Optical imaging system capable of continuously resisting blinding caused by pulse laser damage

Abstract

The invention relates to the technical field of optical imaging systems, in particular to an optical imaging system capable of continuously resisting blinding caused by pulse laser damage. The system comprises a secondary imaging optical system, an imaging detector, a nonlinear absorption type optical limiter and a two-dimensional moving unit, the secondary imaging optical system comprises a primary imaging optical assembly and a secondary imaging optical assembly; after entering the secondary imaging optical system, the light beam is focused by the primary imaging optical assembly to form a primary image plane focus, and then is imaged on the imaging detector through the secondary imaging optical assembly; the nonlinear absorption type optical limiter is mounted on the two-dimensional moving unit and is arranged near a primary image plane position of a primary optical axis of the secondary imaging optical system; the two-dimensional moving unit drives the non-linear absorption type optical limiter to move, so that an incident light beam passes through different positions on the non-linear absorption type optical limiter. The device has the advantages that continuous laser protection is carried out on an imaging detector, and automatic protection of an optical imaging system is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of optical imaging systems, and in particular to an optical imaging system capable of continuously resisting blinding caused by pulse laser damage. Background Art

[0002] With the development and widespread application of laser technology, lasers have become an increasingly serious threat to the working safety of optical imaging systems, such as optoelectronic countermeasure equipment, laser ranging equipment, laser autonomous navigation equipment, etc. In conventional optical systems, the imaging spot of parallel light beams converged on the surface of the imaging detector through the optical system is extremely small (the typical spot size is about 1 to 2 pixels. For example, a certain type of CMOS imaging detector has a pixel size of 2.4µm×2.4µm, and the spot size corresponding to 2 pixels is about 23µm). 2 ), resulting in extremely high power / energy density of the laser beam on the surface of the imaging detector, especially pulsed laser (common pulse width is in the order of milliseconds to nanoseconds). Compared with continuous laser, pulsed laser is more likely to cause damage and blinding to the imaging detector in the optical imaging system under the action of pulsed laser due to its short action time and high peak power, thus causing failure of the optical imaging system. From the perspective of optoelectronic countermeasures and laser protection of high-value optoelectronic imaging targets, it is urgent to develop an optical imaging system with strong resistance to laser damage and continuous resistance to laser damage and blinding.

[0003] By improving the optical system, the laser power / energy density on the surface of the imaging detector can be reduced, reducing the risk of laser damage and blinding to the optical imaging system. In the prior art, a Chinese invention patent application with publication number CN109931817A, publication date June 25, 2019, and invention name “Anti-laser damage adaptive protection device and optical detection system using the device” discloses an anti-laser damage technical solution mainly based on phase change materials. In the solution, a spectroscopic grating, a protection unit, and a beam combining grating are arranged in sequence along the optical path direction. The protection unit includes a phase change unit and a reflection unit. The phase change unit can allow light to pass when there is no phase change to ensure the normal operation of the detector. When the incident light power or the temperature of the phase change unit reaches a set threshold, the phase change unit undergoes a semiconductor metal phase change to prevent light from passing through. The reflection unit is used to reflect and / or scatter the light incident on the unit out of the device; the spectroscopic grating projects the light within the working band of the detector onto the phase change unit, and projects the light outside the working band of the detector onto the reflection unit; the beam combining grating is used to combine the light coming out of the spectroscopic grating; the spectroscopic grating and the beam combining grating are transmission gratings.

[0004] The invention patent application with publication number CN105865268A, publication date August 17, 2016, and invention name "An infrared optical system and method for counteracting laser blinding" discloses a technical solution for counteracting laser blinding mainly based on a dual detection system. In this solution, the optical system consists of a medium-wave imaging detection unit and a medium-wave laser four-quadrant detection unit with a common aperture. The data switching and steering of the medium-wave imaging detection unit and the medium-wave laser four-quadrant detection unit are realized by a conversion logic device. When the infrared target radiation intensity is less than a certain threshold, the medium-wave imaging detection unit works; when the infrared target radiation intensity reaches a certain threshold, the output image of the medium-wave imaging detection unit becomes saturated and shuts down for self-protection, the medium-wave laser four-quadrant detection unit starts to work, and the guidance system switches to using the four-quadrant detection unit mode for detection and tracking to continue searching, so as to overcome the blinding problem caused by laser.

