On-chip topological metasurface and applications thereof

Abstract

The application belongs to the technical field of micro-nano optics, and discloses a topological metasurface on a chip and application thereof.The topological metasurface on a chip comprises, from top to bottom, a nano-brick array, an optical waveguide layer and a dielectric substrate layer; the nano-brick array is composed of a plurality of T-shaped topological metasurface atoms, and the nano-brick array is prepared from a dielectric material.The topological metasurface on a chip is applied to multipath information multiplexing and storage, wearable display devices or intelligent integrated optical systems.The application can solve the problem that the topological metasurface in the prior art relies on metal materials to create singular points, which introduces large ohmic loss and has poor integration compatibility.The all-dielectric topological metasurface on a chip can avoid the inherent ohmic loss of metal and is easy to be compatible with other mainstream on-chip optical devices.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of micro-nano optics, and more particularly relates to a chip-on-topological metasurface and application thereof. BACKGROUND

[0002] As a two-dimensional artificial material, metasurfaces have shown great potential due to their excellent ability to control the amplitude, phase and polarization of light in the field of nanophotonics. This ability to control light fields at subwavelength scales has promoted the development of a variety of practical functions, including beam steering and spectral engineering. In particular, its excellent potential in optical coding and modulation opens up new paths for the advancement of metasurface holography. From a systematic point of view, a metasurface device can be regarded as an open system that continuously exchanges or absorbs energy between the incident field and the resonant nanostructure. Such a system is classified as a typical non-Hermitian system, which has a remarkable feature, i.e., the appearance of a unique singularity, called a singular point. Specifically, at the singular point, the eigenvalues and eigenvectors become degenerate, triggering a sharp phase transition and extraordinary optical response. Based on this, metasurfaces, with their excellent ability to manipulate light fields, are considered an ideal platform for creating and surrounding singular points to obtain new degrees of freedom in optical phase coding. Specifically, a unique phase change from 0 to 2π can be provided by surrounding the singular point in an arbitrary path, which is called topological phase. Therefore, based on the previous research on topological metasurfaces, a variety of advanced functions have been achieved by surrounding the singular point, including polarization control, coherent perfect absorption and optical holographic coding.

[0003] However, current topological metasurfaces usually rely on metal materials to create singular points, which inevitably introduces large ohmic losses inherent to metal materials. This severely reduces the overall optical efficiency and limits its compatibility with mainstream dielectric metasurface devices. In addition, the typical free-space architecture also limits the integration capability of metasurface optical devices on compact optical platforms. SUMMARY

[0004] The present application provides a chip-on-topological metasurface and application thereof, which solves the problem of large ohmic losses and poor integration compatibility caused by the reliance of topological metasurfaces on metal materials to create singular points in the prior art.

[0005] The present application provides a chip-on-topological metasurface, comprising: a nanobrick array from top to bottom, a waveguide layer and a dielectric substrate layer; the nanobrick array is composed of a plurality of T-shaped topological metasurface atoms, and the nanobrick array is prepared from dielectric materials.

[0006] Preferably, the nanobrick array is divided into a plurality of unit structures, each of which serves as a meta-atomic pixel; an xoy coordinate system is established in a direction parallel to two edges of the working surface of the optical waveguide layer, and the meta-atomic pixels have the same period in the x direction and the y direction;

[0007] Each of the unit structures includes a T-shaped topological metaatom, which is composed of a first rectangular nanobrick with a first length L1, a width W and a height H1, and a second rectangular nanobrick with a second length L2, the width W and the height H1, and the T-shaped topological metaatom is accompanied by a rotation angle θ; the distance between the center points of the first rectangular nanobrick and the second rectangular nanobrick is d, and the rotation angle θ is the angle at which the T-shaped topological metaatom rotates around its center within the period.

