A coherent wave vector multiplexed frequency-shifted illumination chip

Abstract

This invention discloses a coherent wavevector multiplexing frequency-shifting illumination chip, comprising: a substrate and a MIM waveguide structure thereon; subwavelength grooves are etched on the MIM waveguide structure, and the material and thickness of the MIM waveguide structure can support the propagation of two superimposed ultra-high transverse wavevector surface plasmon modes; under TM-polarized excitation light illumination, the excitation light is coupled into the MIM waveguide structure through the grooves and excites two superimposed ultra-high transverse wavevectors, which then propagate on the chip surface and coherently superimpose to generate new enhanced transverse wavevectors, achieving wavevector multiplexing, so as to form a highly localized superimposed illumination field containing three enhanced transverse wavevectors on the chip surface. This invention also discloses a method for achieving deep subwavelength label-free super-resolution microscopy using this chip, where multiple deep subwavelength periodic structures contained in the sample can be simultaneously resolved. This invention can achieve single-exposure label-free super-resolution imaging of deep subwavelengths, and has advantages such as high-speed imaging and high-frequency enhancement.

Description

Technical Field

[0001] This invention belongs to the field of optical super-resolution microscopy technology, specifically relating to a coherent wave vector multiplexing frequency-shifting illumination chip. Background Technology

[0002] Deep subwavelength (sub) λ / 20, <50 nm@ λ =400 nm ~ 1100 nm, λ Label-free ultra-high resolution optical super-resolution microscopy (with illumination wavelength) is of great significance in nanoscale scientific research, including non-destructive characterization of nanomaterial structures, observation of chemical reaction processes, and revelation of biological phenomena. Label-free deep frequency-shifting super-resolution microscopy overcomes the diffraction limit of existing objective imaging systems by altering the transverse wave vector of the illumination field interacting with the sample. Current on-chip frequency-shifting super-resolution imaging methods rely on waveguide modulation of the transverse wave vector of the illumination field, eliminating the need for complex light field manipulation and special sample labeling, thus offering significant advantages in ultra-high resolution imaging. However, the resolution of current on-chip frequency-shifting super-resolution imaging is determined by the range of the specific microstructure units being fabricated, and the generated transverse wave vector is entirely determined by the morphology and arrangement of the microstructure, making it difficult to simultaneously manipulate multiple wave vectors in a single operation.

[0003] Patent application CN105301753A proposes a multiscattering super-resolution microscopy method under micro / nano illumination, capable of achieving super-resolution imaging of samples with a single spatial frequency and structure. The proposed micro / nano light source relies on substrate coupling, and the transverse wave vector generated by this method to achieve frequency-shifting super-resolution imaging is single and deterministic, limiting imaging of samples with complex periodic structures and spatial frequencies. To achieve deep subwavelength-level single-shot imaging of such samples, the nanowire light source and substrate need to be replaced, making the experimental operation complex and limiting the application of on-chip deep frequency-shifting super-resolution imaging technology in the ultra-high resolution imaging and characterization of complex nanostructures.

[0004] Patent application CN108982456A proposes a three-dimensional live-cell super-resolution microscopy imaging method based on evanescent wave illumination. This method improves axial resolution by adjusting the incident angle and polarization state, utilizing the exponential decay characteristic of evanescent waves, and reconstructs lateral super-resolution images using a super-resolution radial wave algorithm. However, this method relies on fluorescent labeling and cannot achieve label-free imaging. Furthermore, its axial resolution is still limited by the number of original images required for multi-angle scanning, making it difficult to achieve deep subwavelength-level three-dimensional resolution while maintaining high temporal resolution, thus limiting its application in fast dynamic processes and label-free sample observation.

