Topological Thouless pump based on one-dimensional photonic moiré lattice and its implementation method

Abstract

The present invention discloses a topological Solis pump based on a one-dimensional photonic moiré lattice and its implementation method. The present invention arranges waveguides to form a lattice-varying photonic crystal and a lattice-constant photonic crystal, respectively, which together form a moiré lattice. During the transmission of signal light along the waveguides, the period of the moiré lattice changes slowly and continuously, enabling boundary-to-boundary topological pumping. The present invention has simple and universal preparation conditions, is capable of experiments and measurements in the optical band, and features a simple measurement process. It does not require external mechanical or manual control to adjust to the next parameter, and does not require any type of lateral constraint or nonlinearity as a self-constraint mechanism.

Description

Technical Field

[0001] The present invention relates to the field of nano-optics, and in particular to a topological Solis pump based on a one-dimensional photon moiré lattice and an implementation method thereof. Background Art

[0002] An Archimedean screw is a mechanical device used to pump water from a low point to a high point. Its main structure consists of a cylinder with a long series of spiral blades inside. With each rotation of the blades, the water in the cylinder is pushed upward by one pitch. The Thouless pump is a quantum version of the Archimedean screw and can be used to observe the topological variables of a system. Consider a one-dimensional, infinitely long periodic potential well that binds a microscopic particle. The shape of the potential well is adjusted slowly enough to maintain its spatial periodicity and restore the potential well to its original shape at the end of the adjustment. The particle transport induced by this process is integer, equivalent to a dynamic version of the integer quantum Hall effect. This integer is related to the topological properties of the parameter space.

[0003] A moiré lattice is a composite structure formed by the overlapping of two sublattices with identical or similar periodic structures. Due to differences in rotation angles or lattice constants between the two sublattices, the composite structure produces a set of long-periodic patterns, known as moiré fringes, based on the original sublattice period. Its unique physical properties stem primarily from the interlayer coupling of the van der Waals heterojunction structure, and twisted electronics is a newly developed discipline based on this. Moiré lattices can generate photonic bands distinct from those of a single sublattice, enriching the properties of light field transmission and localization. When the rotation angles of the two layers meet specific relationships, flat bands are often generated within the dispersion band.

[0004] The structure of a two-dimensional optical Moiré lattice Solis pump is based on the three-dimensional rotation of two tilted, mutually twisted, and displaced square lattices. The cross-section is a superposition of two square lattices with an angled rotation. While the refractive index of the material is uniform as it propagates along the crystal, the relative angle of rotation continuously changes, causing the Moiré fringes to adiabatically slide and periodically appear and disappear. The energy bands also undergo periodic variations during this evolution. The Moiré lattice flattens the energy bands and introduces a nontrivial topological band gap, ensuring that there is no band crossing during the evolution process, thus generating directional pumping independent of any confinement mechanism. Writing a three-dimensional lattice into a photorefractive crystal requires optical lattice sensing techniques within the crystal, which is demanding and difficult to perform. Under acoustic experimental conditions, a dynamic topological Solis pump is realized using a double-layer one-dimensional acoustic metamaterial. The acoustic bilayer consists of a periodic array of cylindrical acoustic resonators with asymmetric lattice constants at the top and bottom. The top crystal slides at a constant velocity while the bottom crystal remains fixed, resulting in periodic energy band variations throughout the system. The system generates directional topological pumping from one boundary to the other. This system requires a mechanical device to move the top lattice at a constant speed, and the double-layer structure is difficult to prepare under optical experimental conditions, so it is not applicable to the optical scale. Summary of the Invention

[0005] In response to the above problems existing in the prior art, the present invention proposes a topological Thouless pump based on a one-dimensional photonic moiré lattice and an implementation method thereof.

[0006] An object of the present invention is to propose a topological Thouless pump based on a one-dimensional photonic moiré lattice.