[0005] The invention patent application with publication number CN116931283A, publication date August 17, 2016, and invention name “An optoelectronic imaging system with laser protection function” provides an optoelectronic imaging system that is mainly based on a wavefront coding element and is resistant to laser damage. The system includes: an imaging lens, an image sensor, an image processing system, and a cubic vortex phase control element; the cubic vortex phase control element is located between a laser source and an imaging lens, and is close to the imaging lens to form an equivalent phase plane with the imaging lens; when there is no interfering laser, the object image is focused by the imaging lens and modulated by the phase control element, and then received by the image sensor, and the image sensor sends the received blurred coded image to the image processing system for decoding processing to obtain a clear decoded image, which is then output for display; when there is an interfering laser, the phase control effect of the cubic vortex phase control element can redistribute the energy reaching the image sensor, and the light spot at the image sensor is similar to an isosceles triangle light spot, the main lobe energy is weakened, and the position of the maximum light intensity is shifted, thereby reducing the maximum single-pixel receiving power on the image sensor to achieve the purpose of resisting laser damage.

[0006] The above three anti-laser damage blinding schemes have a certain effect in resisting continuous laser damage blinding, but they are insufficient in resisting pulsed laser damage blinding. Their main disadvantages include the following aspects: (1) Slow response speed. Photoelectric countermeasure systems or laser ranging systems generally use nanosecond pulse lasers as working laser sources, with pulse widths ranging from a few nanoseconds to tens of nanoseconds. "Anti-laser damage adaptive protection device and optical detection system using the device" mainly use the high-temperature phase change mechanism of materials as a means to reduce the laser power / energy density at the imaging detector. The response time of the phase change process is generally in the millisecond range, which is greater than the pulse width of the nanosecond pulse laser, and it is impossible to make a protective response within the laser pulse action time; "An infrared optical system and method for counteracting laser blindness" determines the presence of laser interference based on the appearance of saturated light spots in the image of the medium-wave imaging detection unit. The process of starting the protection mechanism requires computer or electronic data processing processes such as imaging, image processing, laser interference judgment, conversion logic device operation, and guidance mode conversion. The entire processing process takes more than tens of milliseconds, which is greater than the pulse width of the nanosecond pulse laser, and it is impossible to make a protective response within the laser pulse action time.

[0007] (2) Damage to protective components or units. After being damaged by pulsed laser, the optical system cannot work normally. The main protective components of the "anti-laser damage adaptive protection device and optical detection system using the device" are transmission gratings, phase change films and other components; "an infrared optical system and method for combating laser blindness" has no protective components, and the laser is directly focused on the imaging detection device or the four-quadrant detector; "an optoelectronic imaging system with laser protection function" mainly uses a cubic vortex phase control element (the pattern of the cubic vortex phase control element is strictly matched with the back-end image processing algorithm. If the component is damaged, even if the imaging detector is not damaged, the imaging system cannot correctly decode and obtain a clear decoded image). The above protective components are mostly precision optical components or the imaging detector itself, which are fragile optical components. Under the condition of high power / energy density laser incidence, the protective components are also at risk of damage. Damage to the protective components will cause the imaging system to fail. Therefore, in the above technical solution, if the protective component is damaged, even if the laser disappears, the protective component will not be able to provide laser protection for the imaging system, or the imaging system can no longer continue to work normally, which has certain defects. Summary of the invention

[0008] In order to solve the above problems, the present invention provides an optical imaging system which is continuously resistant to blinding caused by pulse laser damage.

[0009] The present invention aims to provide an optical imaging system that is continuously resistant to blinding caused by pulse laser damage, comprising: a secondary imaging optical system, an imaging detector, a nonlinear absorption type optical limiting device, and a two-dimensional mobile unit; The secondary imaging optical system includes a primary imaging optical component and a secondary imaging optical component; after the light beam enters the secondary imaging optical system, it is focused by the primary imaging optical component to form a primary image plane focus, and then is imaged on the imaging detector after passing through the secondary imaging optical component; The nonlinear absorption type optical limiting device is mounted on a two-dimensional moving unit and is placed near the primary image plane position of the principal optical axis of the secondary imaging optical system; The nonlinear absorption type optical limiting device is driven to move by a two-dimensional moving unit, so that the incident light beam passes through different positions on the nonlinear absorption type optical limiting device, thereby achieving a continuous anti-laser damage blinding function.

