CN108919301B - Multi-wavelength ozone laser radar based on single photon CCD - Google Patents
Multi-wavelength ozone laser radar based on single photon CCD Download PDFInfo
- Publication number
- CN108919301B CN108919301B CN201810800130.1A CN201810800130A CN108919301B CN 108919301 B CN108919301 B CN 108919301B CN 201810800130 A CN201810800130 A CN 201810800130A CN 108919301 B CN108919301 B CN 108919301B
- Authority
- CN
- China
- Prior art keywords
- laser
- wavelength
- ozone
- photon
- raman
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/88—Lidar systems specially adapted for specific applications
- G01S17/95—Lidar systems specially adapted for specific applications for meteorological use
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/481—Constructional features, e.g. arrangements of optical elements
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/481—Constructional features, e.g. arrangements of optical elements
- G01S7/4818—Constructional features, e.g. arrangements of optical elements using optical fibres
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
- Y02A90/10—Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Computer Networks & Wireless Communication (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Electromagnetism (AREA)
- Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)
Abstract
The invention discloses a multi-wavelength ozone laser radar based on a single photon CCD, which comprises: the device comprises an Nd-YAG quadruple frequency laser, an optical lens, a Raman tube, a beam expander, a plane mirror, an optical receiving module, a spectroscopic spectrometer, a detection module and a data acquisition and synchronous control unit. The invention generates multi-wavelength laser based on the stimulated Raman of the single Raman tube, and can carry out high-precision measurement on the ozone concentration in a larger vertical height range by carrying out differential inversion on echo signals of different wavelength pairs. In addition, the use of the single-photon CCD not only simplifies the composition of a detection part and reduces the measurement error caused by the difference of detectors, so that the laser radar device has larger upgrading space, but also increases the maximum measurement height of the device due to the high sensitivity of single-photon detection.
Description
Technical Field
The invention relates to the field of ozone differential absorption laser radar devices, in particular to a multi-wavelength ozone laser radar based on single photon CCD.
Background
Ozone is a key component of the atmosphere, about 90 percent of ozone exists in a stratosphere which is 10km to 50km away from the ground surface, and the ozone can absorb ultraviolet rays in sunlight, so that organisms on the earth are prevented from being directly irradiated by the ultraviolet rays; the rest 10 percent of ozone exists in a troposphere which is closer to the ground surface, the ozone is involved in photochemical reaction in the atmosphere and plays an important role in atmospheric pollution of the troposphere, and in addition, the high ozone content can stimulate and damage mucous membrane tissues such as eyes, respiratory systems and the like, thereby having negative effects on human health. Therefore, the measurement of ozone space-time distribution has very important significance, and currently, remote sensing observation based on differential absorption laser radar is an important means for ozone measurement.
The differential absorption radar detects the echo signal and carries out inversion to obtain the concentration of the target gas by transmitting two beams of pulse laser respectively positioned in a stronger wave band and a weaker wave band of the target gas absorption. In the measurement of the differential absorption radar, the selection of the laser wavelength is very important, on one hand, the absorption difference of the target gas corresponding to the two wavelengths is as large as possible so as to increase the differential signal; on the other hand, the wavelength difference between the two laser beams cannot be too large, so that the system deviation caused by the backscattering difference and the aerosol extinction difference under different wavelengths is reduced.
Ozone molecules have stronger continuous absorption bands near 260nm, and can be used for remote sensing measurement of ozone. The acquisition of an ultraviolet light source is a difficult point of an ozone laser radar device, and the common method is to quadruple frequency Nd-YAG laser to obtain 266nm ultraviolet light, and then charge H into the obtained ultraviolet light2Or D2The Raman tube can excite the stimulated Raman process to obtain ultraviolet laser with different wavelengths.
The inventors of the present invention found that: in the currently commonly used differential absorption lidar device, a detector is a detection system combined by a plurality of photomultiplier tubes and is used for measuring multi-wavelength echo signals. However, such a combination of detectors not only further complicates the apparatus, but also causes systematic deviations in the lidar measurements due to differences in the response capabilities of the individual detectors.
Disclosure of Invention
The invention aims to provide a multi-wavelength ozone laser radar based on a single Raman tube light source, which has the advantages of simple structure, good light beam consistency, large detection range, compact structure, high measurement result precision, continuous work in day and night and the like.
The purpose of the invention is realized by the following technical scheme:
the method comprises the following steps: the device comprises a laser light source, a Raman tube, an optical emission module, an optical receiving module, a spectral spectrometer, a single photon CCD (charge coupled device), a photon counter and a main control module;
the laser light source is used for outputting laser light, and the laser light comprises first wavelength laser light; the first wavelength is located in an absorption band of ozone;
the Raman tube is used for receiving laser input by the laser light source and generating Raman scattering light with at least two wavelengths; the Raman scattering light comprises second wavelength laser and third wavelength laser;
the optical emission module is used for emitting laser emitted by the Raman tube to a detection target;
the optical receiving module is used for collecting echo signals returned by the detection target;
the spectral spectrometer is used for carrying out spatial separation on the echo signals with different wavelengths collected by the optical receiving module;
the single-photon CCD is used for performing photoelectric conversion on a plurality of echo signals with different wavelengths output by the spectrometer;
the photon counter is used for recording the number of photons measured by the single photon CCD and sending the recorded information to the main control module;
the main control module is used for processing the information sent by the photon counter so as to obtain target information of a target position; the target information includes an ozone concentration.
