A sub-hundred-nanometer particle manipulation method based on near-field optics

Abstract

This invention relates to a method for manipulating sub-100-nanometer particles based on near-field optics, comprising long-distance transport and sorting. By designing a metal horseshoe-shaped nanopore array, the laser is confined within the nanopores using the localized plasmon resonance effect and the thermal effect of metal, forming hotspots that enhance near-field electromagnetic waves and create local temperature gradients, generating photodynamic and thermophoretic forces. The structurally excited near-field is designed as a wavelength-tunable optical hotspot array. By changing the wavelength, the positions of the hotspots in the optical and thermal fields periodically change, driving the particles to move under their combined action. Based on the different forces experienced by particles of different sizes, a preset illumination strategy is used to separate particles during long-distance transport in a static liquid environment. Compared with existing technologies, this invention can achieve high-precision long-distance transport and sorting of particles of different sizes, offering advantages such as long-distance transport capability, high sorting efficiency, and high control precision.

Description

Technical Field

[0001] This invention relates to the fields of micro / nano particle manipulation and biodetection technology and integrated circuit standard wafer fabrication, and in particular to a method for manipulating sub-100 nanometer particles based on near-field optics. Background Technology

[0002] High-precision manipulation and sorting of nanoparticles have significant applications in biomedical detection and integrated circuit standard particles. Traditional particle manipulation techniques mainly include electrophoresis and magnetophoresis; traditional sorting methods mainly include filtration, flow cytometry, and size elution. These methods suffer from drawbacks such as poor sorting accuracy, low sorting efficiency, difficulty in sorting nanoscale particles, high equipment costs, and complex operation. Optical sorting technology, with its advantages of high resolution, non-invasiveness, nanoscale precision, and direct and simple operation, holds the promise of overcoming these limitations and standing out among a range of sorting methods, making high-precision and high-accuracy particle manipulation and sorting possible. In recent years, the rapid development of optical tweezers technology has provided a new solution for the high-precision sorting of large quantities of micro and nanoparticles. However, existing techniques still face challenges in sorting particles at the hundred-nanometer scale.

[0003] Currently, there is a lack of a high-precision (≤100nm) method for sorting large quantities of polystyrene nanoparticles, which limits its in-depth application in fields such as biomedical detection and integrated circuit standard particles.

[0004] Chinese invention patent CN116130139B discloses a nanoparticle transport device and a method for particle capture and long-distance transport. The device includes a silica substrate, a droplet-shaped gold nanoparticle array, a polarized light wave, and nanoparticles. The silica substrate serves as the base. The droplet-shaped gold nanoparticle array, disposed on the silica substrate, acts as a driving unit, interacting with the polarized light field to form an excited local electric field, thereby capturing and directionally transporting the nanoparticles over a long distance. The polarized light wave provides the light source and interacts with the droplet-shaped gold nanoparticle array to generate an evanescent field. The nanoparticles are the objects to be captured and transported. The droplet-shaped gold nanoparticle array comprises periodically arranged droplet-shaped plasma gold nanostructures, each consisting of a droplet-shaped tail and a circular body, with the transport direction of the nanoparticles forming a certain angle with the droplet-shaped tail. This invention achieves more stable capture with lower optical power and enables highly operable transport of target particles. However, traditional methods still suffer from problems such as low particle manipulation precision, inability to utilize light loss, reliance on fluid flow for particle transport, poor sorting accuracy, low sorting efficiency, and difficulty in sorting nanoscale particles.

[0005] In summary, there is currently a lack of a near-field optics-based method for manipulating sub-100 nanometer particles to solve or partially solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a sub-100-nanometer particle manipulation method based on near-field optics, so as to solve or partially solve the problems of low particle manipulation accuracy, easy light loss, reliance on fluid flow for particle transmission, poor sorting accuracy, low sorting efficiency, and difficulty in sorting nanoscale particles in traditional methods.

