A successor optical path architecture and lidar for combining different wavelengths of laser light

Abstract

The present application relates to the technical field of laser radar, and particularly relates to a follow-up optical path architecture and laser radar adaptive to different wavelength laser combinations; the follow-up optical path architecture is provided with a light shielding cylinder and a main light cavity in sequence along a transmission direction of a main optical axis of a return signal; a detection mode compatible structure and a reconfigurable light splitting module are integrated on the main light cavity; the reconfigurable light splitting module is installed inside the main light cavity, and is composed of a plurality of adjustable and switchable optical elements; three detection channel interfaces are arranged on a side of the main light cavity, and are used for being connected with corresponding detectors respectively; the detection mode compatible structure is composed of a two-dimensional fine adjustment structure which penetrates through the first detection channel interface and is used for being compatible with two types of detectors of spatial light and optical fiber; the two-dimensional fine adjustment structure carries a coupling mirror; the present application can be combined according to different wavelength specifications, and the main light cavity does not need to be designed and processed twice, and can be completed by adjusting different optical standard part combinations.

Description

Technical Field

[0001] This invention relates to the field of lidar technology, specifically to a subsequent optical path architecture and lidar that adapts to different combinations of laser wavelengths. Background Technology

[0002] Existing aerosol radar consists of a laser emitting unit, an echo signal receiving unit, and a subsequent optical path, and is used for optical remote sensing of the atmosphere.

[0003] Because the wavelength or combination of wavelengths emitted by the laser emitting unit changes, the wavelength of the echo signal also changes accordingly. Therefore, conventional aerosol radar designs different follow-up optical paths for different wavelength combinations. This often results in a set of parts and a set of processes for each specification, leading to poor reusability of parts, low interchangeability of components, and complex material and BOM management during the production and manufacturing of radars of different specifications.

[0004] Common solutions in existing lidar technologies include: 1) Constructing a unified back-end optical path using modular and standardized optical components, such as the technical document titled "Optimization -Through Optical Design- Of A Multi-Wavelength Fiber-Based Raman Lidar System In The Near-Field For Vertical Aerosol Measurements In The Troposphere," published by the Cesar observatory of the Ruisdael Observatory in the Netherlands; 2) Designing an integrated receiving unit capable of simultaneously processing multi-wavelength echoes, such as the Chinese patent CN201910337146.8, titled "A Hyperspectral Lidar System for Aerosol-Scale Spectrum Measurement." Both solutions involve a single optical path and wavelength-separated detection. However, designs based on this concept often focus only on how to solve a specific atmospheric science detection problem using specific optical principles. Therefore, improvements are made to the dedicated design of the optical system, often neglecting the versatility of the mechanical design.

[0005] That is, those skilled in the art have not focused on how to construct various optical receiving systems more economically and flexibly. Based on this, those skilled in the art urgently need to design a new and universal successor optical path architecture that can improve the above-mentioned defects from the perspective of manufacturing and utilization. Summary of the Invention

[0006] Therefore, the technical problem to be solved by the present invention is to overcome the defects in the prior art, thereby providing a follow-up optical path architecture and lidar that are adapted to different wavelength laser combinations.

[0007] A follow-up optical path architecture adapted to different wavelength laser combinations is adapted to a laser emitting unit that emits n lasers of different wavelengths, where n is an integer, 3≥n≥2. The follow-up optical path structure is provided with a light shielding tube and a main optical cavity in sequence along the transmission direction of the main optical axis of the echo signal. The follow-up optical path structure also includes: a detection mode compatible structure and a reconfigurable beam splitting module integrated on the main optical cavity.

[0008] The reconfigurable beam splitter is installed inside the main optical cavity. The reconfigurable beam splitter consists of multiple adjustable and switchable optical elements. Specifically, the reconfigurable beam splitter consists of a two-phase beam splitter, a first dual filter assembly, and a dual prism assembly arranged sequentially along the echo signal transmission direction, as well as a second dual filter assembly arranged on the beam splitting path of the two-phase beam splitter.

[0009] The main optical cavity has three detection channel interfaces on its side, which are used to connect to the corresponding detectors respectively; among them, the first detection channel interface is connected to the beam splitting path of the two-phase beam splitting component; the dual prism assembly is adapted to the detection channel interfaces other than the first detection channel interface;

[0010] The detection mode compatible structure consists of a two-dimensional fine-tuning structure that runs through the first detection channel interface and is compatible with both space light and fiber optic detectors.