[0007] The topological Solis pump based on a one-dimensional photonic moiré lattice of the present invention comprises: a substrate, a lattice constant gradient photonic crystal, and a lattice constant constant photonic crystal; wherein the substrate is made of a dielectric material, and a plurality of mutually parallel waveguides are formed in two upper and lower rows of one-dimensional arrangement, the direction of the waveguides being perpendicular to the one-dimensional arrangement direction, the refractive index of the waveguides being greater than the refractive index of the substrate, the shape and size of each waveguide being the same, and the central axis of each row of waveguides being located in the same plane, and the planes tangent to the upper and lower surfaces of each row of waveguides respectively forming the lattice constant gradient photonic crystal and the lattice constant constant photonic crystal; the plurality of waveguides in the lattice constant gradient photonic crystal are divided into M groups, each group comprising N waveguides, the distance between adjacent waveguides in each group of waveguides being the same, that is, the lattice constants being consistent, the lattice constants of the M groups of waveguides varying arithmetic differences along the arrangement direction, and the lattice constant d of the waveguides in the i-th group being equal to the lattice constant of the waveguides. i=d1±δ(i-1), i=1,…,M, d1 is the lattice constant of the first group of waveguides, δ is the tolerance; the plane where the waveguides arranged in one dimension in the constant lattice constant photonic crystal are located is parallel to the plane where the waveguides arranged in one dimension in the gradient lattice constant photonic crystal are located, and there is a distance between the two and the distance is greater than the diameter of the waveguide. The distance between adjacent waveguides in the constant lattice constant photonic crystal is constant, and the lattice constant is d c The portion of each waveguide group in the lattice constant gradient photonic crystal and the portion of the photonic crystal with constant lattice constant corresponding to their position, as well as the substrate between the two, form a moiré lattice. The periods of each moiré lattice are different, forming M moiré lattices with different periods. The i-th group of waveguides in the lattice constant gradient photonic crystal and the portion of the waveguides in the photonic crystal with constant lattice constant corresponding to their position form the i-th moiré lattice. The period of the i-th moiré lattice is There is always a topological band gap in the Moiré lattice energy band. The Moiré lattice has a topological edge state. The periods of two adjacent Moiré lattices are different. The signal light incident on the Moiré lattice from one side changes from the edge state on one side to the bulk state and then to the edge state on the other side during the propagation process in one Moiré lattice. The laser outputs an optical signal, and the frequency of the optical signal is consistent with the operating frequency of the topological Solis pump. At the operating frequency, the propagation modes of the topological Solis pump include the left edge state, the bulk state and the right edge state. The left edge state, the bulk state and the right edge state have different effective mode refractive indices, respectively. The effective mode refractive index is the propagation constant. The lattice constant of the signal light from the topological Solis pump is The leftmost waveguide of the constant photonic crystal is incident along the waveguide direction. There is a difference in the period between the adjacent j+1th moiré lattice and the jth moiré lattice, j=1,…M-1. During the transmission process, the signal light first matches the effective mode refractive index of the left edge state, and the light field of the signal light is localized in the leftmost waveguide of the jth moiré lattice to produce the left edge state, that is, there is signal light in the upper and lower waveguides on the leftmost side of the jth moiré lattice; in the process of transmission along the waveguide, the signal light matches the effective mode refractive index of the bulk state, and the light field of the signal light diffuses into the entire jth moiré lattice. At this time, the left edge state disappears, and the mode evolves from the left edge state to the bulk state; in the process of continuing to transmit along the waveguide, the signal light is reflected by the effective mode refractive index of the bulk state. During the transmission process, the effective mode refractive index of the signal light matches that of the right boundary state. At this time, the mode is localized in the right waveguide of the jth moiré lattice to generate the right boundary state. The mode evolves from the body state to the right boundary state. The signal light completes the transmission of the jth moiré lattice according to the mode of the left boundary state, the body state and the right boundary state. The signal light continues to transmit to the adjacent j+1th moiré lattice on the right. There is a difference in the period of the adjacent j+2 moiré lattice and the j+1th moiré lattice. During the transmission process along the waveguide, the signal light continues to complete the transmission of the j+1th moiré lattice according to the mode of the left boundary state, the body state and the right boundary state until the rightmost moiré lattice is output from the two rightmost waveguides. Similarly, the signal light from The rightmost waveguide of the topological Solis pump's lattice constant photonic crystal is incident along the waveguide direction. The period of the adjacent j+1th moiré lattice differs from that of the jth moiré lattice, j=1,…M-1. During transmission, the signal light first matches the effective mode refractive index of the right-edge state. The light field of the signal light is localized in the rightmost waveguide of the jth moiré lattice, generating a right-edge state. That is, signal light exists in both the upper and lower waveguides on the rightmost side of the jth moiré lattice. During transmission along the waveguide, the signal light matches the effective mode refractive index of the bulk state, and the light field of the signal light diffuses into the entire jth moiré lattice. At this time, the right-edge state disappears, and the mode evolves from the right-edge state to the bulk state.As the signal light continues to propagate along the waveguide, the effective mode refractive index of the left edge state matches that of the signal light. This mode is then localized in the left waveguide of the jth moiré lattice, generating a left edge state. The mode then evolves from the bulk state to the left edge state. The signal light then propagates through the jth moiré lattice in a pattern of right edge state, bulk state, and left edge state. The signal light then propagates to the j+1th moiré lattice on the left. The adjacent j+2 moiré lattice has a different period from the j+1th moiré lattice. As the signal light propagates along the waveguide, it continues to propagate through the j+1th moiré lattice in a pattern of right edge state, bulk state, and left edge state until it reaches the leftmost moiré lattice and is output from the two leftmost waveguides, forming an unassisted directional pumping system for the topological Solis pump.