[0007] The objective of this invention can be achieved through the following technical solutions: This invention provides a method for manipulating sub-100 nanometer particles based on near-field optics, specifically including: S1. Construct a three-layer structure integrating a metal horseshoe-shaped nanopore array. By exciting the localized surface plasmon resonance (LSP) effect of the metal, the incident laser is locally confined in the nanopores, forming a hot spot with enhanced near-field electromagnetic waves and local temperature gradient, which generates photodynamic and thermophoretic forces on the particles. S2. Determine the micro-nano aperture parameters of the metal horseshoe-shaped nanopore array, so that the three-layer structure of the metal horseshoe-shaped nanopore array is excited by the preset incident laser wavelength to produce local surface plasmon resonance (LSP) effect within a period, and the force fields of adjacent structures of the particles overlap to obtain periodically changing optical and thermal fields. S3. In the obtained light field and thermal field, calculate the photodynamic force and thermophoretic force of the particle at each point in the plane at a preset depth to obtain a two-dimensional photothermal potential trap under a preset excitation light source wavelength. Combine the drag force and Brownian motion of the liquid environment to perform dynamic simulation on particles of different sizes. The dynamic simulation includes capture and guidance. S4. Based on the results of dynamic simulation, the spatial distribution of near-field optical hotspots and thermal hotspots is dynamically adjusted through a preset illumination strategy, so as to realize the periodic change of the hotspot positions of the light field and thermal field, forming a dynamic potential field that can drive the directional motion of particles. S5. Based on the difference in force experienced by particles of different sizes in a dynamic coupling field, and combining drag force and Brownian motion, the dynamic potential field that can drive the directional motion of particles is used to realize the long-distance transport of nanoscale target particles of different diameters in a static liquid environment, and the sorting of particles is completed during the long-distance transport process.

[0008] As a preferred technical solution, the metal horseshoe-shaped nanopore array is made of gold, and the unit structure is a combination of three nanopores with a gradually increasing horseshoe shape. This allows the plasmon effects of the three structures to respond to different wavelengths with low mutual interference. The nanopores are arranged according to a periodic square lattice, and the unit structures of the three nanopores are arranged in the same direction.

[0009] As a preferred technical solution, the preset excitation light source is a linearly polarized plane wave with variable wavelength, and the polarization direction is consistent with the orientation of the rod-shaped structure in the aperture.

[0010] As a preferred technical solution, the wavelength of the preset excitation light source includes 950nm, 1010nm and 1095nm.

[0011] As a preferred technical solution, the center-to-center spacing of the nanopores in the metal horseshoe-shaped nanopore array is 125 nm, the period of the overall nanopore unit structure in the x and y directions is 3 × 125 nm and 125 nm, respectively, the outer circular diameters of the nanopores in the metal horseshoe-shaped nanopore array are 76 nm, 95 nm and 114 nm, the lengths of the internal rod-shaped structures are 48 nm, 60 nm and 72 nm, the widths are 32 nm, 40 nm and 52 nm, and the pore thickness is 150 nm.

[0012] As a preferred technical solution, the three-layer structure includes a liquid environment, a substrate, and a micro / nano structure and an adjacent film layer. The liquid environment is made of water with a low refractive index and no damage. The substrate is made of silicon dioxide with a high refractive index and no damage. The micro / nano structure and the adjacent film layer are made of gold and copper. The thermal field originates from the absorption and loss of light by the gold layer. A copper film layer is added between the gold and the substrate.

[0013] As a preferred technical solution, the motion of the particles simultaneously considers the multi-physics field coupling effects, including optical force, thermophoretic force, liquid drag force and Brownian motion, and is implemented on the particles in the form of direct force.

[0014] As a preferred technical solution, the preset lighting strategy includes a combination of different parameters such as laser power density, switching speed of different wavelength lasers, and illumination duration duty cycle. The long-distance transmission and sorting situation can be adjusted by adjusting the preset lighting strategy.

[0015] As a preferred technical solution, the method is applicable to the manipulation and sorting of thermophilic polystyrene particles with a particle size of 40-100nm, a quantity of more than 99 particles, and modified with SDS, wherein the center-to-center spacing of the various particle size groups obtained by sorting is greater than or equal to 20μm.

[0016] As a preferred technical solution, the width of the metal horseshoe-shaped nanopore array structure in the y-direction perpendicular to the transmission direction is greater than one period of the array structure, and the length in the x-direction of the transmission direction is greater than 200 periods of the array structure.