[0011] A two-dimensional fine-tuning structure carries a coupling mirror.

[0012] Preferably, the main optical cavity is provided with:

[0013] The first chamber is used to install the two-phase beam splitter;

[0014] The second chamber is used to install the first dual-filter assembly;

[0015] The third chamber is used to install the dual prism assembly;

[0016] The fourth chamber is used to install the second dual-filter assembly;

[0017] The first and second chambers share a circular optical path channel on their common cavity wall.

[0018] Preferably, the two-dimensional fine-tuning structure consists of an adjustment base, an adjustable base, a coupling mirror, and a disc spring;

[0019] The adjustment base is installed on the outer wall of the side of the main optical cavity, and the central optical path channel of the adjustment base is connected to the interface of the first detection channel.

[0020] The fixed seat and the adjustable seat are connected by a first screw, and a disc spring is fitted on the first screw.

[0021] The adjustable seat has an internal thread that matches the external thread of the coupling mirror, so that the adjustable seat and the coupling mirror are locked together by a set screw.

[0022] Preferably, the second dual filter assembly includes a pressure ring;

[0023] In the second dual-filter assembly, two filters are press-fitted into the third filter holder by a pressure ring.

[0024] Preferably, it also includes a reflective cavity, the exit end of which constitutes a fourth detection channel interface; the entrance end of the reflective cavity and the optical path channel of the main optical cavity away from the light-shielding tube are connected.

[0025] Preferably, the reflecting cavity is rotated at a right angle;

[0026] An opening is provided at the bend of the reflective cavity;

[0027] Furthermore, a stepped groove that gradually widens from the inside out is created at the opening;

[0028] A reflector is also provided inside the reflecting cavity; the reflector is installed on the innermost step of the stepped groove;

[0029] A sealing cover is also provided outside the reflection cavity; the sealing cover seals the opening at the bend of the reflection cavity with screws.

[0030] A lidar that adapts to different combinations of laser wavelengths, with the subsequent optical path employing a subsequent optical path architecture adapted to different combinations of laser wavelengths.

[0031] The technical solution of this invention has the following advantages:

[0032] The present invention has a simple overall structure and is versatile enough to adapt to a variety of wavelength combinations. Attached Figure Description

[0033] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the overall structure of the follow-up optical path architecture in Example 1;

[0035] Figure 2 This is a schematic diagram of the internal structure of the follow-up optical path architecture in Example 1;

[0036] Figure 3 This is a plan view of the optical path architecture following Example 1;

[0037] Figure 4 This is a schematic diagram of the longitudinal section of the reflector cavity in Example 1;

[0038] Figure 5 This is a schematic diagram of the optical path in Example 2;

[0039] Figure 6 This is a schematic diagram of the optical path in Example 3.

[0040] Explanation of reference numerals in the attached figures:

[0041] 1-Main optical cavity, 2-Dichromatic mirror holder, 3-Dichromatic beam splitter, 4-Light shield, 5-Adjustable base, 6-Adjustable base, 7-Coupled mirror, 8-First filter holder, 9-Second filter holder, 10-First prism, 11-Second prism, 12-First detector, 13-Reflection cavity, 14-Second detector, 15-Third detector, 16-Cover plate, 17-Pressure ring, 18-First filter, 19-Second filter, 20-Disc spring, 21-Third filter, 22-Fourth filter, 23-First prism holder, 24-Second prism holder, 25-Reflector, 26-First spare groove, 27-Second spare groove, 28-Fiber optic connector, 29-Sealing cover plate, 30-Third filter holder. Detailed Implementation

[0042] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0044] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0045] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0046] Example 1

[0047] like Figure 1-6 As shown, a follower optical path architecture adapted to different wavelength laser combinations is adapted to a laser emitting unit that emits n lasers of different wavelengths, where n is an integer, 3≥n≥2. The follower optical path structure is provided with a light shielding tube 4 and a main optical cavity 1 in sequence along the transmission direction of the main optical axis of the echo signal. In this embodiment, the follower optical path structure also includes a detection mode compatible structure and a reconfigurable beam splitting module integrated on the main optical cavity 1.

