Wavelength multiplexed metasurface structure and optical imaging system

Abstract

The application discloses a wavelength multiplexing metasurface structure and an optical imaging system. The wavelength multiplexing metasurface structure has a first working mode and a second working mode. In the first working mode, a light source irradiates a sample and transmits to the wavelength multiplexing metasurface structure. First incident light transmitted to the wavelength multiplexing metasurface structure has a first wavelength. The wavelength multiplexing metasurface structure performs wavefront regulation on the first incident light to form a first light beam. In the second working mode, the light source irradiates the sample and transmits to the wavelength multiplexing metasurface structure. Second incident light transmitted to the wavelength multiplexing metasurface structure has a second wavelength. The wavelength multiplexing metasurface structure performs wavefront regulation on the second incident light to form a second light beam. The first wavelength is not equal to the second wavelength. The wavelength multiplexing metasurface structure can independently generate the first light beam and the second light beam in the first working mode and the second working mode, respectively, and effectively reduces crosstalk between the first light beam and the second light beam.

Description

Technical Field

[0001] This invention belongs to the field of micro-nano optics technology, specifically relating to a wavelength multiplexing metasurface structure and an optical imaging system. Background Technology

[0002] In existing imaging fields, such as biological imaging, machine recognition, and industrial inspection, there is an increasing demand for imaging systems capable of simultaneously performing multiple modes or functions. Currently, many systems employ single-wavelength imaging to achieve different imaging functions within the same system, but this approach is prone to channel crosstalk problems.

[0003] Dual-wavelength multiplexing imaging schemes can effectively solve the crosstalk problem that may occur when single-wavelength imaging schemes achieve multi-mode integration. However, existing technologies require the integration of multiple sets of refractive or reflective optical elements into the imaging system to achieve multiplexing of two or more wavelengths. This results in complex structures, large volumes, and limited functional switching, which also restricts design freedom and the accuracy of functional response.

[0004] Metasurface structures, as artificially designed two-dimensional ultrathin materials, consist of a substrate and an array of nanopillars on the substrate. By changing parameters such as the material, geometry, and orientation of the nanopillars, precise modulation of electromagnetic waves can be achieved, helping to overcome the size limitations of traditional optical devices and thus providing advantages for integrating functions such as beam shaping, holography, and sensing. However, most existing imaging systems based on metasurface structures have fixed or difficult-to-switch functions, failing to achieve flexible switching between multiple imaging modes.

[0005] Therefore, in order to address the above-mentioned technical problems, it is necessary to provide a wavelength-reused metasurface structure and an optical imaging system. Summary of the Invention

[0006] The purpose of this invention is to provide a wavelength-reusable metasurface structure and an optical imaging system that can conveniently and efficiently achieve bright-field imaging and edge-enhanced imaging of samples under different wavelength conditions.

[0007] To achieve the above objectives, an embodiment of the present invention provides the following technical solution:

[0008] A wavelength-reusing metasurface structure, the wavelength-reusing metasurface structure comprising a substrate and an array of nanopillars disposed on the substrate, the wavelength-reusing metasurface structure having a first operating mode and a second operating mode;

[0009] In the first working mode, the light source illuminates the sample and passes through the wavelength multiplexing metasurface structure. The first incident light passing through the wavelength multiplexing metasurface structure has a first wavelength. The wavelength multiplexing metasurface structure performs wavefront modulation on the first incident light to form a first beam.

[0010] In the second working mode, the light source illuminates the sample and passes through the wavelength multiplexing metasurface structure. The second incident light passing through the wavelength multiplexing metasurface structure has a second wavelength. The wavelength multiplexing metasurface structure performs wavefront modulation on the second incident light to form a second beam. The first wavelength and the second wavelength are not equal.

[0011] In one embodiment, the first beam is either a focused beam or a collimated beam.

[0012] In one embodiment, the second beam is any one of a vortex beam, a Bessel beam, or an Airy beam.

[0013] In one embodiment, the first incident light has a first polarization state, the second incident light has a second polarization state, and the first polarization state and the second polarization state are different.

