High-efficiency single-wavelength six-channel Raman laser radar atmospheric temperature and humidity profile detection system

Abstract

The invention discloses a high-efficiency single-wavelength six-channel Raman laser radar atmospheric temperature and humidity profile detection system, and the system employs a high-frequency 355 nm LD pump laser as a light source, and combines a beam expander to optimize the beam divergence angle of a light beam, so as to enhance the excitation efficiency of a backscattering signal. The system adopts a Cassegrain reflection telescope and a light beam terminator to reduce stray light interference and improve the signal-to-noise ratio; the light splitting system separates a 354 nm Raman signal, a 353 nm Raman signal, 355 nm parallel and vertical elastic scattered light, a 386 nm Raman signal and a 407 nm Raman signal through an interference filter and a dichroscope, and six-channel synchronous acquisition is combined with high-speed data acquisition and an inversion algorithm to generate an atmosphere temperature and humidity and aerosol vertical profile. The system is compact in structure, is suitable for field monitoring and unattended long-term operation, has the remarkable advantages of high temporal-spatial resolution, high sensitivity and long-term stability compared with the traditional technology, and provides an integrated, efficient and reliable solution for atmosphere multi-parameter remote sensing measurement.

Description

Technical Field

[0001] The invention relates to the technical field of atmospheric remote sensing monitoring, and in particular to an efficient single-wavelength six-channel Raman laser radar atmospheric temperature and humidity profile detection system. Background Art

[0002] LiDAR is a technology based on optical remote sensing. It transmits laser beams to scatter with aerosols or molecules in the atmosphere, receives backscattered signals, and then inverts and calculates atmospheric physical parameters, such as temperature and humidity profiles and aerosol concentrations. Such systems are widely used in meteorological monitoring, atmospheric environment research, and climate change assessment. However, high-precision detection of temperature, humidity, and aerosols on high-altitude vertical profiles has always been a technical challenge.

[0003] In the existing technology, temperature and humidity lidar usually uses a lamp-pumped laser light source combined with a Fabry-Perot (FP) interferometer to achieve spectral splitting. The system integration is complex, the service life is short, the operation and maintenance costs are high, and it is difficult to meet the needs of long-term efficient operation. These systems have the following main disadvantages in practical applications: 1. Light source problem: The pulse frequency of traditional lamp pump light sources is low (10Hz), the energy output is unstable, and the life span is only about 50 million times. Frequent maintenance is required, and it cannot meet the detection requirements of high temporal and spatial resolution.

[0004] 2. Spectroscopic technology issues: Although the FP interferometer has a certain spectral resolution, it has a bulky structure and complex debugging. It is easily affected by mechanical vibration and ambient temperature changes, resulting in a decrease in accuracy during long-term operation.

[0005] 3. System adaptability issues: Due to the complex structure, large size and high power consumption of traditional lidar systems, they are difficult to operate stably in unmanned or long-term outdoor monitoring scenarios and cannot meet the needs of engineering applications.

[0006] In order to solve the above problems, the industry has tried to use higher-frequency laser light sources or optimize optical structures. However, these methods can only solve part of the problem. For example, the introduction of multi-wavelength lasers can improve the dimension of detection parameters, but the optical path adjustment of the multi-wavelength system is difficult, the equipment cost is high, and the detection synchronization of each wavelength is poor; and although the improved design of the FP spectrometer has improved some stability, it has not fundamentally solved the engineering problems of the system.

[0007] Therefore, how to achieve synchronous detection of atmospheric temperature, humidity and aerosol information with high temporal and spatial resolution, and make the system operate stably for a long time in unmanned and complex outdoor environments, has become a technical problem to be solved by the present invention. Summary of the invention

[0008] The technical problem solved by the present invention is to provide a high-efficiency single-wavelength six-channel Raman lidar atmospheric temperature and humidity profile detection system in response to the defects existing in the above-mentioned prior art, so as to solve the problems of short light source life, complex spectroscopic system and difficult engineering realization proposed in the above-mentioned background technology.