[0008] Preferably, multiple groups of unit structures are obtained through electromagnetic simulation optimization, and the optimized unit structures of the multiple groups all have topological characteristics; for each meta-atom pixel, a group of unit structures with a phase distribution closest to the target topological phase is selected from the multiple groups of unit structures for arrangement, and the rotation angle θ of each T-shaped topological meta-atom is determined according to the target geometric phase;

[0009] The unit structures of different groups have different first lengths L1 and / or center point distances d, and the unit structures of different groups have the same second length L2, width W, and height H1.

[0010] Preferably, by performing parameter scanning on the T-shaped topological metaatom in the parameter space (L1, d), the parameters of the T-shaped topological metaatom that meet the encoding requirements are found based on the amplitude and phase of the guided wave extracted under different parameter conditions.

[0011] Preferably, the phase distribution of the unit structure of each group includes the left-handed circularly polarized light phase φ L and the right-handed circularly polarized light phase φ R ; Use multiple group-type unit structures to step the topological phase.

[0012] Preferably, the first holographic phase is calculated based on the first target holographic image, and the second holographic phase is calculated based on the second target holographic image; the first holographic phase and the second holographic phase are added together to obtain the target topological phase.

[0013] Preferably, the nanobrick array is made of silicon.

[0014] Preferably, the optical waveguide layer is made of silicon nitride, and the dielectric substrate layer is made of silicon dioxide.

[0015] In another aspect, the present application provides an application of the on-chip topological metasurface as described above, which is applied to multiplexing and storage of information, wearable display devices or intelligent integrated photonics.

[0016] Preferably, the on-chip topological metasurface is conducive to realizing dual-channel holographic and AR display.

[0017] The one or more technical solutions provided in the present application have at least the following technical effects or advantages:

[0018] The on-chip topological metasurface provided by the present application comprises a nanobrick array from top to bottom, a light waveguide layer and a dielectric substrate layer; wherein the nanobrick array is composed of a plurality of T-shaped topological metasurface atoms, and the nanobrick array is prepared from a dielectric material. The present application successfully creates a singular point in a full dielectric environment by screening the on-chip metasurface atom geometry at the nanoscale, and realizes the encoding of the topological phase of 2π generated around the point. In addition, by combining the geometric phase, the on-chip topological metasurface proposed by the present application can unlock new coding degrees of freedom and can decouple the orthogonal circularly polarized light extracted from the light waveguide layer. In summary, the present application realizes the creation and manipulation of singular points in a full dielectric environment and on-chip scheme, which can reduce the intrinsic ohmic loss and improve the integration compatibility. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is the comparison of the real and imaginary refractive indices of silicon and aluminum materials.

[0020] Figure 2 is a structural schematic diagram of the on-chip topological metasurface provided by the present application.

[0021] Figure 3 is the phase and amplitude of left-handed circularly polarized light and right-handed circularly polarized light extracted when the silicon metasurface atom is scanned in simulation.

[0022] Figure 4 is a schematic diagram of introducing geometric phase into waveguide modulation by using the corner of the metasurface atom.

[0023] Figure 5 is a schematic diagram of realizing orthogonal circularly polarized light decoupling based on the on-chip topological metasurface.

[0024] Figure 6 is the distribution of topological phase and geometric phase obtained by simulation.

[0025] Figure 7 is the simulation result of the extraction efficiency and phase distribution of the four metasurface atoms selected in the embodiment of the present application.

[0026] Figure 8The design process of the super-atom arrangement designed by the target holographic phase of the application.

[0027] Figure 9 The measuring device for measuring holography and augmented reality display in the embodiment of the application.

[0028] Figure 10 The double-channel holographic image measured in the embodiment of the application.

[0029] Figure 11 The actual shooting picture of the measuring device for shooting the augmented reality holographic image in the embodiment of the application.

[0030] Figure 12 The experimental result display of the augmented reality image in the embodiment of the application. DETAILED DESCRIPTION

[0031] In order to better understand the above technical solutions, the above technical solutions will be described in detail below in combination with the drawings in the specification and specific embodiments.

