Optical window device and preparation method thereof

Abstract

The invention relates to the technical field of multifunctional regulation and control materials, and particularly provides an optical window device and a preparation method thereof. The optical window device comprises a dielectric substrate, a metal functional layer and a metal reflecting layer which are formed on the surfaces of the two sides of the dielectric substrate, and an anti-reflection dielectric layer formed on the outer side of the metal functional layer and the outer side of the metal reflecting layer. Since the metal functional layer comprises a plurality of annular metal structures which are provided with openings and have phase responses meeting phase distribution requirements corresponding to RCS reduction, the device can form an electromagnetic scattering regulation and control layer based on the annular metal structures and the centrosymmetric metal ring structures, so as to guide electromagnetic waves to generate phase responses and realize RCS reduction and microwave diffuse scattering. The anti-reflection dielectric layer can reduce the infrared spectrum transmission loss of the prepared optical window device and enhance the infrared wave wide angular domain transmission performance of the optical window device so as to meet the cross-spectrum electromagnetic regulation and control requirement in a complex scene.

Description

Technical Field

[0001] This application relates to the technical field of multifunctional regulation materials, and more specifically, to an optical window device and a preparation method thereof. Background Art

[0002] The emergence of optical windows is to meet the protection requirements for the working environment of optoelectronic devices in modern science and technology. With the development of technology, optoelectronic devices are increasingly widely used in various fields. How to ensure their stable operation in various environments has become an important issue. As a transparent flat plate with optical properties, an optical window can effectively protect optoelectronic devices and prevent the influence of environmental factors on their operation.

[0003] With the development of technology, optoelectronic devices are increasingly widely used, and the demand for optical windows is also increasing. In view of the development needs of integrated technologies for multi-spectrum optoelectronic detection systems and electromagnetic regulation materials with different working modes in fields such as remote sensing detection, radar electromagnetic regulation, and communication, the optical transmission bandwidth of existing optical window devices is relatively narrow and cannot meet the cross-spectrum electromagnetic regulation requirements in complex scenarios. Summary of the Invention

[0004] In view of this, the purpose of the embodiments of this application is to provide an optical window device and a preparation method thereof to solve the above technical problems.

[0005] In a first aspect, the embodiments of this application provide an optical window device, which includes: a dielectric substrate, a metal functional layer and a metal reflection layer formed on both side surfaces of the dielectric substrate, and two antireflection dielectric layers formed outside the metal functional layer and the metal reflection layer;

[0006] The metal functional layer includes a plurality of annular metal structures with openings; wherein, the phase response of the annular metal structure meets the phase distribution requirements corresponding to RCS reduction;

[0007] The metal reflection layer includes a plurality of randomly arranged centrosymmetric metal ring structures;

[0008] The antireflection dielectric layer includes a plurality of periodically arranged gradient structures.

[0009] In the above implementation process, the optical window device includes a dielectric substrate, metal functional layers and metal reflection layers formed on both side surfaces of the dielectric substrate, and an anti-reflection dielectric layer formed on the outer sides of the metal functional layers and the metal reflection layers; the metal functional layer includes a plurality of annular metal structures with openings; wherein, the phase response of the annular metal structure meets the phase distribution requirements corresponding to RCS reduction; the metal reflection layer includes a plurality of centrally symmetric metal ring structures randomly arranged. Since the metal functional layer includes a plurality of annular metal structures with openings and the phase response meets the phase distribution requirements corresponding to RCS reduction, the device can form an electromagnetic scattering control layer based on the annular metal structures in the metal functional layer and the centrally symmetric metal ring structures in the metal reflection layer to guide the electromagnetic wave to generate a phase response, realizing RCS reduction and microwave diffuse scattering. Based on the anti-reflection dielectric layer including a plurality of periodically arranged gradient structures, the infrared spectral transmission loss of the prepared optical window device can be reduced, and the infrared wide-angle transmission performance of the optical window device can be enhanced to meet the cross-spectrum electromagnetic control requirements in complex scenarios. By introducing an anti-reflection dielectric layer on the basis of the electromagnetic scattering control structure layer (metal functional layer and metal reflection layer), while realizing RCS reduction and visible light transparency, the entire optical window device can achieve wide-angle anti-reflection at 1.550 μm single-wavelength laser in the infrared band, and has functions such as low diffraction loss imaging and surface hydrophobicity.

[0010] Optionally, in the embodiment of the present application, the annular metal structure includes an annular hollow metal structure; the centrally symmetric metal ring structure includes a centrally symmetric hollow metal ring structure.

