On-chip topology metasurface and application thereof

Abstract

The invention belongs to the technical field of micro-nano optics, and discloses an on-chip topological metasurface and application thereof. The on-chip topological metasurface provided by the invention comprises a nano brick array, an optical waveguide layer and a dielectric substrate layer from top to bottom, the nano brick array is composed of a plurality of T-shaped topological super-structure atoms, and the nano brick array is prepared from a dielectric material. The on-chip topological metasurface is applied to multiplexing and storage of multi-channel information, wearable display equipment or an intelligent integrated photonic system. According to the topological metasurface on the full-dielectric sheet, the problems that in the prior art, due to the fact that the topological metasurface depends on metal materials to create singular points, large ohmic loss can be introduced, and integration compatibility is poor can be solved, the intrinsic ohmic loss of the metal can be avoided, and the overall performance of the topological metasurface on the full-dielectric sheet is improved. And the method is easy to be compatible with other mainstream on-chip optical devices.

Description

Technical Field

[0001] The present invention belongs to the field of micro-nano optical technology, and more specifically, relates to an on-chip topological metasurface and applications thereof. Background Art

[0002] Metasurfaces, as two-dimensional artificial materials, have shown great potential in the field of nanophotonics due to their outstanding ability to control the amplitude, phase, and polarization of light waves. 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 outstanding potential in optical encoding and modulation has opened up new paths for the advancement of metasurface holography. From a fundamental system 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 systems are classified as typical non-Hermitian systems and have a remarkable property, namely the appearance of a unique singular point, called a singularity. Specifically, at the singularity, the eigenvalues ​​and eigenvectors become degenerate, which leads to a sharp phase transition and extraordinary optical response. Based on this, metasurfaces, with their outstanding ability to manipulate light fields, are considered to be an ideal platform for creating and surrounding singularities to obtain new degrees of freedom for optical phase encoding. Specifically, circling a singularity with an arbitrary path can provide a unique phase change from 0 to 2π, called the topological phase. Therefore, previous studies based on topological metasurfaces have achieved a variety of advanced functions by focusing on singular points, including polarization control, coherent perfect absorption, and optical holographic encoding.

[0003] However, current topological metasurfaces usually rely on metallic materials to create singularities, which inevitably introduces Ohmic losses inherent to larger metallic materials. This severely reduces the overall optical efficiency and limits its compatibility with mainstream dielectric metadevices. In addition, the typical free-space architecture also limits the integration capabilities of metasurface optical devices on compact optical platforms. Summary of the invention

[0004] The present invention provides an on-chip topological metasurface and its application, thereby solving the problem in the prior art that the topological metasurface relies on metal materials to create singular points, which introduces large ohmic losses and has poor integration compatibility.

[0005] The present invention provides an on-chip topological metasurface, comprising: a nanobrick array, an optical waveguide layer and a dielectric substrate layer from top to bottom; the nanobrick array is composed of a plurality of T-shaped topological metaatoms, and the nanobrick array is made of dielectric material.

[0006] Preferably, the nanobrick array is divided into a plurality of unit structures, each of which serves as a super-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 super-atomic pixels have the same period in the x direction and the y direction;

[0007] Each of the unit structures comprises a T-shaped topological superatom, which 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 superatom 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 superatom rotates around its center within a period.

[0008] Preferably, multiple groups of unit structures are obtained through electromagnetic simulation optimization, and the optimized multiple groups of unit structures all have topological characteristics; for each super-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 super-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, a first holographic phase is calculated based on a first target holographic image, and a second holographic phase is calculated based on a 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] On the other hand, the present invention provides an application of an on-chip topological metasurface as described above, wherein the on-chip topological metasurface is applied to multiplexed information multiplexing and storage, wearable display devices, or intelligent integrated photonic systems.

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

[0017] One or more technical solutions provided in the present invention have at least the following technical effects or advantages:

[0018] The on-chip topological metasurface provided by the present invention includes a nanobrick array, an optical waveguide layer and a dielectric substrate layer from top to bottom; wherein the nanobrick array is composed of a number of T-shaped topological metaatoms, and the nanobrick array is made of dielectric materials. The present invention successfully creates a singular point in a fully dielectric environment by screening the geometric shapes of on-chip metaatoms at the nanoscale, and realizes the encoding of the 2π topological phase generated around the point. In addition, by combining the geometric phase, the on-chip topological metasurface proposed by the present invention can unlock new coding degrees of freedom and can decouple the orthogonal circularly polarized light extracted from the optical waveguide layer. In summary, the present invention realizes the creation and manipulation of singular points in a fully dielectric environment and on-chip solution, which can reduce intrinsic ohmic losses and improve its integrated compatibility. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0021] Figure 3 The phase and amplitude of left-handed and right-handed circularly polarized light extracted when performing a parameter sweep of the silicon metaatom in the simulation.