[0008] The substrate is made of glass, silicon nitride or silicon. If the substrate is glass, the cross-sectional shape of the waveguide is circular. If the substrate is silicon nitride or silicon, the cross-sectional shape of the waveguide is rectangular. The refractive index of the waveguide of the lattice constant gradient photonic crystal is the same as that of the waveguide of the lattice constant constant photonic crystal. The refractive index of the waveguide is 1.441 to 1.443, the cross-sectional radius is 1μm to 3μm, and the length is 20mm to 60mm. The width of the lattice constant gradient photonic crystal and the lattice constant constant photonic crystal perpendicular to the length of the waveguide is the array width. The longer the array width, the longer the waveguide length. The length of the waveguide is greater than the array width. The lattice constant d1 of the first group of waveguides of the lattice constant gradient photonic crystal is 16μm to 20μm; the tolerance δ is 1μm to 2μm; the lattice constant d of the lattice constant constant photonic crystal is 16μm to 20μm. c The lattice constant of the constant lattice constant photonic crystal is smaller than the lattice constant of any group of waveguides in the graded lattice constant photonic crystal. The distance between the plane containing the graded lattice constant photonic crystal and the plane containing the constant lattice constant photonic crystal is 6 to 10 μm. The number of groups M of waveguides in the graded lattice constant photonic crystal is ≥ 2, and the number N of waveguides in each group is 5 to 20.

[0009] Another object of the present invention is to propose a method for realizing a topological Solis pump based on a one-dimensional photonic moiré lattice.

[0010] The method for realizing a topological Solis pump based on a one-dimensional photonic moiré lattice of the present invention comprises the following steps:

[0011] 1. Preparation of Topological Solis Pump:

[0012] i. Providing a dielectric material as a substrate, and forming a plurality of mutually parallel waveguides in two upper and lower rows arranged in one dimension within the substrate by laser direct writing or electron beam lithography-coating-electron beam lithography, wherein the direction of the waveguides is perpendicular to the one-dimensional arrangement direction, the refractive index of the waveguides is greater than the refractive index of the substrate, each waveguide has the same shape and size, and the central axis of each row of waveguides is located in the same plane, and the planes tangent to the upper and lower surfaces of each row of waveguides respectively form a lattice constant gradient photonic crystal and a lattice constant constant photonic crystal;

[0013] ii. Multiple waveguides in a lattice constant gradient photonic crystal are divided into M groups, each group includes N waveguides, and the distance between adjacent waveguides in each group is the same, that is, the lattice constant is consistent. The lattice constants of the M groups of waveguides vary arithmetic along the arrangement direction. The lattice constant d of the waveguide in the i-th group is i =d1±δ(i-1), i=1,…,M, d1 is the lattice constant of the first group of waveguides, δ is the tolerance;

[0014] iii. The plane where the waveguides in the one-dimensional arrangement of the photonic crystal with constant lattice constant are located is parallel to the plane where the waveguides in the one-dimensional arrangement of the photonic crystal with gradient lattice constant are located, and there is a distance between the two that is greater than the diameter of the waveguide. The distance between adjacent waveguides in the photonic crystal with constant lattice constant is constant, and the lattice constant is d c ;

[0015] iv. The portion of each waveguide group in the lattice constant gradient photonic crystal, the portion of the photonic crystal with constant lattice constant corresponding to the group, and the substrate between the two constitute a moiré lattice. The periods of each moiré lattice are different, forming M moiré lattices with different periods. The i-th group of waveguides in the lattice constant gradient photonic crystal and the portion of the waveguides in the photonic crystal with constant lattice constant corresponding to the group of waveguides in the photonic crystal with constant lattice constant constitute the i-th moiré lattice. The period of the i-th moiré lattice is

[0016]

[0017] v. A topological band gap always exists in the moiré lattice energy band. The moiré lattice has topological edge states. The periods of two adjacent moiré lattices are different. When a signal light is incident on the moiré lattice from one side, the mode in one moiré lattice changes from the edge state on one side to the bulk state, and then to the edge state on the other side during propagation.

