Anti-laser broadband efficient retroreflector for satellite

Abstract

The invention relates to the technical field of satellite protection, in particular to an anti-laser broadband efficient retroreflector for satellites, which comprises a metal substrate, a phase change alloy array, a retroreflection microstructure array and a multi-layer optical dielectric film, and is characterized in that the metal substrate is of a hollow box type structure consisting of an upper substrate, a lower substrate and side plates with grids; the phase change alloy array is arranged in the metal substrate and is composed of an Al-Si alloy phase change material; the retro-reflection microstructure array is arranged above the upper substrate, the bottom of the retro-reflection microstructure array is triangular, hexagonal or rectangular, and the top of the retro-reflection microstructure array is of a pointed cone structure composed of three inclined planes; and a plurality of layers of optical medium films are plated on the surface of the retroreflection microstructure array. The Al-Si alloy layer prepared through the substrate can absorb a large amount of heat through phase change, so that the laser damage threshold value and the protection performance are improved, and efficient retroreflection of incident laser is achieved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of satellite protection, in particular to a satellite anti-laser wide-band high-efficiency retroreflector. BACKGROUND

[0002] With the rapid development of high-energy laser weapons, high-power laser attacks on satellites have become a major threat in the field of space security. High-energy laser beams (wavelength is usually 1064 nm, 2700 nm, 3800 nm, etc.) can cause the optical sensor of a satellite to saturate, the solar cell panel to burn out, the thermal control multilayer of the satellite to be damaged, and even directly destroy the key components in a very short time, thereby seriously threatening the normal operation and safety of the satellite. For example, laser irradiation with a power density of more than 1000 W / cm2 can cause the optical system of a satellite to permanently fail within milliseconds.

[0003] For satellite laser protection, patents CN119758500A and CN118465904A both use a multilayer dielectric film to achieve high reflection in typical laser bands, thereby achieving good laser protection capability. However, the above laser protection technology belongs to a completely passive protection technology, and its protection capability will gradually decrease with continuous laser irradiation. In addition, measures such as maneuvering and escaping from orbit consume a large amount of propellant, and using a carried laser weapon to attack requires hundreds of kilograms of load resources and dozens of kilowatts of power consumption, which is a cost that most satellites cannot bear. Therefore, to ensure the safety of satellites in orbit, it is urgent to develop a low-cost, active and passive combined protection strategy to achieve passive protection while having attack countermeasures, thereby preventing satellites from being attacked and damaged or even failing. SUMMARY

[0004] The application provides a satellite anti-laser wide-band high-efficiency retroreflector for satellite high-power laser protection, which simultaneously has a passive retroreflected laser damage function and realizes integrated protection and countermeasures.

[0005] In order to achieve the above purpose, the application provides a satellite anti-laser wide-band high-efficiency retroreflector, which comprises a metal substrate, a phase change alloy array, a retroreflective microstructure array and a multilayer optical dielectric film, wherein: the metal substrate is a hollow box structure composed of an upper substrate, a lower substrate and a side plate with a grid; the phase change alloy array is arranged inside the metal substrate and is composed of an Al-Si alloy phase change material and is distributed in the form of an array below the upper substrate; the retroreflective microstructure array is arranged above the upper substrate, the bottom thereof is a triangle, a hexagon or a rectangle, and the top thereof is a sharp cone structure composed of three inclined surfaces; the surface of the retroreflective microstructure array is coated with a multilayer optical dielectric film; and the multilayer optical dielectric film is a superlattice non-periodic reflection layer designed based on the Fibonacci sequence and comprises alternatingly stacked high-refractive-index material layers and low-refractive-index material layers.

[0006] Further, the material of the metal substrate is high-thermal-conductivity nickel or copper, the thickness is 0.1-1mm, and the height of the internal cavity is 0.3mm.

[0007] Further, the content of Si in the Al-Si alloy phase-change material is 5%-40%, and the melting point is 500-700℃.