[0014] In one embodiment, the first polarization state is transverse electric polarization, and the second polarization state is transverse magnetic polarization; or,

[0015] The first polarization state is transverse magnetic polarization, and the second polarization state is transverse electric polarization.

[0016] In one embodiment, the first polarization state is left-handed circular polarization, and the second polarization state is right-handed circular polarization; or,

[0017] The first polarization state is right-handed circular polarization, and the second polarization state is left-handed circular polarization.

[0018] In one embodiment, the first wavelength is 440nm~480nm; and / or,

[0019] The second wavelength is 510nm~570nm.

[0020] Another embodiment of the present invention provides the following technical solution:

[0021] An optical imaging system includes a light source and control module arranged along the beam propagation direction, a wavelength multiplexing metasurface structure and an imaging module, wherein the wavelength multiplexing metasurface structure is the aforementioned wavelength multiplexing metasurface structure, and the optical imaging system includes a first imaging mode and a second imaging mode.

[0022] In the first imaging mode, the light source and control module are used to generate a light source to illuminate the sample, and make the light transmitted through the sample to the wavelength multiplexing metasurface structure a first incident light with a first wavelength. The wavelength multiplexing metasurface structure is in a first working mode, thereby obtaining a bright field imaging image of the sample in the imaging module.

[0023] In the second imaging mode, the light source and control module are used to generate a light source to illuminate the sample, and make the light transmitted through the sample to the wavelength multiplexed metasurface structure a second incident light with a second wavelength. The wavelength multiplexed metasurface structure is in the second working mode, thereby obtaining an edge imaging image of the sample in the imaging module.

[0024] In one embodiment, the light source and control module includes a light source and a wavelength control component, wherein the wavelength control component is disposed between the sample and the light source, or the wavelength control component is disposed between the sample and the wavelength multiplexing metasurface structure.

[0025] In one embodiment, the light source and control module further includes a polarization control component, which is located between the sample and the light source, or between the sample and the wavelength multiplexing metasurface structure.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The wavelength multiplexing metasurface structure of the present invention has different phase responses to incident light of different wavelengths, and can generate different beams independently. After being integrated into an optical imaging system, it can perform bright-field imaging and edge-enhanced imaging on the sample respectively.

[0028] The wavelength multiplexing metasurface structure of the present invention is small in size and light in weight, and is easy to integrate into an optical imaging system to obtain a compact and lightweight optical imaging system;

[0029] The optical imaging system of the present invention can be used for imaging various types of samples, including standard test targets, complex geometric patterns, and biological cells, and has good versatility and broad application potential. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the structure and principle of the wavelength multiplexing metasurface structure in Embodiment 1 of the present invention, wherein a is a schematic diagram of the structure of a single nanopillar, b is a schematic diagram of the working principle of the wavelength multiplexing metasurface structure, c is a scanning electron microscope characterization image of the wavelength multiplexing metasurface structure, and d is a partial magnified view of the scanning electron microscope characterization image of the wavelength multiplexing metasurface structure in c.

[0032] Figure 2This is a schematic diagram of the optical imaging system in Embodiment 1 of the present invention;

[0033] Figure 3 This is a schematic diagram illustrating the principle of edge-enhanced imaging achieved by the optical imaging system in Embodiment 1 of the present invention.

[0034] Figure 4 for Figure 3 The response curve corresponding to the schematic diagram of the optical imaging system for edge enhancement imaging;

[0035] Figure 5 These are bright-field imaging images and edge-enhanced imaging images of the star sample in Embodiment 1 of the present invention;

[0036] Figure 6 These are bright-field imaging images and edge-enhanced imaging images of the badge sample in Embodiment 1 of the present invention;

[0037] Figure 7 These are the bright-field imaging image and edge-enhanced imaging image of the triangular sample in Embodiment 1 of the present invention;

[0038] Figure 8 These are bright-field imaging images and edge-enhanced imaging images of the seal sample in Example 1 of this invention;

[0039] Figure 9 For along Figure 5 and Figure 6 Intensity curve extracted from the dashed line;