[0005] Therefore, there is an urgent need to develop a super-resolution microscopy method that can achieve label-free, single-shot multi-wave vector modulation, and deep subwavelength resolution, in order to overcome the operational complexity and resolution bottleneck of existing technologies in imaging complex nanostructures. Summary of the Invention

[0006] In view of the above, the purpose of this invention is to provide a coherent wave vector multiplexing frequency-shifting illumination chip, which forms a multilayer waveguide structure with subwavelength grooves etched on a chip substrate, capable of supporting the transmission of ultra-high wave vector surface plasmon polariton (SPP) modes. The generated SPP modes can simultaneously enhance multiple different transverse wave vectors. Simultaneously, the enhanced wave vectors coherently superimpose in the frequency domain to generate new enhanced transverse wave vectors, achieving wave vector multiplexing. Furthermore, a highly localized aliasing illumination field is generated on the chip surface. Further, the sample located on the upper surface of the imaging chip is illuminated once by the highly localized aliasing illumination field, shifting the spatial frequencies of the sample that are undetectable by a microscope to within a detectable cutoff frequency. Each enhanced transverse wave vector corresponds to a spatial frequency and also to a resolvable deep subwavelength periodic structure. Therefore, multiple deep subwavelength periodic structures contained in the sample can be simultaneously resolved, thereby achieving deep subwavelength label-free super-resolution imaging.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a coherent wave vector multiplexing frequency-shifting illumination chip, comprising: a chip substrate, and a metal-dielectric-metal multilayer waveguide structure formed on the substrate, namely a MIM waveguide structure; Subwavelength grooves are etched on the MIM waveguide structure. The materials and thicknesses of each layer of the MIM waveguide structure are configured to support the transmission of two superimposed, ultra-high transverse wave vector surface plasmon modes. Under TM polarized excitation light irradiation, the excitation light is coupled into the MIM waveguide structure through grooves and two superimposed ultra-high transverse wave vectors are excited. The two superimposed ultra-high transverse wave vectors propagate on the chip surface and coherently superimpose to generate a third enhanced ultra-high transverse wave vector, realizing wave vector multiplexing, so as to form a highly localized superimposed illumination field containing the above three ultra-high transverse wave vectors on the chip surface.

[0008] Preferably, the MIM waveguide structure comprises a groove array consisting of multiple sets of parallel periodic units; wherein each periodic unit includes two scribe lines and a MIM retention portion between the two scribe lines, and the center-line spacing between adjacent scribe lines is the period of the groove. .

[0009] Preferably, the period of the groove With the highest transverse wave vector that can be enhanced, the excitation wavelength and the transverse wave vector of the excitation light and the numerical aperture of the imaging system objectives. Matching, satisfying: , in, , This represents two superimposed ultra-high transverse wave vectors.

[0010] Preferably, the depth of the groove The total thickness of the MIM waveguide structure is greater than or equal to that of the MIM waveguide structure. This ensures the coupling efficiency and propagation characteristics of the ultra-high transverse wave vector mode.

[0011] Optionally, the specific method of grooving depends on the designed grooving cycle. The fabrication process is selected and carried out using micro-nano fabrication techniques, including focused ion beam (FIB), electron beam lithography (EBL), photolithography, or nanoimprinting.

[0012] Preferably, in the MIM waveguide structure, the thickness of each metal thin film is less than or equal to 10 nm, and the thickness of the dielectric thin film is less than or equal to 12 nm, to ensure support for ultra-high transverse wave vector modes. z Directional coupling.

[0013] Preferably, the metallic material in the MIM waveguide structure is Ag or Au with a complex refractive index, and the dielectric material is GaP, Al2O3, TiO2 or Si3N4 with a high refractive index in the excitation light band.

[0014] Optionally, appropriate micro / nano fabrication methods, including magnetron sputtering, atomic layer deposition (ALD), and chemical vapor deposition (PVD), can be selected based on the designed waveguide geometry thickness and material to ensure the accuracy of the waveguide thickness.