[0017] Compared with the prior art, the present invention has at least one of the following beneficial effects: (1) This invention constructs a three-layer structure integrating a metal horseshoe-shaped nanopore array to locally confine the incident laser within the nanopore. The optimized structural parameters can form a large-scale, strong near-field electromagnetic wave enhancement and a hot spot of local temperature gradient at a specific wavelength. This solves the problems of low particle manipulation precision and unusable light loss in traditional methods. It avoids reaching high temperatures that could damage biological samples while rationally utilizing the temperature gradient, thus strengthening the synergistic effect of photothermal coupling.

[0018] (2) The present invention adopts a wavelength-dependent, horseshoe-shaped nanopore array structure with gradually increasing shape. The plasmon response of different sized structures is highly dependent on wavelength. By using different preset illumination strategies, the spatial distribution of near-field optical hotspots and thermal hotspots is dynamically controlled, so that the hotspot positions of the light field and thermal field change periodically, forming a dynamic potential field that can drive the directional movement of particles, thus solving the problem that the transmission of particles depends on fluid flow in the prior art. The structure is arranged according to the periodicity of the square lattice, and the three nanopore unit structures are arranged in the same direction in one direction, which solves the problem that the particle size that can be sorted and transmitted in the prior art is not small enough. It realizes high-precision and high-accuracy directional long-distance transmission and sorting of target particles with different diameters and smaller particle size than those in the prior art.

[0019] (3) By controlling the combination of different parameters such as laser power density, switching speed of different wavelength lasers, and duty cycle of illumination duration, this invention solves the problems of poor sorting accuracy, low sorting efficiency, and difficulty in sorting nano-sized particles in the prior art, realizes long-distance transmission and sorting of particles of various sizes with different precision, and improves sorting efficiency and control accuracy. Attached Figure Description

[0020] Figure 1 This is a flowchart of the method of the present invention; Figure 2 This is a schematic diagram illustrating the structure and principle of the sub-100 nanometer particle manipulation method based on near-field optics according to an embodiment of the present invention; Figure 3 The structural materials and dimensional parameters used in the simulation calculations of the light and thermal fields in this embodiment of the invention; Figure 4 The electric field strength enhancement value at 10nm on the horseshoe-shaped aperture structure surface and the optical force and optical potential trap of 80nm particles are shown in the embodiments of the present invention. Figure 5 This invention relates to the temperature distribution at 45 nm on the surface of the horseshoe-shaped aperture structure and the thermophoretic force and thermophoretic potential trap of 80 nm particles. Figure 6The images show the trajectory diagrams and distribution histograms of three particle sizes over time in the transport direction under illumination strategy 1, under the combined effects of light force, thermophoretic force, liquid drag force, and Brownian motion, according to an embodiment of the present invention. Figure 7 The images show the trajectory diagrams and distribution histograms of three particle sizes over time in the transport direction under illumination strategy 2, under the combined effects of light force, thermophoretic force, liquid drag force, and Brownian motion, according to an embodiment of the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0022] Addressing the particle sorting size and quantity issues mentioned in the background section, achieving the smallest possible sorting size while ensuring both quantity and quality remains a bottleneck problem that urgently needs to be solved for the further development of micro / nano particle manipulation and biodetection technologies. Therefore, it is necessary for researchers in this field to develop a near-field optical sorting method with high quantity and precision, thereby realizing a particle manipulation chip platform with a clear physical mechanism, excellent sorting effect, and simple operation.

[0023] Based on this, this embodiment provides a method for manipulating sub-100-nanometer polystyrene particles using near-field optics. Through the design and optimization of metallic plasmonic nanostructures, the study of particle dynamics within a photothermally coupled two-dimensional potential well, and the investigation of long-distance particle transport and sorting under different illumination strategies, the method achieves dynamic manipulation, long-distance transport, and high-precision sorting of a large number of particles of different sizes. The optical tweezers technology of this invention can generate hundreds of femtonews of photodynamic and thermophoretic forces at temperatures below 35°C. By designing illumination strategies and utilizing dynamic periodic photothermal potential wells, long-distance transport of sub-100-nanometer particles (tens to hundreds of micrometers) and sorting of a large number of particles of different sizes can be achieved in a static aquatic environment.

