extract multiple harmonic signals and performing ratio normalization processing on the harmonic signals, the influence of various interference factors such as light intensity fluctuations, radiation background, particle / droplet extinction, and signal scattering attenuation is fundamentally eliminated, obtaining a stable absorption characteristic signal independent of light intensity changes. This solves the problems of signal submersion and spectral distortion in traditional optical measurements in strongly disturbed combustion and explosion environments, and can work stably in extremely complex combustion and explosion flow fields.

Description

Technical Field

[0001] This invention belongs to the field of laser diagnostic technology, specifically relating to an anti-interference ultra-high time-resolution laser diagnostic method and device. Background Technology

[0002] In highly disturbed flow fields such as combustion, detonation, and supersonic combustion, pressure, temperature, and component concentration change rapidly and coupled within nanosecond to microsecond scales. This is accompanied by extinction from numerous particles and droplets, as well as strong infrared radiation background, resulting in significant scattering, attenuation, and radiation interference of optical signals. Traditional optical measurement methods under these conditions often face problems such as signal submersion, spectral distortion, and harmonic distortion, making it difficult to achieve high time resolution and accurate, interference-resistant acquisition of key combustion parameters. Therefore, achieving reliable temperature and multi-component concentration analysis at the nanosecond to microsecond level in extreme combustion environments has always been a core technical challenge in the field of combustion flow field detection and safety monitoring.

[0003] Laser absorption spectroscopy (LAS) has become the mainstream method for transient combustion and explosion diagnosis due to its elimination of gas sampling and rapid response. Wavelength modulation spectroscopy (WMS) is a representative technique within LAS. Because light intensity changes are normalized, it possesses strong anti-interference capabilities and has significant application value in combustion and explosion environments. However, the current world record for time resolution is only in the hundreds of kHz range, achieved by the Goldenstein team in 2020 during temperature and water vapor concentration measurements in their fireball research. Existing WMS technology cannot simultaneously achieve both high time resolution and anti-interference capabilities, making it difficult to realize GHz-level ultra-high-speed, precise, and anti-interference detection capabilities for nanosecond-level evolution processes in combustion and explosion flow fields. Therefore, there is an urgent need to develop a novel laser diagnostic method and device that simultaneously possesses ultra-high-speed response and strong anti-interference performance. Summary of the Invention

[0004] To address the shortcomings of the aforementioned background technologies, this invention proposes an anti-interference ultra-high time-resolution laser diagnostic method and device, belonging to the field of laser absorption spectroscopy technology. This invention employs an ultra-high-speed wavelength modulation device to achieve GHz-level wavelength modulation, overcoming the time resolution bottleneck caused by the limited modulation rate of traditional lasers. Simultaneously, through the extraction and normalization of multiple harmonic signals, the influence of light intensity fluctuations and radiation background is effectively eliminated, thereby obtaining stable and anti-interference absorption feature resolution capabilities. This scheme can achieve GHz-level ultra-high-speed anti-interference multi-parameter detection capabilities in strongly disturbed combustion and explosion environments.

[0005] The present invention employs the following technical solution.

[0006] An anti-interference ultra-high time-resolution laser diagnostic method includes: S1: The function signal generator outputs a GHz-level sinusoidal modulated signal and simultaneously outputs a reference signal; S2: The ultra-high-speed modulation signal output by the function signal generator is input to the ultra-high-speed wavelength modulation device, which modulates the output light of the laser at the GHz level. S3: The laser, after being modulated by ultra-high speed wavelength, is output from the modulator and enters the target field. It passes through the combustion and explosion flow field in the target field and is absorbed. Then the transmitted light passes through the combustion and explosion flow field. S4: The transmitted light is received by the photodetector and converted into an electrical signal, which is then distributed to mixer one and mixer two respectively. S5: The signal output by the photodetector is mixed with the reference signal in mixer one and mixer two respectively. S6: The output signal of mixer one is further filtered by low-pass filter one to extract harmonic component one; the output signal of mixer two is further filtered by low-pass filter two to obtain harmonic component two. S7: The signals output from low-pass filter one and low-pass filter two are simultaneously input into the data acquisition system, which samples and records them, and compares the two harmonic components to obtain a signal independent of light intensity changes.

