A dual-polarization metasurface phased array based on phase change material and its application

Abstract

The present invention discloses a dual-polarization metasurface phased array based on phase change material and its application, which belongs to the field of metasurface radar, including a reflective metasurface phased array, which includes a plurality of periodically arranged Sb2S3 metasurface units, and the Sb2S3 metasurface units include a metal patch layer, a sandwich dielectric layer and a metal reflective substrate layer arranged in sequence; the sandwich dielectric layer includes an upper SiO2 material layer, a middle Sb2S3 phase change material layer, and a lower SiO2 material layer. The present invention adopts the above-mentioned dual-polarization metasurface phased array based on phase change material and its application, realizes the function of dual-polarization beam scanning, and has the advantages of large phase shift, dual-polarization scanning, high unit reflection coefficient, etc.

Description

Technical Field

[0001] The present invention relates to the technical field of metasurface radar, and in particular to a dual-polarization metasurface phased array based on phase change material and applications thereof. Background Art

[0002] Meteorological LiDAR is one of the key core equipment for atmospheric detection. It plays an important role in atmospheric science research, meteorological monitoring, disaster warning, etc. It is widely used in aviation, aerospace, national defense, agriculture, forestry, hydrology and other fields. Dual-polarization LiDAR in meteorological LiDAR has more advantages than single-polarization LiDAR. It can emit two orthogonal polarization lasers at the same time. It can use the depolarization effect of atmospheric aerosol on laser to distinguish the type of aerosol and identify the cloud phase. Dual-polarization LiDAR can also obtain more other observation parameters. It is more sensitive to the type, shape, size and falling posture of hydrometeor particles. It has the ability to identify the phase and type of hydrometeor particles in the cloud. At the same time, it has the ability to reduce the impact of precipitation estimation with distance changes and the impact of hail on precipitation estimation. It has a wide range of applications in radar quantitative measurement of precipitation, phase identification of precipitation particles, identification of non-meteorological echoes, and clutter suppression.

[0003] Metasurfaces are a type of device that builds an artificially designed sub-wavelength optical structure on a two-dimensional plane and controls the transmission or reflection phase of the laser on the unit structure to regulate the coherent synthesis characteristics of the far-field beam. By designing the shape and size of the phase element structure, the radiation direction of the transmitted or reflected beam can be controlled, thereby realizing device functions such as planar lenses and anomalous refraction.

[0004] At the same time, compared with integrated optical waveguide phased arrays, metasurface phased arrays have more advantages in the field of atmospheric detection. For the dual polarization technology required by atmospheric detection instruments, metasurfaces have more design space and degrees of freedom, thereby realizing the fast and large-range scanning function of phased arrays in the meteorological field. In addition, metasurfaces have the advantage of small size, which facilitates integration and miniaturization.

[0005] LiDAR has a wide range of application prospects in atmospheric detection. However, research in this field has just started, and the following problems have not yet been solved: (1) Currently, most LiDARs used in the meteorological field use mechanical beam scanning, and their temporal and spatial resolution is limited by the accuracy of the stepper motor and is far below the theoretical limit. (2) Most existing LiDARs use a single polarization detection mode, which makes it difficult to analyze the morphology and form of the object to be detected in the atmosphere. However, if dual polarization detection is to be achieved, the light transmission and reception circuit will be more complicated, greatly increasing the size, weight and manufacturing cost of the equipment.

[0006] Therefore, the dual-polarization phased array technology based on metasurface is the basis for the further widespread application of meteorological lidar and has very important research significance. Summary of the invention

[0007] To solve the above problems, the present invention provides a dual-polarization metasurface phased array based on phase change materials and its application, which realizes the function of dual-polarization beam scanning and has the advantages of large phase shift, dual polarization scanning, and high unit reflection coefficient.

[0008] To achieve the above-mentioned object, the present invention provides a dual-polarization metasurface phased array based on phase change materials, including a reflective metasurface phased array, the reflective metasurface phased array includes a plurality of periodically arranged Sb2S3 metasurface units, the Sb2S3 metasurface unit includes a metal patch layer, a sandwich-type dielectric layer and a metal reflective substrate layer arranged in sequence;

[0009] The sandwich-type dielectric layer includes an upper SiO2 material layer, a middle Sb2S3 phase-change material layer, and a lower SiO2 material layer.