[0009] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows: An efficient single-wavelength six-channel Raman lidar atmospheric temperature and humidity profile detection system, the system comprising: A laser emission system configured to emit a 355nm narrow pulse width, high repetition rate, high energy laser beam, the laser emission system comprising an LD pump laser, a beam expander and a reflector; the laser emission system optimizes the beam divergence angle of the laser beam through the beam expander to improve the excitation efficiency of the backscattered signal in the atmosphere, the LD pump laser having a single pulse energy of ≥60mJ and a frequency of ≥100Hz; A receiving system, comprising a Cassegrain reflecting telescope and a beam terminator, the receiving system being used to receive backscattered echo signals from the atmosphere and collimate the echo signals through a collimation system; The spectroscopic system includes a dichroic mirror, an interference filter and a polarization spectroscopic prism. The spectroscopic system separates the received echo signal into six independent wavelength signals, namely: 354nm Raman signal and 353nm Raman signal generated by Raman scattering; 355nm parallel polarized light and 355nm vertical polarized light generated by elastic scattering; The 386nm nitrogen Raman signal and 407nm water vapor Raman signal generated by Raman scattering; A data acquisition system, which includes a photoelectric detector and a high-speed data acquisition device, is used to perform photoelectric conversion and acquisition on the six independent signals separated by the optical splitting system; The terminal control system includes a control module and a computer system, wherein the control module is used for power supply and module control, and the computer system is used for generating and displaying the concentration profile, temperature profile and humidity profile of aerosol in the atmosphere through an inversion algorithm based on the collected signals.

[0010] As a further solution of the present invention, the beam expander of the laser emission system is used to shape the 355nm laser beam to reduce the beam divergence angle of the beam, improve the interaction efficiency between the laser and atmospheric components, and optimize the intensity and stability of the backscattered signal.

[0011] As a further solution of the present invention, the Cassegrain reflecting telescope in the receiving system realizes efficient reception and collimation of signals through a collimating lens combination, and reduces the interference of stray light in combination with the design of a beam terminator, thereby improving the signal-to-noise ratio of the received backscattered signal.

[0012] As a further solution of the present invention, the optical splitting system preliminarily separates the echo signal according to the wavelength range through a dichroic mirror, and the signal with a wavelength less than 360nm is reflected by the dichroic mirror, and the signal with a wavelength greater than 360nm passes through the dichroic mirror; the separated signal is further accurately purified by an interference filter, thereby obtaining: 354nm high-order rotational Raman signal; 353nm low-order rotational Raman signal; 386nm nitrogen Raman signal; 407nm water vapor Raman signal; 355nm parallel polarized light; 355nm vertically polarized light.

[0013] As a further solution of the present invention, the photodetector is designed with six independent channels, which are respectively used to receive and convert 354nm high-order rotational Raman signals, 353nm low-order rotational Raman signals, 355nm parallel polarized light, 355nm vertically polarized light, 386nm nitrogen Raman signals and 407nm water vapor Raman signals. The photodetector has high-sensitivity detection capabilities for weak Raman signals.

[0014] As a further solution of the present invention, the high-speed data acquisition device can synchronously acquire and process six-channel signals, and in combination with the inversion algorithm of the terminal control system, the acquired signals are converted in real time into: Temperature vertical profile; Humidity vertical profile; Aerosol concentration profiles; And it is presented in the form of data products.

[0015] As a further solution of the present invention, the inversion algorithm of the terminal control system is based on the time resolution and intensity distribution of the echo signal, generates multi-parameter distribution information of atmospheric temperature, humidity and aerosols through model calculation, and supports real-time detection with high temporal and spatial resolution.

[0016] As a further solution of the present invention, the overall design structure of the system is compact, suitable for remote field monitoring and unmanned long-term operation scenarios, and achieves all-weather efficient detection by optimizing the efficiency of scattered signal reception and data processing.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. The stability of single-wavelength high-frequency laser combined with the synergy of multi-channel synchronous processing can achieve synchronous measurement of multiple parameters such as atmospheric temperature and humidity, aerosol extinction coefficient, etc. in one system. Traditional systems often require multi-wavelength lasers or multiple measurements to complete similar tasks, while the present invention significantly improves the efficiency and consistency of data collection through the collaborative work of single-wavelength six channels.

[0018] 2. The combined spectroscopic technology of interference filter and dichroic mirror is used to replace the traditional FP spectroscopic solution, which greatly simplifies the structural design of the spectroscopic system. The precise spectroscopic analysis of six independent channels can extract signals with different physical meanings (such as 354nm high-order rotation Raman signal, 353nm low-order rotation Raman signal, 386nm nitrogen Raman signal, etc.), and combined with photoelectric detectors and high-speed data acquisition devices, high-sensitivity detection of weak Raman signals is achieved.