[0007] Furthermore, in S1, the reference signal is a reference electrical signal that is synchronously output by the function signal generator and is of the same origin as the GHz-level sinusoidal modulation signal. It is the reference signal for realizing the mixing and extraction of harmonic components.

[0008] Furthermore, in S1, the frequency and modulation characteristics of the reference signal are matched with the GHz-level sinusoidal modulation signal output by the function signal generator.

[0009] Furthermore, in S6, both harmonic component one and harmonic component two are proportional to the change in light intensity.

[0010] Furthermore, in S7, the signal, which is independent of changes in light intensity, carries information about the component concentration and temperature of the target field.

[0011] An anti-interference ultra-high time-resolution laser diagnostic device, comprising: Mixer 1, Mixer 2, and the ultra-high-speed wavelength modulation device are all connected to the function signal generator; A laser, an ultra-high-speed wavelength modulation device, a target field, a photodetector, a mixer, a low-pass filter, and a data acquisition system are connected in sequence. The photodetector, mixer II, low-pass filter II, and data acquisition system are connected in sequence.

[0012] Furthermore, the ultra-high-speed wavelength modulation device is used to cause a GHz-level change in the laser output wavelength, and the ultra-high-speed wavelength modulation device includes a phase modulator with a GHz bandwidth.

[0013] Furthermore, the laser includes, but is not limited to, semiconductor tunable lasers, continuous lasers, pulsed lasers, or any other type of laser capable of wavelength modulation in conjunction with ultra-high-speed wavelength modulation devices.

[0014] Furthermore, the harmonic components include harmonic signals of the first, second, third, or higher harmonics of the ultra-high-speed modulation signal, and may also be DC components.

[0015] Furthermore, the anti-interference ultra-high time-resolution laser diagnostic device achieves concentration measurement of any gas component by selecting the absorption spectral line of any gas component, and achieves temperature measurement by selecting the double absorption line of any gas component.

[0016] The beneficial effects of the present invention are as follows: Compared with the prior art, the technical effects of the present invention include: By employing ultra-high-speed wavelength modulation devices with GHz bandwidth, GHz-level wavelength modulation of laser output light is achieved, improving the time resolution of laser diagnostics to the GHz level and reaching nanosecond-level detection. This allows for precise capture of the rapid evolution of combustion and explosion flow fields at the nanosecond to microsecond scale, filling the technological gap in ultra-high-speed detection of nanosecond-level combustion and explosion flow fields. Through frequency mixing and filtering to extract multiple harmonic signals, and then performing ratio normalization processing on the harmonic signals, the influence of various interference factors such as light intensity fluctuations, radiation background, particle / droplet extinction, and signal scattering attenuation is fundamentally eliminated. This yields stable absorption characteristic signals independent of light intensity changes, solving the problems of signal submersion and spectral distortion in traditional optical measurements under strong disturbances in combustion and explosion environments. This enables stable operation in extremely complex combustion and explosion flow fields. By selecting characteristic absorption lines and double absorption lines of different gas components, precise measurement of single / multiple component concentrations and temperatures can be achieved. Simultaneously, multiple systems can be used in parallel to realize multi-parameter detection of combustion and explosion flow fields. This system features synchronous ultra-high-speed detection with flexibly configurable detection parameters to adapt to diverse detection needs in combustion and explosion flow fields. Various laser types are available, including tunable semiconductor lasers, continuous-wave lasers, and pulsed lasers. The ultra-high-speed wavelength modulation device is a general-purpose phase modulator, and all components are standard devices in the laser detection field, ensuring strong compatibility and ease of assembly. Furthermore, the detection process requires no gas sampling, and the non-contact detection does not interfere with the combustion and explosion flow field. It boasts a fast detection response and simple operation, making it highly valuable for practical applications in combustion and explosion flow field detection, industrial safety monitoring, and supersonic combustion research. The ultra-high-speed wavelength modulation device maintains low insertion loss and good linear stability under GHz-level high-frequency modulation, avoiding spectral distortion caused by high-frequency modulation. The data acquisition system achieves GHz-level high-speed sampling and synchronous processing, combined with a normalized stable absorption characteristic signal, ensuring the accuracy and repeatability of the detection results and providing reliable parameter data support for the mechanism research and safety monitoring of combustion and explosion flow fields. Attached Figure Description

[0017] Figure 1 This is a schematic diagram illustrating the technical principle of the anti-interference ultra-high time resolution laser diagnostic device described in this invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, any other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention.