[0011] In the above implementation process, since the annular metal structure includes an annular hollow metal structure and the centrally symmetric metal ring structure includes a centrally symmetric hollow metal ring structure, the metal duty ratio corresponding to the metal functional layer and the metal reflection layer can be reduced through the hollow structure, thereby improving the optical transmittance of the optical window device.

[0012] Optionally, in the embodiment of the present application, the centrally symmetric hollow metal ring structure includes: an outer metal ring and a plurality of centrally symmetric inner metal rings uniformly arranged inside the outer metal ring.

[0013] In the above implementation process, since the centrally symmetric hollow metal ring structure includes an outer metal ring and a plurality of centrally symmetric inner metal rings disposed inside the outer metal ring, it is possible to provide the same reflection ability as the metal plate while significantly reducing the metal coverage rate of the optical window device, thereby further improving the optical transmittance of the device. In addition, since the centrally symmetric inner metal rings are uniformly disposed inside the outer metal ring, based on the randomly arranged centrally symmetric metal ring structure, the diffracted energy distribution can be more evenly dispersed in different directions, thereby reducing the energy concentration degree of the high-order diffracted waves and reducing the interference of the high-order diffracted waves on the imaging system, and can significantly improve the imaging quality of the corresponding imaging system.

[0014] Optionally, in the embodiments of the present application, the annular hollow metal structure includes: an annular outer metal unit having an opening and a plurality of metal connection lines uniformly disposed inside the annular outer metal unit and connected to the annular outer metal unit.

[0015] In the above implementation process, since the annular hollow metal structure includes an annular outer metal unit having an opening and a plurality of metal connection lines uniformly disposed inside the annular outer metal unit and connected to the annular outer metal unit, it is possible to provide the same reflection ability as the metal plate while significantly reducing the metal coverage rate of the optical window device, thereby further improving the optical transmittance of the device.

[0016] Optionally, in the embodiments of the present application, the area of the cross-section of the gradient structure is inversely correlated with the cross-section substrate distance; the cross-section is the cross-section parallel to the dielectric substrate in the gradient structure, and the cross-section substrate distance is the distance between the cross-section and the dielectric substrate.

[0017] Optionally, in the embodiments of the present application, the preparation materials of the dielectric substrate and the anti-reflection dielectric layer are the same.

[0018] In the above implementation process, since the preparation materials of the dielectric substrate and the anti-reflection dielectric layer are the same, the stability of the optical window device can be improved.

[0019] Optionally, in the embodiments of the present application, the preparation materials of the dielectric substrate and the anti-reflection dielectric layer include zinc sulfide; the shape of the gradient structure is a frustum shape, a pyramid shape, a truncated cone shape or a cone shape; the arrangement period of the gradient structure is 1 μm to 2 μm, and the structure height is 1.5 μm to 2 μm.

[0020] In a second aspect, embodiments of the present application provide a method for manufacturing an optical window device, the method including:

[0021] Etch to form a metal functional layer and a metal reflection layer on both sides of the dielectric substrate; wherein, the metal functional layer includes a plurality of annular metal structures with openings; the phase response of the annular metal structures meets the phase distribution requirements corresponding to RCS reduction; the metal reflection layer includes a plurality of randomly arranged centrosymmetric metal ring structures;

[0022] Form an antireflection dielectric layer on the outside of the metal functional layer and the metal reflection layer respectively;

[0023] Etch to form a plurality of periodically arranged gradient structures on the antireflection dielectric layer.

[0024] In the above implementation process, the preparation method of the optical window device includes: etching to form a metal functional layer and a metal reflection layer on both sides of the dielectric substrate; wherein, the metal functional layer includes a plurality of annular metal structures with openings; the phase response of the annular metal structures meets the phase distribution requirements corresponding to RCS reduction; the metal reflection layer includes a plurality of randomly arranged centrosymmetric metal ring structures. Since the metal functional layer includes a plurality of annular metal structures with openings and the phase response meets the phase distribution requirements corresponding to RCS reduction, the optical window device prepared based on this method can form an electromagnetic scattering control layer based on the annular metal structures in the metal functional layer and the centrosymmetric metal ring structures in the metal reflection layer to guide the electromagnetic wave to generate a phase response, realizing RCS reduction and microwave diffuse scattering; furthermore, the transmission bandwidth of the optical window device is improved, and it can meet the cross-spectrum electromagnetic regulation requirements in complex scenarios.