[0032] Embodiment 1:

[0033] Embodiment 1 provides an on-chip topological super surface, referring to Figures 1 to 5 , comprising: a nanobrick array from top to bottom, a light waveguide layer and a dielectric substrate layer; the nanobrick array is composed of a plurality of T-shaped topological super atoms, and the nanobrick array is prepared by using a dielectric material.

[0034] Specifically, the nanobrick array is divided into a plurality of unit structures, and each unit structure serves as a super atom pixel; an xoy coordinate system is established in the direction parallel to the two edges of the working surface of the light waveguide layer, and the super atom pixel has the same period P in the x direction and the y direction; each unit structure contains a T-shaped topological super atom, and the T-shaped topological super atom is composed of a first rectangular nanobrick (see Figure 3 in the horizontal nanobrick) with a first length L1, a width W and a height H1, and a second rectangular nanobrick (see Figure 3 in the vertical nanobrick) with a second length L2, the width W and the height H1, and the T-shaped topological super atom is accompanied by an angle θ (see Figure 4 ); the center point distance of the first rectangular nanobrick and the second rectangular nanobrick is d, and the angle θ is the angle of rotation of the T-shaped topological super atom around the center in the period. That is, the super atom is a T-shaped structure composed of two nanobricks, one horizontal and one vertical, and the angle of rotation can be understood as the angle between the horizontal nanobrick of the counterclockwise rotating super atom and the y axis, as shown in Figure 3 a is a schematic diagram of the angle of rotation being 0° in Figure 4is a schematic diagram of a clockwise rotation angle θ of a superatom a in the figure. It should be noted that the rotation is the rotation of the two nanobricks as a whole T-shaped structure with the geometric center point. The distance between the center points of the two nanobricks is d. It can be understood that the horizontal nanobrick has a center line parallel to the y-axis, and the vertical nanobrick also has a center line parallel to the y-axis, and the distance between the two center lines is d. It should be noted that the present application is to determine the structure parameters first, and then rotate. When the length L1 of the horizontal nanobrick and the distance (i.e. the center point distance d) between the two nanobricks along the x-axis are changed in the parameter space, the phase of the LCP part of the extracted guided wave can be controlled, and the introduction of the rotation angle θ combined with the geometric phase can control the phase of the other part RCP of the guided wave.

[0035] Specifically, a plurality of groups of unit structures are obtained through electromagnetic simulation optimization, and the plurality of groups of unit structures obtained through optimization all have topological characteristics; for each superatom pixel, a unit structure of a group closest to a target topological phase in phase distribution is selected from the plurality of groups of unit structures for arrangement, and a rotation angle θ of each T-shaped topological superatom is determined according to a target geometric phase; wherein the unit structures of different groups have different first lengths L1 and / or center point distances d, and the unit structures of different groups have the same second length L2, width W and height H1.

[0036] By performing parameter scanning on the T-shaped topological superatom in the parameter space (L1, d), the parameters of the T-shaped topological superatom meeting the coding requirements are found based on the amplitude and phase of the extracted guided wave under different parameter conditions.

[0037] Specifically, the parameter scanning is performed to confirm that the T-shaped topological superatom has topological characteristics, and to screen out structure parameters meeting the coding requirements, the coding requirements being that there is a uniform phase difference under the LCP component and a uniform phase distribution under the RCP component.

[0038] The phase distribution of each group of unit structures includes a left-handed circularly polarized light phase φ L and a right-handed circularly polarized light phase φ R The plurality of groups of unit structures can also be used to step the topological phase.

[0039] For example, a first holographic phase can be calculated according to a first target holographic image, and a second holographic phase can be calculated according to a second target holographic image; the first holographic phase and the second holographic phase are added to obtain the target topological phase.

[0040] The nanobrick array is preferably prepared from silicon, and the length and width of the silicon superatom on the superstructure surface are both subwavelength sizes. The material of the optical waveguide layer can be silicon nitride, and the material of the dielectric substrate layer can be silicon dioxide.

[0041] That is, the on-chip topological metasurface provided by the application is composed of a two-dimensional array of screened T-shaped topological metasurface atoms arranged above the optical waveguide layer.