[0019] 3. The light source uses a 355nm narrow pulse width, high repetition rate, high energy LD pump laser, with a single pulse energy ≥ 60mJ and a frequency ≥ 100Hz. Compared with the traditional lamp pump light source (10Hz, life span of only 50 million times), it greatly improves the signal excitation efficiency and the long-term stability of the system. At the same time, with the beam shaping components (beam expander and reflector), the beam divergence control is further optimized to ensure that the backscattered signal of the laser and the atmosphere has higher stability and signal-to-noise ratio.

[0020] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0022] Figure 1 It is a structural schematic diagram of the single-wavelength six-channel Raman-Mi temperature and humidity profile laser radar detection system of the present invention. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] See also Figure 1 In an embodiment of the present invention, a highly efficient single-wavelength six-channel Raman lidar atmospheric temperature and humidity profile detection system is provided, the system comprising: A laser emission system configured to emit a 355nm narrow pulse width, high repetition rate, high energy laser beam, the laser emission system comprising an LD pump laser, a beam expander and a reflector; the laser emission system optimizes the beam divergence angle of the laser beam through the beam expander to improve the excitation efficiency of the backscattered signal in the atmosphere, the LD pump laser having a single pulse energy of ≥60mJ and a frequency of ≥100Hz; A receiving system, comprising a Cassegrain reflecting telescope and a beam terminator, the receiving system being used to receive backscattered echo signals from the atmosphere and collimate the echo signals through a collimation system; The spectroscopic system includes a dichroic mirror, an interference filter and a polarization spectroscopic prism. The spectroscopic system separates the received echo signal into six independent wavelength signals, namely: The 354nm high-order rotational Raman signal and 353nm low-order rotational Raman signal generated by Raman scattering; 355nm parallel polarized light and 355nm vertical polarized light generated by elastic scattering; The 386nm nitrogen Raman signal and 407nm water vapor Raman signal generated by Raman scattering; A data acquisition system, which includes a photoelectric detector and a high-speed data acquisition device, is used to perform photoelectric conversion and acquisition on the six independent signals separated by the optical splitting system; The terminal control system includes a control module and a computer system, wherein the control module is used for power supply and module control, and the computer system is used for generating and displaying the concentration profile, temperature profile and humidity profile of aerosol in the atmosphere through an inversion algorithm based on the collected signals.

[0025] As a further solution of the present invention, the beam expander of the laser emission system is used to shape the 355nm laser beam to reduce the beam divergence angle of the beam, improve the interaction efficiency between the laser and atmospheric components, and optimize the intensity and stability of the backscattered signal.

[0026] As a further solution of the present invention, the Cassegrain reflecting telescope in the receiving system realizes efficient reception and collimation of signals through a collimating lens combination, and reduces the interference of stray light in combination with the design of a beam terminator, thereby improving the signal-to-noise ratio of the received backscattered signal.

[0027] As a further solution of the present invention, the optical splitting system preliminarily separates the echo signal according to the wavelength range through a dichroic mirror, and the signal with a wavelength less than 360nm is reflected by the dichroic mirror, and the signal with a wavelength greater than 360nm passes through the dichroic mirror; the separated signal is further accurately purified by an interference filter, thereby obtaining: 354nm high-order rotational Raman signal; 353nm low-order rotational Raman signal; 386nm nitrogen Raman signal; 407nm water vapor Raman signal; 355nm parallel polarized light; 355nm vertically polarized light.

[0028] As a further solution of the present invention, the photodetector is designed with six independent channels, which are respectively used to receive and convert 354nm high-order rotational Raman signals, 353nm low-order rotational Raman signals, 355nm parallel polarized light, 355nm vertically polarized light, 386nm nitrogen Raman signals and 407nm water vapor Raman signals. The photodetector has high-sensitivity detection capabilities for weak Raman signals.

[0029] As a further solution of the present invention, the high-speed data acquisition device can synchronously acquire and process six-channel signals, and in combination with the inversion algorithm of the terminal control system, the acquired signals are converted in real time into: Temperature vertical profile; Humidity vertical profile; Aerosol concentration profiles; And it is presented in the form of data products.

[0030] As a further solution of the present invention, the inversion algorithm of the terminal control system is based on the time resolution and intensity distribution of the echo signal, generates multi-parameter distribution information of atmospheric temperature, humidity and aerosols through model calculation, and supports real-time detection with high temporal and spatial resolution.