[0025] Optionally, in the embodiments of the present application, the area of the cross-section of the gradient structure is inversely correlated with the cross-section substrate distance; the cross-section is the cross-section parallel to the dielectric substrate in the gradient structure, and the cross-section substrate distance is the distance between the cross-section and the dielectric substrate.

[0026] Optionally, in the embodiments of the present application, the preparation materials of the dielectric substrate and the antireflection dielectric layer are the same.

[0027] In the above implementation process, since the preparation materials of the dielectric substrate and the antireflection dielectric layer are the same, the stability of the prepared optical window device can be improved.

[0028] The beneficial effects of the present application at least include: The optical window device includes a dielectric substrate, metal functional layers and metal reflection layers formed on both side surfaces of the dielectric substrate, and an anti-reflection dielectric layer formed on the outer sides of the metal functional layers and the metal reflection layers; the metal functional layer includes a plurality of annular metal structures having openings; wherein, the phase response of the annular metal structure meets the phase distribution requirements corresponding to RCS reduction; the metal reflection layer includes a plurality of randomly arranged centrosymmetric metal ring structures; the anti-reflection dielectric layer includes a plurality of periodically arranged gradient structures. Since the metal functional layer includes a plurality of annular metal structures having openings and the phase response meets the phase distribution requirements corresponding to RCS reduction, the device can form an electromagnetic scattering control layer based on the annular metal structures in the metal functional layer and the centrosymmetric metal ring structures in the metal reflection layer to guide the electromagnetic wave to generate a phase response, realizing RCS reduction and microwave diffuse scattering. Based on the anti-reflection dielectric layer including a plurality of periodically arranged gradient structures, the infrared spectral transmission loss of the prepared optical window device can be reduced, and the infrared wide-angle transmission performance of the optical window device can be enhanced, meeting the cross-spectral electromagnetic control requirements in complex scenarios. Based on the optical window device provided by the present application, by introducing an anti-reflection dielectric layer on the basis of the electromagnetic scattering control structure layer (metal functional layer and metal reflection layer), while realizing RCS reduction and visible light transparency, the entire optical window device can achieve wide-angle anti-reflection at 1.550 μm single wavelength of infrared compatibility, and has functions such as low diffraction loss imaging and surface hydrophobicity. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required to be used in the embodiments of the present application. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0030] Figure 1 It is a schematic structural diagram of an optical window device provided by an embodiment of the present application;

[0031] Figure 2 It is a schematic structural diagram of a metal functional layer and a metal reflection layer provided by an embodiment of the present application;

[0032] Figure 3 It is a schematic diagram of the simulation result of the microwave control phase of the optical window device provided by an embodiment of the present application;

[0033] Figure 4 It is a schematic diagram of the RCS reduction curve of the optical window device provided by an embodiment of the present application;

[0034] Figure 5 The far - field 3D scattering pattern for RCS reduction of the optical window device provided by the embodiment of the present application;

[0035] Figure 6 Schematic diagram of the simulation result of the optical transmission characteristic of the optical window device provided by the embodiment of the present application;

[0036] Figure 7 Schematic diagram of the simulation result of the optical diffraction characteristic of the optical window device provided by the embodiment of the present application;

[0037] Figure 8 Schematic flow chart of a preparation method of an optical window device provided by the embodiment of the present application. Detailed implementation manners

[0038] Hereinafter, embodiments of the technical solutions of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solutions of the present application more clearly, so they are only examples and cannot be used to limit the protection scope of the present application.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0040] In the description of the embodiments of the present application, technical terms such as "first", "second", etc. are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity, specific order or primary - secondary relationship of the indicated technical features. In the description of the embodiments of the present application, "a plurality" means two or more unless otherwise specifically defined.

[0041] Please refer to Figure 1 The structural schematic diagram of an optical window device 10 provided by the embodiment of the present application shown. Figure 1 The overall structural schematic diagram of the optical window device 10 is shown on the left, and the schematic diagram of a plurality of periodically arranged gradient structures included in the antireflection dielectric layer 103 is shown separately on the right. The optical window device 10 includes: a dielectric substrate 100, metal functional layers 101 and metal reflection layers 102 formed on both side surfaces of the dielectric substrate 100, and two antireflection dielectric layers 103 formed outside the metal functional layer 101 and the metal reflection layer 102;

[0042] The metal functional layer 101 includes a plurality of annular metal structures with openings; wherein, the phase response of the annular metal structure meets the phase distribution requirements corresponding to RCS reduction;

[0043] The metal reflection layer 102 includes a plurality of randomly arranged centrosymmetric metal ring structures;

[0044] The antireflection dielectric layer 103 includes a plurality of periodically arranged gradient structures.