[0042] Embodiment 2:

[0043] Embodiment 2 provides an application of the on-chip topological metasurface as described in Embodiment 1, which is applied to multiplexing and storage of information, wearable display devices, or intelligent integrated optical systems.

[0044] For example, the on-chip topological metasurface facilitates two-channel holographic and augmented reality (AR) display.

[0045] The application can create singular points and realize coding of topological phase in an on-chip environment by precisely adjusting the parameters of the unit structure, i.e., adjusting the relative positions and sizes of the two nanobricks in the T-shaped topological metasurface atom, and is compatible with geometric phase to realize complete decoupling of orthogonally circularly polarized light. Through coding of topological phase and geometric phase, the metasurface can realize two-channel holographic and AR display.

[0046] Compared with conventional free-space topological metasurfaces, the design of the application adopts an on-chip and all-dielectric configuration environment, eliminates the inherent ohmic loss caused by metal materials, and the extracted guided waves continue to propagate and are extracted by subsequent metasurface atoms, without energy loss. In addition, due to the on-chip propagation mechanism, the generated holographic image and AR display can effectively suppress zero-order background light interference.

[0047] The following examples are given in conjunction with the parameters.

[0048] Figure 1 The refractive index contrast between the dielectric silicon material (silicon) and the common metal aluminum material used in this example is shown, and the green dashed line is the working wavelength. It can be seen that the imaginary refractive index of the aluminum material is much higher than that of the silicon material at the working wavelength.

[0049] Specifically, the refractive index of the material is a complex number, the real part of the refractive index determines the speed and refraction angle of light propagation in the medium, and the imaginary part of the refractive index represents the absorption loss of light propagation in the medium. Compared with metals, the imaginary part of the refractive index of dielectrics is very low, which means that the absorption loss of dielectrics for light propagation is small, which is conducive to improving efficiency. One of the purposes of the application is to avoid the ohmic loss caused by metals, that is, to strive to reduce the imaginary part of the refractive index (the imaginary part of the refractive index of metals is very high, i.e., the loss is very large).

[0050] Figure 2 The on-chip topological metasurface proposed by the application is schematically illustrated as being arranged by carefully designed silicon atom nanobricks with attached corners. Figure 2a is a schematic diagram of a local structure array of the on-chip topological superstructure surface, and the guided wave propagates in the waveguide in a TE0 mode. Figure 2 b is an enlarged view of the on-chip silicon superatom, the height H1 of the silicon atom nanobrick on the waveguide is 350 nm, the thickness H2 of the Si3N4 planar waveguide is 220 nm, the waveguide has a higher effective refractive index (n is about 2.05), and the lower part is a thick (H3 = 500 microns) SiO2 substrate.

[0051] Figure 3 is the phase and amplitude of the left circularly polarized light and the right circularly polarized light extracted when the silicon superatom is parameter scanned in simulation in the embodiment of the application.

[0052] The key working principle of the on-chip topological superstructure surface proposed in the application is based on the encodability of the topological phase, and the decoupling of the orthogonal circularly polarized light is realized by introducing the geometric phase. By performing parameter scanning on the designed nanobrick (a in the figure) in the parameter space (L1, d), the amplitude and phase of the extracted guided wave under different parameter conditions are analyzed, and the parameters of the T-shaped topological superatom meeting the coding requirements are found. Specifically, Figure 3 Figure 3 a in the figure is a top view of the silicon superatom, and the superatom is composed of one horizontal nanobrick and one vertical nanobrick, wherein the parameters are L2 = 440 nm, P = 500 nm and W = 70 nm. By scanning the length L1 of the horizontal nanobrick in the parameter range (200 nm, 300 nm) and the center distance d of the horizontal and vertical nanobricks along the x-axis in the parameter range (50 nm, 150 nm), the topological characteristics of the extracted guided wave are analyzed.

