Topological acoustic structure, design method and acoustic device

Abstract

The application provides a topological acoustic structure, a design method and an acoustic device. The topological acoustic structure comprises a first plate, a second plate and an acoustic unit array formed by a plurality of acoustic units and arranged between the first plate and the second plate, a single acoustic unit comprises a central resonant cavity, three peripheral resonant cavities, an intra-cell coupling sound channel and an inter-cell coupling sound channel with a coupling strength of J, the coupling strengths of the intra-cell coupling sound channels between the three peripheral resonant cavities and the central resonant cavity are (1+)J, (1+)J and (1+)J respectively; 、 and a direction angle α of the Berry dipole of the topological acoustic structure with respect to the x direction, 、 and a spatial distribution in the topological acoustic structure is used for forming an effective pseudo-magnetic field with a direction angle β, the direction angle α is equal to the direction angle β, so as to form a zero-mode sound propagation channel extending along a zero-mode sound propagation axis corresponding to the direction angle α inside the topological acoustic structure.

Description

Technical Field

[0001] This application relates to the field of acoustic devices, and in particular to a topological acoustic structure, design method, and acoustic device. Background Technology

[0002] Existing acoustic waveguides typically utilize rigid sidewalls, narrow channels, defect chains, or interfaces between different acoustic lattice regions to define the acoustic wave propagation path. When it is necessary to change the direction of acoustic wave propagation, the macroscopic boundaries, defect paths, or heterogeneous interfaces of the acoustic cavity need to be redesigned, which is highly challenging and makes it difficult to achieve acoustic wave transmission in different directions while maintaining the overall shape of the sample. Summary of the Invention

[0003] The first aspect of this application provides a topological acoustic structure, including: First board; The second plate is arranged parallel to the first plate; A channel topology layer is disposed between the first plate and the second plate. The channel topology layer includes a solid frame layer and an acoustic cell array formed by the frame layer in cooperation with the first plate and the second plate. The acoustic cell array includes a plurality of acoustic cells arranged in an array and interconnected. Each acoustic cell includes: Central resonant cavity; The number of peripheral resonant cavities is three, and they are evenly distributed around the central resonant cavity on the same circumference with respect to the central resonant cavity as the center. An intercellular coupling channel is disposed on the side of the peripheral resonant cavity away from the central resonant cavity and is used to connect adjacent acoustic cells; An intracellular coupling acoustic channel is disposed between each of the peripheral resonant cavities and the central resonant cavity and connects the corresponding peripheral resonant cavity and the central resonant cavity; The coupling strength of a single intercellular coupling channel is defined as J, and the coupling strengths of the intracellular coupling channels between the three peripheral resonant cavities and the central resonant cavity are respectively (1+ J). )J、(1+ )J and (1+ )J, where, 、 and For dimensionless control parameters, And at least some of the acoustic unit cell's control parameters 、 and Not all are 0; The control parameters 、 and The control parameter is used to determine the direction angle α between the Berry dipole and the x-direction of the topological acoustic structure. 、 and The spatial distribution within the topological acoustic structure is used to form an effective pseudomagnetic field with a direction angle β, where the direction angle α is equal to the direction angle β. This is to close the zero-order Landau level gap near the Γ point of the first Brillouin zone of the band structure of the topological acoustic structure and form a zero-mode correlated branch, and to form a zero-mode acoustic propagation channel extending along the zero-mode acoustic propagation axis corresponding to the direction angle α within the topological acoustic structure. In some embodiments, the control parameters... 、 and The relationship between the direction angle α and the given direction angle α satisfies: .

[0004] In some embodiments, the line connecting the geometric centers of the two peripheral resonant cavities extends along the x-direction, defining a dimensionless lateral coordinate along the normal of the zero-mode acoustic propagation channel. The control parameters are as follows: In the formula, x and y are respectively expressed in terms of lattice constants. The normalized x and y coordinates of the center of the acoustic cell, The effective pseudomagnetic field amplitude parameter is positive.

[0005] In some embodiments, the magnitude of the orientation angle α is 0, and ; Alternatively, the magnitude of the direction angle α is ,and .

[0006] In some embodiments, along the normal of the zero-mode acoustic propagation channel, the acoustic cell array is divided into at least two isoparametric cell bands, and within each of the isoparametric cell bands, each acoustic cell has the same control parameter. 、 and .