[0045] Among them, the metal functional layer 101 and the metal reflection layer 102 can be etched on the dielectric substrate 100. The preparation materials of the dielectric substrate 100 can include silicon dioxide, titanium pentoxide, and / or zinc sulfide, etc. The preparation materials of the metal functional layer 101 and the metal reflection layer 102 can include metal materials such as copper and / or silver. The number of the annular metal structures included in the metal functional layer 101, the opening direction of the annular metal structures, the opening size and other parameters can all be adjusted according to the actual application situation. Exemplarily, it can be based on to determine the phase distribution requirements for RCS reduction, representing the phase mask of the annular metal structure at the position of (x c , y c ), δ represents the modulation index, and D represents the side length of the metal functional layer 101. The phase distribution requirements corresponding to RCS reduction can also be a checkerboard phase distribution. For example, the annular metal structures with a phase response of 0° and the circumferential metal structures with a phase response of 180° are alternately distributed (alternately distributed in both the horizontal and vertical directions). The annular metal structure can be a circular ring structure or a polygonal ring structure (such as a hexagon or an octagon, etc.). The phase response of the corresponding annular metal structure can be adjusted by adjusting parameters such as the opening direction and the opening angle size of the circular ring structure. Please refer to Figure 2 , Figure 2 which is a schematic structural diagram of the metal functional layer and the metal reflection layer provided by the embodiment of the present application. It should be noted that Figure 2 only one annular metal structure in the metal functional layer 101 is exemplarily shown on the left, and this annular metal structure is realized by a circular ring structure with an opening angle size of 90°; Figure 2 only a part of the randomly arranged centrosymmetric metal ring structures in the metal reflection layer 102 is exemplarily shown on the right.

[0046] Please refer to Figure 3 , Figure 3 which is a schematic diagram of the simulation results of the microwave-controlled phase of the optical window device provided by the embodiment of the present application. Figure 3 The left side shows the reflection amplitude control parameters corresponding to the annular metal structure, Figure 3 and the right side shows the phase control parameters corresponding to the annular metal structure. As Figure 3As shown, by changing the phase parameters of the annular metal structure (taking the annular metal structure realized by a circular ring structure as an example, the phase parameters of the annular metal structure may include: parameters such as the inner radius, outer radius, opening direction, and opening angle size of the circular ring structure), the reflection amplitude and phase of the annular metal structure can be regulated. From Figure 3 it can be seen that the designed structure has a reflection amplitude lower than -10 dB in the operating frequency band of 8 - 18 GHz, with extremely high polarization conversion ability; and it can achieve 2π phase coverage.

[0047] Please refer to Figure 4 , Figure 4 which is a schematic diagram of the RCS reduction curve of the optical window device provided by the embodiment of the present application. Figure 4 It is the RCS reduction curve obtained by simulating the super-surface array formed by arranging the optical window devices according to a certain phase. As Figure 4 shown, the super-surface array based on the optical window device provided by the present application can basically achieve RCS reduction lower than -10 dB throughout the operating frequency band, with lower values at 10.5 GHz, 14 GHz, and 17.5 GHz respectively. Please refer to Figure 5 , Figure 5 which is the far-field 3D scattering diagram of the RCS reduction achieved by the optical window device provided by the embodiment of the present application. θ = 0° indicates that the incident angle of light is 0°. Figure 5 The first row shows the far-field 3D scattering diagram of the RCS reduction of a metal reflector of the same size, and the second row shows the far-field 3D scattering diagram of the RCS reduction achieved by the optical window device provided by the embodiment of the present application. As Figure 5 shown, by comparing the simulation results with a metal reflector of the same size at three frequency points of 10.5 GHz, 14 GHz, and 17.5 GHz respectively, it can be seen that compared with the metal plate, the super-surface array based on the optical window device provided by the present application can achieve better RCS reduction effect and there is no high-energy beam in any direction.