[0048] Specifically:

[0049] The reconfigurable beam splitter module is installed inside the main optical cavity 1. The reconfigurable beam splitter module consists of multiple adjustable and switchable optical elements, specifically: such as... Figure 3 After removing the cover plate 16 of the main optical cavity 1, the reconstructed beam splitting module inside the main optical cavity 1 is specifically composed of a two-phase beam splitting component, a first dual-filter component and a dual-prism component arranged sequentially along the echo signal transmission direction, and a second dual-filter component arranged on the beam splitting path of the two-phase beam splitting component.

[0050] The main optical cavity 1 has three detection channel interfaces on its side, which are used to connect to the corresponding detectors respectively; among them, the first detection channel interface is connected to the beam splitting path of the two-phase beam splitting component; the dual prism assembly is adapted to the detection channel interfaces other than the first detection channel interface;

[0051] The detection mode compatible structure consists of a two-dimensional fine-tuning structure that runs through the first detection channel interface and is compatible with both space light and fiber optic detectors; the two-dimensional fine-tuning structure carries a coupling mirror 7.

[0052] Furthermore, the main optical cavity 1 is equipped with:

[0053] The first chamber is used to install a two-phase beam splitter assembly. The two-phase beam splitter assembly includes a two-phase mirror holder 2 installed in the first chamber and a two-phase beam splitter 3 installed on the two-phase mirror holder 2. The main optical cavity 1 and the two-phase mirror holder 2 are connected by screws. The two-phase beam splitter 3 is glued to the two-phase mirror holder 2. The flange surface of the two-phase mirror holder 2 is provided with arc-shaped mounting holes, which can be adjusted appropriately during installation and adjustment.

[0054] The second chamber is used to install the first dual-filter assembly; the first dual-filter assembly includes: a first filter holder 8 and a third filter 21 installed on the first filter holder 8; a second filter holder 9 and a fourth filter 22 installed on the second filter holder 9; the third filter 21 and the fourth filter 22 are respectively glued to the first filter holder 8 and the second filter holder 9;

[0055] The third chamber is used to install the dual prism assembly; the dual prism assembly includes: a first prism base 23, a first prism 10 mounted on the first prism base 23, a second prism base 24, and a second prism 11 mounted on the second prism base 24;

[0056] The fourth chamber is used to install the second dual filter assembly; the second dual filter assembly includes: a third filter holder 30, a pressure ring 17, a first filter 18 and a second filter 19; wherein, the two filters in the second dual filter assembly are press-fitted into the third filter holder 30 by the pressure ring 17.

[0057] The first filter holder 8, the second filter holder 9, and the third filter holder 30 are respectively installed in the grooves of the corresponding chambers of the main optical cavity 1 by screws.

[0058] The first and second chambers share a circular optical path channel on their common cavity wall.

[0059] The specific parameters of rectangular and circular optical path channels depend on the size of the final overall device, so they are not specifically limited in this embodiment.

[0060] In this embodiment, the two-dimensional fine-tuning structure consists of an adjustment base 5, an adjustable base 6, a coupling mirror 7, and a disc spring 20.

[0061] The adjusting base 5 is installed on the outer side wall of the main optical cavity 1, and the central optical path channel of the adjusting base 5 is connected to the interface of the first detection channel.

[0062] The fixed seat 5 and the adjustable seat 6 are connected by a first screw, and a disc spring 20 is fitted on the first screw.

[0063] The adjustable seat 6 has an internal thread that matches the external thread of the coupling mirror 7, so that the adjustable seat 6 and the coupling mirror 7 are locked together by a set screw and glue is applied to prevent the coupling mirror 7 from loosening.

[0064] In this embodiment, a reflective cavity 13 is also provided at the end of the main optical cavity 1 away from the light-shielding tube 4. The outlet end of the reflective cavity 13 constitutes the fourth detection channel interface. The inlet end of the reflective cavity 13 is connected to the optical path channel at the end of the main optical cavity 1 away from the light-shielding tube 4.

[0065] Reflecting cavity 13 is rotated at a right angle;

[0066] An opening is provided at the bend of the reflective cavity 13;

[0067] Furthermore, a stepped groove that gradually widens from the inside out is created at the opening;

[0068] A reflector 25 is also provided inside the reflective cavity 13; the reflector 25 is installed on the innermost step of the stepped groove;

[0069] A sealing cover plate 29 is also provided outside the reflective cavity 13; the sealing cover plate 29 seals the opening at the fold of the reflective cavity 13 by screws.