[0040] Figure 10 For along Figure 7 and Figure 8 Intensity curve extracted from the dashed line;

[0041] Figure 11 These are bright-field imaging images and edge-enhanced imaging images of the USAF 1951 resolution plate sample in Embodiment 1 of the present invention;

[0042] Figure 12 For along Figure 11 Intensity curve extracted from the dashed line;

[0043] Figure 13 For along Figure 11 The intensity curve extracted from another dashed line in the middle;

[0044] Figure 14 The images shown are bright-field imaging and edge-enhanced imaging images of transverse stem cells of monocotyledonous plants in Embodiment 1 of the present invention.

[0045] Figure 15 This refers to the logarithmic-scale radial power corresponding to the imaging process of the optical imaging system in Embodiment 1 of the present invention during the imaging of transverse stem cells of monocotyledonous plants in the first imaging mode and the second imaging mode.

[0046] Figure 16 This invention provides an example of CDF analysis of the side gradient during imaging of transverse stem cells of monocotyledonous plants using the optical imaging system in the first and second imaging modes of the present invention.

[0047] Figure 17 These are bright-field imaging images and edge-enhanced imaging images of the cell wall plane of a multicellular sample in Embodiment 1 of the present invention;

[0048] Figure 18 This is a bright-field imaging image of the nuclear plane of a multicellular sample in Example 1 of the present invention;

[0049] Figure 19 This is an edge-enhanced imaging image of the nuclear plane of a multi-cell sample in Embodiment 1 of the present invention. Detailed Implementation

[0050] To enable those skilled in the art to better understand the technical solutions in this disclosure, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this disclosure.

[0051] This invention discloses a wavelength-reusing metasurface structure, including a substrate and a nanopillar array disposed on the substrate. The wavelength-reusing metasurface structure has a first operating mode and a second operating mode.

[0052] In the first working mode, the light source illuminates the sample and passes through the wavelength multiplexing metasurface structure. The first incident light passing through the wavelength multiplexing metasurface structure has a first wavelength. The wavelength multiplexing metasurface structure modulates the first incident light to form a first beam.

[0053] In the second working mode, the light source illuminates the sample and passes through the wavelength multiplexing metasurface structure. The second incident light passing through the wavelength multiplexing metasurface structure has a second wavelength. The wavelength multiplexing metasurface structure performs wavefront modulation on the second incident light to form a second beam. The first wavelength and the second wavelength are not equal.

[0054] The present invention also discloses an optical imaging system, including a light source and control module arranged along the beam propagation direction, a wavelength multiplexing metasurface structure and an imaging module, wherein the wavelength multiplexing metasurface structure is the wavelength multiplexing metasurface structure described above, and the optical imaging system includes a first imaging mode and a second imaging mode.

[0055] In the first imaging mode, the light source and the control module are used to generate a light source for irradiating the sample, and make the light transmitted through the sample to the wavelength multiplexing metasurface structure be the first incident light with the first wavelength. The wavelength multiplexing metasurface structure is in the first working mode, so as to obtain a bright-field imaging image of the sample in the imaging module;

[0056] In the second imaging mode, the light source and the control module are used to generate a light source for irradiating the sample, and make the light transmitted through the sample to the wavelength multiplexing metasurface structure be the second incident light with the second wavelength. The wavelength multiplexing metasurface structure is in the second working mode, so as to obtain an edge imaging image of the sample in the imaging module.

[0057] The present invention will be further described below in conjunction with specific examples.

[0058] Example 1:

[0059] Refer Figure 1 As shown, the wavelength multiplexing metasurface structure in this embodiment includes a substrate and a nano-column array disposed on the substrate. The wavelength multiplexing metasurface structure has a first working mode and a second working mode;

[0060] In the first working mode, the light source irradiates the sample and transmits through to the wavelength multiplexing metasurface structure. The first incident light transmitted through to the wavelength multiplexing metasurface structure has the first wavelength, and the wavelength multiplexing metasurface structure performs wavefront modulation on the first incident light to form a first light beam;

[0061] In the second working mode, the light source irradiates the sample and transmits through to the wavelength multiplexing metasurface structure. The second incident light transmitted through to the wavelength multiplexing metasurface structure has the second wavelength, and the wavelength multiplexing metasurface structure performs wavefront modulation on the second incident light to form a second light beam. The first wavelength and the second wavelength are not equal.