[0010] Preferably, the two-dimensional moving unit includes a one-dimensional rotating platform and a one-dimensional linear translation platform; the one-dimensional rotating platform is arranged on the one-dimensional linear translation platform, and the nonlinear absorption type optical limiting device is installed on the one-dimensional rotating platform; the one-dimensional rotating platform and the one-dimensional linear translation platform move in coordination so that the incident light beam passes through a different position on the nonlinear absorption type optical limiting device at each moment.

[0011] Preferably, a plurality of groups of sheet-shaped nonlinear absorption type optical limiting devices are installed on the one-dimensional rotating platform, and the performance of each sheet of nonlinear absorption type optical limiting device is the same or different.

[0012] Preferably, a ring-shaped nonlinear absorption type optical limiting device is installed on the one-dimensional rotating platform.

[0013] Preferably, the material of the nonlinear absorption type optical limiting device includes at least one of phthalocyanine, porphyrin, graphene, graphene, fullerene, carbon nanotubes, organic small molecules and metal nanoparticles.

[0014] Preferably, the nonlinear absorption type optical limiting device is located on a side of the primary image plane focus close to the primary imaging optical component.

[0015] Preferably, the size of the nonlinear absorption type optical limiting device is larger than the spot size near the focus of the primary image plane.

[0016] Preferably, it also includes laser detectors installed around the system; A plurality of groups of sheet-shaped nonlinear absorption-type optical limiting devices with different performances are installed on the one-dimensional rotating platform; After detecting the incident lasers of different systems or different wavelengths, the laser detector provides warning or laser parameter information to the main system of the optical imaging system that is continuously resistant to blinding caused by pulsed laser damage. The main system automatically controls the rotation of the one-dimensional rotating platform and selects nonlinear absorption-type optical limiting devices with different performances for protection.

[0017] Preferably, the energy density of the incident pulse laser on the surface of the imaging detector is less than the damage / blinding threshold of the imaging detector.

[0018] Preferably, the energy density of the incident pulse laser on the surface of the nonlinear absorption type optical limiting device is less than the breakdown threshold of the nonlinear absorption type optical limiting device.

[0019] Compared with the prior art, the present invention can achieve the following beneficial effects: In view of the problem that the existing technology can only resist blinding caused by low-power / energy density continuous laser damage, the present invention proposes a protection scheme for the optical imaging system to continuously resist blinding caused by pulsed laser damage. The use of a nonlinear absorption type optical limiting device with an autonomous response speed of nanoseconds can effectively reduce the power / energy density of continuous lasers and pulsed lasers with a pulse width ≥ nanoseconds reaching the surface of the imaging detector, thereby realizing automatic protection of the optical imaging system; and after the incident laser disappears, the normal working characteristics of the optical imaging system can be restored. A displacement platform and / or a rotating platform is added to the imaging system. When the incident laser power / energy is large, the nonlinear absorption type optical limiting device is used as a sacrificial material to protect the imaging detection device. The nonlinear absorption type optical limiting device is moved by the displacement platform, so that the laser is irradiated at different positions of the nonlinear absorption type optical limiting device that are not damaged at each moment, thereby realizing continuous laser protection for the imaging detection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of an optical imaging system that is continuously resistant to blinding caused by pulse laser damage according to an embodiment of the present invention.

[0021] Figure 2 1 is a front view schematic diagram of an optical imaging system that is continuously resistant to blinding caused by pulse laser damage according to an embodiment of the present invention.

[0022] Figure 3 This is a photograph of an example of a nonlinear absorption-type optical limiting device provided according to an embodiment of the present invention.

[0023] Figure 4 1 is an input-output energy density curve of a nonlinear absorption-type optical limiting device provided according to an embodiment of the present invention.