The laser light source is an Nd-YAG laser; the first wavelength is 266 nm; the second wavelength is 289nm, and the third wavelength is 299 nm; the Raman tube is filled with H2、D2And a buffer gas, said D2For generating Raman scattered light at 289nm, said H2For generating 299nm Raman scattered light; the buffer gas is used for suppressing laser mixing in the Raman tube.
Further, the optical spectrometer comprises a grating and a beam splitter, wherein the grating is used for separating laser signals with different wavelengths output by the optical receiving module, and the beam splitter is used for splitting the received laser with the second wavelength into two beams, wherein one beam is a first branch occupying a percentage of A%, the other beam is a second branch occupying a percentage of B%, and B is greater than A; the first wavelength laser beam and the first shunt form a first channel; the second branch and the third wavelength laser form a second channel; and the first channel is provided with an attenuation element which is used for attenuating the optical signal energy of the first channel.
Furthermore, the spectrometer also comprises at least a first slit, a second slit and a third slit, wherein the first slit is used for enabling the first wavelength laser separated by the grating to pass through and filtering other wavelength laser signals; the second slit is used for enabling second wavelength laser separated by the grating to pass through and filtering other wavelength laser signals; the third slit is used for enabling the third wavelength laser separated by the grating to pass through and filtering laser signals with other wavelengths.
The difference between the width of the first slit and the diameter of the light spot of the first wavelength laser is less than 0.1 nm; preferably, the first slit width is the same as the spot diameter of the first wavelength laser.
The difference between the width of the second slit and the diameter of the light spot of the laser with the second wavelength is less than 0.1 nm; preferably, the second slit width is the same as the spot diameter of the second wavelength laser.
The difference between the width of the third slit and the diameter of the light spot of the third wavelength laser is less than 0.1 nm; preferably, the third slit width is the same as the spot diameter of the laser light of the third wavelength.
Furthermore, the main control module comprises a time sequence control unit and a data processing unit; the time sequence control unit is used for respectively controlling the working time sequences of different pixels on the single-photon CCD and realizing the independent control of the measurement time of each wavelength echo signal;
furthermore, the time sequence control unit is respectively connected with the laser light source and the single-photon CCD, and is used for controlling the pixel on the single-photon CCD for collecting the first channel to work after the laser light source emits the first time interval of the laser pulse; the single-photon CCD is used for acquiring pixels of a first channel and controlling the pixels on the single-photon CCD to work after a first time interval when the laser source emits laser pulses; the second time interval is greater than the first time interval.
Further, the device also comprises a first optical lens and a second optical lens; the optical emission module comprises a beam expander and a plane mirror; the first optical lens is used for focusing laser emitted by the laser light source to the Raman tube; the second optical lens is used for converging the laser emitted by the Raman tube; the plane mirror is used for reflecting the laser emitted by the beam expander to a target direction.
Further, the grating is a holographic grating or a blazed grating.
Further, the buffer gas is Ar or He.
Further, the laser light source is also used for generating fourth wavelength laser light; and the fourth wavelength laser is used for measuring atmospheric aerosol information.
Further, the Raman tube is also used for generating 316nm laser; the combination of the 316nm laser and the 299nm laser is used for measuring the ozone concentration information of the target position.
According to the technical scheme provided by the invention, the single Raman tube can generate multi-wavelength laser, and the difference inversion is carried out by using the echo signals of different wavelength combinations, so that the ozone concentration can be measured with high precision in a larger vertical height range; the use of the single Raman tube not only simplifies the device, but also reduces the difference of the geometrical factors of the emitted laser and reduces the measurement error. Mutual interference among echo signals with different wavelengths is eliminated through the light splitting spectrometer, the influence of background sunlight can be reduced to a great extent, and the ozone laser radar device has the capability of continuous measurement day and night. The use of single photon CCD simplifies the composition of the detecting part, reduces the measuring error caused by the difference of the detectors, makes the laser radar device have larger upgrading space, and increases the maximum measuring height of the device by benefiting from the high sensitivity of single photon detection.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions and advantages of the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a schematic structural diagram of a multi-wavelength ozone laser radar based on single photon CCD provided by an embodiment of the present invention;
FIG. 2 is another schematic structural diagram of a multi-wavelength ozone laser radar based on single photon CCD provided by an embodiment of the present invention;
fig. 3 is a schematic structural diagram of a spectrometer of a multi-wavelength ozone lidar based on a single photon CCD according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
Example (b):
fig. 1 is a schematic structural diagram of a multi-wavelength ozone lidar based on a single photon CCD, which includes: the device comprises a laser light source 1, a Raman tube 3, an optical emission module, an optical receiving module 7, a spectrometer 9, a single photon CCD10, a photon counter 11 and a main control module 12;
the laser light source 1 is used for outputting laser light, and the laser light comprises first wavelength laser light; the first wavelength is located in an absorption band of ozone.