[0048] Among them, a zinc sulfide thin layer (about 2 μm thick) can be evaporated on the outer sides of the metal functional layer 101 and the metal reflection layer 102 respectively, and then a plurality of periodically arranged gradient structures can be formed by etching. The phase response of the antireflection dielectric layer 103 can be regulated in the form of transmission phase modulation, geometric phase modulation, resonance phase modulation, or a combination of multiple phase modulation methods. When electromagnetic waves are incident on the optical window device 10, electromagnetic waves at a specific frequency will first directly pass through the antireflection dielectric layer 103, pass through the metal functional layer 101, and undergo diffuse scattering, so as to achieve the purpose of low electromagnetic scattering; when light in the infrared band is incident on the optical window device 10, it will interact with the sub-wavelength antireflection dielectric layer 103 to generate surface plasmon resonance, thereby generating a strong local field enhancement on the surface of the structure. By regulating this resonance phenomenon, the light transmittance can be changed to achieve the transmission enhancement effect. Through this hierarchical design, the cross-spectrum working ability of the optical window device 10 can be improved.

[0049] Please refer to Figure 6 , Figure 6 which is a schematic diagram of the simulation results of the optical transmission characteristics of the optical window device provided by the embodiment of the present application. Taking the preparation material of the dielectric substrate 100 as zinc sulfide as an example, Figure 6 The left side shows a schematic diagram of the simulation results of the transmittance of the optical window device for laser light, Figure 6 and the right side shows a schematic diagram of the simulation results of the transmittance of the optical window device for light with a wavelength of 3 μm to 5 μm. As Figure 6 shown, based on the optical window device structure provided by the present application, the average optical transmittance of zinc sulfide can be increased from 75% to 90%, the transmittance at the laser wavelength of 1.550 μm reaches more than 95%, and it has a certain angular stability (the average transmittance within the range of 0° to 60° exceeds 90%). Therefore, based on the optical window device 10 provided by the present application, by arranging two antireflection dielectric layers 103 on the outer sides of the metal functional layer 101 and the metal reflection layer 102, and the antireflection dielectric layer 103 includes a plurality of periodically arranged gradient structures; the infrared spectral transmission loss of the optical window device 10 can be reduced based on the antireflection dielectric layer 103, and the infrared wide-angle transmission performance of the optical window device 10 can be enhanced. By introducing the antireflection dielectric layer 103 on the basis of the electromagnetic scattering regulation structure layer (metal functional layer 101 and metal reflection layer 102), while realizing RCS reduction and visible light transparency, the entire optical window device 10 can achieve infrared compatibility and wide-angle transmission enhancement at a single wavelength of 1.550 μm laser, and has functions such as low diffraction loss imaging and surface hydrophobicity. It provides a new idea for the integration of multifunctional devices in the field of optical detection and microwave radar collaborative regulation of metasurfaces for engineering applications.

[0050] It can be seen that since the metal functional layer 101 includes a plurality of annular metal structures having openings and the phase response satisfies the phase distribution requirements corresponding to RCS reduction, the optical window device 10 provided by the embodiment of the present application can form an electromagnetic scattering control layer based on the annular metal structures in the metal functional layer 101 and the centrosymmetric metal ring structure in the metal reflection layer 102 to guide the electromagnetic wave to generate a phase response, realizing RCS reduction and microwave diffuse scattering; based on the antireflection dielectric layer including a plurality of periodically arranged gradient structures, the infrared spectral transmission loss of the prepared optical window device can be reduced, and the infrared wide-angle transmission performance of the optical window device can be enhanced, meeting the cross-spectrum electromagnetic regulation requirements in complex scenarios.

[0051] In some alternative embodiments, the annular metal structure includes an annular hollow metal structure; the centrosymmetric metal ring structure includes a centrosymmetric hollow metal ring structure.

[0052] Among them, the annular hollow metal structure may include: an annular peripheral metal unit having an opening and a plurality of internal metal hollow structures uniformly arranged inside the annular peripheral metal unit and connected to the annular peripheral metal unit. The internal metal hollow structures are specifically arranged between the outer ring and the inner ring of the annular peripheral metal unit. The internal metal hollow structures may include a plurality of metal connection lines (as Figure 2 shown), or may include a plurality of internal metal hollow rings. The centrosymmetric metal ring structure may include an outer peripheral metal ring and a plurality of centrosymmetric internal hollow metal structures uniformly arranged inside the outer peripheral metal ring (as Figure 2 shown). The centrosymmetric internal hollow metal structures may be internal metal circular rings or internal metal regular polygon rings, etc. Since the annular metal structure includes an annular hollow metal structure and the centrosymmetric metal ring structure includes a centrosymmetric hollow metal ring structure, the metal duty ratio corresponding to the metal functional layer and the metal reflection layer can be reduced without changing the phase distribution of the metal structure itself, thereby improving the optical transmittance of the optical window device.