[0019] The anti-interference ultra-high time-resolution laser diagnostic method of the present invention includes: S1: Function signal generator 1 outputs a GHz-level sinusoidal modulation signal and simultaneously outputs a reference signal for subsequent mixing. In a preferred but non-limiting embodiment of the present invention, in S1, the reference signal is a reference electrical signal synchronously output by function signal generator 1 and originating from the same source as the GHz-level sinusoidal modulation signal. It serves as the reference signal for frequency mixing to extract harmonic components. That is, the reference signal and the GHz-level sinusoidal modulation signal used to drive the ultra-high-speed wavelength modulation device are generated by the same function signal generator and are of the same origin, ensuring accurate synchronization of frequency and phase. This is a prerequisite for accurate extraction of harmonic components in subsequent frequency mixing. As the reference signal for frequency mixing, it is mixed with the electrical signal converted by the photodetector in mixer one and mixer two, respectively. This operation achieves preliminary separation of different harmonic components in the ultra-high-speed modulation signal, providing a foundation for subsequent low-pass filtering to extract accurate harmonic components.

[0020] In a preferred but non-limiting embodiment of the present invention, in S1, the frequency and modulation characteristics of the reference signal are matched with the GHz-level sinusoidal modulation signal output by the function signal generator, which can adapt to the characteristics of the laser signal after ultra-high-speed wavelength modulation and meet the signal processing requirements of GHz-level ultra-high-speed detection of combustion and explosion flow fields.

[0021] The reference electrical signal is mixed with the probe electrical signal to achieve accurate extraction of the target harmonic components, while relying on homology to ensure the accuracy of signal processing under ultra-high speed modulation.

[0022] S2: The ultra-high speed modulation signal output by the function signal generator 1 is input to the ultra-high speed wavelength modulation device 3, which modulates the output light of the laser 2 at the GHz level. Ultra-high-speed wavelength modulation devices refer to core optical modulation devices capable of GHz-level laser wavelength modulation and possessing GHz-level bandwidth. Phase modulators with GHz bandwidth are primarily selected. These devices can be directly connected to the laser output, are compatible with the 1260nm–1625nm wavelength band, and maintain low insertion loss and good linear stability under high-frequency modulation. They are key components for achieving ultra-high-speed laser wavelength modulation. From the perspective of device applicability, any similar optical modulation device that can work with a laser to achieve GHz-level wavelength modulation falls within the scope of ultra-high-speed wavelength modulation devices in this invention, with the phase modulator being the core and preferred device. The electro-optic effect (Pockels effect) of this ultra-high-speed wavelength modulation device achieves GHz-level laser wavelength modulation. The core principle is to change the refractive index of the optical medium through an external GHz-level electromodulation signal, thereby achieving ultra-high-speed control of the laser phase / wavelength. In the context of this invention's application, the specific implementation process is divided into two core stages: signal driving and optical modulation, and is deeply integrated with the system control flow. The GHz-level sinusoidal ultra-high-speed modulation signal is directly input to the phase modulator. This electrical signal provides high-frequency electric field excitation to the modulator, and its frequency is precisely matched with the GHz-level bandwidth of the modulator, ensuring the synchronization and effectiveness of the modulation. The phase modulator is an optical medium with electro-optic properties. Its working principle is as follows: when the GHz-level high-frequency electrical modulation signal is applied to the electro-optic medium of the modulator, the refractive index of the medium will change linearly and rapidly with the applied high-frequency electric field. When the laser output from the laser passes through the medium, the propagation constant of the light wave will change with the refractive index, thereby realizing the GHz-level ultra-high-speed modulation of the laser phase, and finally converting it into the GHz-level dynamic change of the laser wavelength. The phase change in this process is continuously excited by the GHz-level electrical signal, and the refractive index of the medium will change synchronously with the electric field at a high frequency, realizing the continuous and high-speed modulation of the laser wavelength. After the laser wavelength is modulated by the phase modulator, it maintains low power loss and stable linearity, and is directly output from the modulator and enters the target field, preparing for subsequent absorption through the combustion and explosion flow field and parameter detection. The modulator's GHz-level bandwidth perfectly matches the GHz-level modulation signal of the function signal generator, ensuring that the laser wavelength modulation rate reaches the GHz level, breaking through the bottleneck of traditional laser modulation rate. The modulator can be directly connected to the laser output without complex optical path conversion, realizing direct laser modulation and improving system integration and modulation efficiency. Under 40GHz ultra-high frequency modulation, it can still maintain low insertion loss and good linear stability, avoiding laser signal distortion and ensuring the accuracy of subsequent detection. The phase modulator, an ultra-high-speed wavelength modulation device, converts the GHz-level high-frequency changes of the electrical signal into GHz-level dynamic changes of the laser wavelength through electro-optic effect, realizing ultra-high-speed modulation of the laser wavelength and laying the optical path foundation for subsequent GHz-level ultra-high-speed detection.