[0062] Among them, the substrate is a conventional light-transmitting substrate in the metasurface structure, and the nano-column array is a titanium oxide nano-column array. The period of a single nano-column unit is P, the width is W, the length is L, and the height is H.

[0063] Further, the first light beam includes, but is not limited to, any one of light beams capable of realizing the bright-field imaging function such as a focused light beam or a collimated light beam, and the second light beam includes, but is not limited to, any one of light beams having spatial filtering characteristics capable of realizing the edge imaging function such as a vortex light beam, a Bessel light beam or an Airy light beam.

[0064] Specifically, the first light beam in this embodiment is a focused light beam, and the second light beam is a vortex light beam.

[0065] Further, the first wavelength is 440 nm to 480 nm, and the second wavelength is 510 nm to 570 nm. In this embodiment, the first wavelength is preferably 450 nm, and the second wavelength is preferably 532 nm.

[0066] It is worth noting that in other embodiments, other wavelength combinations can be selected according to the needs of the actual application scenario. Any band suitable for bright-field imaging can be selected as the first wavelength, and any band suitable for edge enhancement imaging can be selected as the second wavelength, as long as the first wavelength and the second wavelength are not equal.

[0067] Furthermore, the first incident light has a first polarization state, and the second incident light has a second polarization state, the first polarization state and the second polarization state are different. By adjusting the polarization states of the first and second incident lights according to actual needs, the applicable scenarios can be broadened to obtain better imaging results.

[0068] Specifically, in this embodiment, the first polarization state is transverse electric polarization and the second polarization state is transverse magnetic polarization, that is, the first incident light is a 450nm transverse electric wave (TE, x-pol) and the second incident light is a 532nm transverse magnetic wave (TM, y-pol).

[0069] It is worth noting that, in other embodiments, the combination of the first polarization state and the second polarization state includes, but is not limited to, a combination in which the first polarization state is transverse magnetic polarization and the second polarization state is transverse electric polarization; a combination in which the first polarization state is left-handed circular polarization and the second polarization state is right-handed circular polarization; or a combination in which the first polarization state is right-handed circular polarization and the second polarization state is left-handed circular polarization.

[0070] In this embodiment, nanopillars are screened based on the wavelength and polarization state of the first incident light and the wavelength and polarization state of the second incident light using the complex transmission coefficient (CTC). The CTC comprehensively considers the phase coverage and transmittance of the wavelength-reused metasurface structure at the target wavelength. Simultaneously, based on a preset target phase distribution, suitable combinations of geometric parameters (including period P, width W, length L, and height H) are selected from the candidate nanopillars, and the nanopillar array is arranged on the substrate to construct a phase distribution that meets functional requirements, i.e., a focused phase response under the first incident light and a vortex phase response under the second incident light.

[0071] In this embodiment, the wavelength-reusing metasurface structure is prepared using conventional processes, which will not be elaborated further here. Figure 1 As shown, the fabricated wavelength-reused metasurface structure is of good quality.

[0072] It should be noted that in the design process of the wavelength multiplexing metasurface structure in this embodiment, a parabolic focusing phase is selected, and the topological charge number of the vortex phase is 1. In other embodiments, other types of focusing phases and vortex phases with other topological charge numbers can also be selected.

[0073] The wavelength multiplexing metasurface structure in this embodiment has different phase responses to incident lights of different wavelengths. Therefore, by changing the wavelength of the incident light, it can be switched between the first working mode and the second working mode to independently generate a focused beam and a vortex beam respectively. Compared with a single wavelength design, it has good channel isolation and can effectively reduce crosstalk in the subsequent imaging process.