[0053] In some alternative embodiments, the centrosymmetric hollow metal ring structure includes: an outer peripheral metal ring and a plurality of centrosymmetric internal metal rings uniformly arranged inside the outer peripheral metal ring.

[0054] Among them, the internal metal ring can be a metal circular ring or a metal polygon ring, etc. Both the outer metal ring and the internal metal ring can be formed by winding metal wires. The wire widths of the metal wires used for the outer metal ring and the internal metal ring can be the same (for example, 2μm, 5μm, 10μm, etc.) or different. Since the centrally symmetric hollow metal ring structure includes an outer metal ring and a plurality of centrally symmetric internal metal rings disposed inside the outer metal ring, it is possible to provide the same reflection ability as the metal plate while greatly reducing the metal coverage of the optical window device to further improve the optical transmittance of the device.

[0055] Please refer to Figure 7 , Figure 7 which is a schematic diagram of the simulation result of the optical diffraction characteristics of the optical window device provided by the embodiment of the present application. Specifically, based on the relevant knowledge of image processing, the metal functional layer 101 and the metal reflection layer 102 are discretized by software to obtain a discrete point array corresponding to the metal reflection layer 102 (establish an x0y rectangular coordinate system with the center point of the array as the coordinate origin). Based on the discrete point array, the transmission function of the metal reflection layer 102 is determined, and operations such as Fourier transform are performed on the discrete point array to obtain the diffraction energy distribution diagram of the optical window device 10. Among them, Figure 7 On the left side of the first row is the structural diffraction simulation model established by binarizing the metal functional layer 101 and the metal reflection layer 102 by software. The black part is the light-blocking part, and the white part is the light-transmitting part. Figure 7 The right side of the first row shows the structural optical diffraction characteristics obtained by software simulation. It can be seen that there is no strong high-order diffraction energy around the microwave structure (the microwave structure formed by the metal functional layer 101 and the metal reflection layer 102), and it can be considered that the microwave structure equalizes the distribution of diffraction energy. Figure 7 The second row shows the normalized diffraction energy distribution diagram of the microwave structure (the abscissa is the distance from the coordinate origin, and the unit is mm). It can be seen that the high-order diffraction energy of this microwave structure is as low as about 0.009908% (-4.004dB), that is, it basically does not affect the imaging quality of the infrared camera.

[0056] Therefore, since the centrally symmetric internal metal rings are uniformly arranged inside the outer metal ring, based on the randomly arranged centrally symmetric metal ring structure, the diffraction energy distribution can be more evenly dispersed in different directions, thereby reducing the energy concentration degree of the high-order diffraction waves and reducing the interference of the high-order diffraction waves on the imaging system, and can significantly improve the imaging quality of the corresponding system.

[0057] In some alternative embodiments, the annular hollow metal structure includes: an annular peripheral metal unit having an opening, and a plurality of metal connection lines uniformly disposed inside the annular peripheral metal unit and connected to the annular peripheral metal unit.

[0058] Among them, the annular peripheral metal unit with an opening can be formed by winding a metal wire. The line width of the metal wire used for the annular peripheral metal unit can be 5μm, 10μm, 15μm, etc.; when the line width of the metal wire used for the annular peripheral metal unit is 10μm, the line width of the metal connection line, and the line widths of the metal wires used for the outer peripheral metal ring and the inner metal ring can all be 5μm. Exemplarily, when the arrangement period of the annular hollow metal structure is 7mm, the outer radius of the annular peripheral metal unit can be 2.68mm, the inner radius can be 2.58mm, and the opening angle can be 52°; correspondingly, the centrally symmetric hollow metal ring structure can specifically include: a circular outer peripheral metal ring (the diameter can be 1070μm) and a plurality of circular inner metal rings (the diameter can be 386μm) uniformly disposed inside the outer peripheral metal ring. The metal connection line can be a straight line or a curve (for example, a semi-circular arc metal connection line), and the present application does not make specific limitations in this regard. Since the annular hollow metal structure includes an annular peripheral metal unit having an opening and a plurality of metal connection lines uniformly disposed inside the annular peripheral metal unit and connected to the annular peripheral metal unit, while providing the same reflection ability as the metal plate, the metal coverage rate of the optical window device can be reduced to a greater extent to further improve the optical transmittance of the device.