[0023] S3: The laser, after being modulated by ultra-high speed wavelength, is output from the modulator 3 and enters the target field 4. It passes through the combustion and explosion flow field in the target field and is absorbed. Then the transmitted light passes through the combustion and explosion flow field. S4: The transmitted light is received by the photodetector 5 and converted into an electrical signal, and the electrical signal is distributed to mixer 6 and mixer 7 respectively. The electrical signal distribution is achieved through signal splitting transmission. This is primarily achieved by using a passive RF splitter (compatible with GHz-level high-frequency signals) to divide the single-channel output electrical signal of the photodetector into two independent signals with equal power / amplitude. These signals are then connected to mixer one and mixer two via RF transmission lines. One GHz-level high-frequency electrical signal is first input to an RF power divider, which then splits the single-channel signal into two identical electrical signals without distortion and synchronously. These two signals are then directly transmitted to the signal input terminals of mixer one and mixer two via RF cables / microwave transmission lines, completing the signal distribution. Since the electrical signal from GHz-level ultra-high-speed detection is a high-frequency signal, the distribution process must meet the core requirement of high-frequency compatibility to avoid signal distortion, delay, or loss, ensuring the accuracy of subsequent mixing processing. Specifically, the selected splitting device (power divider) must have GHz-level bandwidth to match the frequency of the high-frequency electrical signal output by the photodetector and the reference signal, meeting the signal transmission requirements of 40GHz-level ultra-high-speed modulation; the two electrical signals after splitting must ensure that the amplitude, phase, and frequency are completely consistent, and that no additional noise is introduced, ensuring that the input signals of mixer one and mixer two are from the same source and have the same characteristics, avoiding deviations in subsequent harmonic component extraction; the splitting device and transmission line (RF cable) must have low insertion loss to reduce power loss of high-frequency electrical signals during distribution and transmission, ensuring the signal strength of the mixing stage; the transmission path length of the two signals must be consistent to ensure that the electrical signals arrive at the two mixers synchronously, avoiding time differences in mixing processing due to transmission delays, which would affect the accuracy of harmonic component extraction.