[0008] Further, the angle between the top slope and the bottom surface of the retroreflective microstructure array is 30-50°, and the angle between adjacent slopes is 80-95°.

[0009] Further, the high-refractive-index material layer is composed of one or more of Ta2O5, HfO2, ZrO2 and TiO2, and the low-refractive-index material layer is composed of one or more of SiO2, MgF and Al2O3.

[0010] Further, the thickness of the film layers of the multilayer optical medium film is arranged according to the Fibonacci sequence, and the 6th layer and the 10th layer are modified based on the λ / 4n optical thickness at a wavelength of 1064nm.

[0011] Further, the surface of the multilayer optical medium film is further coated with an anti-static layer, and the anti-static layer is an indium tin oxide film with a thickness of 10-50nm.

[0012] The satellite anti-laser wide-band high-efficiency retroreflector provided by the application has the following beneficial effects: The Al-Si alloy layer prepared on the substrate can absorb a large amount of heat through phase change, thereby improving the laser damage threshold and protection performance; the retroreflective microstructure prepared on the structure surface and the Fibonacci superlattice aperiodic reflection layer coated on the surface can realize high-efficiency retroreflection of the incident laser, thereby achieving protection of the high-value satellite and counterattacking the attacking laser weapon with small resources, so as to eliminate the threat. BRIEF DESCRIPTION OF DRAWINGS

[0013] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application and are incorporated in and constitute a part of this application. The drawings illustrate embodiments of the present application and, together with the description, serve to explain the principles of the present application.

[0014] In the drawings: Figure 1 is a structural schematic diagram of the satellite anti-laser wide-band high-efficiency retroreflector provided by the embodiment of the application; Figure 2 is a top view of the retroreflective microstructure array provided by the embodiment of the application; Figure 3is a structural schematic diagram of a multilayer optical medium film provided by an embodiment of the present application; Figure 4 is a schematic diagram of a film layer reflectivity curve in embodiment one; Figure 5 is a schematic diagram of a film layer reflectivity curve in embodiment two; In the figure: 1-upper substrate, 2-lower substrate, 3-side plate, 4-phase change alloy array, 5-retroreflective microstructure array, 6-multilayer optical medium film, 7-antistatic layer. DETAILED DESCRIPTION

[0015] In order to make the person skilled in the art better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative labor should belong to the scope of protection of the present application.

[0016] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units does not have to be limited to only those steps or units clearly listed, but can include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0017] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0018] In addition, in addition to being used to indicate the orientation or positional relationship, the above-mentioned part of the terms can also be used to indicate other meanings, for example, the term "upper" can also be used to indicate a certain dependent relationship or connection relationship in some cases. For the person skilled in the art, the specific meaning of these terms in the present application can be understood according to the specific circumstances.

[0019] In addition, the term "multiple" should mean two or more.

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0021] like Figures 1-2 As shown, this application provides a high-efficiency, wide-band anti-laser retroreflector for satellites, comprising a metal substrate, a phase change alloy array 4, a retroreflective microstructure array 5, and a multilayer optical dielectric film 6. The metal substrate is a hollow box structure composed of an upper substrate 1, a lower substrate 2, and a gridded side plate 3. The phase change alloy array 4 is disposed inside the metal substrate, composed of Al-Si alloy phase change material, and is distributed in an array below the upper substrate 1. The retroreflective microstructure array 5 is disposed above the upper substrate 1, with a triangular, hexagonal, or rectangular bottom and a pointed cone structure composed of three inclined planes at the top. The surface of the retroreflective microstructure array 5 is coated with a multilayer optical dielectric film 6. The multilayer optical dielectric film 6 is a superlattice aperiodic reflective layer designed based on the Fibonacci sequence, comprising alternating layers of high-refractive-index material and low-refractive-index material.