[0053] Figure 3 b in the figure is the amplitude and phase of the left circularly polarized light component of the extracted guided wave in the parameter space (L1, d). Figure 3 c in the figure is the amplitude and phase of the right circularly polarized light component of the extracted guided wave in the parameter space, wherein the z-axis indicates the high and low of the normalized amplitude, and the color covered indicates the phase (phase) gradient distribution. Specifically, the left circularly polarized light (LCP) in the guided wave is extracted for analysis (see b in the figure), and it can be seen that the amplitude distribution in the figure presents a funnel shape, and there is a singular point with an amplitude of almost zero. Around the singular point in any path, a phase change of 0 to 2pi will be generated. In the right circularly polarized light (RCP) analysis (see c in the figure) in the guided wave, the phase is almost flat, and there is no singular point. It is this topological characteristic of the inconsistent effect on the left and right circularly polarized light that is the key to breaking the geometric phase effect on the left and right circularly polarized light and realizing decoupling. Figure 3 Figure 3

[0054] Figure 4 ​​​Schematic diagram of using the rotation angle of meta-atoms to introduce geometric phase into waveguide modulation in an embodiment of the present invention. Figure 4 The a in the figure indicates that the metaatom can extract the guided wave and decompose it into left-hand circularly polarized light (LCP) and right-hand circularly polarized light (RCP), and produce a phase modulation effect with opposite effects on left-hand and right-hand circular polarization by introducing a rotation angle (θ). Figure 4 b in the figure is the distribution of the phase of the left-handed circularly polarized component of the waveguide extracted in the simulation as a function of the rotation angle (θ). Figure 4 Figure c shows the distribution of the phase of the right-handed circularly polarized component of the waveguide extracted from the simulation as a function of the rotation angle (θ). The color overlay indicates the phase gradient distribution.

[0055] Right now Figure 4 The response of the on-chip atoms designed by the present invention to the geometric phase generated by the introduced rotation angle is demonstrated. Figure 4 The a in the figure shows a 3D schematic diagram under the TE0 mode incident condition. The guided wave extracted by the silicon atom can be decomposed into left-handed circularly polarized light and right-handed circularly polarized light. By analyzing the phase distribution of the left-handed circularly polarized light, it can be seen that the left-handed circularly polarized light ( Figure 4 The phase distribution of right circularly polarized light (b) shows a two-fold relationship with the rotation angle, while the phase distribution of right circularly polarized light ( Figure 4 The phase distribution in c) is opposite to that of left-handed circularly polarized light, but also shows a two-fold relationship. This means that when extracting waveguides for on-chip atoms with rotation angles, the influence of the rotation angle cannot be decoupled for left-handed and right-handed circularly polarized light. Therefore, here we propose the idea of ​​introducing geometric phase into topological phase to completely decouple orthogonal circular polarization. See the schematic diagram of orthogonal circularly polarized light decoupling based on on-chip topological metasurface for details. Figure 5 .

[0056] In order to achieve phase encoding, the present invention carefully selects four metaatoms to step the topological phase. The selection is based on the expectation that the phase of left-handed circularly polarized light (φ L ) distribution has a uniform phase difference, while the right circularly polarized light phase (φ R ) distribution as evenly as possible to avoid adding extra variables to the encoding of the geometric phase.

[0057] Figure 6 These are the topological phase and geometric phase distributions obtained by simulation in the embodiments of the present invention. Figure 6 A and Figure 6 b in the parameter space (L1, d) are the phases (φ) of the left-handed circularly polarized light extracted in the parameter space (L1, d). L ) distribution and the phase of right-handed circularly polarized light (φ R ) distribution. The red stars in the figure are the locations of the singularities, and the black stars are the parameters of the meta-atoms selected in the experiment. Figure 6c is the distribution of the geometric phase with the introduction of the rotation angle (θ), and the black origin in the figure is the rotation angle selection of the superatom in the experiment. The color distribution indicates the distribution of the phase.