[0022] Figure 4 It is a schematic diagram of the present invention using the rotation angle of meta-atoms to introduce geometric phase into waveguide modulation.

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

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

[0025] Figure 7 It is the simulation result of the extraction efficiency and phase distribution of four meta-atoms selected in the embodiment of the present invention.

[0026] Figure 8This is the design process of the present invention for obtaining a meta-atomic arrangement from a target holographic phase design.

[0027] Fig. 9 It is a measuring device for experimentally measuring holographic and augmented reality displays in an embodiment of the present invention.

[0028] Fig.10 It is a dual-channel holographic image experimentally measured in an embodiment of the present invention.

[0029] Fig.11 This is a real picture of the measuring device for shooting augmented reality holographic images in an embodiment of the present invention.

[0030] Fig.12 It is a display of the experimental results of augmented reality images in the embodiments of the present invention. DETAILED DESCRIPTION

[0031] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0032] Embodiment 1:

[0033] Embodiment 1 provides an on-chip topological metasurface, see Figures 1 to 5 , including: a nanobrick array, an optical waveguide layer and a dielectric substrate layer from top to bottom; the nanobrick array is composed of a number of T-shaped topological superatoms, and the nanobrick array is made of dielectric materials.

[0034] Specifically, the nanobrick array is divided into a plurality of unit structures, each of which is a super-atomic pixel; an xoy coordinate system is established in a direction parallel to the two sides of the working surface of the optical waveguide layer, and the super-atomic pixels have the same period P in the x direction and the y direction; each of the unit structures comprises a T-shaped topological super-atom, and the T-shaped topological super-atom is composed of a first rectangular nanobrick having a first length L1, a width W and a height H1 (see Figure 3 and a second rectangular nanobrick having a second length L2, the width W and the height H1 (see Figure 3 The T-shaped topological super-atoms are composed of vertical nanobricks, and the T-shaped topological super-atoms are accompanied by a rotation angle θ (see Figure 4 ); 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 superatom rotates around its center within a period. That is, the superatom is a T-shaped structure, consisting of two nanobricks, one horizontal and one vertical. The rotation angle can be understood as the angle between the lateral nanobrick of the superatom rotating counterclockwise and the y-axis, such as Figure 3 a in the figure is a schematic diagram of a rotation angle of 0°. Figure 4a in is a schematic diagram of the counterclockwise rotation angle θ of the superstructure atom. It should be noted that the rotation is that the two nanobricks are rotated as a T-shaped whole with the geometric center point. The center point distance between the two nanobricks is d, which can be understood as the horizontal nanobrick has a midline parallel to the y-axis, and the vertical nanobrick also has a midline parallel to the y-axis, and the distance between the two lines is d. It should be noted that the present invention first determines the structural parameters and then rotates. When the length L1 of the lateral nanobrick and the distance between the two nanobricks along the x-axis (i.e., the center point distance d) are changed in the parameter space, the phase of the LCP part of the extracted waveguide can be adjusted, and after introducing the angle θ combined with the geometric phase, the phase of the other part of the waveguide RCP can be controlled.

[0035] Specifically, 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 unit structure of a group whose phase distribution is closest to the target topological phase is selected from the unit structures of the multiple groups for arrangement, and the rotation angle θ of each T-shaped topological meta-atom is determined according to the target geometric phase; wherein unit structures of different groups have different first lengths L1 and / or center point distances d, and 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 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.

[0037] Specifically, parameter scanning is performed to confirm that the T-shaped topological metaatom has topological characteristics and to screen out structural parameters that meet the encoding requirements. The encoding requirements are to have a uniform phase difference under the LCP component and a uniform phase distribution under the RCP component.

[0038] 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 The topological phase can also be stepped by using multiple groups of unit structures.

[0039] For example, a first holographic phase may be calculated based on a first target holographic image, and a second holographic phase may be calculated based on a second target holographic image; the first holographic phase and the second holographic phase may be added together to obtain the target topological phase.

[0040] The nanobrick array is preferably made of silicon, and the length and width of the silicon superstructure atoms on the surface of the superstructure are both sub-wavelength 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 present invention is composed of a screened two-dimensional array of T-shaped topological metaatoms, which is arranged above the optical waveguide layer.

[0042] Embodiment 2:

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

[0044] For example, the on-chip topological metasurface is advantageous for realizing dual-channel holographic and augmented reality (AR) display.

[0045] The present invention can create singular points in an on-chip environment and achieve encoding of topological phase by precisely adjusting the parameters of the unit structure, that is, adjusting the relative position and size of the two nanobricks in the T-shaped topological meta-atom, and can also achieve complete decoupling of orthogonal circularly polarized light by being compatible with geometric phase. By encoding topological phase and geometric phase, the metasurface can achieve dual-channel holographic and AR display.