[0022] Specifically, the satellite anti-laser wideband high-efficiency retroreflector provided in this application embodiment can achieve a high reflectivity of over 99% in typical laser bands of 1.064μm, 2.7μm, and 3.8μm, thereby achieving high-efficiency protection against high-power lasers in these bands. Furthermore, based on the high-efficiency retroreflective microstructure array 5 integrated in the reflector, the incident high-power laser can be reflected back to the enemy's attack laser. The energy density of the reflected laser is over 80% of that of the incident laser, thereby effectively damaging the enemy satellite's laser aiming, ranging, and observation optical systems, and even damaging the enemy laser's optical components, achieving the integration of overall satellite protection and countermeasures.

[0023] Furthermore, the metal substrate is made of highly thermally conductive nickel or copper, with a thickness of 0.1-1 mm and an internal cavity height of 0.3 mm.

[0024] Furthermore, the Si content in Al-Si alloy phase change materials is 5%-40%, and the melting point is 500℃-700℃.

[0025] Specifically, in the embodiments of the present application, the metal substrate is made of high-thermal-conductivity materials such as nickel or copper, and mainly comprises an upper substrate 1, a side plate 3 with a grid, and a lower substrate 2, wherein the thickness of the upper substrate 1 and the lower substrate 2 is preferably 0.1-1 mm, the thickness of the side plate 3 is preferably 0.1 mm-1 mm, and the size of the mesh hole is preferably 1 mm-5 mm. An array of 0.1-0.5 mm thick Al-Si alloy phase change materials is arranged in the cavity region below the upper substrate 1. By using the high-thermal-conductivity characteristics of the metal substrate, the absorbed laser heat is quickly transferred laterally inside the substrate, preventing the highest energy of the Gaussian spot center from damaging and avoiding causing avalanche damage. At the same time, by using the phase change characteristics of the Al-Si alloy, the large heat flux during laser irradiation is stored by phase change heat absorption, preventing damage caused by instantaneous high temperature.

[0026] Further, the angle between the top inclined surface and the bottom surface of the retroreflective microstructure array 5 is 30°-50°, and the angle between adjacent inclined surfaces is 80°-95°.

[0027] Specifically, the incident laser is reflected back by the retroreflective microstructure array 5, achieving high-power laser attack protection and passive damage countermeasures for satellites. In the embodiments of the present application, the retroreflective microstructure can be a sharp cone structure with a triangular, hexagonal, or rectangular bottom and three inclined surfaces at the top. The angle between the top inclined surface and the bottom surface is 30°-50°, and the angle between adjacent two inclined surfaces is 80°-95°, achieving high-efficiency retroreflection of the incident laser.

[0028] Further, the high-refractive-index material layer is composed of one or more of Ta2O5, HfO2, ZrO2, and TiO2; and the low-refractive-index material layer is composed of one or more of SiO2, MgF, and Al2O3.

[0029] Further, the thickness of the film layers of the multilayer optical medium film 6 is arranged according to the Fibonacci sequence, taking the λ / 4n optical thickness of 1064 nm wavelength as a reference, and the 6th layer and the 10th layer are modified.

[0030] Specifically, as shown in FIG. 1, the multilayer optical medium film 6 is arranged on the side plate 3 of the metal substrate, and the incident laser is reflected back by the multilayer optical medium film 6 and the retroreflective microstructure array 5. Figure 3As shown, the wide-band high-reflection film is deposited on the surface of the retroreflective microstructure array 5 by using the electron beam evaporation plating technology, and the film system adopts Fibonacci superlattice non-periodic reflection layer. The film layer is defined by Fibonacci sequence, and the high refractive index material can be selected from one or more of Ta2O5, HfO2, ZrO2, and TiO2, and the low refractive index material can be selected from one or more of SiO2, MgF, and Al2O3. According to the Fibonacci sequence definition, the film layer structure is designed, and the A and B basic thicknesses are calculated based on the 1064 nm reference wavelength with λ / 4 optical thickness. At the same time, in order to adapt to the high reflectivity at 2700 nm and 3800 nm wavelengths, the key node layers 6 and 10 need to be modified to meet the high reflectivity requirements of the three laser wavelength bands. Compared with the traditional λ / 4 stack, the Fourier spectrum of the Fibonacci sequence produces diffraction peaks at multiple wavelengths, which can match the multi-band high-reflection design requirements of 1064 nm, 2700 nm, and 3800 nm, reduce the interface number of the multi-layer film by 30%-50%, and the sequence has fractal characteristics, which can naturally suppress the local concentration of electric field, thereby effectively improving the laser damage threshold.