[0024] S5: The signal output by photodetector 5 is mixed with the reference signal in mixer 6 and mixer 7 to extract different harmonic components. The method of mixing the output signal of the photodetector with the reference signal in two mixers to extract different harmonic components is a high-frequency signal processing scheme that uses a common reference signal, dual-channel independent mixing, and targeted filtering. It relies on the frequency transformation characteristics of mixing to separate and extract harmonic components. The two mixers perform parallel mixing processing with the same principle but different harmonic targets. Specifically, the electrical signal output by the photodetector is a high-frequency detection signal carrying information about the combustion and explosion flow field absorption and synchronized with a GHz-level modulated laser. It includes the fundamental frequency and harmonic components of the modulated signal, and is also superimposed with interference from light intensity fluctuations and radiation background. The mixing reference signal is a GHz-level reference electrical signal synchronously output by a function signal generator, which is mixed with the signal modulated by the driving laser. Matching sinusoidal modulation signals to their source and frequency (either at the same source or in a harmonic) provides a precise frequency reference for mixing, which is crucial for extracting specific harmonics. The frequency matching design for two different harmonic components employs a dual-path parallel, independent processing approach. This includes: connecting the two identical high-frequency detection signals from the split photodetector to the detection signal inputs of mixer one and mixer two, respectively; simultaneously, connecting the reference signal output from the function generator to the reference signal inputs of the two mixers according to the frequency requirements of different harmonic extractions (the reference signal can be adapted for harmonic multiplexing / division based on the target harmonic; for example, inputting a harmonic reference signal for extracting a second harmonic, and inputting a reference signal at the same frequency for extracting the fundamental harmonic). The mixers utilize nonlinear frequency transformation characteristics to adjust the input frequency. The input detection signal and reference signal are mixed. Since the detection signal contains the fundamental frequency, harmonics, and interference signals of the modulation signal, by mixing with a reference signal of a specific frequency, the high-frequency signal of the target harmonic component can be converted into a low-frequency (or intermediate-frequency) signal, while other non-target harmonics and interference signals retain their high-frequency characteristics, achieving preliminary frequency separation between the target harmonics and clutter. Mixer 1 and Mixer 2 are respectively matched to the reference signal frequencies of the corresponding harmonic component 1 and harmonic component 2, thereby locking and transforming the two different target harmonic components. The output signal of Mixer 1 is connected to Low-Pass Filter 1, and the output signal of Mixer 2 is connected to Low-Pass Filter 2. The low-pass filters only allow low-frequency / intermediate-frequency signals to pass through and block them. The high-frequency isolation signal characteristics allow the target harmonic low-frequency signal to be filtered out after mixing, while non-target harmonics and high-frequency interference signals that have not been transformed are filtered out, ultimately yielding pure harmonic component one and harmonic component two respectively. Mixer one and mixer two are independent hardware units, each extracting different harmonic components without interference, ensuring the signal purity of the two harmonic components. The frequency of the reference signal can be flexibly adjusted to adapt to the extraction of harmonics at the first, second, third, or higher harmonics, or even DC components, matching the harmonic component extraction range in the claims. The entire mixing process uses a high-frequency mixer adapted to GHz-level signals, meeting the signal processing requirements of the ultra-high-speed modulation of this invention, with no signal distortion or delay issues.The two harmonic components extracted using this method are both proportional to changes in light intensity, laying the signal foundation for subsequent ratio normalization and elimination of light intensity interference.

[0025] This step is used to modulate a reference signal of the same origin. The probe signal is subjected to targeted frequency transformation by two mixers and then filtered by a dedicated low-pass filter. By utilizing the frequency separation characteristics of mixing and the signal filtering characteristics of filtering, the two different harmonic components are accurately and independently extracted. This is the key signal processing step for the present invention to achieve GHz-level ultra-high-speed detection and subsequent anti-interference processing.

[0026] S6: The output signal of mixer 16 is further filtered by low-pass filter 18 to extract harmonic component 1; the output signal of mixer 27 is further filtered by low-pass filter 29 to obtain harmonic component 2. In a preferred but non-limiting embodiment of the present invention, in S6, both harmonic component one and harmonic component two are proportional to the change in light intensity.

[0027] S7: The signals output by low-pass filter 8 and low-pass filter 9 are simultaneously input into data acquisition system 10, where they are sampled and recorded at high speed. The two harmonic components are then compared to obtain a signal independent of light intensity changes.

[0028] In a preferred but non-limiting embodiment of the present invention, in S7, a signal independent of changes in light intensity carries information about the component concentration and temperature of the target field.

[0029] The harmonic components I and II extracted through mixing and filtering are both proportional to the change in light intensity. The interference factors such as light intensity fluctuations and radiation background contained in both are linearly correlated terms. During the comparison calculation, these light intensity-related interference factors will cancel each other out and be completely eliminated, ultimately retaining only the information related to the physical characteristics of the combustion flow field of the target field, that is, the characteristic signals carrying the concentration and temperature of the target field components.

[0030] like Figure 1 As shown, the anti-interference ultra-high time resolution laser diagnostic device of the present invention includes: Mixer 1 (6), Mixer 2 (7), and Ultra-high-speed wavelength modulation device 3 are all connected to function signal generator 1; The laser 2, ultra-high speed wavelength modulation device 3, target field 4, photodetector 5, mixer 6, low-pass filter 8, and data acquisition system 10 are connected in sequence. The photodetector 5, mixer 2 7, low-pass filter 2 9, and data acquisition system 10 are connected in sequence.