[0018] 2. Achieve unassisted directional pumping:

[0019] 1) The laser outputs an optical signal, the frequency of which is consistent with the operating frequency of the topological Solis pump. At the operating frequency, the propagation modes of the topological Solis pump include the left boundary state, the bulk state, and the right boundary state, each of which has a different effective mode refractive index.

[0020] 2) Topological pumping from left to right:

[0021] a) Signal light is incident along the waveguide direction from the leftmost waveguide of a topological Solis-pumped photonic crystal with a constant lattice constant. The period of the adjacent j+1th moiré lattice differs from that of the jth moiré lattice, where j = 1, … M-1. During transmission, the signal light first matches the effective mode refractive index of the left edge state. The signal light field is localized in the leftmost waveguide of the jth moiré lattice, generating a left edge state. That is, signal light exists in both the upper and lower waveguides on the leftmost side of the jth moiré lattice.

[0022] b) During the propagation along the waveguide, the effective mode refractive index of the signal light matches that of the bulk state, and the light field of the signal light diffuses into the entire j-th moiré lattice. At this time, the left edge state disappears, and the mode evolves from the left edge state to the bulk state.

[0023] c) As the signal light continues to propagate along the waveguide, the effective mode refractive index of the signal light matches that of the right-edge state. At this point, the mode is localized in the right waveguide of the j-th moiré lattice, generating a right-edge state. The mode evolves from the bulk state to the right-edge state. The signal light then completes the propagation of the j-th moiré lattice in the pattern of the left-edge state, the bulk state, and the right-edge state.

[0024] d) The signal light is transmitted to the adjacent j+1th moiré lattice on the right. The adjacent j+2th moiré lattice has a different period from the j+1th moiré lattice. During the transmission along the waveguide, the signal light repeats steps a) to c) and continues to complete the transmission of the j+1th moiré lattice in the pattern of left edge state, bulk state, and right edge state until it reaches the rightmost moiré lattice and is output from the two rightmost waveguides, forming an unassisted directional pumping of the topological Solis pump.

[0025] 3) Pumping from right to left topology:

[0026] a) Signal light is incident along the waveguide direction from the rightmost waveguide of a topological Solis-pumped photonic crystal with a constant lattice constant. The period of the adjacent j+1th moiré lattice differs from that of the jth moiré lattice, where j = 1, … M-1. During transmission, the signal light first matches the effective mode refractive index of the right-edge state. The signal light field is localized in the rightmost waveguide of the jth moiré lattice, generating a right-edge state. That is, signal light exists in both the upper and lower waveguides on the rightmost side of the jth moiré lattice.

[0027] b) During the propagation along the waveguide, the effective mode refractive index of the signal light matches that of the bulk state, and the light field of the signal light diffuses into the entire j-th moiré lattice. At this time, the right edge state disappears, and the mode evolves from the right edge state to the bulk state.

[0028] c) As the signal light continues to propagate along the waveguide, the effective mode refractive index of the signal light matches that of the left edge state. At this point, the mode is localized in the left waveguide of the j-th moiré lattice, generating a left edge state. The mode evolves from the bulk state to the left edge state, and the signal light completes the propagation of the j-th moiré lattice in the pattern of the right edge state, bulk state, and left edge state.

[0029] d) The signal light is transmitted to the adjacent j+1th moiré lattice on the left. The adjacent j+2th moiré lattice has a different period from the j+1th moiré lattice. During the transmission along the waveguide, the signal light repeats steps a) to c) and continues to complete the transmission of the j+1th moiré lattice in the pattern of right edge state, bulk state and left edge state until it reaches the leftmost moiré lattice and is output from the two leftmost waveguides, forming an unassisted directional pumping of the topological Solis pump.

[0030] Advantages of the present invention:

[0031] The present invention forms a lattice constant gradient photonic crystal and a lattice constant constant photonic crystal by arranging the waveguides, and the two form a moiré lattice; during the transmission of signal light along the waveguide, the period of the moiré lattice changes slowly and continuously, realizing boundary-to-boundary topological pumping; the preparation conditions of the present invention are simple and universal, and it can be used for experiments and measurements in the optical band. The measurement process is simple, does not require external mechanical or manual control to adjust to the next parameter, and does not require any type of lateral constraint or nonlinearity as a self-constraint mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of an embodiment of a topological Thouless pump based on a one-dimensional photonic moiré lattice according to the present invention;

[0033] Figure 2 This is a cross-sectional view of an embodiment of a topological Thouless pump based on a one-dimensional photonic moiré lattice according to the present invention. DETAILED DESCRIPTION

[0034] The present invention will be further described below through specific embodiments in conjunction with the accompanying drawings.