[0031] Further, the surface of the multi-layer optical medium film 6 is also plated with an anti-static layer 7, which is a 10-50 nm thick indium tin oxide film, which can prevent space cosmic rays and plasma from causing discharge damage due to the charging of the surface of the insulating layer.

[0032] The application will be further described below in conjunction with specific examples.

[0033] Example 1 A 300mm×300mm×0.15mm thick nickel is selected as the upper substrate 1, and a 300mm×300mm×0.1mm thick nickel substrate is selected as the lower substrate 2; a 5cm×5cm×0.3mm thick Al-Si alloy array pattern is deposited on the lower surface of the upper substrate 1 by electroplating technology as a phase change material, wherein the Si content is 20%, and the alloy has a melting point of 570℃; a 0.4mm thick mesh plate with a mesh shape of 5cm×5cm is used as the side plate 3 of the intermediate spacing layer, and the upper and lower nickel substrates are welded together to form a substrate with an internal hollow and phase change material.

[0034] Then, a single-point diamond precision lathe is used to mill V-shaped groove arrays on the metal plate with a 90° angle V-shaped diamond milling cutter, the groove depth is 50μm, and the pitch is 120μm; after milling, the workpiece is rotated by 60°, and the same process is used to mill V-shaped groove arrays, the groove depth is 50μm, and the pitch is 120μm; the workpiece is rotated by 60°, and the same process is used to mill V-shaped groove arrays, the groove depth is 50μm, and the pitch is 120μm; finally, a right cubic cone retroreflective microstructure array 5 is obtained.

[0035] Subsequently, on the surface of the processed reflection microstructure array, a standard coating process cleaning is performed, and then a wide-band high-reflection film is deposited by using an electron beam evaporation coating technology. The film system adopts a Fibonacci superlattice non-periodic reflection layer design scheme. The Fibonacci sequence definition is adopted, the high-refractive-index material is selected as Ta2O5, and the low-refractive-index material is selected as SiO2. According to the Fibonacci sequence definition, the film layer structure is designed. The basic thickness of Ta2O5 and SiO2 is calculated based on the 1064 nm reference wavelength, and the optical thickness is calculated based on the 1 / 4n. The refractive index n is calculated. The basic thickness of Ta2O5 is 126 nm, and the basic thickness of SiO2 is 183 nm. At the same time, in order to adapt to the 2700 nm and 3800 nm wavelengths to achieve high reflectivity, the 6th layer and the 10th layer of the key node layer need to be modified. The modification formula is: modified layer thickness = reference layer thickness x target wavelength ÷ reference wavelength. The target wavelengths are 2700 nm and 3800 nm, respectively, and the reference wavelength is 1064 nm, that is: , The 6th layer (2700 nm band modification) is: 183 nm x 2700 / 1064 = 465 nm, The 10th layer (3800 nm band modification) is: 183 nm x 3800 / 1064 = 653 nm.