[0046] Compared with the traditional free-space topological metasurface, the design of the present invention adopts an on-chip and all-dielectric configuration environment, eliminating the inherent ohmic loss caused by metal materials, and the unextracted guided waves will continue to propagate and be extracted by subsequent metaatoms without energy loss. In addition, due to the on-chip propagation mechanism, the generated holographic images and AR displays can effectively suppress zero-order background light interference.

[0047] The following is an example with parameters.

[0048] Figure 1 This is a comparison of the refractive index of the dielectric silicon material (silicon) used in this example and the common metal aluminum material. The green dotted line is the operating wavelength. It can be seen that the imaginary refractive index of the aluminum material is much higher than the imaginary refractive index of the silicon material at the operating wavelength.

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

[0050] Figure 2 The on-chip topological metasurface proposed in the present invention is schematically illustrated as being composed of an arrangement of carefully designed silicon atom nanobricks with corners. Figure 2Figure a is a schematic diagram of the local structure array of the on-chip topological metasurface, and the guided wave propagates in the waveguide in the TE0 mode. Figure 2 Figure b is an enlarged image of the on-chip silicon superstructure atoms. The height of the silicon atom nanobrick located on the waveguide is H1=350nm, and the thickness of the Si3N4 planar waveguide is H2=220nm. The waveguide has a high effective refractive index (n is about 2.05), and underneath is a thick (H3=500μm) SiO2 substrate.

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

[0052] The key working principle of the on-chip topological metasurface proposed in this invention is based on the codability of topological phase, and the decoupling of orthogonal circularly polarized light is achieved by introducing geometric phase. Figure 3 a) in the figure performs parameter scanning, analyzes the amplitude and phase of the waveguide extracted under different parameter conditions, and searches for the parameters of the T-shaped topological superatom that meets the encoding requirements. Specifically, Figure 3 a in the figure is a top view of a silicon superatom, which consists of two nanobricks, one horizontal and one vertical, with parameters L2=440nm, P=500nm and W=70nm. The topological characteristics of the waveguide are analyzed and extracted by scanning the length L1 of the lateral nanobrick within the parameter range (200nm, 300nm) and the center distance d of the longitudinal and lateral nanobricks along the x-axis within the parameter range (50nm, 150nm).

[0053] Figure 3 b in the figure is the amplitude and phase of the guided left-handed circularly polarized light component extracted in the parameter space (L1, d). Figure 3 The c in the figure is the amplitude and phase of the right circularly polarized light component of the waveguide extracted in the parameter space, where the z axis indicates the normalized amplitude and the overlay color indicates the phase gradient distribution. Specifically, the left circularly polarized light (LCP) in the waveguide is extracted for analysis (see Figure 3 b), we can see that the amplitude distribution in the figure is funnel-shaped, with a singular point where the amplitude is almost zero. Going around the singular point in any path will produce a phase change of 0 to 2π. Figure 3 In c), the phase is almost flat and there is no singular point. It is this topological property that acts inconsistently on left and right circularly polarized light that is the key to breaking the opposite effects of the geometric phase on left and right circularly polarized light and achieving decoupling.

[0054] Figure 4is a schematic diagram of using the rotation angle of a meta-atom to introduce a 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 The 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 the rotation angle (θ) increases. Figure 4 The c in the figure is the distribution of the phase of the right-hand circularly polarized component of the waveguide extracted in the simulation along with the rotation angle (θ). The color coverage 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 TE0 mode incidence conditions. 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-hand circularly polarized light (b) shows a two-fold relationship with the rotation angle, while Figure 4 The phase distribution in c) is opposite to that of left-handed circularly polarized light, but it 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. 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 hope that the left-handed circularly polarized light phase (φ L ) distribution has a uniform phase difference, while the right-handed 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 It is the topological phase and geometric phase distribution obtained by simulation in the embodiment of the present invention. Figure 6 A and Figure 6 b in the figure 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 position of the red star in the figure is the position of the singular point, and the black star is the parameter of the superatom selected in the experiment. Figure 6The c in the figure is the distribution of the geometric phase obtained by simulation with the introduced rotation angle (θ), and the black origin in the figure is the rotation angle selected by the meta-atom in the experiment. The distribution of colors indicates the distribution of phase.

[0058] For example, Figure 6 a and Figure 6 The positions marked by black stars in b are the parameters of the selected four atoms, and the red stars are the parameters of the singular points. Figure 6 In the figure, c is the distribution of geometric phases, and the black dots are the angles introduced by topological silicon atoms. In order to avoid cross-adhesion of metaatoms, only two phase steps are selected, that is, only two rotation angles are introduced.