[0007] A second aspect of this application provides a method for designing a topological acoustic structure, comprising: A channel topology layer is arranged between two parallel plates to form a topological acoustic structure; The acoustic channel topology layer includes a solid frame layer and an acoustic cell array formed by the frame layer in conjunction with the first plate and the second plate. The acoustic cell array includes a plurality of acoustic cells arranged in an array and interconnected with each other. Each acoustic cell includes: Central resonant cavity; The number of peripheral resonant cavities is three, and they are evenly distributed around the central resonant cavity on the same circumference with respect to the central resonant cavity as the center. An intercellular coupling channel is disposed on the side of the peripheral resonant cavity away from the central resonant cavity and is used to connect adjacent acoustic cells; Intracellular coupling channels are positioned between each of the peripheral resonant cavities and the central resonant cavity, and connect the corresponding peripheral resonant cavity to the central resonant cavity; the coupling strength of a single intercellular coupling channel is set to J, and the coupling strength of the intracellular coupling channels between the three peripheral resonant cavities and the central resonant cavity is set to (1+ J) respectively. )J、(1+ )J and (1+ )J, where, 、 and For dimensionless control parameters, And at least some of the acoustic unit cell's control parameters 、 and Make the control parameter 、 and Determine the direction angle α between the Berry dipole and the x-direction of the topological acoustic structure, so that the control parameters... 、 and The spatial distribution within the topological acoustic structure forms an effective pseudomagnetic field with a direction angle β, making the direction angle α equal to the direction angle β. This causes the band structure of the periodic supercell of the topological acoustic structure to close the zero-order Landau level gap near the Γ point in the first Brillouin zone and form a zero-mode correlated branch. Furthermore, it creates a zero-mode acoustic propagation channel within the topological acoustic structure extending along the zero-mode acoustic propagation axis corresponding to the direction angle α. In some embodiments, the control parameters are... 、 and The relationship between the direction angle α and the given direction angle α satisfies: .

[0008] In some embodiments, the line connecting the geometric centers of the two peripheral resonant cavities is extended along the x-direction to define a dimensionless lateral coordinate along the normal of the zero-mode acoustic propagation channel. The control parameters are as follows: In the formula, x and y are respectively expressed in terms of lattice constants. The normalized x and y coordinates of the center of the acoustic cell, The effective pseudomagnetic field amplitude parameter is positive.

[0009] In some embodiments, the acoustic cell array is divided into at least two isoparametric cell bands along the normal of the zero-mode acoustic propagation channel, and within each of the isoparametric cell bands, each acoustic cell has the same control parameter. 、 and .

[0010] A third aspect of this application provides an acoustic device, including a topological acoustic structure, wherein the topological acoustic structure is any of the aforementioned topological acoustic structures, or the topological acoustic structure is designed using any of the aforementioned topological acoustic structure design methods.

[0011] This application has at least the following beneficial effects: (1) The coupling strength of the intercellular coupling channel remains constant, and the adjustment parameters are adjusted. 、 and Used to adjust the coupling strength of each intracellular coupling channel and form different symmetry breaks, thereby controlling the direction of the direction angle α between the Berry dipole and the x-direction. Through the spatial distribution in the topological acoustic structure, an effective pseudomagnetic field consistent with the direction of the Berry dipole is formed, thereby forming a zero-mode acoustic propagation channel extending along the axis corresponding to the direction angle α inside the topological acoustic structure. (2) By adjusting the control parameters 、 and The size of the intercellular coupling channel can change the relative relationship and spatial arrangement between different intracellular coupling channels, thereby changing the direction of sound wave propagation under the condition that the outer contour of the topological acoustic structure remains basically unchanged. (3) The coupling strength of the intercellular coupling channel is J. The direction of sound wave propagation is mainly adjusted by the geometric parameters and spatial distribution of the intracellular coupling channel. There are few parameters to be adjusted, which is convenient for structural calibration, manufacturing and experimental reproduction. (4) The central resonant cavity, the peripheral resonant cavity, the intercellular coupling channel and the intracellular coupling channel can be scaled or recalibrated as a whole according to the target frequency and processing scale, which has good structural adaptability and engineering expansion capability. Attached Figure Description

[0012] Figure 1 This is a perspective view of a topological acoustic structure according to an embodiment of this application.

[0013] Figure 2 for Figure 1 The structural diagram of the acoustic cell array in the image.

[0014] Figure 3 for Figure 2 A schematic diagram of the acoustic channel structure of a single acoustic cell.

[0015] Figure 4 To reduce Figure 3 A schematic diagram of the structure when the coupling strength of the intracellular coupled vocal tract is measured.

[0016] Figure 5 To increase Figure 3 A schematic diagram of the structure when the coupling strength of the intracellular coupled vocal tract is measured.

[0017] Figure 6 This is a comparison diagram of the band structure of an acoustic unit cell under different single control parameters.

[0018] Figure 7 This is a schematic diagram of the zero-mode acoustic propagation axis and the gradient direction of the intracellular coupling parameters when both the direction angle α and the direction angle β are 0°.

[0019] Figure 8 This is a schematic diagram of the zero-mode acoustic propagation axis and the gradient direction of the intracellular coupling parameters when both the direction angle α and the direction angle β are 45°.

[0020] Figure 9 This is a diagram of the band structure of a periodic supercell of an acoustic unit cell.

[0021] Figure 10 The image shows the simulation results of the acoustic field of the finite structure when both the direction angle α and the direction angle β are 0°.

[0022] Figure 11 The image shows the simulation results of the acoustic field of the finite structure when both the direction angle α and the direction angle β are 45°.

[0023] Figure 12 The diagram shows the experimental sound pressure mapping results when both the direction angle α and the direction angle β are 0°.

[0024] Figure 13 The diagram shows the experimental sound pressure mapping results when both the direction angle α and the direction angle β are 45°.

[0025] Figure 14 This is a schematic diagram of the structure of an acoustic device according to an embodiment of this application.