[0035] like Figure 1As shown, the topological Solis pump based on the one-dimensional photonic moiré lattice of this embodiment includes: a substrate, a lattice constant gradient photonic crystal and a lattice constant constant photonic crystal; wherein, laser direct writing is used to form a plurality of mutually parallel waveguides arranged in two dimensions, the direction of the waveguide is perpendicular to the one-dimensional arrangement direction, the refractive index of the waveguide is greater than the refractive index of the substrate, the shape and size of each waveguide are the same, and the central axis of each row of waveguides is located in the same plane, the plane tangent to the upper and lower surfaces of the upper row of waveguides constitutes a lattice constant gradient photonic crystal, and the plane tangent to the upper and lower surfaces of the lower row of waveguides constitutes a lattice constant constant photonic crystal; the multiple waveguides of the lattice constant gradient photonic crystal are divided into four groups, i.e., M=4, each group includes five waveguides, i.e., N=5, the distance between adjacent waveguides in each group of waveguides is the same, i.e., the lattice constant is consistent, the lattice constants of the five groups of waveguides vary arithmetically along the arrangement direction, and the lattice constant d of the waveguide in the i-th group is 1. i =d1±δ(i-1), i=1,…,5, d1 is the lattice constant of the first group of waveguides, δ is the tolerance; the distance between adjacent waveguides in the photonic crystal is constant, and the lattice constant is d c The first and last waveguides of the i-th group of waveguides in the lattice constant gradient photonic crystal correspond to a waveguide in the constant lattice constant photonic crystal respectively. The portion of the lattice constant gradient photonic crystal where the i-th group of waveguides is located and the portion of the constant lattice constant photonic crystal corresponding thereto, as well as the substrate therebetween, form a moiré lattice. The periods of each moiré lattice are different, forming M moiré lattices with different periods. The i-th group of waveguides in the lattice constant gradient photonic crystal and the portion of the waveguides in the constant lattice constant photonic crystal corresponding thereto form the i-th moiré lattice. The period of the i-th moiré lattice is There is always a topological band gap in the Moiré lattice energy band. The Moiré lattice has topological edge states. The periods of two adjacent Moiré lattices are different. The signal light incident on the Moiré lattice from one side changes from the edge state on one side to the bulk state and then to the edge state on the other side during the propagation process within a Moiré lattice.

[0036] The laser outputs an optical signal, the frequency of which is consistent with the operating frequency of the topological Solis pump, 375 THz (wavelength 800 nm). At the operating frequency, the propagation modes of the topological Solis pump include the left boundary state, the bulk state, and the right boundary state, each of which has a different effective mode refractive index. The waveguide located on the boundary line of two adjacent moiré lattices is shared by the two moiré lattices, that is, the last waveguide of the j-th moiré lattice is the first waveguide of the j+1-th moiré lattice, and the vertical line where the center of the last waveguide of the j-th moiré lattice is located serves as the boundary line dividing the two adjacent moiré lattices, as shown in FIG. Figure 2As shown by the middle dotted line; the signal light is incident from the leftmost waveguide of the lattice constant constant photonic crystal of the topological Solis pump along the waveguide direction. There is a difference in the period of the adjacent j+1th moiré lattice and the jth moiré lattice, j=1,…M-1. During the transmission process, the signal light first matches the effective mode refractive index of the left boundary state, and the light field of the signal light is localized in the leftmost waveguide of the jth moiré lattice to produce the left boundary state, that is, there is signal light in the upper and lower waveguides on the leftmost side of the jth moiré lattice; in the process of transmission along the waveguide, the signal light first matches the effective mode refractive index of the body state, and the light field of the signal light diffuses into the entire jth moiré lattice. At this time, the left boundary state disappears, and the mode evolves from the left boundary state to the body state, and then continues along the waveguide. During the waveguide transmission process, the effective mode refractive index of the signal light matches that of the right boundary state. At this time, the mode is localized in the right waveguide of the jth moiré lattice to generate the right boundary state. The mode evolves from the body state to the right boundary state. The signal light completes the transmission of the jth moiré lattice according to the pattern of the left boundary state, the body state and the right boundary state. The signal light continues to be transmitted to the adjacent j+1th moiré lattice on the right. There is a difference in the period of the adjacent j+2 moiré lattice and the j+1th moiré lattice. During the transmission process along the waveguide, the signal light continues to complete the transmission of the j+1th moiré lattice according to the pattern of the left boundary state, the body state and the right boundary state until the rightmost moiré lattice is reached and output from the two rightmost waveguides, forming an unassisted directional pumping of the topological Solis pump, as shown in FIG. Figure 1 As shown, in this embodiment, the left side is the input end I of the topological Solis pump, the right side is the output end O of the topological Solis pump, and the arrow indicates the transmission direction of the signal light.