[0031] As a further solution of the present invention, the overall design structure of the system is compact, suitable for remote field monitoring and unmanned long-term operation scenarios, and achieves all-weather efficient detection by optimizing the efficiency of scattered signal reception and data processing.

[0032] Embodiment 1: This embodiment provides a specific application scenario and implementation method of a single-wavelength six-channel Raman-Mie temperature and humidity profile lidar detection system, which is used to demonstrate the significant advantages of the technical solution of the present invention in practical applications.

[0033] In practical applications, high-altitude vertical profile detection of atmospheric temperature, humidity and aerosol concentration is usually used for meteorological research, atmospheric pollution monitoring and climate change assessment. For example, to study the changing patterns of atmospheric temperature and humidity during the monsoon in a certain region, it is necessary to conduct long-term continuous monitoring of the temperature, humidity and aerosol concentration distribution at different altitudes with high temporal and spatial resolution. However, traditional lidar is difficult to meet this requirement due to its short light source life, complex spectroscopic system and insufficient signal detection accuracy. The application of this system in this scenario is as follows: First, the laser emission system is started, and a 355nm high repetition rate (≥100Hz), narrow pulse width, and high energy (single pulse energy ≥60mJ) laser beam is generated through the LD pump laser. The emitted laser beam is shaped and optimized by the beam expander to reduce the beam divergence angle, thereby maintaining a high energy density when passing through the atmosphere. The expanded laser is guided into the atmosphere through a reflector, and Raman scattering and elastic scattering occur with nitrogen, oxygen, water vapor, and aerosol particles in the atmosphere.

[0034] Subsequently, the Cassegrain reflecting telescope in the receiving system captures the backscattered signal and collimates it through a collimating lens combination. In order to reduce the interference of stray light in the environment on the signal, the receiving system is equipped with a beam terminator to effectively shield external noise light. This design is particularly suitable for night monitoring or observation in urban areas with heavy light pollution.

[0035] After being collimated, the received signal enters the spectroscopic system. The system uses a dichroic mirror to perform preliminary separation of the signal in the wavelength range, for example, reflecting the short-waveband signal with a wavelength less than 360nm to the interference filter, and transmitting the long-waveband signal with a wavelength greater than 360nm to another set of filters. Subsequently, the interference filter further purifies the reflected signal, accurately separating the 354nm high-order rotation Raman signal, the 353nm low-order rotation Raman signal, the 386nm nitrogen Raman signal, and the 407nm water vapor Raman signal; at the same time, the 355nm elastic scattering signal in the transmission signal is further separated into 355nm parallel polarized light and 355nm vertically polarized light by a polarization splitter prism. This six-channel spectroscopic scheme ensures the wavelength independence and purity of each signal.

[0036] The signals after spectroscopic processing enter the photoelectric detector in the data acquisition system, and the signals of the six channels are synchronously received and converted into electrical signals. These electrical signals are collected in real time by the high-speed data acquisition device and processed by the inversion algorithm of the terminal control system to generate atmospheric physical parameters in the form of vertical profiles, including temperature, humidity and aerosol concentration distribution.

[0037] Specifically, in a practical application, the system was deployed at a monitoring station in a mountainous area to observe the changes in high-altitude humidity during the monsoon period for a long time. Through the light beam emitted by a 355nm high-frequency laser, the system collects data at a frequency of 100Hz. Compared with the traditional 10Hz lamp pump light source, the data sampling rate is increased by 10 times, ensuring the accurate capture of key meteorological events (such as sudden changes in humidity, changes in aerosol transport paths, etc.) during the monitoring process. At the same time, the interference filter and polarization beam splitter prism in the spectroscopic system ensure the high purity of the signal and avoid the error accumulation caused by environmental vibration or temperature drift in traditional FP spectrometry. Under the synergistic effect of multi-channel synchronous acquisition, the temperature, humidity and aerosol vertical profiles generated by the system clearly reflect the meteorological characteristics of different altitude layers, providing high-precision data support for the correction of regional meteorological models.

[0038] In addition, the system can work continuously for several months in unattended mode through compact structural design and low power operation, solving the problem of unstable operation caused by complex structure and difficult optical path debugging in traditional systems in field monitoring. For example, in a northern dust weather research project, this system used six channels to detect the vertical distribution of aerosols in real time, clearly capturing the variation of dust particle concentration with height, and providing an important reference for accurate modeling of dust transport paths.