It should be noted that ozone has multiple absorption bands, and can absorb ultraviolet light of 200-320 nm, and the currently common method for measuring ozone uses a light source with a wavelength of 266nm, but the present invention is not limited to a laser light source with a wavelength of 266nm, and other wavelengths, such as 290nm and 300nm, are suitable for the present invention as long as ozone can be measured.
The Raman tube 3 is used for receiving laser input by the laser light source 1 and generating Raman scattering light with at least two wavelengths; the Raman scattered light comprises laser light of a second wavelength and laser light of a third wavelength. And the wavelength difference between the second wavelength laser and the third wavelength laser is not more than 5 nm.
In one embodiment, the laser light source 1 is a Nd-YAG laser; the first wavelength is 266 nm; the second wavelength is 289nm, and the third wavelength is 299 nm; the Raman tube 3 is filled with H2、D2And a buffer gas, said D2For generating Raman scattered light at 289nm, said H2For generating 299nm pull(ii) a raman scattered light; the buffer gas is used for suppressing laser mixing in the Raman tube.
The optical emission module is used for emitting laser emitted by the Raman tube 3 to a detection target.
The optical receiving module 7 is used for collecting echo signals returned by the detection target.
The spectrometer 9 is used for spatially separating the echo signals with different wavelengths collected by the optical receiving module 7.
The single-photon CCD10 is used for performing photoelectric conversion on echo signals of a plurality of different wavelengths output by the spectroscopic spectrometer 9.
The photon counter 11 is used for recording the number of photons measured by the single photon CCD and sending the recorded information to the main control module 12.
The main control module 12 is configured to process information sent by the photon counter 11, so as to obtain target information of a target position; the target information includes an ozone concentration.
When the laser signal output by the laser light source 1 includes a plurality of wavelengths, the target information may further include information such as atmospheric aerosol.
Further, the optical spectrometer 9 includes a grating for separating laser signals with different wavelengths output by the optical receiving module 7 and a beam splitter. Specifically, when the laser signal received by the spectroscopic spectrometer 9 includes signals of a plurality of wavelengths, the spectroscopic spectrometer 9 spatially separates the signals of each wavelength.
The beam splitter is used for splitting the received second wavelength laser into two beams, wherein one beam is a first branch accounting for A%, and the other beam is a second branch accounting for B%. A + B is 100.
Further, the grating is a holographic grating or a blazed grating. When the grating is a holographic grating, the resolution of the spectrometer 9 is higher, and optical signals with wavelength difference less than 1nm can be distinguished.
The first wavelength laser beam and the first shunt form a first channel; and the second branch and the third wavelength laser form a second channel. The first channel is used for measuring ozone information of a first target position (low layer), and the second channel is used for measuring ozone information of a second target position (high layer); the first target location may be at an elevation of 10km from the ground and the second target location may be at an elevation of 50km from the ground.
Because the echo signal of the lower layer is stronger, in order to avoid the saturation of the detector of the first channel, B > A in the invention.
And the first channel is provided with an attenuation element which is used for attenuating the optical signal energy of the first channel. The attenuation element can be a filter or an attenuation sheet. When the attenuation element is a neutral density filter, the attenuation efficiency is higher, and the laser signal is more suitable for the laser signal of the invention.
Further, the spectrometer 9 further includes at least a first slit, a second slit, and a third slit, where the first slit is used to allow the first wavelength laser light separated by the grating to pass through and filter other wavelength laser signals; the second slit is used for enabling second wavelength laser separated by the grating to pass through and filtering other wavelength laser signals; the third slit is used for enabling the third wavelength laser separated by the grating to pass through and filtering laser signals with other wavelengths.
The difference between the width of the first slit and the diameter of the spot of the laser with the first wavelength is less than 0.5 nm. Preferably, the first slit width is equal to the spot diameter of the laser light of the first wavelength, and in this case, laser signals of other wavelengths can be completely filtered.
The difference between the width of the second slit and the diameter of the laser spot with the second wavelength is less than 0.5 nm. Preferably, the second slit width is the same as the spot diameter of the laser light of the second wavelength, and in this case, laser signals of other wavelengths can be completely filtered.
The difference between the width of the third slit and the diameter of the light spot of the third wavelength laser is less than 0.5 nm. Preferably, the third slit width is equal to the spot diameter of the laser beam of the third wavelength, and in this case, laser signals of other wavelengths can be completely filtered.
Further, the main control module 12 includes a timing control unit and a data processing unit; the time sequence control unit is used for respectively controlling the working time sequences of different pixels on the single-photon CCD10 and realizing the independent control of the measurement time of each wavelength echo signal.
The time sequence control unit is connected with the single-photon CCD10, the single-photon CCD10 comprises a plurality of pixel points, and each pixel point can be independently controlled.
Further, the timing control unit is respectively connected with the laser light source 1 and the single-photon CCD10, and the timing control unit is configured to control the single-photon CCD10 to collect pixels of a first channel after a first time interval when the laser light source 1 emits laser pulses; and the single-photon CCD10 is used for controlling the pixel work of the second channel collected by the single-photon CCD10 after the second time interval of the laser pulse emitted by the laser source 1; the second time interval is greater than the first time interval.