[0074] The optical imaging system integrated with the above wavelength multiplexing metasurface structure in this embodiment includes a light source and a control module, a wavelength multiplexing metasurface structure, and an imaging module arranged along the light beam propagation direction. The optical imaging system includes a first imaging mode and a second imaging mode;

[0075] In the first imaging mode, the light source and the control module are used to generate a light source for irradiating the sample, and make the light transmitted through the sample to the wavelength multiplexing metasurface structure be the first incident light with the first wavelength. The wavelength multiplexing metasurface structure is in the first working mode, so as to obtain a bright-field imaging image of the sample in the imaging module;

[0076] In the second imaging mode, the light source and the control module are used to generate a light source for irradiating the sample, and make the light transmitted through the sample to the wavelength multiplexing metasurface structure be the second incident light with the second wavelength. The wavelength multiplexing metasurface structure is in the second working mode, so as to obtain an edge imaging image of the sample in the imaging module.

[0077] Furthermore, the light source and the control module include a light source and a wavelength control component. The wavelength control component is arranged between the sample and the light source, or between the sample and the wavelength multiplexing metasurface structure. Preferably, the wavelength control component is arranged between the sample and the light source.

[0078] Specifically, the light source and the control module in this embodiment further include a polarization control component. The polarization control component is located between the sample and the light source, or between the sample and the wavelength multiplexing metasurface structure. Preferably, the polarization control component is arranged between the sample and the light source.

[0079] See Figure 2As shown, the light source in this embodiment is a laser. Along the light beam propagation direction between the light source and the sample, an Acousto-Optic Tunable Filter (AOTF), a first lens, a light homogenizer, a second lens, a Half Wave Plate (HWP), and a third lens are successively arranged. In addition, the imaging module in this embodiment includes an Objective Lens (OL), a Tube Lens (TL), and an industrial camera arranged along the light beam propagation direction.

[0080] Specifically, as shown in Figure 1 In this embodiment, in the first imaging mode, that is, the bright-field imaging mode, the light source and the control module generate a transverse electric wave of 450 nm to irradiate the sample and transmit it to the wavelength multiplexing metasurface structure. The wavelength multiplexing metasurface structure focuses the transmitted light. After the focused light beam passes through the objective lens and the tube lens, a bright-field imaging image of the sample is obtained on the industrial camera; in the second imaging mode, that is, the edge-enhanced imaging mode, the light source and the control module generate a transverse magnetic wave of 532 nm to irradiate the sample and transmit it to the wavelength multiplexing metasurface structure. The wavelength multiplexing metasurface structure regulates the transmitted light to generate a vortex beam with an annular intensity distribution, so that the edge and structure contour information of the sample are enhanced during imaging. Thus, when the generated vortex beam passes through the objective lens and the tube lens, an edge-enhanced imaging image of the sample is obtained on the industrial camera.

[0081] The optical imaging system in this embodiment uses a wavelength multiplexing metasurface structure. By changing the wavelength of the incident light, the optical imaging system can be conveniently switched between the first imaging mode and the second imaging mode. Compared with the traditional optical imaging system that requires multiple lens combinations or beam splitter device combinations, it no longer depends on the mechanical switching of the optical path, reduces redundant devices, and reduces the complexity of the optical imaging system.

[0082] Refer to Figure 3 And as shown in Figure 4 When the wavelength multiplexing metasurface structure is in the second working mode, the originally smooth background change (low-frequency information) of the sample is suppressed, while the high-frequency information of the sample edge is selectively enhanced, and its effect is equivalent to a high-pass filter, so that the optical imaging system can achieve edge-enhanced imaging of the sample in the second imaging mode.

[0083] Refer to Figures 5-8As shown, the optical imaging system in this embodiment is used to image a sample prepared by 3D printing technology. In the first imaging mode, the optical imaging system reproduces the overall geometry and layout of the Star, Badge, Triangle, and Seal samples, and clearly shows the outline and structural details. In the second imaging mode, the vortex phase response of the wavelength multiplexing metasurface structure enhances the high-frequency information at the geometric boundary of the sample, while suppressing the uniform region. Therefore, the optical imaging system obtains an edge-enhanced imaging image with obvious edge topography and relief-like appearance.