[0039] It can be seen from the description of this embodiment that this system achieves high temporal and spatial resolution, multi-parameter synchronous measurement and long-term stable operation that are difficult to achieve with traditional technologies through the high-frequency and high-energy design of the light source, high-precision purification of the spectroscopic technology and multi-channel synchronous detection, especially showing unexpected technical effects in complex environments. This system not only meets the research needs of meteorology and environmental science, but also provides an efficient and reliable technical means for disaster warning and long-term climate monitoring.

[0040] Embodiment 2: This embodiment demonstrates the application scenario of the present invention in air pollution monitoring in a complex urban environment, and reflects the advantages of the system in high-precision detection and engineering operation.

[0041] In urban air quality monitoring, the key to achieving refined governance is to quickly identify the distribution of aerosols and pollutant gases. For example, an industrial city often experiences a sudden increase in pollutant concentrations due to the influence of surrounding factory emissions and meteorological conditions. In order to study the law of pollution diffusion, it is necessary to dynamically monitor the aerosol concentration and related temperature and humidity data at different levels in the high altitude to evaluate the pollution source and its diffusion path.

[0042] System deployment and startup: The single-wavelength six-channel Raman-mi temperature and humidity profile lidar system of the present invention is deployed on the top of a high-rise building in the city center. After the system is started, the LD pump laser generates a 355nm narrow pulse width, high repetition rate, and high-energy laser beam, which is shaped by the beam expander and emitted into the atmosphere, where elastic scattering and Raman scattering occur with aerosol particles and gas molecules. Since the light source has a high frequency (≥100Hz) and stable energy output (≥60mJ), dynamic monitoring with high time resolution can be achieved under conditions of rapid changes in pollutant concentrations.

[0043] Signal reception and spectroscopic processing: The echo signal is received by a Cassegrain reflecting telescope, and the beam terminator is used to reduce the interference of stray light from strong solar radiation and city night lights. The received echo signal passes through a collimating lens and enters the spectroscopic system.

[0044] The interference filter and dichroic mirror of the spectrometer system accurately separate the echo signals and extract: 354nm and 353nm Raman signals are used to analyze the vertical profile of atmospheric temperature; 355nm parallel polarized light and 355nm vertical polarized light are used to evaluate the polarization characteristics of aerosol particle size; 386nm and 407nm Raman signals are used to analyze the vertical distribution of atmospheric water vapor. These separated signals are synchronously processed by photoelectric detectors and high-speed data acquisition systems to ensure the time consistency of data in each channel.

[0045] Data inversion and pollution tracking: The terminal control system processes the collected multi-channel signals in real time, and inverts information such as temperature and humidity profiles, aerosol concentrations, and polarization characteristics through a dedicated algorithm. The monitoring data clearly shows the trend of aerosol concentration changes at different altitudes. For example, during a certain monitoring period, the system captured a 2-kilometer-high pollutant transport layer, whose aerosol concentration was significantly higher than other altitude layers. By analyzing wind direction and humidity changes, it was further inferred that the pollution source came from the industrial area in the north of the city.

[0046] All-weather operation and urban governance: The system works continuously in unattended mode. Through compact design and low-power operation, it solves the problem of limited space and difficult operation and maintenance of monitoring equipment in urban environments. In practical applications, the six-channel synchronous detection of the present invention significantly improves data accuracy. Compared with the traditional single-channel system, it can simultaneously provide the vertical distribution of pollutants and their dynamic changes, providing refined data support for urban air pollution control.

[0047] For example, in one monitoring session, the system detected that the concentration of pollutants increased rapidly after sunrise, while the humidity in the upper air dropped significantly. By analyzing the optical properties of aerosols and temperature and humidity data, it was found that the pollution source may be related to the morning emissions from ground industrial areas. This discovery provides data basis for relevant departments to optimize the time of industrial emissions.

[0048] In summary, this embodiment demonstrates the significant advantages of the present invention in monitoring multi-parameter atmospheric information in complex urban environments, not only achieving high-precision dynamic monitoring, but also providing strong technical support for urban air pollution control and emergency response. This scenario application highlights the innovation and practicality of the system in terms of real-time, precision and engineering, and solves the technical problem that traditional lidar systems are difficult to cope with the needs of complex urban environments.

[0049] Embodiment 3: This embodiment combines Figure 1 The structure and working principle of a single-wavelength six-channel Raman-Mie temperature and humidity profile lidar detection system are described in detail to demonstrate its specific implementation in practical applications.