[0010] Preferably, the reflective metasurface phased array includes M×N periodically arranged Sb2S3 metasurface units, wherein M=48, N=16, and M=dx×4×T, T≥2, dx is the phase change step, and T is the phase change period.

[0011] Preferably, the metal patch layer is a metal patch made of Au material in a "X" shape, and the metal patch made of Au material in a "X" shape is attached to the top of the sandwich-shaped dielectric layer;

[0012] The metal reflective substrate layer is a metal reflective substrate made of Au material.

[0013] Preferably, the metal patch made of Au material in the shape of an "X" includes a first vertical side, a first horizontal side, a second vertical side, a second horizontal side, and a third vertical side arranged in sequence in the shape of an "X", and the width and thickness of the first vertical side, the first horizontal side, the second vertical side, the second horizontal side, and the third vertical side are equal.

[0014] Preferably, the width w of the first vertical side, the first horizontal side, the second vertical side, the second horizontal side, and the third vertical side is 0.06 um; the thickness h1 of the first vertical side, the first horizontal side, the second vertical side, the second horizontal side, and the third vertical side is 0.05 um;

[0015] The length of the first vertical side a1=0.16um; the length of the second vertical side a2=0.06um; the length of the third vertical side a3=0.16um; the length of the first horizontal side b1 and the length of the second horizontal side b2 are both 0.2um.

[0016] Preferably, the cross-section of the sandwich-type dielectric layer and the metal reflective substrate layer is a square with a side length L=0.5 um;

[0017] The thickness of the upper SiO2 material layer is h2=0.02um; the thickness of the middle Sb2S3 phase change material layer is h3=0.1um; the thickness of the lower SiO2 material layer is h4=0.02um;

[0018] The thickness of the metal reflective substrate layer is h5 = 0.05 um.

[0019] Preferably, the dielectric constant calculation formula of the crystalline and amorphous Sb2S3 phase change material used in the middle Sb2S3 phase change material layer is as follows:

[0020]

[0021] Among them, ε a (λ) is the dielectric constant of the Sb2S3 phase change material in the amorphous state, where m = 1, and m is the crystal fraction of the Sb2S3 phase change material; ε c (λ) is the dielectric constant of Sb2S3 phase change material in the crystalline state, where m = 0; ε eff (λ) is the dielectric constant of Sb2S3 phase change material in different crystalline states.

[0022] The dual-polarization metasurface phased array based on phase change material is applied in dual-polarization beam scanning. The wavelength of the dual-polarization metasurface phased array based on phase change material is 1.4um, the incident wave is inclined at 45°, and the generated electric field produces a phase regulation of 0 to 221° for X polarization and a phase regulation of 0 to 239° for Y polarization.

[0023] The present invention has the following beneficial effects:

[0024] The metasurface can be guaranteed to have a high reflection coefficient and dual polarization response at a wavelength of 1.4 microns.

[0025] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a front view of a Sb2S3 metasurface unit of a dual-polarization metasurface phased array based on phase change material of the present invention;

[0027] Figure 2 It is a top view of a Sb2S3 metasurface unit of a dual-polarization metasurface phased array based on phase change material of the present invention;

[0028] Figure 3 It is a graph showing the relationship between the reflectivity of the Sb2S3 metasurface unit to X polarization and wavelength in the simulation experiment of the present invention;

[0029] Figure 4It is a graph showing the relationship between the reflection phase of the Sb2S3 metasurface unit to X polarization and the wavelength in the simulation experiment of the present invention;

[0030] Figure 5 It is a graph showing the relationship between the reflection coefficient of the Sb2S3 metasurface unit to Y polarization and wavelength in the simulation experiment of the present invention;

[0031] Figure 6 It is a graph showing the relationship between the reflection phase of the Sb2S3 metasurface unit to Y polarization and the wavelength in the simulation experiment of the present invention;

[0032] Figure 7 1 is a schematic diagram showing an example of the phase arrangement of the metasurface phased array when the m value of the phase change material Sb2S3 in the Sb2S3 metasurface unit in the embodiment of the present invention is 0.1, 0.4, 0.6, and 0.8 from right to left, the phase decreases from right to left, and when M=48, N=16, dx=4, and T=3;

[0033] Figure 8 is a schematic diagram of the reflective metasurface phased array structure in an embodiment of the present invention;