[0026] Explanation of key component symbols: 100: Topological acoustic structure 10: First board 20: Second board 30: Audio Channel Topology Layer 31: Framework Layer 33: Acoustic cell 331: Central resonant cavity 332: Peripheral resonant cavity 333: Intercellular coupling vocal tract 334: Intracellular coupling vocal tract 3341: First intracellular coupled vocal tract 3342: Second intracellular coupled vocal tract 3343: Third intracellular coupled vocal tract 40: Isoparametric unit cell band 41: Isoparametric unit cell zone boundaries 200: Acoustic Instruments The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation

[0027] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0028] In the embodiments of this application, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature.

[0029] References to "one embodiment" or "some embodiments" as described in this specification mean that at least one embodiment of this application includes a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "at least one, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including, but not limited to," unless otherwise specifically emphasized.

[0030] In the description of the embodiments of this application, the terms "upper," "lower," "inner," "outer," "vertical," and "horizontal," etc., indicate orientations or positional relationships relative to the indicated placement of components in the accompanying drawings. It should be understood that these directional terms are relative concepts, used for relative description and clarification, and not to indicate or imply a specific orientation that the device or component must have, or its construction and operation in a specific orientation. They can change accordingly depending on the orientation of the components in the accompanying drawings, and therefore should not be construed as limiting this application. Furthermore, "vertical" in this application is not strictly vertical, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range.

[0031] Please see Figure 1 and Figure 2 The topological acoustic structure 100 includes a first plate 10, a second plate 20 arranged parallel to the first plate 10, and a channel topology layer 30 disposed between the first plate 10 and the second plate 20. The channel topology layer 30 includes a solid frame layer 31. Figure 2 The black portion in the middle) and the acoustic cell array formed by the frame layer 31 in conjunction with the first plate 10 and the second plate 20, the acoustic cell array comprising a plurality of acoustic cells 33 arranged in an array and interconnected with each other ( Figure 2 (The portion enclosed by a single white dashed frame). The first plate 10 and the second plate 20 can also be referred to as the two parallel plates.

[0032] Please continue reading. Figures 3 to 5 Each acoustic cell 33 includes a corresponding frame layer 31, a central resonant cavity 331, a peripheral resonant cavity 332, an intercellular coupling channel 333, and an intracellular coupling channel 334. Each resonant cavity and channel is formed by the frame layer 31 in conjunction with the first plate 10 and the second plate 20. The height of the frame layer 31 is equal to the distance between the two parallel plates, meaning the frame layer 31 is in contact with each plate. The frame layer 31 can be integrally manufactured with the two parallel plates using 3D printing.

[0033] There are three peripheral resonant cavities 332, and the three peripheral resonant cavities 332 are evenly distributed around the central resonant cavity 331 on the same circumference with the central resonant cavity 331 as the center. The corresponding central angle between two adjacent peripheral resonant cavities 332 is 120°.

[0034] Intercellular coupling channels 333 are located on the side of the peripheral resonant cavity 332 away from the central resonant cavity 331 and are used to connect adjacent acoustic cells 33. When the acoustic cells 33 are arranged in an array, since each peripheral resonant cavity 332 needs to be connected to the peripheral resonant cavities 332 of the other two acoustic cells 33, each peripheral resonant cavity 332 is equipped with an intercellular coupling channel 333 that connects to the other two peripheral resonant cavities 332.

[0035] Intracellular coupling channels 334 are disposed between each peripheral resonant cavity 332 and the central resonant cavity 331 and connect the corresponding peripheral resonant cavity 332 and the central resonant cavity 331. Since there are three peripheral resonant cavities 332, there are also three intracellular coupling channels 334, namely the first intracellular coupling channel 3341, the second intracellular coupling channel 3342, and the third intracellular coupling channel 3343.

[0036] Define the coupling strength of a single intercellular coupling channel 333 as J, and the coupling strengths of the intracellular coupling channels 334 between the three peripheral resonant cavities 332 and the central resonant cavity 331 as (1+ J). )J、(1+ )J and (1+ )J, where, 、 and For dimensionless control parameters, And at least some of the control parameters of the acoustic cell 33 、 and Not all values ​​are 0. Define the control parameters. 、 and Acoustic cell 33 with all values ​​set to 0 is a balanced acoustic cell, and the parameters are adjusted. 、 and Acoustic cells with values ​​not all equal to zero (e.g., 33) are non-equilibrium acoustic cells. For non-equilibrium acoustic cells... 、 and Not all are equal, thus resulting in the breaking of local triple rotational symmetry.

[0037] It should be noted that for non-equilibrium acoustic units, due to 、 and Not all are equal, and ,so 、 and There must be negative numbers in it. 、 or When the value is negative, it indicates that the coupling strength of the corresponding intracellular coupling channel 334 is less than the coupling strength of the intercellular coupling channel 333; in 、 or When the value is positive, it means that the coupling strength of the corresponding intracellular coupling channel 334 is greater than the coupling strength of the intercellular coupling channel 333.

[0038] In some embodiments, each resonant cavity is cylindrical with a circular cross-section. Within a cross-section, with the center of the central resonant cavity 331 as the origin, the distance R from the center of the three peripheral resonant cavities 332 to the center of the central resonant cavity 331 is also considered. Since the three peripheral resonant cavities 332 are evenly distributed around the central resonant cavity 331, the coordinates of the centers of the three peripheral resonant cavities 332 are respectively... , , .