[0070] Example 2

[0071] Based on Example 1, examples of specific wavelength combinations are now provided for explanation.

[0072] This embodiment is for two different wavelength channel combinations of 532-P laser and 532-S laser;

[0073] like Figure 5 The detector at the outlet of the reflected cavity 13 shown does not need to be installed;

[0074] The first prism 10 is a polarizing prism, which allows 532-P laser to pass through and 532-S laser to be reflected.

[0075] The second prism 11 selects a reflecting prism, and at this time the second detector 14 installed at the second detection channel interface receives a 532-P laser signal.

[0076] The third detector 15, installed at the interface of the third detection channel, receives a 532-S laser signal.

[0077] During assembly and adjustment, in order to make the echo light signal fall more effectively at the center of each detector target surface, it is advisable to make appropriate fine adjustments in practical applications: shift and adjust the first prism mount 23 and the second prism mount 24.

[0078] In this embodiment, the third filter 21 is selected as a filter with a wavelength of 532nm±0.5nm and an optical density value of OD7, and the fourth filter 22 is selected as a filter with a wavelength of 532nm±10nm and an optical density value of OD5. The superposition of the two filters can limit the background noise of the sky through the narrow transmission bandwidth of optical density value OD5, and can also create a deeper blocking band of optical density value OD12, thus ensuring the signal-to-noise ratio of the received signal.

[0079] Example 3

[0080] Based on Example 2, this example increases the number of wavelength combinations to three, and provides further examples:

[0081] This embodiment describes an implementation method for combinations of 532-P, 532-S, and 1064 laser wavelengths, such as... Figure 6 As shown, the third filter 21 is selected at this time as a filter with a wavelength of 532nm±0.5nm and an optical density value of OD7;

[0082] The fourth filter 22 is a filter with a wavelength of 532nm±10nm and an optical density value of OD5;

[0083] Dichroic beam splitter 3 uses dichroic lenses that reflect 1064nm laser and transmit 532nm laser;

[0084] The first filter 18 is selected as a filter with a wavelength of 1064nm±0.7nm and an optical density value of OD6;

[0085] The second filter 19 is selected as a filter with a wavelength of 1064nm±2nm and an optical density of OD5. The purpose of superimposing the two is also to ensure the blocking depth of the 1064 laser channel.

[0086] The first prism 10 is a selective polarization prism; 532-P laser passes through, and 532-S laser is reflected.

[0087] The second prism 11 is a semi-reflective and semi-transparent prism. In this embodiment, a spare groove is provided at each of the two detection channel interfaces corresponding to the two prisms: a first spare groove 26 and a second spare groove 27. In this embodiment, a neutral density attenuator is also attached to the first spare groove 26 located at the detection channel interface that is compatible with the first prism 10 to ensure that 1% of the laser beam is transmitted.

[0088] At this point, the light entering the subsequent optical path includes 532-P laser, 532-S laser and 1064nm laser;

[0089] After the light passes through the dichroic beam splitter 3, the 1064nm wavelength is reflected, while the 532-P laser and the 532-S laser are transmitted.

[0090] The 1064nm laser light enters the coupler 7 after passing through two filters in the fourth chamber. The coupler 7 is equipped with an optical fiber connector 28, through which the 1064nm light can be guided into the fiber-optic 1064nm detector. Since the field of view of the coupler 7 is extremely small, it is extremely sensitive to the angle of the coupler 7 relative to the incident light in the subsequent optical path. The angle of the coupler 7 can be adjusted by adjusting the screw between the adjusting base 5 and the adjustable base 6. After the optical path is aligned, silicone is injected between the adjusting base 5 and the adjustable base 6 for reinforcement.

[0091] In this embodiment, the third detector 15 receives a 532-S laser.

[0092] The second detector 14 receives a very small portion of the 532-P signal, while the first detector 12 receives the vast majority. This design is because when this type of lidar detects atmospheric aerosols vertically to the ground, the echo signal intensity difference between the lower and upper atmospheres is significant. To ensure sufficient radar detection range, the echo signal from the lower atmosphere can easily saturate the detector, leading to signal distortion. Therefore, the 532-P signal is split into two parts: the relatively higher-energy signal is received by one detector, and the relatively lower-energy signal is received by another. The high-energy detector collects the echo signal from the upper atmosphere, while the low-energy detector collects the echo signal from the lower atmosphere. These two signals are then combined. This ensures both a long detection range for the 532-P radar and prevents saturation in the lower atmosphere. Specifically, the signal strength ratio between the second detector 14 and the first detector 12 is subject to actual conditions; however, in this embodiment, the 532-P signal received by the second detector 14 is less than that received by the first detector 12.