[0015] Preferably, the substrate material is transparent in the excitation light wavelength range: when the excitation light wavelength... λ When the wavelength is >600 nm, the substrate material is GaP or GaN; when 400 nm ≤ λ For ≤600 nm, the substrate material is Al2O3 or TiO2.

[0016] Optionally, the substrate material is GaP to ensure the production yield of the fabricated coherent wave vector multiplexed frequency-shifting illumination chip.

[0017] Optionally, the substrate thickness is 250 ~ 500 μm, and a thinning process is required after coating.

[0018] Preferably, the coherent superposition process is represented as follows: , in, and These represent the two superimposed ultra-high transverse wave vectors, respectively. and The wave function of surface plasmon modes propagating on the chip surface. Represents the imaginary unit. Indicates the spatial coordinates of lateral transmission along the chip surface. This indicates the third type of enhanced ultra-high transverse wave vector. The corresponding third type of enhanced light field amplitude distribution propagating on the chip surface, This represents the phase term for the third type of enhanced light field propagation.

[0019] Preferably, the incident angle of the excitation light Numerical aperture of imaging system objectives and the cycle of grooving The following conditions must be met: , in, , This indicates the wavelength of the excitation light.

[0020] For the aforementioned coherent wave vector multiplexing frequency-shifting illumination chip, the highest transverse wave vector of the transmission modes supported by the MIM multilayer waveguide structure depends on the dielectric constants (complex refractive indices) of the metal and dielectric at the excitation wavelength, as well as the geometric thickness of each layer. Specifically, given the metal and dielectric materials, the dispersion relation of the MIM waveguide can be obtained by solving the continuity and boundary conditions of Maxwell's equations in the layered structure, thereby determining the transverse wave vectors of the supported surface plasmon modes. Preferably, by rationally selecting the metal and dielectric materials and controlling the metal layer thickness ≤10 nm and the dielectric layer thickness ≤12 nm, the present invention enables the highest transverse wave vector supported by the MIM waveguide to exceed [a certain value]. This ultra-high transverse wave vector corresponds to a highly localized surface plasmon mode, and its near-field distribution has a subwavelength scale, providing a foundation for subsequent wave vector multiplexing and deep frequency-shifting super-resolution imaging.

[0021] Secondly, an embodiment of the present invention provides a method for deep subwavelength label-free super-resolution microscopy imaging using the aforementioned coherent wave vector multiplexing frequency-shifting illumination chip, comprising the following steps: Step 1: Place the coherent wave vector multiplexed frequency-shifting illumination chip on the sample stage of an upright microscope, and place the sample to be tested in the groove area on the upper surface of the chip; Step 2: Adjust the incident excitation light to TM polarization and adjust its incident angle to generate an evanescent field in the substrate and MIM waveguide structure, thereby exciting an aliased illumination field to illuminate the sample; Step 3: Use a microscope to observe the complex periodic structure of the sample placed on the chip.

[0022] Furthermore, the upright microscope should have a transmission imaging optical path structure.

[0023] Furthermore, the sample should be placed in the vicinity of the grooves on the chip to ensure that the highly localized aliasing illumination field can effectively illuminate the sample.

[0024] Furthermore, the polarization state of the incident excitation light can be adjusted using spatial light modulators (SLMs), diffractive optical elements (DOEs), or polarization-selective metamaterials.

[0025] Furthermore, the angle of incidence of the excitation light can be adjusted using a spatial light modulator (SLM), a digital micromirror array (DMD), a scanning galvanometer (Galvo Mirror), or a custom-designed variable-angle prism.

[0026] Based on the aforementioned deep subwavelength label-free super-resolution microscopy method, this coherent wave vector multiplexing frequency-shifting illumination chip provides an aliased illumination field with ultra-high transverse wave vectors. It is compatible with conventional microscopes, enabling the observation of multiple super-diffraction-limited sample structures in a single imaging session, without requiring special labeling or preprocessing of the samples. Specifically, this chip allows existing microscopes to observe the following three types of samples with periods smaller than the diffraction limit (respectively...). , and The structure of the instrument is enhanced so that it can be resolved by a conventional microscope: , And the achievable maximum resolution satisfies: , , in, This indicates the limiting resolution for coherent imaging of unlabeled samples. This indicates the limiting resolution for incoherent imaging of fluorescently labeled samples.