[0024] Reference numerals: 1. One-shot imaging optical components; 2. Secondary imaging optical components; 3. Imaging detector; 4. Nonlinear absorption optical limiting device; 5. One-dimensional rotating platform; 6. One-dimensional linear translation stage; 7. Principal optical axis of the secondary imaging optical system. DETAILED DESCRIPTION

[0025] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same modules are represented by the same reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, the detailed description thereof will not be repeated.

[0026] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation of the present invention.

[0027] See also Figure 1-Figure 2 As shown, the present invention provides an optical imaging system that is continuously resistant to blinding caused by pulse laser damage, including: a secondary imaging optical system, an imaging detector 3, a nonlinear absorption type optical limiting device 4, and a two-dimensional mobile unit; The secondary imaging optical system includes a primary imaging optical component 1 and a secondary imaging optical component 2. After light enters the secondary imaging optical system, it is focused by the primary imaging optical component 1 to form a primary image plane focus, and then imaged by the secondary imaging optical component 2 to the imaging detector 3. The nonlinear absorption type optical limiting device 4 is mounted on the two-dimensional moving unit and is placed near the primary image plane position of the main optical axis 7 of the secondary imaging optical system; Specifically, the nonlinear absorption type optical limiting device 4 is located on the side of the primary image plane focus close to the primary imaging optical component 1, and its position relative to the primary image plane focus needs to be precisely designed to ensure its working performance; Specifically, the two-dimensional moving unit includes a one-dimensional rotating platform 5 and a one-dimensional linear translation platform 6; the one-dimensional rotating platform 5 is arranged on the one-dimensional linear translation platform 6; the nonlinear absorption type optical limiting device 4 is installed on the one-dimensional rotating platform 5; the one-dimensional rotating platform 5 and the one-dimensional linear translation platform 6 move in coordination, so that the incident light beam passes through different positions on the nonlinear absorption type optical limiting device 4 at each moment.

[0028] Typical materials of the nonlinear absorption type optical limiting device 4 may be, but are not limited to, phthalocyanine, porphyrin, graphene, graphene, fullerene, carbon nanotubes, organic small molecules or metal nanoparticles.

[0029] The spot size near the primary image focus on the main optical axis 7 of the secondary imaging optical system is much smaller than the size of the nonlinear absorption type light limiting device 4. Through the coordinated movement of the one-dimensional rotating platform 5 and the one-dimensional linear translation platform 6, the small spot can be translated on the nonlinear absorption type light limiting device 4. The translation step size and speed need to be designed according to the size of the damaged spot in the preliminary experiment.

[0030] The front view schematic diagram of the optical imaging system that is continuously resistant to blinding caused by pulsed laser damage is shown in Figure 2 As shown; In a specific embodiment, the one-dimensional rotating platform 5 can be installed with multiple nonlinear absorption type optical limiting devices 4; the one-dimensional rotating platform 5 and the one-dimensional linear translation stage 6 are moved through programming control, so that the nonlinear absorption type optical limiting device 4 performs small step two-dimensional movement in a direction perpendicular to the main optical axis 7 of the secondary imaging optical system; when the main system determines that the nonlinear absorption type optical limiting device 4 is damaged and cannot be used or the protection parameters are inappropriate, the one-dimensional rotating platform 5 rotates over a large range to place another nonlinear absorption type optical limiting device 4 on the main optical axis 7 of the secondary imaging optical system, and then the one-dimensional rotating platform 5 and the one-dimensional linear translation stage 6 control the nonlinear absorption type optical limiting device 4 to perform small step two-dimensional movement again; this reciprocating process ensures that the main optical axis 7 of the secondary imaging optical system passes through different positions of the nonlinear absorption type optical limiting device 4 at each moment, thereby realizing the continuous anti-laser damage and blinding function of the secondary imaging optical system.

[0031] In a specific embodiment, the nonlinear absorption type optical limiting device 4 is typically in the shape of a circular sheet (eg Figure 3 As shown), it is mounted on a one-dimensional rotating platform 5, and the main optical axis 7 of the secondary imaging optical system passes through a nonlinear absorption type optical limiting device 4; In a specific embodiment, according to actual changes in the production process, the nonlinear absorption type optical limiting device 4 can be prepared in a large size. For example, the nonlinear absorption type optical limiting device 4 can be made into a ring structure, and the installation method on the one-dimensional rotating platform 5 is adjusted accordingly; at the same time, the movement methods of the one-dimensional rotating platform 5 and the one-dimensional linear translation platform 6 will change. The one-dimensional rotating platform 5 and the one-dimensional linear translation platform 6 can be changed into a two-dimensional linear translation platform to realize the position change of the nonlinear absorption type optical limiting device 4 relative to the main optical axis 7 of the secondary imaging optical system.