[0037] In this embodiment, the substrate is made of glass with a refractive index of 1.44 and a height h of 2 mm. The refractive index of the waveguide is 1.442, the cross-section of the waveguide is circular, the cross-section radius r is 2 μm, and the length is 16 mm. The lattice constant d1 of the first group of waveguides of the lattice constant gradient photonic crystal is 16 μm; the tolerance δ is 2 μm, and the lattice constant d2 of the second group of waveguides is 14 μm. The lattice constant d c The distance between the plane where the lattice constant gradient photonic crystal is located and the plane where the lattice constant constant photonic crystal is located is 8 μm.

[0038] Finally, it should be noted that the purpose of disclosing the embodiments is to facilitate a further understanding of the present invention. However, those skilled in the art will appreciate that various substitutions and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the present invention should not be limited to the contents disclosed in the embodiments; the scope of protection claimed by the present invention shall be determined by the scope defined in the claims.

Claims

1. A topological Thouless pump based on a one-dimensional photonic moiré lattice, characterized in that: The topological Solis pump comprises: a substrate, a lattice constant gradient photonic crystal and a lattice constant constant photonic crystal; wherein the substrate is made of dielectric material, and a plurality of mutually parallel waveguides are formed in two rows, one-dimensionally arranged in an upper and lower direction, respectively, in the substrate, the direction of the waveguides is perpendicular to the one-dimensional arrangement direction, the refractive index of the waveguides is greater than the refractive index of the substrate, the shape and size of each waveguide are the same, and the central axis of each row of waveguides is located in the same plane, and the planes tangent to the upper surface and the lower surface of each row of waveguides respectively form a lattice constant gradient photonic crystal and a lattice constant constant photonic crystal; the plurality of waveguides in the lattice constant gradient photonic crystal are divided into M groups, each group includes N waveguides, the distance between adjacent waveguides in each group of waveguides is the same, that is, the lattice constant is consistent, the lattice constants of the M groups of waveguides vary arithmetically along the arrangement direction, and the lattice constant d of the waveguide in the i-th group is 1. i =d1±δ(i-1), i=1,…,M, d1 is the lattice constant of the first group of waveguides, δ is the tolerance; the plane where the waveguides arranged in one dimension in the constant lattice constant photonic crystal are located is parallel to the plane where the waveguides arranged in one dimension in the gradient lattice constant photonic crystal are located, and there is a distance between the two and the distance is greater than the diameter of the waveguide. The distance between adjacent waveguides in the constant lattice constant photonic crystal is constant, and the lattice constant is d c The portion of each group of waveguides in the lattice constant gradient photonic crystal and the portion of the photonic crystal with constant lattice constant corresponding to their position, as well as the substrate between the two, form a moiré lattice. The periods of each moiré lattice are different, forming M moiré lattices with different periods. The i-th group of waveguides in the lattice constant gradient photonic crystal and the portion of the waveguides in the photonic crystal with constant lattice constant corresponding to their position form the i-th moiré lattice. The period of the i-th moiré lattice is There is always a topological band gap in the Moiré lattice energy band. The Moiré lattice has topological edge states. The periods of two adjacent Moiré lattices are different. The signal light incident on the Moiré lattice from one side changes from the edge state on one side to the bulk state and then to the edge state on the other side during the propagation process in one Moiré lattice. The laser outputs an optical signal, and the frequency of the optical signal is consistent with the operating frequency of the topological Solis pump. At the operating frequency, the propagation modes of the topological Solis pump include the left edge state, the bulk state and the right edge state, which have different effective mode refractive indices respectively. The signal light is transmitted from the leftmost side of the photonic crystal where the lattice constant of the topological Solis pump is constant. The waveguide is incident along the waveguide direction. There is a difference in the period between the adjacent j+1th moiré lattice and the jth moiré lattice, j=1,…M-1. During the transmission process, the signal light first matches the effective mode refractive index of the left edge state. The light field of the signal light is localized in the leftmost waveguide of the jth moiré lattice to produce the left edge state, that is, the signal light exists in the upper and lower waveguides on the leftmost side of the jth moiré lattice. During the transmission along the waveguide, the signal light matches the effective mode refractive index of the bulk state, and the light field of the signal light diffuses into the entire jth moiré lattice. At this time, the left edge state disappears, and the mode evolves from the left edge state to the bulk state. During the process of continuing to transmit along the waveguide, the signal light The effective mode refractive index of the right boundary state is matched. At this time, the mode is localized in the right waveguide of the jth moiré lattice to produce the right boundary state. The mode evolves from the body state to the right boundary state. The signal light completes the transmission of the jth moiré lattice according to the mode of the left boundary state, the body state and the right boundary state. The signal light continues to be transmitted to the adjacent j+1th moiré lattice on the right. There is a difference in the period of the adjacent j+2 moiré lattice and the j+1th moiré lattice. During the transmission process along the waveguide, the signal light continues to complete the transmission of the j+1th moiré lattice according to the mode of the left boundary state, the body state and the right boundary state until the rightmost moiré lattice is output from the two rightmost waveguides. Similarly, the signal light from the topological branch The rightmost waveguide of the photonic crystal with a constant lattice constant of the Liss pump is incident along the waveguide direction. The period of the adjacent j+1th moiré lattice and the jth moiré lattice is different, j=1,…M-1. During transmission, the signal light first matches the effective mode refractive index of the right edge state. The light field of the signal light is localized in the rightmost waveguide of the jth moiré lattice to produce the right edge state, that is, the signal light exists in the upper and lower waveguides on the rightmost side of the jth moiré lattice. During transmission along the waveguide, the signal light matches the effective mode refractive index of the bulk state, and the light field of the signal light diffuses into the entire jth moiré lattice. At this time, the right edge state disappears, and the mode evolves from the right edge state to the bulk state.As the signal light continues to propagate along the waveguide, the effective mode refractive index of the left edge state matches that of the signal light. This mode is then localized in the left waveguide of the jth moiré lattice, generating a left edge state. The mode then evolves from the bulk state to the left edge state. The signal light then propagates through the jth moiré lattice in a pattern of right edge state, bulk state, and left edge state. The signal light then propagates to the j+1th moiré lattice on the left. The adjacent j+2 moiré lattice has a different period from the j+1th moiré lattice. As the signal light propagates along the waveguide, it continues to propagate through the j+1th moiré lattice in a pattern of right edge state, bulk state, and left edge state until it reaches the leftmost moiré lattice and is output from the two leftmost waveguides, forming an unassisted directional pumping system for the topological Solis pump.