[0027] Compared with the prior art, the beneficial effects of the present invention include at least the following: (1) This invention constructs an integrated illumination unit by etching subwavelength periodic grooves on a MIM waveguide structure. This unit can be directly placed on the sample stage of a conventional upright microscope without any optical path modification to the microscope. By simply adjusting the incident light to TM polarization and increasing the angle, two surface plasmon modes with ultra-high transverse wave vectors can be simultaneously excited and coherently superimposed on the chip surface, generating a third enhanced transverse wave vector. Thus, a single excitation can obtain a mixed illumination field with three different ultra-high transverse wave vectors. This illumination field enables deep subwavelength scale structures to be directly resolved by conventional microscopes, achieving low-cost, plug-and-play super-resolution imaging.

[0028] (2) By rationally selecting the substrate material to make it transparent in the excitation light band, and rationally designing the metal / dielectric material and the thickness of each layer of the MIM waveguide structure, the waveguide can support the stable transmission of two ultra-high transverse wave vector surface plasmon modes, thereby realizing the reuse of transverse wave vectors, breaking the limitation of traditional single transverse wave vector illumination, and providing multiple spatial frequency components with a single excitation, greatly improving the imaging information throughput.

[0029] (3) This invention does not require fluorescent labeling of samples, nor does it require special staining or pretreatment. It is compatible with both unlabeled material samples and fluorescently labeled biological samples. Compared with the complex probe labeling or multiple scanning acquisitions required by existing deep subwavelength super-resolution technologies, this invention eliminates all sample preparation steps. At the same time, it can acquire multi-wave vector information in a single imaging, which greatly reduces the complexity and cost of experiments. It is especially suitable for non-destructive, real-time, high-resolution observation of samples that are sensitive to labeling or cannot be labeled. 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 of 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 the coherent wave vector multiplexing frequency-shift illumination chip provided in the embodiments of the present invention. xz plane and xy Schematic diagram of the planar structure; Figure 2 This is a schematic diagram of the distribution of the transverse wave vector and the wave vector multiplexing process of the chip used for enhanced SPP mode provided in this embodiment of the invention. Figure 3 This is a schematic flowchart of a method for achieving deep subwavelength label-free super-resolution microscopy using a coherent wave vector multiplexing frequency-shifting illumination chip, provided in an embodiment of the present invention. Figure 4This is a schematic diagram of the spectral range detected by the deep subwavelength label-free super-resolution microscopy method using a coherent wave vector multiplexing frequency-shifting illumination chip, as provided in an embodiment of the present invention. Figure 5 This is a simulation diagram of the imaging results of a sample with a continuous period and spatial frequency distribution using a coherent wave vector multiplexing frequency-shifting illumination chip and a super-resolution microscopy method provided in the embodiments of the present invention, and a comparison with imaging under wide-field illumination without the above chip. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the scope of protection of this invention.

[0033] like Figure 1 As shown, this embodiment of the invention provides a coherent wave vector multiplexing frequency-shifting illumination chip, including: a chip substrate 101, a MIM waveguide structure 102, a subwavelength groove 103, and a highly localized aliasing illumination field 104.

[0034] In this embodiment, the excitation wavelength was selected as 780 nm. Figure 1 middle Indicates the angle of incidence The wave vector of excitation light with an angle greater than 70° The transverse wave vector of the excitation light satisfies , The transverse wave vector of the aliased field obtained by wave vector multiplexing (containing two aliased ultra-high transverse wave vectors) , And the third type of enhanced ultra-high transverse wave vector ), which are distributed on the upper surface of the chip.