The inventors of the present invention have found that when the first time interval is in the order of sub-microsecond, for example 0.1us-0.2 us; the second time interval is 8-15us, for example, the second time interval is 10us, the detection efficiency can be ensured, and meanwhile, the detector is protected from being damaged to the maximum extent.
Further, the device also comprises a first optical lens 2 and a second optical lens 4; the optical emission module comprises a beam expander 5 and a plane mirror 6; the first optical lens 2 is used for focusing the laser emitted by the laser light source 1 to the Raman tube 3; the second optical lens 4 is used for converging the laser emitted by the Raman tube 3; the plane mirror 6 is used for reflecting the laser emitted by the beam expander 5 to a target direction.
Further, the buffer gas is Ar or He. The buffer gas in the raman tube is preferably Ar, and the raman conversion efficiency using Ar as the buffer gas is higher than He.
The multi-wavelength ozone laser radar based on single photon CCD provided by the invention is explained in detail below. As shown in fig. 1, a multi-wavelength ozone laser radar based on single photon CCD mainly includes: the device comprises a laser light source 1, a first optical lens 2, a Raman tube 3, a second optical lens 4, a beam expander 5, a plane mirror 6, an optical receiving module 7, an optical fiber 8, a spectrometer 9, a single photon CCD10, a photon counter 11 and a main control module 12; wherein:
the laser light source 1 is an Nd-YAG laser; the Nd-YAG quadruple frequency laser is used for generating 266nm laser pulses(ii) a The first wavelength is 266 nm; the second wavelength is 289nm, and the third wavelength is 299 nm; the Raman tube 3 is filled with H2、D2And a buffer gas, said D2For generating Raman scattered light at 289nm, said H2For generating 299nm Raman scattered light; the buffer gas is used for suppressing laser mixing in the Raman tube.
The first optical lens 2 and the second optical lens 4 are used for focusing laser at the middle position of the Raman tube; the Raman tube 3 is used for generating Raman scattering light with the wavelength of 289nm-299 nm; the beam expander 5 is used for adjusting the 266nm-289nm-299nm laser divergence angle obtained from the Raman tube and expanding the light spot to a proper size; the plane mirror 6 is used for changing the propagation direction of the laser to enable the laser to be vertically incident into the atmosphere; the optical receiving module 7 is a Cassegrain telescope and is used for collecting an atmosphere echo signal; the optical fiber 8 is connected with the optical receiving module 7 and is used for transmitting the echo signals collected by the optical receiving module 7; the spectroscopic spectrometer 9 is connected with the optical fiber 8 and used for spatially separating echo signals with different wavelengths collected by the optical receiving module 7; the single-photon CCD10 is used for realizing photoelectric conversion of echo signals with different wavelengths obtained by the spectrometer 9; the photon counter 11 is used for recording the number of photons measured by the single photon CCD; the main control module 12 is an industrial personal computer, and can perform time sequence control on pulse emission of Nd-YAG quadruple frequency laser and signal acquisition of the detection module, process signals acquired by the photon counting unit, and perform inversion to obtain ozone concentration.
The first wavelength laser beam and the first shunt form a first channel; and the second branch and the third wavelength laser form a second channel. 266nm-289nm (A%) to form a first channel for measuring low-altitude ozone; and 289nm (B%) -299nm constitute a second channel for measurement of high altitude ozone.
The working process of the invention is as follows:
the main control module 12 controls the Nd-YAG quadruple frequency laser 1 to emit laser pulses through a serial port, and simultaneously triggers the single-photon CCD to enter a detection preparation state; Nd-YAG quadruple frequency laser 1 emits 266nm laser pulse with high energyLaser pulse is focused on the middle position of a Raman tube 3 after passing through a first optical lens 2, the Raman tube body is made of stainless steel, thickened ultraviolet window sheets are arranged at two ends of the Raman tube, and H is filled in the Raman tube2、D2And Ar at high pressure. The 266nm laser pulse excites the stimulated Raman process in the tube and produces 299nm Raman scattered light by Raman shift of H2, by D2Produces 289nm raman scattered light. Ar in the tube is used as buffer gas, so that a four-wave mixing process can be inhibited, and the conversion efficiency of Raman light at 289nm and 299nm is improved; the laser emitted from the Raman tube is mainly 266nm pump light and 289nm and 299nm stimulated Raman light, the three wavelengths of light have higher consistency in the aspects of divergence angle, spot size, propagation direction and the like, and the laser can be used as a transmitting light source to reduce the measurement error of the ozone laser radar; the laser emitted by the Raman tube is converged by the second optical lens 4 and then becomes parallel light again, and the divergence angle of the laser is adjusted by the beam expander, so that the beam is expanded to a preset size, and the quality of the laser emitted by the radar is further improved; the spread laser changes the propagation direction through the plane mirror 6, and is vertically incident into the atmosphere for measuring the vertical distribution of ozone and obtaining the ozone concentration profile.
The optical receiving module 7 collects echo signals of the emitted laser after atmospheric reflection, and the optical receiving module 7 is a telescope combined by Cassegrain type double mirrors and comprises a paraboloid primary mirror and a hyperboloid secondary mirror.