2. The topological Solis pump according to claim 1, characterized in that The cross-sectional radius of the waveguide is 8 μm to 10 μm, and the length is 15 mm to 25 mm.

3. The topological Solis pump according to claim 1, characterized in that The lattice constant d1 of the first group of waveguides of the lattice constant gradient photonic crystal is 18 μm to 20 μm, and the tolerance δ is 1 μm to 2 μm.

4. The topological Solis pump according to claim 1, characterized in that The distance between the lattice constant gradient photonic crystal and the lattice constant constant photonic crystal is 6-10 μm.

5. The topological Solis pump according to claim 1, characterized in that: The number of waveguide groups M in the lattice constant gradient photonic crystal is ≥2, and the number of waveguides N in each group is 5-20.

6. A method for realizing a topological Thouless pump based on a one-dimensional photonic moiré lattice as claimed in claim 1, characterized in that: The implementation method comprises the following steps:

1. Preparation of Topological Solis Pump: i. Providing a dielectric material as a substrate, forming a plurality of mutually parallel waveguides in two upper and lower rows arranged in one dimension within the substrate, wherein the waveguides are oriented perpendicular to the one-dimensional arrangement direction, the refractive index of the waveguides is greater than the refractive index of the substrate, each waveguide has the same shape and size, and the central axis of each row of waveguides is located in the same plane, and planes tangent to the upper and lower surfaces of each row of waveguides respectively form a lattice constant gradient photonic crystal and a lattice constant constant photonic crystal; ii. Multiple waveguides in a lattice constant gradient photonic crystal are divided into M groups, each group includes N waveguides, and the distance between adjacent waveguides in each group is the same, that is, the lattice constant is consistent. The lattice constants of the M groups of waveguides vary arithmetic along the arrangement direction. The lattice constant d of the waveguide in the i-th group is i =d1±δ(i-1), i=1,…,M, d1 is the lattice constant of the first group of waveguides, δ is the tolerance; iii. The plane where the waveguides in the one-dimensional arrangement of the photonic crystal with constant lattice constant are located is parallel to the plane where the waveguides in the one-dimensional arrangement of the photonic crystal with gradient lattice constant are located, and there is a distance between the two that is greater than the diameter of the waveguide. The distance between adjacent waveguides in the photonic crystal with constant lattice constant is constant, and the lattice constant is d c ; iv. The portion of each waveguide group in the lattice constant gradient photonic crystal, the portion of the photonic crystal with constant lattice constant corresponding to the group, and the substrate between the two constitute a moiré lattice. The periods of each moiré lattice are different, forming M moiré lattices with different periods. The i-th group of waveguides in the lattice constant gradient photonic crystal and the portion of the waveguides in the photonic crystal with constant lattice constant corresponding to the group of waveguides in the photonic crystal with constant lattice constant constitute the i-th moiré lattice. The period of the i-th moiré lattice is v. A topological band gap always exists in the moiré lattice energy band. The moiré lattice has topological edge states. The periods of two adjacent moiré lattices are different. When a signal light is incident on the moiré lattice from one side, the mode in one moiré lattice changes from the edge state on one side to the bulk state, and then to the edge state on the other side during propagation.