[0035] In this embodiment, the substrate material used is GaP, with a thickness of 350 μm. Figure 1 On the left is the chip. xz The schematic diagram of the planar structure shows that the MIM waveguide structure 102 is sequentially deposited with Au, GaP, and Au using micro-nano fabrication methods, with thicknesses of 10 nm, 9.5 nm, and 10 nm, respectively. The 10 nm Au layer is fabricated using magnetron sputtering, and a 2 nm Cr film is first deposited between the GaP substrate and the Au layer to enhance the adhesion of the Au film. The 9.5 nm GaP layer is grown using atomic layer deposition, and the top 10 nm Au layer is fabricated using magnetron sputtering. Similarly, a 2 nm Cr film needs to be deposited at the bottom of the Au layer. Figure 1 On the right is the subwavelength groove 103 in the chip. xyA schematic diagram of the planar structure shows that the smallest periodic unit is formed by two adjacent scribing lines and the MIM reserved portion between them, with the groove period... 40 nm, depth It is 30 nm.

[0036] At an excitation wavelength of 780 nm, the complex refractive index of the metallic material Au is 0.14737 + 4.7414. i The refractive index of the dielectric material GaP is 3.2059. Based on the refractive index and geometric thickness parameters of the waveguide material, the distribution of the enhanced transverse wave vector is calculated using Maxwell's equations as follows: Figure 2 As shown by the curve, it can be seen that for those with Figure 1 The chip with the structure shown can support different transmission coefficients for each transverse wave vector illumination mode, and can obtain two enhanced ultra-high transverse wave vectors excited at the groove. , Simultaneously, the SPP modes corresponding to these two enhanced transverse wave vectors coherently superimpose during transverse propagation on the chip surface, generating a third type of enhanced transverse wave vector with beat frequency characteristics. .

[0037] like Figure 3 As shown, based on the aforementioned coherent wave vector multiplexing frequency-shifting illumination chip, this embodiment of the invention also provides a deep subwavelength label-free super-resolution microscopy imaging method, comprising the following steps: Step 1: Place the coherent wave vector multiplexed frequency-shifting illumination chip on the sample stage of an upright microscope, and place the sample to be tested in the groove area on the upper surface of the chip; Step 2: Adjust the incident excitation light to TM polarization and adjust its incident angle to generate an evanescent field in the substrate and MIM waveguide structure, thereby exciting an aliased illumination field to illuminate the sample; Step 3: Use a microscope to observe the complex periodic structure of the sample placed on the chip.

[0038] like Figure 4 As shown in the diagram, this embodiment provides a schematic of the spectral range detected by the deep subwavelength label-free super-resolution microscopy imaging method using a coherent wave vector multiplexing frequency-shifting illumination chip, including the fundamental frequency 201 corresponding to the imaging system objective. The corresponding spectrum 202, The corresponding spectrum 204 represents the third transverse wave vector enhanced by wave vector multiplexing on the chip surface. The corresponding spectrum is 203. The dashed line represents the range of the spectrum that the imaging system objective can detect after illuminating the sample with SPP modes having different transverse wave vectors.

[0039] In the embodiment, the numerical aperture of the imaging system objective lens is used. The radius of the fundamental passband is For the imaging sample being an unlabeled sample, without using the coherent wave vector multiplexing frequency-shifting illumination chip in this embodiment, the spectral range detectable by the imaging system objective lens is the range shown by the fundamental frequency 201, i.e., with the origin of the spatial frequency domain coordinates as the center. The radius is a circular range; after using the chip in this embodiment, the imaging system objective lens can detect a maximum spectral range that extends to a circle centered at the origin. A circular range with radius (corresponding to transverse wave vector) The chip surface also has a transverse wave vector of Its extended spectral range is centered on the origin. The circular range with radius, and the wave vector multiplexing generated Its extended spectral range is centered on the origin. The radius is a circular range. In this embodiment, based on the characteristics of wave vector matching and the characteristics of the wave vector difference frequency conversion in frequency-shift imaging, the three transverse wave vectors correspond to the periodic structure dimensions of the actual sample enhancement as follows: , , , Objects with the aforementioned periodic structural dimensions can satisfy the wave vector matching condition for ultra-high transverse wave vector illumination. During spatial frequency difference conversion, they can be carried into the propagating scattering field and collected by the objective lens. It can be seen that, in this embodiment, the super-resolution imaging method using this chip can achieve sub-resolution imaging. λ / Markerless super-resolution imaging in a single exposure at the order of 20.