[0032] In a specific embodiment, since the optical imaging system that continuously resists blinding caused by pulsed laser damage has protection requirements for lasers of different systems or wavelengths, a variety of nonlinear absorption type optical limiting devices with different performances can be installed on the one-dimensional rotating platform 5. During operation, different nonlinear absorption type optical limiting devices can be selected by rotating the one-dimensional rotating platform 5.

[0033] Furthermore, the position of the nonlinear absorption type optical limiting device 4 relative to the focal plane of the primary image plane needs to be precisely designed. Since the nonlinear absorption type optical limiting material mainly exhibits the following three working characteristics under the action of laser: (1) Linear absorption characteristics (the pulse laser energy density incident on the front surface of the nonlinear absorption type optical limiting device 4 is 0~XJ / cm 2 ), in which case the energy density F1 incident on the nonlinear absorption type light limiting device 4 and the energy density F2 transmitted through the nonlinear absorption type light limiting device 4 basically satisfy a linear proportional relationship: F2 / F1=A<1; (2) Nonlinear absorption characteristics (incident pulse laser energy density is XJ / cm 2 ~YJ / cm 2 ), in this case, as the incident pulse laser energy density F1 increases, the ratio of F2 / F1 decreases, and then, when the incident pulse laser disappears, the nonlinear absorption type optical limiting device 4 can restore the linear absorption characteristics; (3) Damage characteristics (incident pulse laser energy density ≥ YJ / cm 2 The damage threshold of nonlinear absorption optical limiting device 4 is defined as YJ / cm 2 ), in which case the nonlinear absorption type optical limiting device 4 first exhibits nonlinear absorption characteristics and then becomes damaged. When the incident pulse laser disappears, the linear absorption characteristics cannot be restored.

[0034] Based on the above working characteristics of the nonlinear absorption type optical limiting device 4, the position of the nonlinear absorption type optical limiting device 4 relative to the focal plane of the primary image plane can be designed according to the normal operation of the optical imaging system against laser damage and blindness and the performance index requirements of the anti-laser damage and blindness, and then the spot size of the laser beam on the surface of the nonlinear absorption type optical limiting device 4 can be controlled to make the incident pulse laser energy density F1 on the surface of the nonlinear absorption type optical limiting device 4 < YJ / cm 2 At the same time, the incident pulse laser energy density F3 on the imaging detector surface is less than the damage / blinding threshold ZJ / cm 2 ; In the case that the above two conditions cannot be met at the same time, priority should be given to ensuring that the incident pulse laser energy density F3 on the imaging detector surface is less than the damage / blinding threshold ZJ / cm of the imaging detector. 2 .

[0035] Furthermore, laser detectors can be installed around the optical imaging system that continuously resists blinding caused by pulsed laser damage. After detecting the incident lasers of different systems or wavelengths, they provide warnings or laser parameter information to the main system of the optical imaging system that continuously resists blinding caused by pulsed laser damage. The main system automatically controls the rotation of the one-dimensional rotating platform 5 and selects nonlinear absorption-type optical limiting devices with different performances. The above improvement scheme can further expand the application scope of laser protection of optical imaging systems that resist blinding caused by laser damage.

[0036] The anti-laser protection scheme of the present invention is not limited to the application scope described in the present invention, but can also be applied to other photoelectric detection systems.