[0039] In some embodiments, the lattice constant of the acoustic cell 33 =30 mm, characteristic diameter of cylindrical resonant cavity =9 mm, working height of cylindrical resonant cavity =3 mm, Each coupled channel is a cuboid channel with a rectangular cross-section and a height equal to... Equal in length, the axial length of the intracellular coupling channel 334 is R. At the boundary of a single acoustic cell 33, the length of the intercellular coupling channel 333 is half that of the intracellular coupling channel 334. The axial length of a single segment of the intercellular coupling channel 333 is... After two adjacent acoustic cells 33 are periodically spliced, the total axial length of the corresponding two intercellular coupling channels 333 is R. The initial widths of the intracellular coupling channel 334 and the intercellular coupling channel 333 are... According to the control parameters 、 and The coupling strength of the intracellular coupling channels 334 can be controlled by adaptively changing the width of each intracellular coupling channel 334. Control parameters 、 and The specific relationship is explained below.

[0040] It should be noted that the following describes changing the coupling strength of the intracellular coupling channel 334 by adjusting its width. Those skilled in the art will understand that the coupling strength can be controlled by adjusting the width, length, height, and cross-sectional shape of the coupling channel, and all dimensions are positive values. Those skilled in the art can design the coupling strength of the intercellular coupling channel 333 and each intracellular coupling channel 334 as needed.

[0041] In the geometric coupling implementation of this embodiment, each control parameter satisfies To ensure the corresponding actual equivalent coupling strength It remains positive and within the range of geometric coupling achievable by the acoustic structure. Where i = 1, 2, or 3.

[0042] Please see Figure 6 The acoustic cell 33 contains four energy bands near the Γ point at the center of the first Brillouin zone, of which three interconnected energy bands constitute a three-band subspace for describing low-energy physical properties.

[0043] exist At that time, the actual equivalent coupling strength of the intracellular coupling channel 334 is J, and the three-band subspace forms a triple degeneracy near the Γ point.

[0044] In change At any time, regardless ,still The three interconnected energy bands near the Γ point will split, that is, the triple degeneracy will split, thus de-degeneracy near the Γ point can be eliminated.

[0045] Similarly, when the control parameters are changed 、 and At this time, it can cause the three interconnected energy bands near the Γ point to split, thus removing the triple degeneracy near the Γ point.

[0046] The physical basis of the three-band subspace can be explained using the Berry dipole effective Hamiltonian. A schematic form of the parent three-band model is as follows: In the formula, This represents the effective Hamiltonian of the Berry dipole in the three-band subspace; , and These represent the three wave vector components in the effective model of the parent three-band system; For Berry dipole relative to The direction angle of the direction; , , and Let be the third-order Gell-Mann matrix acting on the three-band subspace.

[0047] The two-dimensional cross-section of the acoustic cell 33 in this application corresponds to a two-dimensional effective slice of the aforementioned parent three-band model. It should be noted that the aforementioned... It is the third effective control component in the parent three-band model, and does not imply that the sound wave must propagate along the z-axis of actual space. In the acoustic cell 33, the spatial modulation of the intracellular coupling channel 334 is used to achieve the desired effect with the third effective component. The corresponding gauge potential effect.

[0048] It should be noted that, Figure 6 The two sets of non-equilibrium band structures are only used for comparative calculations of single intracellular coupling parameter perturbations to illustrate that intracellular coupling imbalance can relieve the triple degeneracy near the Γ point, and do not represent the coupling constraints used in the subsequent Berry dipole zero-mode structure; the subsequent zero-mode structure further satisfies .

[0049] In some embodiments, the control parameter 、 and The relationship between the direction angle α and the given direction angle α satisfies: Therefore, control parameters 、 and The relative relationship can be used to determine the orientation angle α of the Berry dipole.

[0050] The unit direction vector of a Berry dipole can be expressed as: .

[0051] The orientation angle α is used to determine the zero-mode sound propagation axis of the zero-mode sound propagation channel. It should be noted that the zero-mode sound propagation axis includes a pair of branches with opposite propagation directions (…). Figure 7 and Figure 8 (Only one branch is shown in the diagram). Therefore, the direction angle α determines the zero-mode sound propagation axis, thereby determining the zero-mode sound propagation channel extending along this axis. When using the topological acoustic structure 100, the specific zero-mode branch that propagates along the positive or negative direction of the zero-mode sound propagation axis can be further selected by the sound source location, sound source phase relationship, or excitation method.

[0052] The effective pseudomagnetic field vector is represented as .

[0053] In the formula, This is the effective pseudomagnetic field vector; The effective pseudomagnetic field amplitude parameter is positive. For an effective pseudo-magnetic field relative to The direction angle in the positive direction of the axis.

[0054] Under the Landau gauge used in this embodiment, the gauge potential only has Directional components It is represented as: In the formula, For the standard potential Directional components; and As a lattice constant The normalized planar coordinates of the center of acoustic cell 33.