[0050] As shown in the figure, the laser radar detection system of the present invention is composed of a laser emission system, a receiving system, a spectroscopic system, a data acquisition system and a terminal control system, and each part forms a complete measurement system through signal and data interaction.

[0051] The laser emission system includes a laser, a beam expander and a reflector. The LD pump laser generates a narrow pulse width, high repetition rate, and high energy laser beam with a central wavelength of 355nm. The laser beam is shaped by a beam expander to reduce the beam divergence angle and increase the energy density of the laser when it is transmitted in the atmosphere. The optical path is adjusted with a reflector to ensure that the laser beam is emitted into the atmosphere in a vertical direction and scatters with the atmospheric components.

[0052] The receiving system adopts a Cassegrain reflecting telescope structure, including a primary mirror and a secondary mirror, which is used to efficiently collect the backscattered signal returned from the atmosphere. A collimating lens is set at the bottom of the telescope to ensure the consistency of the optical path of the signal, and a beam terminator is equipped to reduce the interference of stray light on the sensitivity of the system. The received signal is guided to the spectroscopic system for further processing.

[0053] The spectroscopic system uses multi-stage spectroscopic technology, including components such as color mirrors, interference filters, and polarization spectroscopic prisms, to perform spectral separation and purification on the received optical signals. The specific spectroscopic process is as follows: The echo signal is initially separated by wavelength through the color mirror 1, transmitting the signal with a wavelength greater than 360nm and reflecting the signal with a wavelength less than 360nm.

[0054] After the reflected signal is processed by filter 1 and filter 2, the 354nm high-order rotational Raman signal and the 353nm low-order rotational Raman signal are separated and enter detector 1 and detector 2 respectively.

[0055] The 355 nm elastic scattered light in the transmission signal is divided into parallel polarized light and vertical polarized light by a polarization beam splitter prism and received by detector 3 and detector 4 respectively.

[0056] Another part of the transmission signal is separated into signals with wavelengths of 386 nm and 407 nm by color mirror 2, which are purified by filters 5 and 6 respectively to obtain 386 nm nitrogen Raman signals and 407 nm water vapor Raman signals, which enter detectors 5 and 6 respectively.

[0057] The data acquisition system is connected to the detector and is used to synchronously collect the photoelectric signals of six channels. The acquisition system amplifies and digitizes the signals to form electrical signals that can be used for inversion calculation.

[0058] The terminal control system includes a control module and a computer system. The control module is responsible for the synchronous triggering of the laser and the coordinated distribution of the system power supply. The computer system runs the inversion algorithm to process the six-channel signals into data products such as atmospheric temperature profiles, humidity profiles and aerosol concentration profiles, and display them in a visual form.

[0059] When the system is running, the laser emits high-energy 355nm laser at a frequency of ≥100Hz. The light beam undergoes Raman scattering and elastic scattering with aerosol particles, water vapor, nitrogen and oxygen molecules in the atmosphere. The generated backscattered signals are collected by the receiving system and imported into the spectroscopic system. The spectroscopic system accurately separates the signals by wavelength, so that the six detection channels can obtain Raman or elastic scattering signals with different physical meanings. Subsequently, the data acquisition system synchronously collects the signals and sends them to the terminal control system for inversion calculation, and finally generates meteorological parameter data with high temporal and spatial resolution.

[0060] This system realizes real-time synchronous detection of atmospheric temperature, humidity and aerosol vertical profiles through efficient multi-channel spectroscopic design and compact structural integration. Compared with traditional single-channel or complex optical debugging systems, this system has achieved significant improvements in signal purification, separation accuracy and engineering operation stability, providing a reliable and efficient solution for meteorological monitoring and atmospheric environment research.

[0061] Embodiment 4: See also Figure 1The present invention provides a single-wavelength six-channel Raman-Mi temperature and humidity profile lidar detection system, which emits laser through a high-power 355nm laser, receives atmospheric echo signals through a large-aperture telescopic receiving system, performs spectral separation through a spectroscopic system, and collects data through a collection system after photoelectric conversion through a photoelectric detector, and finally processes and displays radar data products through a terminal control system.