2. Achieve unassisted directional pumping: 1) The laser outputs an optical signal, the frequency of which is consistent with the operating frequency of the topological Solis pump. At the operating frequency, the propagation modes of the topological Solis pump include the left boundary state, the bulk state, and the right boundary state, each of which has a different effective mode refractive index. 2) Topological pumping from left to right: a) Signal light is incident along the waveguide direction from the leftmost waveguide of a topological Solis-pumped photonic crystal with a constant lattice constant. The period of the adjacent j+1th moiré lattice differs from that of the jth moiré lattice, where j = 1, … M-1. During transmission, the signal light first matches the effective mode refractive index of the left edge state. The signal light field is localized in the leftmost waveguide of the jth moiré lattice, generating a left edge state. That is, signal light exists in both the upper and lower waveguides on the leftmost side of the jth moiré lattice. b) During the propagation along the waveguide, the effective mode refractive index of the signal light matches that of the bulk state, and the light field of the signal light diffuses into the entire j-th moiré lattice. At this time, the left edge state disappears, and the mode evolves from the left edge state to the bulk state. c) As the signal light continues to propagate along the waveguide, the effective mode refractive index of the signal light matches that of the right edge state. At this time, the mode is localized in the right waveguide of the jth moiré lattice to generate a right edge state. The mode evolves from the bulk state to the right edge state. The signal light completes the transmission of the jth moiré lattice according to the pattern of left edge state, bulk state and right edge state; d) The signal light is transmitted to the adjacent j+1th moiré lattice on the right. The adjacent j+2th moiré lattice has a different period from the j+1th moiré lattice. During the transmission along the waveguide, the signal light repeats steps a) to c) and continues to complete the transmission of the j+1th moiré lattice in the pattern of left edge state, bulk state, and right edge state until it reaches the rightmost moiré lattice and is output from the two rightmost waveguides, forming an unassisted directional pumping of the topological Solis pump. 3) Pumping from right to left topology: a) Signal light is incident along the waveguide direction from the rightmost waveguide of a topological Solis-pumped photonic crystal with a constant lattice constant. The period of the adjacent j+1th moiré lattice differs from that of the jth moiré lattice, where j = 1, … M-1. During transmission, the signal light first matches the effective mode refractive index of the right-edge state. The signal light field is localized in the rightmost waveguide of the jth moiré lattice, generating a right-edge state. That is, signal light exists in both the upper and lower waveguides on the rightmost side of the jth moiré lattice. b) During the propagation along the waveguide, the effective mode refractive index of the signal light matches that of the bulk state, and the light field of the signal light diffuses into the entire j-th moiré lattice. At this time, the right edge state disappears, and the mode evolves from the right edge state to the bulk state. c) As the signal light continues to propagate along the waveguide, the effective mode refractive index of the signal light matches that of the left edge state. At this point, the mode is localized in the left waveguide of the j-th moiré lattice, generating a left edge state. The mode evolves from the bulk state to the left edge state, and the signal light completes the propagation of the j-th moiré lattice in the pattern of the right edge state, bulk state, and left edge state. d) The signal light is transmitted to the adjacent j+1th moiré lattice on the left. The adjacent j+2th moiré lattice has a different period from the j+1th moiré lattice. During the transmission along the waveguide, the signal light repeats steps a) to c) and continues to complete the transmission of the j+1th moiré lattice in the pattern of right edge state, bulk state and left edge state until it reaches the leftmost moiré lattice and is output from the two leftmost waveguides, forming an unassisted directional pumping of the topological Solis pump.

7. The implementation method according to claim 6, characterized in that: In step i) of step 1), two rows of multiple mutually parallel waveguides arranged in one dimension are formed in the substrate by laser direct writing or electron beam lithography-film deposition-electron beam lithography.

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