[0055] Please see Figure 7 and Figure 8 To facilitate the description of spatial modulation in the periodic acoustic cell 33, the line connecting the geometric centers of the two peripheral resonant cavities 332 is extended along the x-direction, and a dimensionless transverse coordinate is defined along the normal of the zero-mode acoustic propagation channel. for: Therefore, the gauge potential can be written as: The condition for zero-mode formation is that the direction of the effective pseudomagnetic field is consistent with the direction of the Berry dipole, that is, the direction angle α is equal to the direction angle β.

[0056] Under this condition, the Berry dipole direction vector Effective pseudomagnetic field vector It is parallel to the zero-mode sound propagation axis.

[0057] The unit vector representing the direction of propagation of the target zero mode is: The unit vector representation of the actual spatial gradient direction of the intracellular coupling parameter is: Both conditions are met: Therefore, the actual spatial gradient direction of the intracellular coupling parameters is perpendicular to the zero-mode acoustic propagation axis, that is, the gradient direction of the intracellular coupling parameters is perpendicular to the zero-mode acoustic propagation axis.

[0058] Along the normal of the zero-mode acoustic propagation channel, the acoustic cell array is divided into at least two isoparametric cell zones 40, with adjacent isoparametric cell zones 40 separated by isoparametric cell zone boundaries 41. It should be noted that the isoparametric cell zone boundaries 41 are only used to illustrate the parameter division of adjacent isoparametric cell zones 40 and do not correspond to actual material interfaces, structural interfaces, or topological phase transition interfaces. When the parameter is the same constant, that is, within each of the isoparametric cell zones 40, the acoustic cells 33 located within the same isoparametric cell zone 40 have the same control parameter. 、 and The isoparametric unit cell 40 is parallel to the target zero-mode acoustic propagation axis; adjacent isoparametric unit cell 40 , and along The direction changes gradually.

[0059] It should be noted that the direction angle This indicates the direction of the effective pseudomagnetic field and the direction of the zero-mode acoustic propagation axis, but does not indicate the actual direction of the gradual change of the 334 geometric parameters of the intracellular coupling channel. The actual direction of the gradual change of the 334 geometric parameters of the intracellular coupling channel is... The actual gradient direction is orthogonal to the direction of the effective pseudomagnetic field and the zero-mode acoustic propagation axis.

[0060] Each control parameter can also be calculated using a dimensionless horizontal coordinate. The following descriptions are provided, with each control parameter being: The above control parameters 、 and The Berry dipole orientation relationship is automatically satisfied, that is, the following equation is satisfied: because Since it includes x and y, the same control parameters are used within a 40° band of the same isoparameter unit cell. 、 and When moving from one isoparametric unit cell zone 40 to an adjacent isoparametric unit cell zone 40, the parameters are adjusted. 、 and according to The changes are adjusted gradually.

[0061] exist At the 40° band of the isoparameter unit cell, there may be This corresponds to a balanced acoustic unit cell. Other non-zero parameters at the 40° cell band, adjusting parameters 、 and Not all values ​​are 0, corresponding to a non-equilibrium acoustic cell.

[0062] In some embodiments, please refer to Figure 7 Since the magnitude of the direction angle α is 0, the direction angle is... The size is also 0, α= =0° to form a 0° zero-mode structure. At this time, the effective pseudomagnetic field, the zero-mode sound propagation axis, and the zero-mode sound propagation channel all extend along the x-direction.

[0063] In a 0° zero-mode structure, the lateral coordinate The three control parameters are as follows: Therefore, the three control parameters satisfy .

[0064] Furthermore, the three control parameters automatically satisfy the Berry dipole direction relationship, that is, satisfy the following equation: In the 0° zero-mode structure, the isoparametric unit cell zone 40 extends along the x-direction, and the acoustic unit cells 33 within the same isoparametric unit cell zone 40 have the same y-coordinate, thus employing the same control parameters. 、 and Different isoparameter unit cell bands 40 are arranged along the y-direction, so the y-coordinates of the acoustic unit cells 33 in different rows of isoparameter unit cell bands 40 are different, thus forming an intracellular coupling parameter gradient along the y-direction.

[0065] In some embodiments, please refer to Figure 8 The magnitude of the direction angle α is 45°, therefore the direction angle The angle is also 45°, α= =45°, to form a 45° zero-mode structure. At this time, the effective pseudomagnetic field, the zero-mode sound propagation axis, and the zero-mode sound propagation channel all extend along the direction of y=x.

[0066] In a 45° zero-mode structure, the lateral coordinate The three control parameters are as follows: Therefore, the three control parameters satisfy .

[0067] Furthermore, the three control parameters automatically satisfy the Berry dipole direction relationship, that is, satisfy the following equation: In the 45° zero-mode structure, the isoparametric cell band 40 extends along the y=x direction, and the acoustic cells 33 within the same isoparametric cell band 40 have the same transverse coordinates. Therefore, the same control parameters are used. 、 and Different isoparameter unit cell zones 40 are arranged along the y=-x direction, therefore the transverse coordinates of acoustic unit cells 33 within different rows of isoparameter unit cell zones 40 are... The differences result in an intracellular coupling parameter gradient along the y=-x direction.