[0059] In some alternative embodiments, the area of the cross-section of the gradient structure is inversely correlated with the cross-section substrate distance; the cross-section is the cross-section parallel to the dielectric substrate 100 in the gradient structure, and the cross-section substrate distance is the distance between the cross-section and the dielectric substrate 100.

[0060] Among them, the gradient structure can be an infrared wide-angle antireflection frustum structure, or a hexagonal frustum structure, a frustum of a cone structure, etc. Figure 1 The right side exemplarily shows the case where the gradient structure is realized by a frustum structure. Among them, the parameters of the frustum structure can include: the period p = 1.41μm, the side length L of the lower base (the base close to the dielectric substrate 100) = 1.21μm, the side length l of the upper base (the base far from the dielectric substrate 100) = 0.33μm, and the height h = 1.54μm.

[0061] In some alternative embodiments, the preparation materials of the dielectric substrate 100 and the antireflection dielectric layer 103 are the same.

[0062] Among them, the preparation materials of the dielectric substrate 100 and the antireflection dielectric layer 103 can both be silicon dioxide, titanium pentoxide, zinc sulfide, etc. Since the preparation materials of the dielectric substrate 100 and the antireflection dielectric layer 103 are the same, the stability and environmental tolerance of the optical window device 10 can be improved.

[0063] In some alternative embodiments, the preparation materials of the dielectric substrate 100 and the antireflection dielectric layer 103 include zinc sulfide; the shape of the gradient structure is a frustum shape, a pyramid shape, a truncated cone shape or a cone shape; the arrangement period of the gradient structure is 1 μm to 2 μm, and the structure height is 1.5 μm to 2 μm.

[0064] Among them, the shape of the gradient structure can be a frustum shape, a pyramid shape, a truncated cone shape or a cone shape. The arrangement period of the gradient structure can be 1 μm, 1.5 μm, 2 μm or other reasonable values, and the structure height of the gradient structure can be 1.5 μm, 1.7 μm, 2 μm or other reasonable values. Taking the shape of the gradient structure as a frustum shape as an example, the side length of the bottom (the side close to the dielectric substrate 100) of the gradient structure is 1 μm to 1.5 μm, and the side length of the top (the side far from the dielectric substrate 100) is 0.5 μm to 1 μm. Exemplarily, when the side length of the bottom of the gradient structure is 1 μm, the side length of the top can be 0.5 μm or 0.9 μm, etc.; when the side length of the bottom of the gradient structure is 1.5 μm, the side length of the top can be 0.5 μm, 0.7 μm or 1 μm, etc. The specific values of the arrangement period or the structure height of the gradient structure can be adjusted according to the actual application situation (for example, the actual working wavelength of the optical window device).

[0065] Please refer to Figure 8 , Figure 8 which is a schematic flow chart of a method for manufacturing an optical window device provided by an embodiment of the present application. The method for manufacturing the optical window device may include the following steps:

[0066] S201. Etch to form a metal functional layer and a metal reflection layer on both sides of the dielectric substrate; among them, the metal functional layer includes a plurality of annular metal structures with openings; the phase response of the annular metal structure satisfies the phase distribution requirements corresponding to RCS reduction; the metal reflection layer includes a plurality of randomly arranged centrosymmetric metal ring structures;

[0067] S202. Form an antireflection dielectric layer on the outside of the metal functional layer and the metal reflection layer respectively;

[0068] S203. Etch to form a plurality of periodically arranged gradient structures on the antireflection dielectric layer.

[0069] Among them, based on the preparation method of the optical window device provided by this application, a metal functional layer and a metal reflection layer are etched on both sides of the dielectric substrate; wherein, the metal functional layer includes a plurality of annular metal structures with openings; the phase response of the annular metal structure meets the phase distribution requirements corresponding to RCS reduction; the metal reflection layer includes a plurality of randomly arranged centrosymmetric metal ring structures. Since the metal functional layer includes a plurality of annular metal structures with openings and the phase response meets the phase distribution requirements corresponding to RCS reduction, the optical window device prepared based on this method can form an electromagnetic scattering control layer based on the annular metal structure in the metal functional layer and the centrosymmetric metal ring structure in the metal reflection layer to guide the electromagnetic wave to generate a phase response, realizing RCS reduction and microwave diffuse scattering; furthermore, the transmission bandwidth of the optical window device is improved, and the cross-spectrum electromagnetic regulation requirements in complex scenarios can be met.