[0062] The laser uses an LD pump laser, which can achieve the emission of a 355nm single-beam laser. The central wavelength is selected as 355nm, the frequency is ≥100Hz, and the single pulse energy is ≥60mJ. The laser shaping system includes a beam expander and a reflector, wherein the beam expander can be integrated inside the laser or connected to the outside of the laser separately to achieve beam shaping of the output laser and suppress the beam divergence angle of the output laser. The reflector of this system is used to return the laser beam to ensure that the laser beam can be incident into the atmosphere. The reflector can be manually adjusted using a fixed adjustment frame, or it can be adjusted by software using an electric adjustment frame. The reflector can be increased or decreased according to the adjustment method.

[0063] A beam terminator is designed to be placed at the front end of the receiving system to reduce the optical noise generated by the external stray light of the radar entering the telescope. The design form of the beam terminator can be matched in multiple types according to the application scenario. The main system of the telescope adopts a Cassegrain reflection structure to receive the backscattered echo signal in the atmosphere. The collimation system at the bottom uses an optical lens combination for beam collimation, which is not limited to a single convex lens or a concave-convex lens combination.

[0064] After the atmospheric echo signal received by the telescope enters the spectroscopic system through the collimation system at the bottom of the telescope, it is split and purified by a dichroic mirror, an interference filter, and a polarization beam splitter prism. After being reflected by the broadband reflector 1 and the color mirror 1, the long-wave spectrum greater than 360nm passes through the color mirror 1, and the short-wave spectrum less than 360nm is reflected by the color mirror 1. The spectrum reflected by the color mirror 1, the wavelength reflected by the filter 1 passes through the filter 2 at a specific angle, and the 354nm light is separated. The first light is photoelectrically converted by the detector 1, and part of the light is reflected by the filter 2, and then passes through the filter 3 at a specific angle, and the 353nm light is separated. The second light is photoelectrically converted in the detector 2. After the wavelength transmitted by the filter 1 is purified by the narrowband filter 4, it is separated into 355nm parallel light and 355nm vertical light by the polarization beam splitter prism 1. The third and fourth lights are photoelectrically converted in the detectors 3 and 4 respectively. The spectrum transmitted through the color mirror 1 is separated at the color mirror 2, and the spectrum with a wavelength less than 390nm is reflected by the color mirror 2, and then purified by the narrow-band filter 5 to obtain a 386nm spectrum, and the fifth light is photoelectrically converted by the detector 5. The spectrum with a wavelength greater than 390nm is transmitted through the color mirror 2, and then purified by the narrow-band filter 6 to obtain a 407nm spectrum, and the sixth light is photoelectrically converted by the detector 6. The above is only one example of spectrum splitting implementation in this case.

[0065] After being spectroscopically processed by the multi-channel spectroscopic system, the independent atmospheric echo signals enter the detector for photoelectric conversion respectively, and are collected by the shielded signal access data acquisition system. The detector and high-speed acquisition system used in the present invention have the ability to detect and collect weak signals, and can realize the photoelectric conversion and collection of Raman signals.

[0066] It is composed of a control system and a computer system. The control system is responsible for power supply, module control and other functions. The collected data is processed by the computer system, and the inversion data is presented in the software to obtain the vertical profile of the concentration of aerosol data products in the atmosphere, such as temperature profile, humidity profile, extinction coefficient profile, etc. The multi-channel signal reception is simultaneous, realizing the synchronous real-time detection of multiple parameters of the radar.

[0067] In summary, the present invention describes a single-wavelength six-channel Raman-Mie temperature profile lidar detection system, which realizes the synchronous and simultaneous detection of multiple factors such as atmospheric temperature, humidity, and aerosols.

[0068] The invention remotely monitors atmospheric temperature and humidity changes, and adopts a narrow pulse width, high repetition rate, and high energy 355nm laser to realize the monitoring of meteorological elements such as temperature, humidity, and aerosols on the vertical profile of the atmosphere with high temporal and spatial resolution; the 100Hz frequency laser is used, which is 10 times higher than the traditional low 10Hz frequency lamp pump laser light source, and has a long life and is easy to maintain, which can meet the requirements of long-term uninterrupted operation monitoring. The interference filter scheme is used to effectively separate and extract elastic signals and Raman signals, achieving the advantages of simple spectral splitting, compact structure, and simple optical path debugging.