[0036] After the modification is completed, the reflectivity spectrum curve is calculated by using an optical simulation model. By modifying the thickness, the reflectivity of the 1064 nm, 2700 nm and 3800 nm three bands reaches more than 99%. Then, the film layers from bottom to top are respectively: the first layer of Ta2O5 (126 nm), the second layer of SiO2 (183 nm), the third layer of Ta2O5 (126 nm), the fourth layer of SiO2 (183 nm), the fifth layer of Ta2O5 (126 nm), the sixth layer of SiO2 (465 nm), the seventh layer of Ta2O5 (126 nm), the eighth layer of SiO2 (183 nm), the ninth layer of Ta2O5 (126 nm), the tenth layer of SiO2 (653 nm), the eleventh layer of Ta2O5 (126 nm), the twelfth layer of SiO2 (183 nm), and the thirteenth layer of Ta2O5 (126 nm). The specific thickness of the film layers is shown in the following table: Table 1: Multi-layer optical medium film 6 film layer thickness setting table

[0037] The film layer reflectivity curve of the multi-layer optical medium film 6 plated by using the film layer thickness is as follows: Figure 4As shown, it can be seen that the reflectivity is 99.22% at 1064 nm band, 99.14% at 2700 nm band, and 99.11% at 3800 nm band.

[0038] Finally, a 10 nm indium tin oxide film is plated on the surface of the multilayer optical medium film 6 as an anti-static layer 7 to prevent space cosmic rays and plasma from causing the surface of the insulating layer to be charged and causing discharge damage.

[0039] Example Two: A 300mm×300mm×0.15mm thick nickel is selected as the upper substrate 1, and a 300mm×300mm×0.1mm thick nickel substrate is selected as the lower substrate 2; a 5cm×5cm×0.4mm thick Al-Si alloy array pattern is deposited on the lower surface of the upper substrate 1 by electroplating technology as the phase change material, wherein the Si content is 25%, and the overall melting point of the alloy is 510°C; a 0.4mm thick mesh plate with a mesh shape of 5cm×5cm is used as the side plate 3 of the intermediate spacing layer, and the upper and lower nickel substrates are welded together to form a substrate with an internal hollow and phase change material.

[0040] Then, a single-point diamond precision lathe is used on the upper surface of the nickel upper substrate 1, a V-shaped diamond milling cutter with an angle of 90° is used, a V-shaped groove array is first milled horizontally on the metal plate, the groove depth is 90μm, and the pitch is 170μm; after milling, the workpiece is rotated by 60°, and a V-shaped groove array is milled according to the same process, the groove depth is 90μm, and the pitch is 170μm; the workpiece is rotated by 60° again, and a V-shaped groove array is milled according to the same process, the groove depth is 90μm, and the pitch is 170μm; finally, a right cubic cone retroreflective microstructure array 5 is obtained.

[0041] Subsequently, the surface of the processed reflective microstructure array is cleaned by standard plating process, and a wide-band high-reflection film is deposited by electron beam evaporation plating technology, the film system adopts a Fibonacci superlattice non-periodic reflection layer design scheme; the high refractive index material is selected as HfO2, and the low refractive index material is selected as SiO2 according to the Fibonacci sequence definition; the film layer structure is designed according to the Fibonacci sequence definition, the basic thickness of HfO2 and SiO2 is calculated as λ / 4n optical thickness with 1064 nm as the reference wavelength, and n is the refractive index; the calculation can obtain that the basic thickness of HfO2 is 137nm, and the basic thickness of SiO2 is 183nm; at the same time, in order to adapt to the wavelengths of 2700nm and 3800nm to achieve high reflectivity, the 6th layer and the 10th layer of the key node layer need to be modified, the modification formula is: modified layer thickness=reference layer thickness×target wavelength÷reference wavelength, the target wavelengths are 2700nm and 3800nm respectively, and the reference wavelength is 1064nm, i.e.: , The 6th layer (2700nm band correction) is: 183nm x 2700 / 1064 = 465nm, The 10th layer (3800nm band correction) is: 183nm x 3800 / 1064 = 653nm.