[0034] Fig. 9 1 is a graph showing the relationship between the X-polarization beam deflection angle and dx value at 1.4 microns for the metasurface when the crystal fraction m of the phase change material Sb2S3 in the Sb2S3 metasurface unit in the embodiment of the present invention is 0.1, 0.4, 0.6, and 0.8 from right to left, the phase decreases from right to left, and M=48 and N=16;

[0035] Fig.10 1 is a graph showing the relationship between the Y-polarization beam deflection angle and the dx value at 1.4 microns for the metasurface when the crystal fraction m of the phase change material Sb2S3 in the Sb2S3 metasurface unit in the embodiment of the present invention is 0.1, 0.4, 0.6, and 0.8 from right to left, the phase decreases from right to left, and M=48, N=16;

[0036] Fig.11 1 is a graph showing the relationship between the X-polarization beam deflection angle at 1.4 microns and the dx value, when the crystal fraction m of the phase change material Sb2S3 in the Sb2S3 metasurface unit in the embodiment of the present invention is 0.8, 0.6, 0.4, and 0.1 from right to left, the phase increases from right to left, and the metasurface when M=48 and N=16;

[0037] Fig.12This is a graph showing the relationship between the Y-polarization beam deflection angle and dx value at 1.4 microns in the metasurface when M=48 and N=16, and the crystal fraction m of the phase change material Sb2S3 in the Sb2S3 metasurface unit in an embodiment of the present invention is equal to 0.8, 0.6, 0.4, and 0.1 from right to left, respectively, and the phase increases from right to left.

[0038] Among them: 1. Metal patch layer; 11. First vertical side; 12. First horizontal side; 13. Second vertical side; 14. Second horizontal side; 15. Third vertical side; 2. Sandwich-type dielectric layer; 21. Upper SiO2 material layer; 22. Middle Sb2S3 phase change material layer; 23. Lower SiO2 material layer; 3. Metal reflective substrate layer. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical scheme and advantages disclosed in the embodiments of the present invention clearer, the embodiments of the present invention are further described in detail in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the embodiments of the present invention and are not intended to limit the embodiments of the present invention. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions.

[0040] It should be noted that the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or server comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or are inherent to the sandwich media layer of these processes, methods, products or devices.

[0041] Like reference numerals and letters denote similar items in the following drawings, and thus, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0042] A dual-polarization metasurface phased array based on phase change material, including a reflective metasurface phased array, the reflective metasurface phased array includes a plurality of periodically arranged Sb2S3 metasurface units, the Sb2S3 metasurface units include a metal patch layer 1, a sandwich-type dielectric layer 2 and a metal reflective substrate layer 3 arranged in sequence; the sandwich-type dielectric layer 2 includes an upper SiO2 material layer 21, a middle Sb2S3 phase change material layer 22, and a lower SiO2 material layer 23.

[0043] The reflective metasurface phased array includes M×N periodically arranged Sb2S3 metasurface units, where M=48, N=16, and M=dx×4×T, T≥2, dx is the phase change step, and T is the phase change period.

[0044] The metal patch layer 1 is a metal patch made of Au in a "X" shape, which is attached to the top of the sandwich-type dielectric layer 2 without any gap therebetween; the metal reflective substrate layer 3 is a metal reflective substrate made of Au.

[0045] The metal patch made of Au in the shape of an “X” comprises a first vertical side 11, a first horizontal side 12, a second vertical side 13, a second horizontal side 14, and a third vertical side 15 which are arranged in sequence in the shape of an “X”, and the width and thickness of the first vertical side 11, the first horizontal side 12, the second vertical side 13, the second horizontal side 14, and the third vertical side 15 are equal.

[0046] The width w of the first vertical side 11, the first horizontal side 12, the second vertical side 13, the second horizontal side 14, and the third vertical side 15 is 0.06um; the thickness h1 of the first vertical side 11, the first horizontal side 12, the second vertical side 13, the second horizontal side 14, and the third vertical side 15 is 0.05um; and the length a1 of the first vertical side 11 is 0.16um; the length a2 of the second vertical side 13 is 0.06um; the length a3 of the third vertical side 15 is 0.16um; the length b1 of the first horizontal side 12 and the length b2 of the second horizontal side 14 are both 0.2um. The cross-section of the sandwich-type dielectric layer 2 and the metal reflective substrate layer 3 is a square with a side length L = 0.5um; the thickness of the upper SiO2 material layer 21 is h2 = 0.02um; the thickness of the middle Sb2S3 phase change material layer 22 is h3 = 0.1um; the thickness of the lower SiO2 material layer 23 is h4 = 0.02um; the thickness of the metal reflective substrate layer 3 is h5 = 0.05um.