[0068] After setting the combined orientation angle α of the Berry dipole and the orientation angle β of the effective pseudomagnetic field, periodic boundary conditions are applied along the target zero-mode acoustic propagation axis, and multiple parameters with different control parameters are selected along the normal of the target zero-mode acoustic propagation axis. 、 and The parameterized unit cell bands 40 are used to construct a topological acoustic structure 100 with periodic supercells. The supercells maintain periodicity in the direction of the target zero-mode acoustic propagation and contain multiple isoparametric unit cell bands 40 with different tuning parameters in the direction perpendicular to the direction of the zero-mode acoustic propagation.

[0069] Please see Figure 9 , Figure 9 The gray branches in the diagram represent the phantom bands or other bands formed by periodic supercell folding, while the red branches represent bands associated with the zero mode.

[0070] When the direction angle α is equal to the direction angle β, the direction of the effective pseudomagnetic field is consistent with the direction of the Berry dipole. The band structure of the periodic supercell shows a zero-mode correlation branch near the Γ point of the first Brillouin zone and connects the bands on both sides of the zero mode within the target frequency range.

[0071] When the direction angle α is not equal to the direction angle β, the direction of the effective pseudomagnetic field is inconsistent with the direction of the Berry dipole, the zero-mode condition near the Γ point is destroyed, and the local band gap remains open.

[0072] In summary, the control parameters 、 and The adjustment parameters are used to determine the direction angle α between the Berry dipole and the x-direction of the topological acoustic structure 100. 、 and The spatial distribution within the topological acoustic structure 100 is used to form an effective pseudomagnetic field with a direction angle β. The direction angle α is equal to the direction angle β, which closes the gap between the zero-order Landau levels near the Γ point in the first Brillouin zone of the band structure of the periodic supercell of the topological acoustic structure 100, forming a zero-mode correlation branch. This also creates a zero-mode acoustic propagation channel within the topological acoustic structure 100 extending along the zero-mode acoustic propagation axis corresponding to the direction angle α. It should be noted that the direction angle has both magnitude and direction; therefore, when the direction angle α and direction angle β are equal, both their magnitude and direction are equal.

[0073] Please see Figure 10 and Figure 11 Using a 9010 Hz sound wave as the experimental sound wave, the finite structure sound field simulation results of the above-mentioned 0° zero-mode structure and 45° zero-mode structure show that the high sound pressure value region of the 0° zero-mode structure mainly forms a band-shaped local distribution along the x direction, while the high sound pressure value region of the 45° zero-mode structure mainly forms a band-shaped local distribution along the y=x direction.

[0074] Please see Figure 12 and Figure 13 Using a 9010 Hz sound wave as the experimental sound wave, experimental sound pressure mapping tests were conducted on the aforementioned 0° zero-mode and 45° zero-mode structures. The sound source was located inside the topological acoustic structure 100 (at the pentagram) or other preset input positions, and multiple sound pressure measurement points were arranged in a two-dimensional array inside the topological acoustic structure 100. During the test, the sound pressure response at each measurement point was measured sequentially, and the sound pressure amplitude or transmission response at each measurement point was calculated based on the sound source reference signal. The measured sound pressure amplitudes were normalized, and the experimental sound pressure mapping results were plotted based on the planar coordinates of each measurement point. The high-value region of the experimental sound pressure in the 0° zero-mode structure mainly extends along the x-direction, consistent with the finite structure sound field simulation results of the 0° zero-mode structure; the high-value region of the sound pressure in the 45° zero-mode structure mainly extends along the y=x direction, consistent with the finite structure sound field simulation results of the 45° zero-mode structure.

[0075] The above experimental sound pressure mapping results are corroborated by the band structure and finite structure simulation results of the periodic supercell, indicating that the relative coupling relationship of the three intracellular coupling channels 334 is used to determine the direction of the Berry dipole, and the spatial gradient arrangement in the topological acoustic structure 100 is used to form an effective pseudomagnetic field. When the two satisfy β=α, a zero-mode sound propagation channel extending in a preset direction can be formed inside the topological acoustic structure 100.

[0076] The finite structure acoustic field simulation results and experimental sound pressure mapping test results show that, while keeping the main structure type of the topological acoustic structure 100 unchanged, the control parameters corresponding to the intracellular coupling channel 334 can be changed. 、 and By determining the relative relationship between the parameters and setting the isoparameter cell band 40 and the spatial gradient of the intracellular coupling parameters according to the target propagation direction, the direction of the zero-mode propagation axis can be adjusted.

[0077] In addition, those skilled in the art will know that the structural parameters of the topological acoustic structure 100 can be adjusted according to actual needs to adapt to sound waves of different frequencies.

[0078] This application has at least the following beneficial effects: (1) The coupling strength of the intercellular coupling channel 333 remains unchanged, and the adjustment parameters 、 and Used to adjust the coupling strength of each intracellular coupling channel 334 and form different symmetry breaks, thereby controlling the direction of the direction angle α between the Berry dipole and the x-direction. Through the spatial gradient arrangement in the topological acoustic structure 100, an effective pseudomagnetic field consistent with the direction of the Berry dipole is formed, thereby forming a zero-mode acoustic propagation channel extending along the axis corresponding to the direction angle α inside the topological acoustic structure 100. (2) By adjusting the control parameters 、 and The size of the intercellular coupling channel 334 can change the relative relationship and spatial arrangement between the first intracellular coupling channel 3341, the second intracellular coupling channel 3342 and the third intracellular coupling channel 3343, thereby changing the direction of sound wave propagation under the condition that the outer contour of the topological acoustic structure 100 remains basically unchanged. (3) The coupling strength of the intercellular coupling channel 333 is J. The direction of sound wave propagation is mainly adjusted by the geometric parameters and spatial distribution of the intracellular coupling channel 334. There are few parameters to be adjusted, which is convenient for structural calibration, manufacturing and experimental reproduction. (4) The central resonant cavity 331, the peripheral resonant cavity 332, the intercellular coupling channel 333 and the intracellular coupling channel 334 can be scaled or recalibrated as a whole according to the target frequency and processing scale, which has good structural adaptability and engineering expansion capability.