[0042] After the correction, the reflectivity spectrum curve is calculated by using the optical simulation model, and the reflectivity of 1064nm, 2700nm and 3800nm is above 99% by correcting the thickness; then the film layers from bottom to top are respectively the first layer HfO2 (137nm), the second layer SiO2 (183nm), the third layer HfO2 (137nm), the fourth layer SiO2 (183nm), the fifth layer HfO2 (137nm), the sixth layer SiO2 (465nm), the seventh layer HfO2 (137nm), the eighth layer SiO2 (183nm), the ninth layer HfO2 (137nm), the tenth layer SiO2 (653nm), the eleventh layer HfO2 (137nm), the twelfth layer SiO2 (183nm), the thirteenth layer HfO2 (137nm), and the specific thickness of the film layers is shown in the following table: Table 2: Thickness setting table of 6 layers of multilayer optical medium film

[0043] The film layer reflectivity curve of the multilayer optical medium film 6 plated by using the film layer thickness is shown in Figure 5 It can be seen that the reflectivity at 1064nm is 99.13%, the reflectivity at 2700nm is 99.11%, and the reflectivity at 3800nm is 99.07%.

[0044] Finally, a layer of 10nm indium tin oxide film is plated on the surface of the multilayer optical medium film 6 as an anti-static layer 7 to prevent space cosmic rays and plasma from causing discharge damage due to the charging of the surface of the insulating layer.

[0045] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A wide-band high-efficiency anti-laser retroreflector for satellites, characterized in that, The application relates to a metal substrate, a phase-change alloy array, a retroreflective microstructure array and a multilayer optical medium film, wherein: The metal substrate is a hollow box structure composed of an upper substrate, a lower substrate and a grid side plate; The phase-change alloy array is arranged inside the metal substrate, is composed of Al-Si alloy phase-change materials and is distributed in an array form below the upper substrate; The retroreflective microstructure array is arranged above the upper substrate, the bottom of the retroreflective microstructure array is a triangle, a hexagon or a rectangle, and the top of the retroreflective microstructure array is a sharp cone structure composed of three inclined planes; The surface of the retroreflective microstructure array is plated with the multilayer optical medium film; The multilayer optical medium film is a superlattice non-periodic reflective layer based on a Fibonacci sequence and is composed of alternately superposed high-refractive-index material layers and low-refractive-index material layers.

2. The anti-laser wide-band high-efficiency retroreflector for satellites according to claim 1, characterized in that, The material of the metal substrate is high-thermal-conductivity nickel or copper, the thickness of the metal substrate is 0.1-1 mm, and the height of the internal cavity is 0.3 mm.

3. The anti-laser wide-band high-efficiency retroreflector for satellites according to claim 2, characterized in that, The content of Si in the Al-Si alloy phase-change material is 5%-40%, and the melting point is 500-700 DEG C.

4. The anti-laser wide-band high-efficiency retroreflector for satellites according to claim 3, characterized in that, The angle between the top inclined plane and the bottom of the retroreflective microstructure array is 30-50 DEG, and the angle between adjacent inclined planes is 80-95 DEG.

5. The anti-laser wide-band high-efficiency retroreflector for satellites according to claim 4, characterized in that, The high-refractive-index material layer is composed of one or more of Ta2O5, HfO2, ZrO2 and TiO2; and the low-refractive-index material layer is composed of one or more of SiO2, MgF and Al2O3.

6. The anti-laser wide-band high-efficiency retroreflector for satellites according to claim 5, characterized in that, The film layer thickness of the multilayer optical medium film is arranged according to a Fibonacci sequence, the optical thickness of the multilayer optical medium film is 1 / 4n of the wavelength of 1064 nm, the 6th layer and the 10th layer are corrected, and the surface of the multilayer optical medium film is further plated with an antistatic layer.

7. The anti-laser wide-band high-efficiency retroreflector for satellites according to claim 6, characterized in that, The antistatic layer is a 10-50 nm thick indium tin oxide film.

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