[0069] In the present invention, unless otherwise clearly stipulated and limited, the terms "installation", "setting", "connection", "fixation", "screw-on" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0070] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. An efficient single-wavelength six-channel Raman lidar atmospheric temperature and humidity profile detection system, characterized in that: The system includes: A laser emission system configured to emit a 355nm narrow pulse width, high repetition rate, high energy laser beam, the laser emission system comprising an LD pump laser, a beam expander and a reflector; the laser emission system optimizes the beam divergence angle of the laser beam through the beam expander to improve the excitation efficiency of the backscattered signal in the atmosphere, the LD pump laser having a single pulse energy of ≥60mJ and a frequency of ≥100Hz; A receiving system, comprising a Cassegrain reflecting telescope and a beam terminator, the receiving system being used to receive backscattered echo signals from the atmosphere and collimate the echo signals through a collimation system; The spectroscopic system includes a dichroic mirror, an interference filter and a polarization spectroscopic prism. The spectroscopic system separates the received echo signal into six independent wavelength signals, namely: 354nm Raman signal and 353nm Raman signal generated by Raman scattering; 355nm parallel polarized light and 355nm vertical polarized light generated by elastic scattering; The 386nm nitrogen Raman signal and 407nm water vapor Raman signal generated by Raman scattering; A data acquisition system, which includes a photoelectric detector and a high-speed data acquisition device, is used to perform photoelectric conversion and acquisition on the six independent signals separated by the optical splitting system; The terminal control system includes a control module and a computer system, wherein the control module is used for power supply and module control, and the computer system is used for generating and displaying the concentration profile, temperature profile and humidity profile of aerosol in the atmosphere through an inversion algorithm based on the collected signals.

2. According to claim 1, a high-efficiency single-wavelength six-channel Raman lidar atmospheric temperature and humidity profile detection system is characterized in that: The beam expander of the laser emission system is used to perform beam shaping on the 355nm laser beam to reduce the beam divergence angle of the beam, improve the interaction efficiency between the laser and atmospheric components, and optimize the intensity and stability of the backscattered signal.

3. According to claim 1, a high-efficiency single-wavelength six-channel Raman lidar atmospheric temperature and humidity profile detection system is characterized in that: The Cassegrain reflecting telescope in the receiving system realizes efficient reception and collimation of signals through a collimating lens combination, and reduces the interference of stray light in combination with the design of a beam terminator, thereby improving the signal-to-noise ratio of the received backscattered signal.

4. According to claim 1, a high-efficiency single-wavelength six-channel Raman lidar atmospheric temperature and humidity profile detection system is characterized in that: The spectroscopic system preliminarily separates the echo signal according to the wavelength range through a dichroic mirror. The signal with a wavelength less than 360nm is reflected by the dichroic mirror, and the signal with a wavelength greater than 360nm passes through the dichroic mirror. The separated signal is further accurately purified through an interference filter, thereby obtaining: 354nm high-order rotational Raman signal; 353nm low-order rotational Raman signal; 386nm nitrogen Raman signal; 407nm water vapor Raman signal; 355nm parallel polarized light; 355nm vertically polarized light.

5. According to claim 1, a high-efficiency single-wavelength six-channel Raman lidar atmospheric temperature and humidity profile detection system is characterized in that: The photodetector is designed with six independent channels, which are respectively used to receive and convert 354nm high-order rotational Raman signals, 353nm low-order rotational Raman signals, 355nm parallel polarized light, 355nm vertically polarized light, 386nm nitrogen Raman signals and 407nm water vapor Raman signals. The photodetector has high-sensitivity detection capabilities for weak Raman signals.

6. The high-efficiency single-wavelength six-channel Raman lidar atmospheric temperature and humidity profile detection system according to claim 1 is characterized in that: The high-speed data acquisition device can synchronously acquire and process six-channel signals, and combined with the inversion algorithm of the terminal control system, the acquired signals are converted into: Temperature vertical profile; Humidity vertical profile; Aerosol concentration profile.

7. The high-efficiency single-wavelength six-channel Raman lidar atmospheric temperature and humidity profile detection system according to claim 1 is characterized in that: The inversion algorithm of the terminal control system is based on the time resolution and intensity distribution of the echo signal, generates multi-parameter distribution information of atmospheric temperature, humidity and aerosols through model calculation, and supports real-time detection with high temporal and spatial resolution.

8. The high-efficiency single-wavelength six-channel Raman lidar atmospheric temperature and humidity profile detection system according to claim 1, characterized in that: The system is suitable for remote field monitoring and unmanned long-term operation scenarios, and achieves efficient detection around the clock by optimizing the efficiency of scattered signal reception and data processing.

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