[0084] Combined with Figure 9 and Figure 10 as shown, in Figure 5 and Figure 6 the corresponding profile intensity curves are extracted from the horizontal (X-axis) virtual line in the edge-enhanced imaging image, and in Figure 7 and Figure 8 the corresponding profile intensity curves are extracted from the vertical (Y-axis) virtual line in the edge-enhanced imaging image (where, W / O EE is the ideal curve without edge enhancement effect), and both show multiple significant peaks. Comparing the results of Figure 9 and Figure 10 with the edge-enhanced imaging image in Figures 5-8 it is found that these peaks appear at the expected structural boundary positions in the sample, confirming that the optical imaging system in this embodiment can effectively achieve edge-enhanced imaging of the sample based on the wavelength multiplexing metasurface structure.

[0085] In addition, to further evaluate the imaging performance of the optical imaging system in this embodiment, an imaging experiment was carried out on the USAF 1951 resolution test target. As shown in Figure 11 in the first imaging mode, the optical imaging system accurately restores the fine structural details of the USAF 1951 resolution test target. In the second optical imaging mode, the optical imaging system emphasizes the intensity change of the edge and improves the boundary contrast of the image.

[0086] Combined with Figure 12 and 13 as shown, Figure 11 the profile intensity curve in the quantitative analysis of the intensity distribution of the edge-enhanced imaging image in

[0087] shows a spike that exactly corresponds to the edge of the USAF 1951 resolution test target, further confirming the background suppression and edge enhancement effects of the wavelength multiplexing metasurface structure in the second optical imaging mode. Figure 14As shown, the optical imaging system in this embodiment is used to perform biological imaging on monocotyledonous plant transverse stem cells. In the first imaging mode, the optical imaging system clearly resolves and presents the internal structure of monocotyledonous plant transverse stem cells, including the nucleus and cytoplasmic strands; in the second imaging mode, based on the vortex phase response of the wavelength multiplexing metasurface structure, the low-frequency background unique to monocotyledonous plant transverse stem cells as weak scatterers is suppressed, resulting in weakened internal details, while enhancing high-frequency features such as cell walls.

[0088] As shown in Figure 15 , in the first imaging mode, the optical imaging system maintains a constant spectral power over a wide frequency range, while in the second imaging mode, its spectral power decays more steeply at higher spatial frequencies. Combining Figure 16 As shown in, compared with the local intensity variation of the edge-enhanced image (median ≈ 0.25, 90% level ≈ 0.54), the local intensity variation of the bright-field imaging image is more obvious (median gradient ≈ 0.34, 90% level ≈ 0.65), which is consistent with the preservation of intracellular texture.

[0089] Furthermore, the optical imaging system in this embodiment is used to image a multicellular sample. As shown in Figure 17 , in the first imaging mode, the optical imaging system captures the continuous cell contours and overall tissue structure bright-field imaging images in the cell wall plane; in the second imaging mode, the optical imaging system further highlights the cell-cell boundaries and enhances the presentation of the cell-cell demarcation.

[0090] Comparing Figure 18 and Figure 19 , when focused on the nuclear plane, the bright-field imaging image obtained by the optical imaging system in the first imaging mode shows a uniform nucleus structure inside the cell, while in the second imaging mode, it shows subtle intra-nuclear intensity variations, indicating the existence of potential sub-nuclear structures (sub-nuclear variation) inside the multicellular sample that cannot be observed in the first imaging mode. These results show that the optical imaging system integrated with the wavelength multiplexing metasurface structure supports reliable switching between two imaging modes within a single system, namely the bright-field imaging mode for obtaining the overall structural morphology and the edge-enhanced imaging mode for obtaining boundary-specific contrast-enhanced images, and confirms its versatility in multiple imaging scenarios.