In one embodiment, as shown in fig. 1, the plane mirror 6 is disposed at one side of the optical receiving module 7, and the laser light emitted from the plane mirror 6 is parallel to and separated from the light received by the optical receiving module 7, which is called a transmit-receive split-axis structure. In another embodiment, as shown in fig. 2, the plane mirror 6 is disposed at the center of the telescope of the optical receiving module 7, so that the emitted laser light is in the receiving field of view of the optical receiving module 7, which is called a transmit-receive coaxial structure. The angle and direction of the emergent laser can be more conveniently adjusted by adjusting the plane mirror 6.
The telescope of the optical receiving module 7 is connected with the optical fiber 8, and the collected echo signals are transmitted to the high-resolution spectrometer 9 through the optical fiber; the spectrometer 9 uses a holographic grating, can perform high resolution spatial separation on echo signals with different wavelengths, and isolate background light outside the wavelength of 266nm-289nm-299nm through three slits, wherein the 289nm echo signal passing through the slit is divided into two parts (B > A) of A% and B% through a beam splitting piece, and at the moment, four beams of spatially separated laser light exist behind the slit, namely 266nm-289nm (A%) -289nm (B%) -299 nm), wherein the 266nm-289nm (A%) forms a first channel for measuring low-altitude ozone; and 289nm (B%) -299nm constitute a second channel for measurement of high altitude ozone. Since the low-altitude echo signal energy is high, the low-altitude echo signal is attenuated by the neutral density filter.
The single-photon CCD10 receives the four beams of light separated by the spectrometer 9 and performs photoelectric conversion, and the four beams of laser light irradiate different areas of the single-photon CCD10, respectively, without interfering with each other. Since the single-photon CCD10 is chosen to allow individual timing control for each pixel. In this way, the timing control unit of the main control module 12 can individually control the measurement time of each echo signal, thereby avoiding the detector saturation and even damage caused by the over-strong initial signal.
The specific switching time sequence of the single-photon CCD is as follows: under the control of the main control module 12, after the Nd-YAG quadruple frequency laser 1 emits laser pulses about 0.1us (a first time interval), a 266nm + a% 289nm pixel part of a first channel on the single-photon CCD for detecting a low-level echo signal starts to perform photoelectric conversion; after about 10us (second time interval), the pixel part of the second channel B% 289+299nm for detecting the high-altitude echo signal starts to work, after the measuring process lasts about 300us, the whole CCD stops photoelectric conversion, the processes are repeated after the next laser pulse is emitted, and the laser radar system can continuously work in the circulating reciprocating mode; photon signals collected by the single photon CCD are recorded by a single photon counter 11; the main control module 12 can perform time sequence control on pulse emission of the Nd-YAG quadruple frequency laser and signal acquisition of the detection module, and process photon signals recorded by the photon counter 11, thereby obtaining the ozone concentration through inversion.
Fig. 3 is a schematic structural diagram of the spectrometer 9 in fig. 1 (or fig. 2). As shown in fig. 3, the outside of the spectrometer is an aluminum square box, one side of which is equipped with an optical fiber coupling head 91 for emitting the received echo signal through an optical fiber, and the other side is an ultraviolet window 92; echo signal 93 is the set of all echo signals; the holographic grating 94 may spatially separate the echo signals of different wavelengths. The echo signal is divided into 266nm echo signals 97 after passing through the holographic grating; 289nm echo signal 96; 299nm echo signal 95.
And the reflector group (910, 911, 912, 913) is used for further adjusting the propagation directions of the echo signals with different wavelengths.
The first slit 914 allows the echo signal of 266nm to pass; the second slit 915 allows passage of an echo signal at 289 nm; the third slit 916 allows the echo signal of 299nm to pass through, while blocking other wavelengths of laser light and background sunlight. The width of the slit is carefully adjusted to be just the same as the diameter of the laser spot passing through, so that the influence of the background sunlight can be minimized under the condition of not causing signal loss.
The optical beam splitter 917 further splits the 289nm echo signal into two parts of a% and B% (B > a), which are used for high-altitude and low-altitude ozone measurement, respectively, wherein the first branch 98 is the 289nm echo signal of a%, and the second branch 99 is the 289nm echo signal of B%. The mirror 913 is used to adjust the propagation direction of the second shunt 99; a neutral density filter set (918, 919), the neutral density filter set 918 being used for attenuating the energy of the 266nm echo signal 97; a neutral density filter 919 is used to attenuate the energy of the first shunt 98 to avoid saturation of the detector. All signals pass through the ultraviolet window 92 and finally irradiate the single-photon CCD.
In one embodiment of the present invention, the laser light source 1 is further configured to generate a fourth wavelength laser light; and the fourth wavelength laser is used for measuring atmospheric aerosol information.
Specifically, the fourth wavelength laser may be 355nm laser, and the laser light source 1 may be Nd-YAG laser, which generates frequency tripled laser 355nm laser, and the laser may be added to the combination of the emitted lasers and used for the individual measurement of aerosol. Due to the use of the single-photon CCD, when the quantity of emitted laser is increased, the detection requirements of all echo signals can be met only by simply adjusting the light path in the spectrometer.
Specifically, when the laser light source 1 is further configured to generate a fourth wavelength laser, the spectrometer 9 spatially separates an input echo signal including the fourth wavelength laser and outputs the separated echo signal to the single-photon CCD, and the single-photon CCD photoelectrically converts the fourth wavelength laser and outputs the converted echo signal to the photon counter 11. The main control module is also used for controlling the single-photon CCD to collect a fourth wavelength laser signal.