[0031] In a preferred but non-limiting embodiment of the present invention, the ultra-high-speed wavelength modulation device 3 is used to cause a GHz-level change in the laser output wavelength, and the ultra-high-speed wavelength modulation device includes a phase modulator with a GHz bandwidth.

[0032] In a preferred but non-limiting embodiment of the present invention, the laser 2 includes, but is not limited to, a semiconductor tunable laser, a continuous laser, a pulsed laser, or any other type of laser that can cooperate with the ultra-high-speed wavelength modulation device 3 to achieve wavelength modulation.

[0033] In a preferred but non-limiting embodiment of the present invention, the harmonic components include harmonic signals of the first, second, third or higher harmonics of the ultra-high speed modulation signal, or may be DC components.

[0034] In a preferred but non-limiting embodiment of the present invention, the anti-interference ultra-high time-resolution laser diagnostic device can achieve concentration measurement of any gas component by selecting the absorption spectral line of any gas component, and can achieve temperature measurement by selecting the double absorption line of any gas component; when it is necessary to measure the concentration or temperature of multiple components simultaneously, multiple sets of the anti-interference ultra-high time-resolution laser diagnostic devices of the present invention can be used in parallel, with each set of anti-interference ultra-high time-resolution laser diagnostic devices independently covering the corresponding absorption line, thereby achieving synchronous measurement of multiple parameters.

[0035] In this invention, the ultra-high-speed wavelength modulation device 3 is a phase modulator with a bandwidth of 40 GHz, suitable for the 1260 nm to 1625 nm band. It can be directly connected to the laser output to achieve GHz-level high-speed phase modulation of the laser wavelength, ensuring low insertion loss and good linear stability under high-frequency modulation conditions. The laser 2 uses a 1392 nm DFB laser and a 1469 nm DFB laser, respectively. The 1392 nm laser is used for concentration measurement of the water vapor absorption line, and the 1469 nm laser is used for another water vapor absorption line to achieve dual-line temperature measurement. Both lasers can be connected to the phase modulator to achieve stable GHz-level wavelength modulation. The modulated laser passes through the target field 4 and the combustion flow field. The transmitted light is received by the photodetector 5 and mixed, filtered, and harmonic ratio normalized according to the steps described in this invention. This invention can stably extract the multiple harmonic characteristics of the water vapor absorption spectrum, achieving GHz-level ultra-high-speed, anti-interference multi-parameter diagnostic capabilities for water vapor concentration and temperature.

[0036] The beneficial effects of the present invention are as follows: Compared with the prior art, the technical effects of the present invention include: By employing ultra-high-speed wavelength modulation devices with GHz bandwidth, GHz-level wavelength modulation of laser output light is achieved, improving the time resolution of laser diagnostics to the GHz level and reaching nanosecond-level detection. This allows for precise capture of the rapid evolution of combustion and explosion flow fields at the nanosecond to microsecond scale, filling the technological gap in ultra-high-speed detection of nanosecond-level combustion and explosion flow fields. Through frequency mixing and filtering to extract multiple harmonic signals, and then performing ratio normalization processing on the harmonic signals, the influence of various interference factors such as light intensity fluctuations, radiation background, particle / droplet extinction, and signal scattering attenuation is fundamentally eliminated. This yields stable absorption characteristic signals independent of light intensity changes, solving the problems of signal submersion and spectral distortion in traditional optical measurements under strong disturbances in combustion and explosion environments. This enables stable operation in extremely complex combustion and explosion flow fields. By selecting characteristic absorption lines and double absorption lines of different gas components, precise measurement of single / multiple component concentrations and temperatures can be achieved. Simultaneously, multiple systems can be used in parallel to realize multi-parameter detection of combustion and explosion flow fields. This system features synchronous ultra-high-speed detection with flexibly configurable detection parameters to adapt to diverse detection needs in combustion and explosion flow fields. Various laser types are available, including tunable semiconductor lasers, continuous-wave lasers, and pulsed lasers. The ultra-high-speed wavelength modulation device is a general-purpose phase modulator, and all components are standard devices in the laser detection field, ensuring strong compatibility and ease of assembly. Furthermore, the detection process requires no gas sampling, and the non-contact detection does not interfere with the combustion and explosion flow field. It boasts a fast detection response and simple operation, making it highly valuable for practical applications in combustion and explosion flow field detection, industrial safety monitoring, and supersonic combustion research. The ultra-high-speed wavelength modulation device maintains low insertion loss and good linear stability under GHz-level high-frequency modulation, avoiding spectral distortion caused by high-frequency modulation. The data acquisition system achieves GHz-level high-speed sampling and synchronous processing, combined with a normalized stable absorption characteristic signal, ensuring the accuracy and repeatability of the detection results and providing reliable parameter data support for the mechanism research and safety monitoring of combustion and explosion flow fields. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention without departing from the spirit and scope of the present invention. Any modifications or equivalent substitutions should be covered within the protection scope of the claims of the present invention.