[0091] As can be seen from the above technical solutions, the present invention has the following beneficial effects:

[0092] The wavelength multiplexing metasurface structure of the present invention has different phase responses to incident light of different wavelengths and can independently generate different light beams respectively. After integrating it into an optical imaging system, it can perform bright-field imaging and edge-enhanced imaging on samples respectively;

[0093] The wavelength multiplexing metasurface structure of the present invention is small in size and light in weight, and is easy to integrate into an optical imaging system to obtain a compact and lightweight optical imaging system;

[0094] The optical imaging system of the present invention can be used for imaging various types of samples, including standard test targets, complex geometric patterns, and biological cells, and has good versatility and broad application potential.

[0095] It will be apparent to those skilled in the art that this disclosure is not limited to the details of the exemplary embodiments described above, and that this disclosure can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of this disclosure is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this disclosure. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0096] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A wavelength-multiplexing metasurface structure, characterized in that, The wavelength multiplexing metasurface structure includes a substrate and a nanopillar array disposed on the substrate. The wavelength multiplexing metasurface structure has a first operating mode and a second operating mode. In the first working mode, the light source illuminates the sample and passes through the wavelength multiplexing metasurface structure. The first incident light passing through the wavelength multiplexing metasurface structure has a first wavelength. The wavelength multiplexing metasurface structure performs wavefront modulation on the first incident light to form a first beam. In the second working mode, the light source illuminates the sample and passes through the wavelength multiplexing metasurface structure. The second incident light passing through the wavelength multiplexing metasurface structure has a second wavelength. The wavelength multiplexing metasurface structure performs wavefront modulation on the second incident light to form a second beam. The first wavelength and the second wavelength are not equal.

2. The wavelength multiplexing metasurface structure according to claim 1, characterized in that, The first beam is either a focused beam or a collimated beam.

3. The wavelength multiplexing metasurface structure according to claim 1, characterized in that, The second beam is any one of a vortex beam, a Bessel beam, or an Airy beam.

4. The wavelength multiplexing metasurface structure according to claim 1, characterized in that, The first incident light has a first polarization state, and the second incident light has a second polarization state, wherein the first polarization state and the second polarization state are different.

5. The wavelength multiplexing metasurface structure according to claim 4, characterized in that, The first polarization state is transverse electric polarization, and the second polarization state is transverse magnetic polarization; or, The first polarization state is transverse magnetic polarization, and the second polarization state is transverse electric polarization.

6. The wavelength multiplexing metasurface structure according to claim 4, characterized in that, The first polarization state is left-handed circular polarization, and the second polarization state is right-handed circular polarization; or, The first polarization state is right-handed circular polarization, and the second polarization state is left-handed circular polarization.

7. The wavelength multiplexing metasurface structure according to claim 1, characterized in that, The first wavelength is 440nm~480nm; and / or, The second wavelength is 510nm~570nm.

8. An optical imaging system, characterized in that, The optical imaging system includes a light source and control module arranged along the beam propagation direction, a wavelength multiplexing metasurface structure and an imaging module, wherein the wavelength multiplexing metasurface structure is the wavelength multiplexing metasurface structure according to any one of claims 1 to 7, and the optical imaging system includes a first imaging mode and a second imaging mode. In the first imaging mode, the light source and control module are used to generate a light source to illuminate the sample, and make the light transmitted through the sample to the wavelength multiplexing metasurface structure a first incident light with a first wavelength. The wavelength multiplexing metasurface structure is in a first working mode, thereby obtaining a bright field imaging image of the sample in the imaging module. In the second imaging mode, the light source and control module are used to generate a light source to illuminate the sample, and make the light transmitted through the sample to the wavelength multiplexed metasurface structure a second incident light with a second wavelength. The wavelength multiplexed metasurface structure is in the second working mode, thereby obtaining an edge imaging image of the sample in the imaging module.

9. The optical imaging system according to claim 8, characterized in that, The light source and control module includes a light source and a wavelength control component. The wavelength control component is located between the sample and the light source, or between the sample and the wavelength multiplexing metasurface structure.

10. The optical imaging system according to claim 9, characterized in that, The light source and control module also include a polarization control component, which is located between the sample and the light source, or between the sample and the wavelength multiplexing metasurface structure.

Images