[0093] Example 4

[0094] A lidar that adapts to different combinations of laser wavelengths, with the subsequent optical path employing a subsequent optical path architecture adapted to different combinations of laser wavelengths.

[0095] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A follower optical path architecture adaptable to combinations of different wavelength lasers, adapted to a laser emitting unit that emits n laser beams of different wavelengths, where n is an integer, 3 ≥ n ≥ 2, characterized in that, The subsequent optical path structure is provided with a light shield (4) and a main optical cavity (1) in sequence along the transmission direction of the main optical axis of the echo signal. The subsequent optical path structure also includes a detection mode compatible structure and a reconfigurable beam splitter integrated on the main optical cavity (1). The reconfigurable beam splitter is installed inside the main optical cavity (1). The reconfigurable beam splitter is composed of multiple adjustable and switchable optical elements. Specifically, the reconfigurable beam splitter is composed of a two-phase beam splitter, a first dual filter component and a dual prism component arranged sequentially along the echo signal transmission direction, and a second dual filter component arranged on the beam splitting path of the two-phase beam splitter. The main optical cavity (1) has three detection channel interfaces on its side, which are used to connect to the corresponding detectors respectively; among them, the first detection channel interface is connected to the beam splitting path of the two-phase beam splitting component; the dual prism component is adapted to the detection channel interfaces other than the first detection channel interface; The detection mode compatible structure consists of a two-dimensional fine-tuning structure that runs through the first detection channel interface and is compatible with both space light and fiber optic detectors. The two-dimensional fine-tuning structure carries a coupling mirror (7).

2. The subsequent optical path architecture adaptable to different wavelength laser combinations according to claim 1, characterized in that, The main optical cavity (1) is equipped with: The first chamber is used to install the two-phase beam splitter; The second chamber is used to install the first dual-filter assembly; The third chamber is used to install the dual prism assembly; The fourth chamber is used to install the second dual-filter assembly; The first and second chambers share a circular optical path channel on their common cavity wall.

3. The subsequent optical path architecture adaptable to different wavelength laser combinations according to claim 1, characterized in that, The two-dimensional fine-tuning structure consists of an adjustment base (5), an adjustable base (6), a coupling mirror (7), and a disc spring (20); The adjusting base (5) is installed on the outer side wall of the main optical cavity (1), and the central optical path channel of the adjusting base (5) is connected to the interface of the first detection channel. The fixed seat (5) and the adjustable seat (6) are connected by a first screw, and a disc spring (20) is fitted on the first screw. The adjustable seat (6) has an internal thread that matches the external thread of the coupling mirror (7) so that the adjustable seat (6) and the coupling mirror (7) are locked together by a set screw.

4. The subsequent optical path architecture adaptable to different wavelength laser combinations according to claim 3, characterized in that, The second dual filter assembly is provided with a pressure ring (17); In the second dual-filter assembly, two filters are press-fitted into the third filter holder (30) by a pressure ring (17).

5. The subsequent optical path architecture adaptable to different wavelength laser combinations according to claim 1, characterized in that, It also includes a reflective cavity (13), the exit end of which forms the fourth detection channel interface; the entrance end of the reflective cavity (13) and the optical path channel of the main optical cavity (1) away from the light shield (4) are connected.

6. The subsequent optical path architecture adaptable to different wavelength laser combinations according to claim 5, characterized in that, The reflecting cavity (13) is rotated at a right angle; An opening is provided at the bend of the reflective cavity (13); Furthermore, a stepped groove that gradually widens from the inside out is created at the opening; A reflector (25) is also provided inside the reflective cavity (13); the reflector (25) is installed on the innermost step of the stepped groove; A sealing cover plate (29) is also provided outside the reflective cavity (13); the sealing cover plate (29) seals the opening at the fold of the reflective cavity (13) by screws.

7. A lidar adapted to different combinations of laser wavelengths, characterized in that, The subsequent optical path uses a subsequent optical path architecture adapted to different wavelength laser combinations as described in any one of claims 1-6.

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