[0037] Example 1 This embodiment provides an optical imaging system that is continuously resistant to blinding caused by pulsed laser damage, including: a primary imaging optical component 1, a secondary imaging optical component 2, an imaging detector 3, a nonlinear absorption type optical limiting device 4, a one-dimensional rotating platform 5, and a one-dimensional linear translation stage 6; After the light enters the optical system, it is focused by the primary imaging optical component 1 to form a primary image plane focus, and then imaged by the secondary imaging optical component 2 to the imaging detector 3; The nonlinear absorption type optical limiting device 4 is installed on the one-dimensional rotating platform 5, and the main optical axis 7 of the secondary imaging optical system passes through the nonlinear absorption type optical limiting device 4; the nonlinear absorption type optical limiting device 4 is located at the side of the primary image plane focus close to the primary imaging optical component 1; The one-dimensional rotating platform 5 is equipped with a plurality of nonlinear absorption type optical limiting devices 4; the material of the nonlinear absorption type optical limiting device 4 is phthalocyanine (such as Figure 3 The protective material made of phthalocyanine materials shown on the left).

[0038] A method for continuous resistance to blinding caused by pulse laser damage is also provided, which specifically includes: after the optical imaging system for continuous resistance to blinding caused by pulse laser damage is started, the one-dimensional rotating platform 5 and the one-dimensional linear translation platform 6 drive the nonlinear absorption type optical limiting device 4 to perform two-dimensional movement, thereby providing continuous laser protection for the imaging system. The specific protection process is as follows: (1) In the absence of laser incidence, the nonlinear absorption type optical limiting device 4 maintains linear working characteristics, and the optical imaging system that is continuously resistant to blinding caused by pulse laser damage performs imaging tasks normally.

[0039] (2) The damage threshold of the nonlinear absorption optical limiting device 4 is defined as YJ / cm 2 ; When the laser is incident and the incident pulse laser energy density F1 is less than YJ / cm 2 Under this circumstance, the nonlinear absorption type optical limiting device 4 automatically exhibits nonlinear absorption characteristics. At this time, the optical path of the optical imaging system that is continuously resistant to blinding caused by pulse laser damage is basically in a closed state, and the imaging system is equivalent to stopping working; after the incident laser disappears, the nonlinear absorption type optical limiting device 4 restores the linear working state, the optical path of the imaging system is reopened, and the optical imaging system that is continuously resistant to blinding caused by pulse laser damage continues to perform imaging tasks normally.

[0040] (3) When the laser is incident and the incident pulse laser energy density F1 ≥ YJ / cm 2 In this case, the surface of the nonlinear absorption type optical limiting device 4 is damaged, but at the next moment the one-dimensional rotating platform 5 and the one-dimensional linear translation platform 6 move the undamaged area on the surface of the nonlinear absorption type optical limiting device 4 to the main optical path of the imaging system, and the nonlinear absorption type optical limiting device 4 continues to provide laser protection for the imaging system. At this time, the optical path of the optical imaging system that is continuously resistant to blinding caused by pulse laser damage continues to be in a closed state; after the incident laser disappears, the nonlinear absorption type optical limiting device 4 resumes its linear working state, the optical path of the imaging system is reopened, and the optical imaging system that is continuously resistant to blinding caused by pulse laser damage continues to perform imaging tasks normally.

[0041] The optical limiting effect of the nonlinear absorption optical limiting device was tested using a laser. The experimental laser parameters are as follows: the laser is a diode-pumped Q-switched Nd:YAG pulse laser from Quantel Big Sky Centurion, with a wavelength of 532 nm, a pulse width of 8 ns, and a repetition frequency of 1-100 Hz, which is set to 10 Hz in this experiment.

[0042] Test results such as Figure 4 As shown in the figure, the horizontal axis is the laser energy density incident on the nonlinear absorption type optical limiting device, and the vertical axis is the laser energy density transmitted from the nonlinear absorption type optical limiting device. It can be seen from the figure that as the incident laser energy density increases, the ratio of the transmitted energy density to the incident energy density decreases significantly. It proves that the nonlinear absorption type optical limiting device can play a nonlinear optical limiting role at the nanosecond level.

[0043] In summary, the present invention proposes an optical imaging system that is continuously resistant to blinding caused by pulse laser damage, which is mainly composed of a secondary imaging optical system, a nonlinear absorption type optical limiting device, a two-dimensional mobile unit and an imaging detector. The nonlinear absorption type optical limiting device is mounted on the two-dimensional mobile unit and placed near the primary image plane position of the main optical axis of the imaging optical system. When the optical imaging system that is continuously resistant to blinding caused by pulse laser damage is in a working state, the two-dimensional mobile unit drives the nonlinear absorption type optical limiting device to rotate or translate within a certain range perpendicular to the main optical axis direction of the secondary imaging optical system, ensuring that the main optical axis passes through different positions of the nonlinear absorption type optical limiting device at each moment, thereby achieving a continuous function of resisting blinding caused by laser damage.