[0024] like Figure 1 As shown, the method includes the following steps: S1. Design and optimization of metallic plasmonic nanostructures: A three-layer structure integrating a metal horseshoe-shaped nanopore array on a substrate is used to generate "hot spots" that enhance near-field electromagnetic waves and local temperature gradients by exciting the LSP effect of the metal with plane waves and utilizing photothermal effects. The structure is optimized, the micro- and nano-pore parameters are determined, and the desired periodically variable optical and thermal fields are obtained.

[0025] The metal material in S1 is gold, the unit structure is a combination of three metal materials with nanopores, and the shape is a horseshoe shape with gradually increasing size. The excitation light source wavelengths are 950nm, 1010nm and 1095nm respectively.

[0026] S2. Dynamics of particles in a photothermally coupled two-dimensional potential well: In an existing photothermal field, the photodynamic and thermophoretic forces of particles at a specific depth at every point in the plane are calculated, resulting in two-dimensional photothermal potential traps at three wavelengths. By combining the drag force of the liquid environment and Brownian motion, dynamic simulations of particles with different sizes are completed.

[0027] The three-layer structure of the metal horseshoe-shaped nanopore array includes a liquid environment, a substrate, and a micro / nano structure and an adjacent film layer. The liquid environment is made of non-destructive low-refractive-index water, the substrate is made of non-destructive high-refractive-index silicon dioxide, and the micro / nano structure and the adjacent film layer are made of gold and copper. The thermal field originates from the heat loss due to light absorption by the gold layer. In the simulation, a copper film layer is added between the gold layer and the glass substrate.

[0028] The particle motion model was constructed and simulated in the laminar flow module and fluid flow particle tracking module of COMSOL MultiPhysics software: Within a rectangular water environment region, the length and width are 200 x-axis structural cycle lengths and 3 y-axis structural cycle lengths, respectively; room temperature and pressure liquid water enters the structure from the leftmost side at a velocity of 0 and exits from the rightmost side; particles are simultaneously released from an inlet 0.8 μm from the left side. For particles moving in the x-axis, the wall conditions on the left and right sides are set to "rebound," and the wall conditions in the direction of motion are set to "adhesion." The model also considers optical forces. Thermophoretic force Liquid drag force Brownian motion The multiphysics coupling effect is applied to the particles in the form of direct forces, as shown in the equation. Indicates particle radius, Indicates light intensity. Indicates temperature. This represents gradient calculation; motion simulation is performed using Newton's second law. The first two forces originate from the photothermal field. The photothermal force is calculated by integrating the particle surface using the Minkowski stress tensor method, and the thermophoretic force is calculated using the Anderson model formula. The forces and coordinates of these two forces correspond. The latter two forces originate from the Stokes formula and Einstein formula integrated in the COMSOL MultiPhysics model, and the temperature is set to the average temperature of 305K under incident light excitation.

[0029] S3. High-precision sub-100-nanometer polystyrene particle long-distance conveying and sorting: By setting specific illumination strategies and dynamically controlling the spatial distribution of near-field optical and thermal hotspots, the positions of the "hotspots" undergo periodic changes, forming a dynamic potential field that can drive the directional movement of particles. Based on the differences in the forces experienced by particles of different sizes in the dynamic coupling field, and combining drag force and Brownian motion, long-distance transport of polystyrene particles with diameters of 100nm, 80nm, and 50nm, as well as 80nm, 50nm, and 40nm, is achieved in a static liquid environment. During this process, high separation and high-precision sorting are completed with a particle group center-to-center spacing of ≥20μm.