[0059] In order to more intuitively illustrate the parameters and properties of the selected meta-atoms, the simulation results of the extraction efficiency and phase distribution of the four meta-atoms selected in the embodiment of the present invention are given, as shown in FIG. Figure 7 Specifically, Figure 7 a in FIG. 1 shows the structures of four selected T-shaped topological superatoms (superatoms for short), while in Figure 7 b shows the phases of the left-hand and right-hand circularly polarized light components extracted by the four meta-atoms at the working wavelength (φ L and φ R ) and efficiency (including LCPEfficiency and RCP Efficiency); among them, efficiency corresponds to the ability of the meta-atom to extract light, which can be regarded as amplitude, which is determined by the meta-atom itself, and the main basis for selecting the meta-atom is its phase distribution. After the meta-atom is determined according to the phase distribution, its amplitude (extraction efficiency) is also determined accordingly. Figure 7 It can be seen that under the left-handed circularly polarized light (LCP) component, the phase distribution of the four metaatoms is in a linear relationship of a step-like distribution, while under the right-handed circularly polarized light (RCP) component, the phase distribution of the four metaatoms is in a relatively flat distribution, which effectively avoids introducing phase differences into the geometric phase, thereby achieving simple and efficient orthogonal circularly polarized light decoupling.

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

[0061] To experimentally demonstrate whether on-chip all-dielectric topological metasurfaces can fully decouple 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 optical setup for AR holographic characterization (see Fig. 9 ), including lasers, aperture diaphragms, linear polarizers, lenses, quarter-wave plates, and mobile phone cameras. A broadband polarized laser (500nm to 800nm) is coupled into the waveguide through the end face, and the projected holographic image can be directly captured by the mobile phone camera. By adopting 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 the "key" appears, while switching to right-handed circularly polarized light produces a holographic image of the "lock" (see Fig.10 ). This experimental holographic characterization confirms that the all-dielectric on-chip topological metasurface designed by the present invention effectively realizes the decoupling of left-handed 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 demonstrated the AR function of the on-chip topological metasurface provided by the present invention in a real environment. The experimental setup is as follows: Fig.11 It is worth noting that no holographic images appear in the background picture, but the hologram can be projected and appear to float above the background when captured by a mobile phone camera. Fig.12 As shown, the dual-channel AR holograms ("key" and "lock") are switched alternately and presented as floating virtual images in the background provided by another display. 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 holograms are still clearly visible to the observer with satisfactory imaging clarity and contrast.

[0063] In summary, the present invention successfully creates singular points in the all-dielectric on-chip architecture by scanning the geometric structure and parameters of on-chip meta-atoms on a large scale, and realizes the manipulation of the topological phase obtained by surrounding the singular points with arbitrary paths; by combining with the geometric phase, we completely decouple the orthogonal circular polarization channels, unlock the independent coding degrees of freedom under the two channels, and realize the encoding of dual-channel holographic images that are independent of each other and do not interfere with each other. As a proof of concept, the on-chip topological metasurface we proposed can realize holographic visualization in real-world scenes as a practical AR function; compared with the traditional free-space metal topological metasurface, this all-dielectric on-chip solution 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 zero-order background light interference. In general, the on-chip topological metasurface we proposed has the advantages of miniaturization and integration, and has broad application prospects in the next generation of wearable display devices, multiplexed information multiplexing and storage, intelligent integrated photonic systems, and advanced optical displays.

[0064] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. An on-chip topological metasurface, characterized in that: include: From top to bottom, there are a nanobrick array, an optical waveguide layer and a dielectric substrate layer; the nanobrick array is composed of a number of T-shaped topological superatoms, and the nanobrick array is made of dielectric materials.

2. The on-chip topological metasurface according to claim 1, characterized in that: 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 super-structure atomic pixel has the same period in the x direction and the y direction; Each of the unit structures comprises a T-shaped topological superatom, which 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 superatom 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 superatom rotates around its center within a period.

3. The on-chip topological metasurface according to claim 2, characterized in that: Through electromagnetic simulation optimization, multiple groups of unit structures are obtained, and the optimized multiple groups of unit structures all have topological characteristics; for each super-atom pixel, a group of unit structures with a phase distribution closest to the target topological phase is selected from multiple groups of unit structures for arrangement, and the rotation angle θ of each T-shaped topological super-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.

4. The on-chip topological metasurface according to claim 3, 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.

5. The on-chip topological metasurface according to claim 3, characterized in that: 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.

6. The on-chip topological metasurface according to claim 3, characterized in that: 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.

7. The on-chip topological metasurface according to claim 1, characterized in that: The nano brick array is made of silicon.

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

9. An application of an on-chip topological metasurface according to any one of claims 1 to 8, characterized in that: The on-chip topological metasurface is applied to multiplexed information multiplexing and storage, wearable display devices or intelligent integrated photonic systems.

10. The application of the on-chip topological metasurface according to claim 9, characterized in that: This is beneficial for the on-chip topological metasurface to realize dual-channel holographic and AR display.

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