Further, the raman tube 3 is also used for generating 316nm laser; the 316nm laser and the 299nm laser are combined to form a third channel for measuring the ozone concentration information of the target position. The spectrometer 9 spatially separates the input echo signal containing the 316nm laser and outputs the separated echo signal to the single-photon CCD, and the single-photon CCD photoelectrically converts the 316nm laser and outputs the converted echo signal to the photon counter 11. The main control module is also used for controlling the single-photon CCD to collect 316nm laser signals.
The multi-wavelength ozone laser radar based on the single photon CCD provided by the embodiment of the invention has the following beneficial effects:
1. based on the principle of differential absorption laser radar, the invention excites a single Raman tube to generate multi-wavelength Raman light through 266nm laser pulses, and compares the difference of atmospheric echo signals of lasers with different wavelengths to obtain the ozone concentration distribution.
2. According to the invention, the single Raman tube stimulated Raman generates 266nm-289nm-299nm multi-wavelength laser combination, so that the ozone concentration in different height ranges can be measured in a targeted manner, and the measurement range is effectively increased.
3. Compared with an ozone laser radar device based on double Raman tubes, the ozone laser radar based on the single Raman tube provided by the invention not only can simplify the device, but also can avoid the difference of laser geometric factors with different wavelengths, and improve the measurement precision of the device.
4. The invention adopts the high-resolution spectrometer to realize the separation of the echo signals with different wavelengths, not only eliminates the mutual interference among the echo signals with different wavelengths, but also can more effectively reduce the influence of background sunlight compared with the traditional optical filter light splitting mode, so that the ozone laser radar device has the capability of continuous measurement day and night.
5. The invention uses the single-photon CCD to carry out photoelectric conversion on the echo signal, thereby not only simplifying the composition of a detection part and reducing the measurement error caused by the difference of the detectors, but also increasing the maximum measurement height of the device due to the high sensitivity of single-photon detection. In addition, the laser radar device has a large upgrade space due to the characteristics of the CCD itself, for example, the device is excited by 266nm laser and is filled with H2And D2The Raman tube measures the ozone concentration at different heights by using a 266nm-289nm-299nm laser combination, and measures all echo signals through a single photon CCD. The use of single-photon CCD makes the emitted laser not limited to 266nm-289nm-299nm laser combination, D2The second-order stokes line 316nm of (a) can also be used for ozone measurement, so that the detection height of the ozone lidar can be further increased. Furthermore, in order to correct the effect of the aerosol on the ozone measurement, if a Nd-YAG laser can generate 355nm laser light, this laser light can also be added to the emission laser combination and used for the individual measurement of the aerosol. Due to the use of the single-photon CCD, when the quantity of emitted laser is increased, the detection requirements of all echo signals can be met only by simply adjusting the light path in the spectrometer.
6. The single-photon CCD used by the invention can respectively perform time sequence control on the working time of different pixels, so that the measuring time of each echo signal can be independently controlled, the measuring time of each echo signal is controlled, and the detector is prevented from being saturated and even damaged due to over-strong initial signals.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (9)
1. A multi-wavelength ozone laser radar based on single photon CCD is characterized by comprising: the device comprises a laser light source (1), a Raman tube (3), an optical emission module, an optical receiving module (7), a spectrometer (9), a single photon CCD (10), a photon counter (11) and a main control module (12);
the laser light source (1) is used for outputting laser light, and the laser light comprises first wavelength laser light;
the Raman tube (3) is used for receiving laser input by the laser light source (1) and generating Raman scattered light with at least two wavelengths; the Raman scattering light comprises second wavelength laser and third wavelength laser; the wavelength difference between the second wavelength laser and the third wavelength laser is not more than 10 nm;
the optical emission module is used for emitting laser emitted by the Raman tube (3) to a detection target;
the optical receiving module (7) is used for collecting echo signals returned by the detection target;
the spectral spectrometer (9) is used for spatially separating echo signals with different wavelengths collected by the optical receiving module (7);
the single-photon CCD (10) is used for performing photoelectric conversion on a plurality of echo signals with different wavelengths output by the spectroscopic spectrometer (9);
the photon counter (11) is used for recording the number of photons measured by the single photon CCD and sending the recorded information to the main control module (12);
the main control module (12) is used for processing the information sent by the photon counter (11) so as to obtain target information of a target position; the target information includes an ozone concentration;
the main control module (12) comprises a time sequence control unit and a data processing unit; the time sequence control unit is used for respectively controlling the working time sequences of different pixels on the single-photon CCD (10) and realizing the independent control of the measurement time of each wavelength echo signal; the data processing unit is used for processing the information sent by the photon counter (11) so as to obtain target information of a target position;
the time sequence control unit is respectively connected with the laser light source (1) and the single-photon CCD (10), and is used for controlling the pixel work of the single-photon CCD (10) for collecting a first channel after the laser light source (1) emits a first time interval of laser pulses; and the pixel which is used for collecting a second channel on the single-photon CCD (10) is controlled to work after a second time interval that the laser light source (1) emits laser pulses; the second time interval is greater than the first time interval.