[0070] In some optional embodiments, the area of the cross-section of the gradient structure is inversely correlated with the cross-section substrate distance; the cross-section is the cross-section parallel to the dielectric substrate in the gradient structure, and the cross-section substrate distance is the distance between the cross-section and the dielectric substrate.

[0071] In some optional embodiments, the preparation materials of the dielectric substrate and the anti-reflection dielectric layer are the same.

[0072] Among them, since the preparation materials of the dielectric substrate and the anti-reflection dielectric layer are the same, the stability of the optical window device can be improved.

[0073] It should be understood that the preparation method of this optical window device corresponds to the above-mentioned optical window device embodiment. The specific implementation manner of the preparation method of this optical window device can refer to the description in the above text. To avoid repetition, the detailed description is appropriately omitted here.

[0074] In several embodiments provided by the embodiments of the present application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architectures, functions, and operations of the devices and methods according to multiple embodiments of the present application. In this regard, each block in the flowchart or block diagram may represent a module, a program segment, or a part of code, and the module, program segment, or part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order from that marked in the accompanying drawings. For example, two consecutive blocks can actually be executed substantially in parallel, and they can sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, as well as the combination of blocks in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.

[0075] In addition, in each embodiment of the embodiments of the present application, the various functional modules can be integrated together to form an independent part, or each module can exist separately, or two or more modules can be integrated to form an independent part.

[0076] The above description is only an alternative implementation manner of the embodiments of the present application, but the protection scope of the embodiments of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the embodiments of the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the embodiments of the present application.

Claims

1. An optical window device, characterized in that: The device comprises: a dielectric substrate, a metal functional layer and a metal reflective layer formed on both side surfaces of the dielectric substrate, and two anti-reflective dielectric layers formed outside the metal functional layer and the metal reflective layer; The metal functional layer includes a plurality of annular metal structures with openings; wherein the phase response of the annular metal structures meets the phase distribution requirements corresponding to RCS reduction; The metal reflective layer includes a plurality of randomly arranged centrosymmetric metal ring structures; The anti-reflection medium layer includes a plurality of periodically arranged gradual gradient structures.

2. The device according to claim 1, characterized in that The annular metal structure includes an annular hollow metal structure; the centrally symmetrical metal ring structure includes a centrally symmetrical hollow metal ring structure.

3. The device according to claim 2, characterized in that The centrosymmetric hollow metal ring structure comprises: an outer metal ring and a plurality of centrosymmetric inner metal rings uniformly arranged inside the outer metal ring.

4. The device according to claim 2, characterized in that in, The annular hollow metal structure comprises: an annular peripheral metal unit with an opening and a plurality of metal connecting wires uniformly arranged inside the annular peripheral metal unit and connected to the annular peripheral metal unit.

5. The device according to claim 1, characterized in that The area of ​​the cross section of the gradual gradient structure is inversely correlated with the cross-section substrate distance; the cross section is a cross section in the gradual gradient structure parallel to the dielectric substrate, and the cross-section substrate distance is the distance between the cross section and the dielectric substrate.

6. The device according to claim 5, characterized in that in, The dielectric substrate and the anti-reflection dielectric layer are made of the same material.

7. The device according to claim 6, characterized in that in, The preparation materials of the dielectric substrate and the anti-reflection dielectric layer include zinc sulfide; The shape of the gradual gradient structure is a prism shape, a pyramid shape, a truncated cone shape or a cone shape; the arrangement period of the gradual gradient structure is 1 μm to 2 μm, and the structure height is 1.5 μm to 2 μm.

8. A method for preparing an optical window device, characterized in that: The method comprises: A metal functional layer and a metal reflective layer are formed by etching on both sides of the dielectric substrate; wherein the metal functional layer includes a plurality of annular metal structures with openings; the phase response of the annular metal structure meets the phase distribution requirements corresponding to RCS reduction; and the metal reflective layer includes a plurality of randomly arranged centrally symmetrical metal ring structures; forming anti-reflection medium layers on the outer sides of the metal functional layer and the metal reflective layer respectively; A plurality of periodically arranged gradual gradient structures are formed by etching on the anti-reflection medium layer.

9. The method according to claim 8, characterized in that The area of ​​the cross section of the gradual gradient structure is inversely correlated with the cross-section substrate distance; the cross section is a cross section in the gradual gradient structure parallel to the dielectric substrate, and the cross-section substrate distance is the distance between the cross section and the dielectric substrate.

10. The method according to claim 9, characterized in that The dielectric substrate and the anti-reflection dielectric layer are made of the same material.

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