Claims

1. An anti-interference ultra-high time-resolution laser diagnostic method, characterized in that, include: S1: The function signal generator outputs a GHz-level sinusoidal modulated signal and simultaneously outputs a reference signal; S2: The ultra-high-speed modulation signal output by the function signal generator is input to the ultra-high-speed wavelength modulation device, which modulates the output light of the laser at the GHz level. S3: The laser, after being modulated by ultra-high speed wavelength, is output from the modulator and enters the target field. It passes through the combustion and explosion flow field in the target field and is absorbed. Then the transmitted light passes through the combustion and explosion flow field. S4: The transmitted light is received by the photodetector and converted into an electrical signal, which is then distributed to mixer one and mixer two respectively. S5: The signal output by the photodetector is mixed with the reference signal in mixer one and mixer two respectively. S6: The output signal of mixer one is further filtered by low-pass filter one to extract harmonic component one; the output signal of mixer two is further filtered by low-pass filter two to obtain harmonic component two. S7: The signals output from low-pass filter one and low-pass filter two are simultaneously input into the data acquisition system, which samples and records them, and compares the two harmonic components to obtain a signal independent of light intensity changes.

2. The anti-interference ultra-high time-resolution laser diagnostic method according to claim 1, characterized in that, In S1, the reference signal is a reference electrical signal that is synchronously output by the function signal generator and is of the same origin as the GHz-level sinusoidal modulation signal. It is the reference signal for realizing frequency mixing and extracting harmonic components.

3. The anti-interference ultra-high time-resolution laser diagnostic method according to claim 2, characterized in that, In S1, the frequency and modulation characteristics of the reference signal are matched with the GHz-level sinusoidal modulation signal output by the function signal generator.

4. The anti-interference ultra-high time-resolution laser diagnostic method according to claim 3, characterized in that, In S6, both harmonic component one and harmonic component two are proportional to the change in light intensity.

5. The anti-interference ultra-high time-resolution laser diagnostic method according to claim 4, characterized in that, In S7, signals independent of light intensity changes carry information about the component concentration and temperature of the target field.

6. An anti-interference ultra-high time-resolution laser diagnostic device, characterized in that, include: Mixer 1, Mixer 2, and the ultra-high-speed wavelength modulation device are all connected to the function signal generator; A laser, an ultra-high-speed wavelength modulation device, a target field, a photodetector, a mixer, a low-pass filter, and a data acquisition system are connected in sequence. The photodetector, mixer II, low-pass filter II, and data acquisition system are connected in sequence.

7. The anti-interference ultra-high time resolution laser diagnostic device according to claim 6, characterized in that, The ultra-high-speed wavelength modulation device is used to cause a GHz-level change in the laser output wavelength, and the ultra-high-speed wavelength modulation device includes a phase modulator with a GHz bandwidth.

8. The anti-interference ultra-high time-resolution laser diagnostic device according to claim 7, characterized in that, The lasers include, but are not limited to, semiconductor tunable lasers, continuous lasers, pulsed lasers, or any other type of laser that can be used in conjunction with ultra-high-speed wavelength modulation devices to achieve wavelength modulation.

9. The anti-interference ultra-high time resolution laser diagnostic device according to claim 8, characterized in that, The harmonic components include harmonic signals of the first, second, third or higher harmonics of the ultra-high speed modulation signal, and may also be DC components.

10. The anti-interference ultra-high time resolution laser diagnostic device according to claim 9, characterized in that, The anti-interference ultra-high time-resolution laser diagnostic device achieves concentration measurement of any gas component by selecting the absorption spectral line of any gas component, and achieves temperature measurement by selecting the double absorption line of any gas component.

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