2. The single photon CCD based multi-wavelength ozone lidar according to claim 1, characterized in that the laser source (1) is a Nd-YAG laser; the first wavelength is 266 nm; the second wavelength is 289nm, and the third wavelength is 299 nm; the Raman tube (3) is filled with H2、D2And a buffer gas, said D2For generating Raman scattered light at 289nm, said H2For generating 299nm Raman scattered light; the buffer gas is used for suppressing laser mixing in the Raman tube.
3. The single photon CCD-based multi-wavelength ozone lidar according to claim 1 or 2, characterized in that the spectrometer (9) comprises a grating for separating laser signals of different wavelengths output by the optical receiving module (7) and a beam splitter for splitting the received laser light of a second wavelength into two beams, wherein one beam is a first branch accounting for A% and the other beam is a second branch accounting for B%; the first wavelength laser beam and the first shunt form a first channel; the second branch and the third wavelength laser form a second channel; and the first channel is provided with an attenuation element which is used for attenuating the optical signal energy of the first channel.
4. The single photon CCD based multi-wavelength ozone lidar according to claim 3, characterized in that the spectrometer (9) further comprises at least a first slit, a second slit and a third slit, wherein the first slit is used for passing the first wavelength laser separated by the grating and filtering other wavelength laser signals; the second slit is used for enabling second wavelength laser separated by the grating to pass through and filtering other wavelength laser signals; the third slit is used for enabling the third wavelength laser separated by the grating to pass through and filtering laser signals with other wavelengths.
5. The single photon CCD based multi-wavelength ozone lidar according to claim 1 further comprising a first optical lens (2) and a second optical lens (4); the optical emission module comprises a beam expander (5) and a plane mirror (6); the first optical lens (2) is used for focusing laser emitted by the laser light source (1) to the Raman tube (3); the second optical lens (4) is used for converging the laser emitted by the Raman tube (3); the plane mirror (6) is used for reflecting the laser emitted by the beam expander (5) to a target direction.
6. The single photon CCD based multi-wavelength ozone lidar according to claim 3, wherein the grating is a holographic grating or a blazed grating.
7. The single photon CCD based multi-wavelength ozone lidar of claim 2, wherein the buffer gas is Ar or He.
8. The single photon CCD based multi-wavelength ozone lidar according to claim 1, characterized in that the laser light source (1) is further adapted to generate a fourth wavelength laser; and the fourth wavelength laser is used for measuring atmospheric aerosol information.
9. The single photon CCD based multi-wavelength ozone lidar according to claim 2, characterized in that the raman tube (3) is further adapted to generate a 316nm laser; the combination of the 316nm laser and the 299nm laser is used for measuring the ozone concentration information of the target position.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810800130.1A CN108919301B (en) | 2018-07-20 | 2018-07-20 | Multi-wavelength ozone laser radar based on single photon CCD |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810800130.1A CN108919301B (en) | 2018-07-20 | 2018-07-20 | Multi-wavelength ozone laser radar based on single photon CCD |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108919301A CN108919301A (en) | 2018-11-30 |
| CN108919301B true CN108919301B (en) | 2021-12-21 |
Family
ID=64415255
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810800130.1A Active CN108919301B (en) | 2018-07-20 | 2018-07-20 | Multi-wavelength ozone laser radar based on single photon CCD |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108919301B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110471078B (en) * | 2019-09-25 | 2023-06-30 | 浙江缔科新技术发展有限公司 | Light quantum height measurement telescope and height measurement method |
| CN111157493A (en) * | 2019-10-09 | 2020-05-15 | 西安科技大学 | Positionable hydrogen measurement method based on single photon counting |
| CN111487235A (en) * | 2020-04-03 | 2020-08-04 | 中国科学院合肥物质科学研究院 | Based on CO2Ozone time-space differential absorption laser radar system with single Raman tube and detection method |
| CN111982168A (en) * | 2020-07-29 | 2020-11-24 | 电子科技大学 | High-precision fiber grating signal demodulation system and method thereof |
| CN112269260B (en) * | 2020-09-27 | 2023-03-21 | 北京卓镭激光技术有限公司 | Laser switching device and method |
| CN115372292A (en) * | 2022-08-30 | 2022-11-22 | 大连理工大学 | NO based on continuous wave differential absorption laser radar 2 Concentration three-wavelength detection method |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0484815A2 (en) * | 1990-11-05 | 1992-05-13 | Hughes Aircraft Company | Raman converter with variable wavelength distribution |
| CN101408618A (en) * | 2008-11-28 | 2009-04-15 | 北京理工大学 | Wide light beam illumination three-dimensional gating imaging system of airborne laser radar |