[0030] The conveying and sorting process in S3 can be adjusted by regulating the illumination strategy. The results are applicable to the sorting and manipulation of SDS-modified thermophilic polystyrene particles with a diameter of 40-100 nm, with a quantity of 99 or more. The illumination strategy includes combinations of different parameters such as laser power density, switching speed of different wavelengths of laser light, and duty cycle of illumination duration. The illumination strategy designed in this invention achieves the following: larger diameter nanoparticles experience greater photodynamic and thermophoretic forces, resulting in deeper photothermal potential traps in their structure, less influence from Brownian motion diffusion, and better tracking of laser switching speed. Large-diameter particles can overcome Brownian motion and follow the laser switching speed under the designed illumination strategy, moving the fastest. Small-diameter particles are severely affected by Brownian motion, especially 40 nm particles, which experience a small overlap of force fields from adjacent structures, resulting in a particle group distribution as wide as approximately 20 μm. They cannot completely follow the set laser switching speed, but can still move unidirectionally on the conveyor belt under repeated driving. Overall structure: The width in the y-direction is greater than one period of the array structure; the length in the x-direction, depending on the sorting requirements, is at least greater than 200 periods of the array structure. This invention is not only applicable to polystyrene particles, but can also be extended to the manipulation and sorting of various nanoscale targets such as gold nanoparticles, silica particles, exosomes, and viruses by adjusting irradiation parameters, such as light intensity, switching frequency, and irradiation time. It has broad application prospects in fields such as biomedical detection and integrated circuit standards.

[0031] The above technical solution is mainly based on the following technical principles: Localized surface plasmon resonance (LSP) originates from the direct resonant coupling of electrons at the metal surface with excitation light of a specific frequency. This collective oscillation of electrons typically occurs in nanopores or metal structures with dimensions much smaller than the incident wavelength. The resonant frequency and intensity are determined by the metal's geometry and the material's dielectric constant, such as the structure's size and shape, and the dielectric constant of the metal and the surrounding medium. As a common method for confining and enhancing electromagnetic fields, LSP helps explore the nature of light-matter interactions and has extensive applications in nanolasers, nonlinear optics, biosensing, and optical tweezers. However, the inherent ohmic loss of metals limits their use in manipulating sub-100 nanometer-sized biological particles; high laser power, while providing high trapping intensity, also leads to a sharp increase in temperature.

[0032] This invention innovatively utilizes a photothermal coupling field to achieve effective particle manipulation while maintaining a suitable temperature. For example... Figure 2 As shown, LSP is used to enhance the optical field and gradient thermal field, and periodic structures with three structural combinations responding to different wavelengths are designed. The photodynamic force on the particles is calculated using the Minkowski stress tensor method, and the thermophoretic force on the particles under a specific temperature distribution is calculated using a thermophoretic force model. Under the action of light and thermal potential traps, combined with liquid drag force and Brownian motion, an illumination strategy is designed to achieve the manipulation of multi-size particles, including transport and sorting.

[0033] This embodiment also verifies the above method, which will realize a large-scale, high-precision near-field optical sorting method.

[0034] Figure 3 A schematic diagram of a single structure in the simulation of a metal structure is shown. The construction of the local plasmon metal structure is realized through COMSOL Multiphysics. Figure 3 The unit structure in the 3D optical simulation is shown. The three-layer structure from top to bottom consists of a water environment, a gold micro / nano structure film, and a glass substrate. The thickness of the nanoporous metal structure is 150nm, and the thickness of the gold film below is 90nm. Figure 3 b shows the planar structural dimensions of the nanopore structure, with a square lattice of 125 nm in both length and width. The central structure of the three pore structures is a circular structure with a diameter of 95 nm, and a rod-shaped structure within the circle with dimensions of 60 × 40 nm. The two structures on the left and right are 0.8 and 1.2 times the size of the central structure, respectively, with x and y periods of 375 nm and 125 nm, respectively. Figure 3 c shows the overall structure in the 3D thermal field simulation, which, from top to bottom, consists of a glass shell, an aqueous environment, a micro / nano structure, a gold film, a copper film, and a glass substrate and shell. One of the micro / nano structures has a period of 5×5.

[0035] Figure 4The figure shows the electric field enhancement at 10 nm on a single periodic structure surface under different wavelength excitations, and the photodynamic force and potential well at 5 nm on the surface for an 80 nm particle.

[0036] Figure 5 The figure shows the temperature distribution at 45 nm on a single periodic structure surface under different wavelength excitations, and the thermophoretic force and potential well of an 80 nm particle at 5 nm on the surface.