[0079] Accordingly, topological acoustic structure design methods include: A channel topology layer 30 is arranged between two parallel plates to form the topological acoustic structure 100 in any of the above embodiments, the two parallel plates being the first plate 10 and the second plate 20. The acoustic channel topology layer 30 includes a solid frame layer 31 and an acoustic cell array formed by the frame layer 31 in conjunction with the first plate 10 and the second plate 20. The acoustic cell array includes a plurality of acoustic cells 33 arranged in an array and interconnected. Each acoustic cell 33 includes a central resonant cavity 331, peripheral resonant cavities 332, intercellular coupling channels 333, and intracellular coupling channels 334. There are three peripheral resonant cavities 332, which are evenly distributed around the central resonant cavity 331 on the same circumference. The intercellular coupling channels 333 are located on the side of the peripheral resonant cavity 332 away from the central resonant cavity 331 and are used to connect adjacent acoustic cells 33. The intracellular coupling channels 334 are located between each peripheral resonant cavity 332 and the central resonant cavity 331 and connect the corresponding peripheral resonant cavity 332 and the central resonant cavity 331.

[0080] The coupling strength of a single intercellular coupling channel 333 is set to J, and the coupling strength of the intracellular coupling channel 334 between the three peripheral resonant cavities 332 and the central resonant cavity 331 is set to (1+ J) J. )J、(1+ )J and (1+ )J, where, 、 and For dimensionless control parameters, And at least some of the control parameters of the acoustic cell 33 、 and Not all are 0.

[0081] Adjust the control parameters 、 and Determine the direction angle α between the Berry dipole and the x-direction of the topological acoustic structure 100, so that the control parameters 、 and An effective pseudomagnetic field with a direction angle β is formed in the spatial distribution of the topological acoustic structure 100, so that the direction angle α is equal to the direction angle β, so that the band structure of the periodic supercell of the topological acoustic structure 100 closes the gap of the zero-order Landau level near the Γ point of the first Brillouin zone and forms a zero-mode correlation branch, and forms a zero-mode acoustic propagation channel extending along the axis corresponding to the direction angle α inside the topological acoustic structure 100.

[0082] In some embodiments, the control parameter is made 、 and The relationship between the direction angle α and the direction angle α satisfies: .

[0083] In some embodiments, the line connecting the geometric centers of the two peripheral resonant cavities 332 is extended along the x-direction, defining a dimensionless transverse coordinate of the normal to the zero-mode propagation direction along the zero-mode propagation channel. The control parameters are as follows: In the formula, x and y are respectively expressed in terms of lattice constants. The normalized x and y coordinates of the center of the acoustic unit cell. The effective pseudomagnetic field amplitude parameter is positive.

[0084] In some embodiments, the acoustic cell array is divided into at least two isoparametric cell bands 40 along the normal of the zero-mode propagation direction of the zero-mode acoustic propagation channel, and within each isoparametric cell band 40, each acoustic cell 33 has the same control parameter. 、 and .

[0085] Please see Figure 14 The acoustic device 200 includes a topological acoustic structure 100, which may be the topological acoustic structure 100 in any of the above embodiments, or the topological acoustic structure 100 may be designed using the topological acoustic structure design method in any of the above embodiments.

[0086] The acoustic device 200 includes topological acoustic multi-channel acoustic wave routers, directional multiplexed topological acoustic multiplexers, topological acoustic adjustable bandpass filters, topological controllable sound field modulation devices, topological protected acoustic signal transmission waveguide components, topological acoustic sensors, and integrated topological acoustic multi-channel processing chips, etc., which can be applied to scenarios such as acoustic wave routing, directional multiplexing, acoustic filtering, sound field modulation, acoustic signal transmission, acoustic sensing, and multi-channel acoustic transmission.

[0087] The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to the above preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of this application should not depart from the spirit and scope of the technical solutions of this application.