[0058] For example, Figure 6 a in Figure 6 b, the position marked by the black star is the parameter of the selected four atoms, and the red star is the parameter of the singular point. Figure 6 c in

[0059] In order to more intuitively illustrate the parameters and properties of the selected superatoms, the simulation results of the extraction efficiency and phase distribution of the four superatoms selected in the embodiment of the application are given, as shown in Figure 7 Specifically, Figure 7 a shows the structure of the four T-shaped topological superatoms (referred to as superatoms), and b in Figure 7 shows the phase (φ L and φ R ) and efficiency (including LCPEfficiency and RCP Efficiency) of the four superatoms in extracting left and right circularly polarized light components at the working wavelength; wherein the efficiency corresponds to the extraction capability of the superatom to light, which can be regarded as the amplitude, which is determined by the superatom itself, and the main basis for selecting the superatom is the phase distribution. After the phase distribution of the superatom is determined, the amplitude (extraction efficiency) is also determined accordingly. From Figure 7 it can be seen that, under the left circularly polarized light (LCP) component, the phase distribution of the four superatoms is in a linear relationship in a step distribution, and under the right circularly polarized light (RCP) component, the phase distribution of the four superatoms is in a relatively flat distribution, which well avoids introducing phase difference into geometric phase, thereby realizing simple and efficient orthogonal circularly polarized light decoupling.

[0060] In addition, the application further demonstrates the design process of the on-chip topological super surface (see Figure 8 ). First, the holographic phase is calculated from the target holographic image, then the two phases are added according to the phase relationship to obtain the array arrangement of the topological phase; then the arrangement corresponds to the arrangement of the four selected T-shaped topological superatoms to obtain the arrangement of the topological superatom array, and then the rotation angle is introduced by rotating the superatom combined with the arrangement of the geometric phase to obtain the final on-chip topological super surface array. Therefore, in the design theory, we successfully introduce the geometric phase into the on-chip super surface and combine it with the topological phase, and develop a new degree of freedom to decouple orthogonal circularly polarized light.

[0061] To experimentally demonstrate whether the on-chip all-dielectric topological metasurface can completely decouple the orthogonal circularly polarized light without crosstalk, we fabricated the designed samples using plasma-enhanced chemical vapor deposition (PECVD) and conventional electron beam lithography (EBL), and established an AR holographic characterization optical setup (see Figure 9 ), including a laser, an aperture diaphragm, a linear polarizer, a lens, a quarter-wave plate, and a cell phone camera. A broadband polarized laser (500-800 nm) is end-coupled into the waveguide, and the projected holographic image can be directly captured by the cell phone camera. By employing a polarization analyzer to selectively transmit different circularly polarized light, different holographic images can be switched accordingly. When the output channel is set to left-handed circularly polarized light, the target holographic image of "key" appears, while switching to right-handed circularly polarized light produces the holographic image of "lock" (see Figure 10 ). This experimental holographic characterization confirms that the designed all-dielectric on-chip topological metasurface effectively realizes the decoupling of left- and right-handed circularly polarized light, successfully encodes the on-chip topological phase, and has almost no crosstalk between the two channels with high contrast.

[0062] As a proof of concept, we further demonstrate the AR function of the on-chip topological metasurface provided by the present application in a real environment, and the experimental setup is shown in Figure 11 . It is worth noting that no holographic image appears in the background picture, but the projected holographic image can be captured by the cell phone camera and appears to float above the background. Specifically, as shown in Figure 12 , the two-channel AR holographic images ("key" and "lock") are alternately switched and presented as floating virtual images in the background provided by another display screen. Due to the high transparency of the all-dielectric architecture and the unique on-chip propagation scheme without zero-order diffraction interference, the projected AR holographic image is still clearly visible to the observer, with satisfactory imaging clarity and contrast.