[0040] like Figure 5 The image shown is a simulation of the imaging results of a sample with continuous periodicity and spatial frequency distribution using the aforementioned coherent wave vector multiplexing frequency-shifting illumination chip and deep subwavelength label-free super-resolution microscopy, compared with imaging under wide-field illumination without the aforementioned chip. Specifically, the imaging target is two angled but non-connected "V"-shaped lines with a continuously distributed periodic structure and an aliased and complex spatial frequency distribution. The distance between the two lines at their thinnest ends is 20 nm, and at their thickest ends it is 1.2 μm. The distance between the two lines gradually increases from the thinnest and thickest ends, and is considered approximately continuous. Under wide-field illumination, i.e., without the wave vector multiplexing frequency-shifting illumination chip, the imaging resolution is [missing information]. The transverse wave vector of the illumination field is Its spatial frequency distribution is characterized by The image with subscripts; when using the chip illumination in this embodiment, a super-resolution image can be obtained, in which the periods of 300 nm, 66.67 nm, and 37.5 nm in the "V"-shaped line are enhanced and distinguished. This was achieved in the simulation. λ / Super-resolution imaging of 20 single-exposure unlabeled samples. The illumination field is a superimposed field containing three enhanced transverse wave vectors after wave vector multiplexing. The superimposed transverse wave vectors are: Its spatial frequency distribution is characterized by The image shows the subscript. During the generation of the aliasing field, the mechanism of transverse wave vector multiplexing is shown in the lower dashed box of the figure. The chip's design itself supports transverse wave vectors as... and The two modes propagate in a coherent superposition in the frequency domain during propagation, resulting in wave vector multiplexing and thus a third transverse wave vector. Ultimately, a highly localized aliasing illumination field containing the three transverse wave vectors mentioned above will exist on the chip surface.

[0041] Experiments have verified that, compared with FPM (Fourier Transform Microscopy), SIM (Structured Illumination Microscopy), STED (Stimulated Emission Depletion Microscopy), and STORM (Stochastic Emission Microscopy), the deep subwavelength super-resolution imaging method provided by this invention has the advantages of high-speed imaging (single exposure), high-frequency enhancement (ultra-high wave vector multiplexing), and strong compatibility (no special sample preparation required and compatible with traditional microscopes). The specific parameters are compared in Table 1 below.

[0042] Table 1 Parameter Comparison

[0043] In summary, this embodiment fully demonstrates the advantages of the present invention for sub-... λ / The advantages of high-frequency enhanced super-resolution imaging for samples with complex periodic structures and spatial frequency distributions are expected to be applied to research related to nanoscale static material characterization, dynamic life activities and physiological phenomena observation, and high-speed chemical reaction observation.