Claims

1. A topological acoustic structure, characterized in that, include: First board; The second plate is arranged parallel to the first plate; A channel topology layer is disposed between the first plate and the second plate. The channel topology layer includes a solid frame layer and an acoustic cell array formed by the frame layer in cooperation with the first plate and the second plate. The acoustic cell array includes a plurality of acoustic cells arranged in an array and interconnected. Each acoustic cell includes: Central resonant cavity; The number of peripheral resonant cavities is three, and they are evenly distributed around the central resonant cavity on the same circumference with the central resonant cavity as the center. An intercellular coupling channel is disposed on the side of the peripheral resonant cavity away from the central resonant cavity and is used to connect adjacent acoustic cells; An intracellular coupling acoustic channel is disposed between each of the peripheral resonant cavities and the central resonant cavity and connects the corresponding peripheral resonant cavity and the central resonant cavity; The coupling strength of a single intercellular coupling channel is defined as J, and the coupling strengths of the intracellular coupling channels between the three peripheral resonant cavities and the central resonant cavity are respectively (1+ J). )J、(1+ )J and (1+ )J, where, 、 and For dimensionless control parameters, And at least some of the acoustic unit cell's control parameters 、 and Not all are 0; The control parameters 、 and The control parameter is used to determine the direction angle α between the Berry dipole and the x-direction of the topological acoustic structure. 、 and The spatial distribution in the topological acoustic structure is used to form an effective pseudomagnetic field with a direction angle β, where the direction angle α is equal to the direction angle β, so as to close the gap of the zero-order Landau level in the band structure of the periodic supercell of the topological acoustic structure near the Γ point of the first Brillouin zone and form a zero-mode correlated branch, and to form a zero-mode acoustic propagation channel extending along the zero-mode acoustic propagation axis corresponding to the direction angle α inside the topological acoustic structure.

2. The topological acoustic structure as described in claim 1, characterized in that, The control parameters 、 and The relationship between the direction angle α and the given direction angle α satisfies: .

3. The topological acoustic structure as described in claim 1 or 2, characterized in that, The line connecting the geometric centers of the two peripheral resonant cavities extends along the x-axis, defining a dimensionless lateral coordinate along the normal of the zero-mode acoustic propagation channel. The control parameters are as follows: In the formula, x and y are respectively expressed in terms of lattice constants. The normalized x and y coordinates of the center of the acoustic cell, The effective pseudomagnetic field amplitude parameter is positive.

4. The topological acoustic structure as described in claim 3, characterized in that, The magnitude of the direction angle α is 0, and ; Alternatively, the magnitude of the direction angle α is ,and .

5. The topological acoustic structure as described in claim 1 or 2, characterized in that, Along the normal of the zero-mode acoustic propagation channel, the acoustic cell array is divided into at least two isoparametric cell bands, and within each of the isoparametric cell bands, each acoustic cell has the same control parameter. 、 and .

6. A method for designing a topological acoustic structure, characterized in that, include: A channel topology layer is arranged between two parallel plates to form a topological acoustic structure; The acoustic channel topology layer includes a solid frame layer and an acoustic cell array formed by the frame layer in conjunction with the first plate and the second plate. The acoustic cell array includes a plurality of acoustic cells arranged in an array and interconnected with each other. Each acoustic cell includes: Central resonant cavity; The number of peripheral resonant cavities is three, and they are evenly distributed around the central resonant cavity on the same circumference with the central resonant cavity as the center. An intercellular coupling channel is disposed on the side of the peripheral resonant cavity away from the central resonant cavity and is used to connect adjacent acoustic cells; An intracellular coupling acoustic channel is disposed between each of the peripheral resonant cavities and the central resonant cavity and connects the corresponding peripheral resonant cavity and the central resonant cavity; The coupling strength of a single intercellular coupling channel is set to J, and the coupling strength of the intracellular coupling channels between the three peripheral resonant cavities and the central resonant cavity is set to (1+ J) respectively. )J、(1+ )J and (1+ )J, where, 、 and For dimensionless control parameters, And at least some of the acoustic unit cell's control parameters 、 and Not all are 0; Make the control parameter 、 and Determine the direction angle α between the Berry dipole and the x-direction of the topological acoustic structure, so that the control parameters... 、 and The spatial distribution within the topological acoustic structure forms an effective pseudomagnetic field with a direction angle β, making the direction angle α equal to the direction angle β. This causes the band structure of the periodic supercell of the topological acoustic structure to close the gap between the zero-order Landau levels near the Γ point in the first Brillouin zone and form a zero-mode correlated branch. It also causes a zero-mode acoustic propagation channel to be formed inside the topological acoustic structure, extending along the zero-mode acoustic propagation axis corresponding to the direction angle α.

7. The topological acoustic structure design method as described in claim 6, characterized in that, Make the control parameter 、 and The relationship between the direction angle α and the given direction angle α satisfies: .

8. The topological acoustic structure design method as described in claim 6 or 7, characterized in that, Extend the line connecting the geometric centers of the two peripheral resonant cavities along the x-axis, and define a dimensionless lateral coordinate along the normal of the zero-mode acoustic propagation channel. The control parameters are as follows: In the formula, x and y are respectively expressed in terms of lattice constants. The normalized x and y coordinates of the center of the acoustic cell, The effective pseudomagnetic field amplitude parameter is positive.

9. The topological acoustic structure design method as described in claim 6 or 7, characterized in that, Along the normal of the zero-mode acoustic propagation channel, the acoustic cell array is divided into at least two isoparametric cell bands, and within each of the isoparametric cell bands, each acoustic cell has the same control parameter. 、 and .

10. An acoustic device comprising a topological acoustic structure, characterized in that, The topological acoustic structure is the topological acoustic structure according to any one of claims 1 to 5, or the topological acoustic structure is designed using the topological acoustic structure design method according to any one of claims 6 to 9.

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