[0063] In summary, by scanning the geometry and parameters of on-chip superatoms, we successfully created a singularity in a fully dielectric on-chip architecture and achieved the manipulation of the topological phase obtained by surrounding the singularity with an arbitrary path; by combining with the geometric phase, we completely decoupled the orthogonal circular polarization channels, unlocked the independent coding degrees of freedom under the two channels, and realized the encoding of two-channel holographic images independent of each other without interference. As a proof of concept, the on-chip topological metasurface proposed by us can realize holographic visualization in real-world scenarios, serving as a practical AR function; compared with traditional free-space metal topological metasurfaces, this fully dielectric on-chip scheme avoids the inherent ohmic loss of metal and is easy to be compatible with other mainstream on-chip optical devices. In addition, due to the on-chip propagation mechanism, the generated image display can effectively suppress the zero-order background light interference. In general, the on-chip topological metasurface proposed by us has the advantages of miniaturization and integration, and has broad application prospects in the next generation of wearable display devices, multi-channel information multiplexing and storage, intelligent integrated photonics, advanced optical displays and the like.

[0064] Finally, it should be explained that the above specific embodiments are only used to illustrate the technical solutions of the present application and not to limit it, although the present application has been described in detail with reference to examples, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application, which should be covered in the scope of the claims of the present application.

Claims

1. An on-chip topological metasurface, characterized in that: include: From top to bottom, a nanobrick array, an optical waveguide layer, and a dielectric substrate layer; the nanobrick array is composed of a plurality of T-shaped topological metaatoms, and the nanobrick array is made of dielectric materials; The nanobrick array is divided into a plurality of unit structures, each of which serves as a super-structure atomic pixel; An xoy coordinate system is established in a direction parallel to two sides of the working surface of the optical waveguide layer, and the meta-atom pixels have the same period in the x direction and the y direction; Each of the unit structures comprises a T-shaped topological metaatom, wherein the T-shaped topological metaatom is composed of a first rectangular nanobrick having a first length L1, a width W, and a height H1, and a second rectangular nanobrick having a second length L2, the width W, and the height H1, and the T-shaped topological metaatom is accompanied by a rotation angle θ; the center point distance between the first rectangular nanobrick and the second rectangular nanobrick is d, and the rotation angle θ is the angle at which the T-shaped topological metaatom rotates around its center within the period; Through electromagnetic simulation optimization, multiple groups of unit structures are obtained, and the optimized unit structures of multiple groups all have topological characteristics. For each meta-atom pixel, the unit structure of a group with a phase distribution closest to the target topological phase is selected from the multiple groups of unit structures for arrangement, and the rotation angle θ of each T-shaped topological meta-atom is determined according to the target geometric phase. The unit structures of different groups have different first lengths L1 and / or center point distances d, and the unit structures of different groups have the same second length L2, width W, and height H1.

2. The on-chip topological metasurface according to claim 1, characterized in that: By performing parameter scanning on the T-shaped topological metaatom in the parameter space (L1, d), the parameters of the T-shaped topological metaatom that meet the encoding requirements are found based on the amplitude and phase of the guided wave extracted under different parameter conditions.

3. The on-chip topological metasurface according to claim 1, wherein: The phase distribution of the unit structure of each group includes the left-handed circularly polarized light phase φ L and the right-handed circularly polarized light phase φ R ; Use multiple group-type unit structures to step the topological phase.

4. The on-chip topological metasurface according to claim 1, wherein: A first holographic phase is calculated based on the first target holographic image, and a second holographic phase is calculated based on the second target holographic image; the first holographic phase and the second holographic phase are added together to obtain the target topological phase.

5. The on-chip topological metasurface according to claim 1, wherein: The nano brick array is made of silicon.

6. The on-chip topological metasurface according to claim 1, wherein: The material of the optical waveguide layer is silicon nitride, and the material of the dielectric substrate layer is silicon dioxide.

7. An application of an on-chip topological metasurface according to any one of claims 1 to 6, characterized in that: The on-chip topological metasurface is applied to multiplexed information multiplexing and storage, wearable display devices or intelligent integrated photonic systems.

8. The application of the on-chip topological metasurface according to claim 7, characterized in that: This is beneficial for the on-chip topological metasurface to achieve dual-channel holographic and AR displays.

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