[0044] The specific embodiments described above illustrate the technical solution and beneficial effects of the present invention in detail. It should be understood that the above description is only the most preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, additions, and equivalent substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A coherent wavevector multiplexed frequency shifting illumination chip, characterized in that, include: Chip substrate, and metal-dielectric-metal multilayer waveguide structure formed on the substrate, i.e. MIM waveguide structure; Subwavelength grooves are etched on the MIM waveguide structure. The materials and thicknesses of each layer of the MIM waveguide structure are configured to support the transmission of two superimposed, ultra-high transverse wave vector surface plasmon modes. Under TM polarized excitation light irradiation, the excitation light is coupled into the MIM waveguide structure through grooves and two superimposed ultra-high transverse wave vectors are excited. The two superimposed ultra-high transverse wave vectors propagate on the chip surface and coherently superimpose to generate a third enhanced ultra-high transverse wave vector, realizing wave vector multiplexing, so as to form a highly localized superimposed illumination field containing the above three ultra-high transverse wave vectors on the chip surface.

2. The coherent wave vector multiplexing frequency-shifting illumination chip according to claim 1, characterized in that, The MIM waveguide structure is composed of a plurality of groups of periodically arranged units to form a groove array; each unit comprises two grooves and a MIM reserved part between the two grooves, and the center line distance between the adjacent grooves is the period of the grooves .

3. The coherent wave vector multiplexing frequency-shifting illumination chip according to claim 1 or 2, characterized in that, The period of the grooves The highest transverse wave vector that can be enhanced, the excitation light wavelength And the transverse wave vector of the excitation light And the numerical aperture of the imaging system objective Match, meet: ， wherein , denotes two overlapping ultrahigh transverse wave vectors.

4. The coherent wave vector multiplexing frequency-shifting illumination chip according to claim 1 or 2, characterized in that, The depth of the groove The total thickness of the MIM waveguide structure is greater than or equal to that of the MIM waveguide structure. .

5. The coherent wave vector multiplexing frequency-shifting illumination chip according to claim 1, characterized in that, In the MIM waveguide structure, the thickness of each metal thin film is less than or equal to 10 nm, and the thickness of the dielectric thin film is less than or equal to 12 nm.

6. The coherent wave vector multiplexing frequency-shifting illumination chip according to claim 1, characterized in that, The metallic material in the MIM waveguide structure is Ag or Au with a complex refractive index, and the dielectric material is GaP, Al2O3, TiO2, or Si3N4 with a high refractive index in the excitation light band.

7. The coherent wave vector multiplexing frequency-shifting illumination chip according to claim 1, characterized in that, The substrate material is transparent in the excitation light band: when the excitation light wavelength... λ When the wavelength is >600 nm, the substrate material is GaP or GaN; when 400 nm ≤ λ For ≤600 nm, the substrate material is Al2O3 or TiO2.

8. The coherent wave vector multiplexing frequency-shifting illumination chip according to claim 1, characterized in that, The coherent superposition process is represented as follows: ， in, and These represent the two superimposed ultra-high transverse wave vectors, respectively. and The wave function of surface plasmon modes propagating on the chip surface. Represents the imaginary unit. Indicates the spatial coordinates of lateral transmission along the chip surface. This indicates the third type of enhanced ultra-high transverse wave vector. The corresponding third type of enhanced light field amplitude distribution propagating on the chip surface, This represents the phase term for the third type of enhanced light field propagation.

9. The coherent wave vector multiplexing frequency-shifting illumination chip according to claim 1 or 2, characterized in that, Angle of incidence of excitation light Numerical aperture of imaging system objectives and the cycle of grooving The following conditions must be met: ， in, , This indicates the wavelength of the excitation light.

10. A method for deep subwavelength label-free super-resolution microscopy using the coherent wave vector multiplexing frequency-shifting illumination chip according to any one of claims 1 to 9, characterized in that, Includes the following steps: Step 1: Place the coherent wave vector multiplexed frequency-shifting illumination chip on the sample stage of an upright microscope, and place the sample to be tested in the groove area on the upper surface of the chip; Step 2: Adjust the incident excitation light to TM polarization and adjust its incident angle to generate an evanescent field in the substrate and MIM waveguide structure, thereby exciting an aliased illumination field to illuminate the sample; Step 3: Use a microscope to observe the complex periodic structure of the sample placed on the chip.

Images