[0047] The dielectric constant calculation formula of the crystalline and amorphous state of the Sb2S3 phase change material used in the middle Sb2S3 phase change material layer 22 is as follows:

[0048]

[0049] Among them, ε a (λ) is the dielectric constant of the Sb2S3 phase change material in the amorphous state, where m = 1, and m is the crystal fraction of the Sb2S3 phase change material; ε c (λ) is the dielectric constant of Sb2S3 phase change material in the crystalline state, where m = 0; ε eff (λ) is the dielectric constant of Sb2S3 phase change material in different crystalline states.

[0050] The dual-polarization metasurface phased array based on phase change material is applied in dual-polarization beam scanning. The wavelength of the dual-polarization metasurface phased array based on phase change material is 1.4um, the incident wave is inclined at 45°, and the generated electric field produces a phase regulation of 0 to 221° for X polarization and a phase regulation of 0 to 239° for Y polarization.

[0051] Simulation experiment

[0052] Through CST software simulation, the periodic boundary conditions in the x and y directions are considered in this process, and the electromagnetic wave propagates along the z direction. The simulation is carried out in the wavelength range of 1.3μm to 1.5μm, under different crystal fractions m of the Sb2S3 phase change material, and when the incident wave is incident at an angle of 45°, the following is obtained: Figures 3 to 6 From the reflection coefficient and phase shift curves for X polarization and Y polarization shown, it can be seen that the reflection coefficient of the Sb2S3 metasurface unit is relatively high in the wavelength range of 1.3μm to 1.5μm, and the electric field produces a phase regulation of 0 to 221° for X polarization and a phase regulation of 0 to 239° for Y polarization.

[0053] The Sb2S3 metasurface units with crystal fraction m values ​​of Sb2S3 phase change materials of 0.1, 0.4, 0.6, and 0.8 are taken as basic periodic units, and the metasurface phased array phase is arranged to form an increasing or decreasing phase gradient. Figure 4 as well as Figure 6 It can be seen that when the m value is 0.1, 0.4, 0.6, and 0.8, adjacent values ​​have an average phase difference of 55° for X polarization, and adjacent values ​​have an average phase difference of 65° for Y polarization, and the larger the m value, the smaller the phase value.

[0054] Example 1

[0055] In this embodiment, the crystal fraction m of the phase change material Sb2S3 in the metasurface periodic unit structure is equal to 0.1, 0.4, 0.6, and 0.8 from right to left, respectively, and is arranged in a phase decreasing manner, keeping M=48, N=16 unchanged, and changing dx to 3, 4, and 6.

[0056] The above-mentioned metasurface phase arrangement distribution and specific arrangement are as follows Figure 7 shown.

[0057] CST software was used to simulate the far-field beam deflection at 1.4 microns. The crystal fraction m of the phase change material Sb2S3 was calculated to be 0.1, 0.4, 0.6, and 0.8 from right to left. For the X and Y polarization responses, M = 48 and N = 16 were kept unchanged. When dx was 3, 4, and 6, the following results were obtained: Figures 9-10 As shown in the schematic diagram of far-field beam deflection, it can be seen that the far-field deflected beam of the metasurface described in this embodiment is deflected downward based on the total reflection beam of the incident wave incident at an angle of 45°.

[0058] Example 2

[0059] In this embodiment, the crystal fraction m values ​​of the phase change material Sb2S3 in the supersurface periodic unit structure are equal to 0.8, 0.6, 0.4, and 0.1 from right to left, respectively, and are arranged in phase increments, keeping M=48, N=16 unchanged, and changing dx to 3, 4, and 6.