[0044] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the disclosure of the present invention can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document does not limit this.

[0045] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An optical imaging system that is continuously resistant to blinding caused by pulsed laser damage, characterized in that: include: Secondary imaging optical system, imaging detector, nonlinear absorption type optical limiting device, two-dimensional mobile unit; The secondary imaging optical system includes a primary imaging optical component and a secondary imaging optical component; after the light beam enters the secondary imaging optical system, it is focused by the primary imaging optical component to form a primary image plane focus, and then is imaged on the imaging detector after passing through the secondary imaging optical component; The nonlinear absorption type optical limiting device is mounted on a two-dimensional moving unit and is placed near the primary image plane position of the principal optical axis of the secondary imaging optical system; The nonlinear absorption type optical limiting device is driven to move by a two-dimensional moving unit, so that the incident light beam passes through different positions on the nonlinear absorption type optical limiting device, thereby achieving a continuous anti-laser damage blinding function.

2. The optical imaging system according to claim 1, characterized in that: The two-dimensional moving unit includes a one-dimensional rotating platform and a one-dimensional linear translation platform; the one-dimensional rotating platform is arranged on the one-dimensional linear translation platform, and the nonlinear absorption type optical limiting device is installed on the one-dimensional rotating platform; the one-dimensional rotating platform and the one-dimensional linear translation platform move in coordination, so that the incident light beam passes through different positions on the nonlinear absorption type optical limiting device at each moment.

3. The optical imaging system for continuous resistance to blinding caused by pulsed laser damage according to claim 2, characterized in that: A plurality of groups of sheet-shaped nonlinear absorption type optical limiting devices are installed on the one-dimensional rotating platform, and the performance of each sheet of nonlinear absorption type optical limiting device is the same or different.

4. The optical imaging system for continuous resistance to blinding caused by pulsed laser damage according to claim 2, characterized in that: The one-dimensional rotating platform is equipped with an annular nonlinear absorption type optical limiting device.

5. An optical imaging system that is continuously resistant to blinding caused by pulsed laser damage according to any one of claims 1 to 4, characterized in that: The material of the nonlinear absorption type optical limiting device includes at least one of phthalocyanine, porphyrin, graphene, graphene, fullerene, carbon nanotubes, organic small molecules and metal nanoparticles.

6. The optical imaging system according to claim 1, which is continuously resistant to blinding caused by pulsed laser damage, is characterized in that: The nonlinear absorption type optical limiting device is located at a side of the primary image plane focus close to the primary imaging optical component.

7. The optical imaging system for continuous resistance to blindness caused by pulsed laser damage according to claim 6, characterized in that: The size of the nonlinear absorption type optical limiting device is larger than the spot size near the focus of the primary image plane.

8. The optical imaging system for continuous resistance to blindness caused by pulsed laser damage according to claim 2, characterized in that: Also included are laser detectors mounted around the system; A plurality of groups of sheet-shaped nonlinear absorption-type optical limiting devices with different performances are installed on the one-dimensional rotating platform; After detecting the incident lasers of different systems or different wavelengths, the laser detector provides warning or laser parameter information to the main system of the optical imaging system that is continuously resistant to blinding caused by pulsed laser damage. The main system automatically controls the rotation of the one-dimensional rotating platform and selects nonlinear absorption-type optical limiting devices with different performances for protection.

9. The optical imaging system for continuous resistance to blindness caused by pulsed laser damage according to claim 1, characterized in that: The incident pulse laser energy density on the imaging detector surface is less than the damage / blinding threshold of the imaging detector.

10. The optical imaging system for continuous resistance to blinding caused by pulsed laser damage according to claim 9, characterized in that: The incident pulse laser energy density on the surface of the nonlinear absorption type optical limiting device is less than the breakdown threshold of the nonlinear absorption type optical limiting device.

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