| CN103852435A (en) * | 2014-03-27 | 2014-06-11 | 中国科学院合肥物质科学研究院 | Differential absorption laser radar ozone space-time distribution day and night automatic detection device based on double Raman tube light source |
| CN105158230A (en) * | 2015-09-08 | 2015-12-16 | 中国科学院合肥物质科学研究院 | Device for measuring polluting gases in atmospheric boundary layer based on CCD (Charge Coupled Device) imaging laser radar |
| CN106054209A (en) * | 2016-05-19 | 2016-10-26 | 中国科学技术大学 | Atmospheric detection laser radar based on superconducting single-photon detector |
| CN206594294U (en) * | 2017-03-24 | 2017-10-27 | 北京怡孚和融科技有限公司 | A kind of ozone sounding laser radar |
| CN206818876U (en) * | 2017-05-19 | 2017-12-29 | 安徽科创中光科技有限公司 | Ozone sounding Difference Absorption quantum laser radar installations based on single Raman pipe |
-
2018
- 2018-07-20 CN CN201810800130.1A patent/CN108919301B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0484815A2 (en) * | 1990-11-05 | 1992-05-13 | Hughes Aircraft Company | Raman converter with variable wavelength distribution |
| CN101408618A (en) * | 2008-11-28 | 2009-04-15 | 北京理工大学 | Wide light beam illumination three-dimensional gating imaging system of airborne laser radar |
| CN103852435A (en) * | 2014-03-27 | 2014-06-11 | 中国科学院合肥物质科学研究院 | Differential absorption laser radar ozone space-time distribution day and night automatic detection device based on double Raman tube light source |
| CN105158230A (en) * | 2015-09-08 | 2015-12-16 | 中国科学院合肥物质科学研究院 | Device for measuring polluting gases in atmospheric boundary layer based on CCD (Charge Coupled Device) imaging laser radar |
| CN106054209A (en) * | 2016-05-19 | 2016-10-26 | 中国科学技术大学 | Atmospheric detection laser radar based on superconducting single-photon detector |
| CN206594294U (en) * | 2017-03-24 | 2017-10-27 | 北京怡孚和融科技有限公司 | A kind of ozone sounding laser radar |
| CN206818876U (en) * | 2017-05-19 | 2017-12-29 | 安徽科创中光科技有限公司 | Ozone sounding Difference Absorption quantum laser radar installations based on single Raman pipe |
Non-Patent Citations (2)
| Title |
|---|
| 一套测量对流层臭氧的差分吸收激光雷达系统;范广强 等;《中国激光》;20121130;第39卷(第11期);正文第1-7页 * |
| 边界层臭氧差分吸收激光雷达;曹开法 等;《红外与激光工程》;20151031;第44卷(第10期);正文第2912-2916页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108919301A (en) | 2018-11-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108919301B (en) | Multi-wavelength ozone laser radar based on single photon CCD | |
| US7656526B1 (en) | Lidar system for remote determination of calibrated, absolute aerosol backscatter coefficients | |
| CN105675576B (en) | A kind of laser radar system of measurement atmospheric water Raman spectrums and aerosol fluorescence Spectra | |
| CN104122562A (en) | Multiband Raman-fluorescence laser radar system | |
| JP2003130955A (en) | Micropulse rider system | |
| US11754693B2 (en) | Airborne topo-bathy lidar system and methods thereof | |
| CN110031865B (en) | Vegetation detection binary channels fluorescence laser radar system | |
| CN111650600B (en) | Double-spectrum laser imaging device for extremely weak signals | |
| CN111413710A (en) | Raman-polarization laser radar system for cloud phase detection and identification | |
| CN112558106B (en) | Satellite-borne atmospheric ocean high repetition frequency laser radar system and detection method | |
| CN116009017A (en) | Non-visual field imaging system and method based on spectrum space-time double coding | |
| CN113267762A (en) | Laser radar | |
| CN112903123B (en) | Method and device for measuring single signal-to-noise ratio boost degree of plasma mirror based on synchronous chirp probe pulse | |
| CN206740648U (en) | A kind of NO2The device of concentration distribution detection | |
| CN111781629B (en) | X-ray optical framing imaging system | |
| Burlakov et al. | A differential-absorption lidar for ozone sensing in the upper atmosphere-lower stratosphere | |
| CN111487235A (en) | Based on CO2Ozone time-space differential absorption laser radar system with single Raman tube and detection method | |
| CN115032652A (en) | Ozone differential absorption laser radar system and atmospheric ozone distribution detection method | |
| RU2478192C2 (en) | Method for optical remote detection of compounds in medium | |
| KR100540222B1 (en) | Laser Optical Transmitter, Receiver and LIDAR System for Simultaneously Observation of Atmospheric Ozone and Nonspherical Dust | |
| JP2020530902A (en) | How to provide a detection signal to an object to be detected | |
| CN118377030B (en) | Gas detection method for laser radar and laser radar | |
| CN111089855B (en) | Differential absorption laser radar NO 2 Space-time distribution day and night automatic detection device | |
| RU215328U1 (en) | Mobile lidar for sounding tropospheric ozone | |
| CN113687379B (en) | System for reducing interference of background stray light of receiving light path and interference reducing method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| TA01 | Transfer of patent application right | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20210512 Address after: 250101 Room 501, building 5, 747 Shunhua Road, high tech Zone, Jinan City, Shandong Province Applicant after: Shandong Guoyao quantum Radar Technology Co.,Ltd. Address before: 201210 3rd floor, no.665, Zhangjiang Road, Pudong New Area Free Trade Zone, Shanghai Applicant before: GUOYAO QUANTUM RADAR TECHNOLOGY Co.,Ltd. |
|
| GR01 | Patent grant | ||
| GR01 | Patent grant |