[0060] CST software was used to simulate the far-field beam deflection at 1.4 microns. The simulation calculated the X and Y polarization responses of the phase change material Sb2S3 when the crystal fraction m values ​​were 0.8, 0.6, 0.4, and 0.1 from right to left, respectively. When M=48 and N=16 were kept unchanged, and dx was 3, 4, and 6, the following results were obtained: Figures 11-12 As shown in the schematic diagram of far-field beam deflection, it can be seen that the far-field deflected beam of the metasurface of this embodiment is deflected upward based on the total reflection beam of the incident wave incident at an angle of 45°.

[0061] In summary, it can be seen from Examples 1 and 2 that the Sb2S3 metasurface described in the present application can respond well to both X-polarization and Y-polarization at 1.4 microns, can realize dual-polarization beam scanning function, and the scanning angle is about 38°.

[0062] Therefore, the present invention adopts the above-mentioned dual-polarization metasurface phased array based on phase change materials and its application to realize the function of dual-polarization beam scanning, and has the advantages of large phase shift, dual-polarization scanning, high unit reflection coefficient, etc.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A dual-polarization metasurface phased array based on phase change material, characterized by: It includes a reflective metasurface phased array, which includes a plurality of periodically arranged Sb2S3 metasurface units, and the Sb2S3 metasurface units include a metal patch layer, a sandwich-type dielectric layer, and a metal reflective substrate layer arranged in sequence; The sandwich-type dielectric layer includes an upper SiO2 material layer, a middle Sb2S3 phase change material layer, and a lower SiO2 material layer; The metal patch layer is a metal patch made of Au material in a "X" shape, and the metal patch made of Au material in a "X" shape is attached to the top of the sandwich-shaped dielectric layer; The metal reflective substrate layer is a metal reflective substrate made of Au material.

2. The dual-polarization metasurface phased array based on phase change material according to claim 1, characterized in that: The reflective metasurface phased array includes M×N periodically arranged Sb2S3 metasurface units, where M=48, N=16, and M=dx×4×T, T≥2, dx is the phase change step, and T is the phase change period.

3. The dual-polarization metasurface phased array based on phase change material according to claim 2, characterized in that: The metal patch made of Au material in the shape of an "X" includes a first vertical side, a first horizontal side, a second vertical side, a second horizontal side, and a third vertical side arranged in sequence in the shape of an "X", and the width and thickness of the first vertical side, the first horizontal side, the second vertical side, the second horizontal side, and the third vertical side are equal.

4. The dual-polarization metasurface phased array based on phase change material according to claim 3, characterized in that: The width w of the first vertical side, the first horizontal side, the second vertical side, the second horizontal side, and the third vertical side is 0.06 um; the thickness h1 of the first vertical side, the first horizontal side, the second vertical side, the second horizontal side, and the third vertical side is 0.05 um; The length of the first vertical side a1=0.16um; the length of the second vertical side a2=0.06um; the length of the third vertical side a3=0.16um; the length of the first horizontal side b1 and the length of the second horizontal side b2 are both 0.2um.

5. The dual-polarization metasurface phased array based on phase change material according to claim 1, characterized in that: The cross section of the sandwich-type dielectric layer and the metal reflective substrate layer is a square with a side length of L = 0.5 um; The thickness of the upper SiO2 material layer is h2=0.02um; the thickness of the middle Sb2S3 phase change material layer is h3=0.1um; the thickness of the lower SiO2 material layer is h4=0.02um; The thickness of the metal reflective substrate layer is h5 = 0.05 um.

6. The dual-polarization metasurface phased array based on phase change material according to claim 5, characterized in that: The dielectric constant calculation formula of the crystalline and amorphous Sb2S3 phase change material used in the middle Sb2S3 phase change material layer is as follows: Among them, ε a (λ) is the dielectric constant of the Sb2S3 phase change material in the amorphous state, where m = 1, and m is the crystal fraction of the Sb2S3 phase change material; ε c (λ) is the dielectric constant of Sb2S3 phase change material in the crystalline state, where m = 0; ε eff (λ) is the dielectric constant of Sb2S3 phase change material in different crystalline states.

7. Application of a dual-polarization metasurface phased array based on phase change material in dual-polarization beam scanning as claimed in any one of claims 1 to 6, characterized in that: The wavelength of the dual-polarization metasurface phased array based on phase change material is 1.4um, the incident wave is inclined at 45°, and the generated electric field produces a phase control of 0 to 221° for the X polarization and a phase control of 0 to 239° for the Y polarization.

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