[0037] Figure 6 The trajectory diagrams and time-specific histograms of 80nm, 50nm, and 40nm particles in the transport direction are shown under multiphysics coupling. The illumination strategy used was a laser power density of 8mW / μm. 2 The illumination strategy for square wave switching has "period-duty cycle-duty time" of 6ms-0.323-1.2s and 3ms-0.323-0.6s respectively. Figure 6 A demonstrates the simultaneous release of three types of particles and their trajectory in the x-direction over time during a 1.8s dynamic manipulation process. Figure 6 b shows the histogram of the x-direction distribution at 1.8 s during this process. Simulation results show that the present invention can achieve unidirectional long-distance transport of particle groups in a short time and high-precision and high-separation sorting of particle groups with different diameters within 100 nanometers with a resolution of 10 nm.

[0038] Figure 7 The trajectory diagrams and time-specific histograms of 100, 80, and 50 nm particles in the transport direction are shown under multiphysics coupling. The illumination strategy used was a laser power density of 8 mW / μm. 2 The illumination strategy for square wave switching has "period-duty cycle-duty time" of 5.4ms-0.32-1.35s and 2.7ms-0.29-1.755s respectively. Figure 7 A demonstrates the simultaneous release of three types of particles and their trajectory in the x-direction over time during a 3.1s dynamic manipulation process. Figure 7 b shows the histogram of the x-direction distribution during this process at 2.8 s. Simulation results show that the present invention can also achieve the transport and sorting of particle groups with larger particle sizes under different lighting strategies.

[0039] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for manipulating sub-100 nanometer particles based on near-field optics, characterized in that, The method specifically includes: S1. Construct a three-layer structure integrating a metal horseshoe-shaped nanopore array. By stimulating the local surface plasmon effect of the metal, the incident laser is locally confined in the nanopore, forming a hot spot with enhanced near-field electromagnetic waves and local temperature gradient, which generates photodynamic and thermophoretic forces on the particles. S2. Determine the micro-nano aperture parameters of the metal horseshoe-shaped nanopore array, so that the three-layer structure of the metal horseshoe-shaped nanopore array is excited by the preset incident laser wavelength to produce local surface plasmon effect within a period, and the force fields of adjacent structures of the particles overlap to obtain periodically changing optical and thermal fields. S3. In the obtained light field and thermal field, calculate the photodynamic force and thermophoretic force of the particle at each point in the plane at a preset depth to obtain a two-dimensional photothermal potential trap under a preset excitation light source wavelength. Combine the drag force and Brownian motion of the liquid environment to perform dynamic simulation on particles of different sizes. The dynamic simulation includes capture and guidance. S4. Based on the results of dynamic simulation, the spatial distribution of near-field optical hotspots and thermal hotspots is dynamically adjusted through a preset illumination strategy, so as to realize the periodic change of the hotspot positions of the light field and thermal field, forming a dynamic potential field that can drive the directional motion of particles. S5. Based on the difference in force experienced by particles of different sizes in a dynamic coupling field, and combining drag force and Brownian motion, the dynamic potential field that can drive the directional motion of particles is used to realize the long-distance transport of nanoscale target particles of different diameters in a static liquid environment, and the sorting of particles is completed during the long-distance transport process.

2. The method for manipulating sub-100 nanometer particles based on near-field optics according to claim 1, characterized in that, The metal horseshoe-shaped nanopore array is made of gold, and the unit structure is a combination of three nanopores in a gradually increasing horseshoe shape, which makes the plasmon effect of the three structures respond to different wavelengths and has low mutual interference; the nanopores are arranged according to the periodicity of a square lattice, and the unit structures of the three nanopores are arranged in the same direction.

3. The method for manipulating sub-100 nanometer particles based on near-field optics according to claim 1, characterized in that, The preset excitation source is a linearly polarized plane wave with variable wavelength, and the polarization direction is consistent with the orientation of the rod-shaped structure in the aperture.

4. The method for manipulating sub-100-nanometer particles based on near-field optics according to claim 3, characterized in that, The wavelengths of the preset excitation light source include 950nm, 1010nm, and 1095nm.

5. The method for manipulating sub-100 nanometer particles based on near-field optics according to claim 1, characterized in that, The metal horseshoe-shaped nanopore array has a center-to-center spacing of 125 nm for the nanopores. The overall nanopore unit structure has a period of 3 × 125 nm and a period of 125 nm in the x and y directions, respectively. The outer circular diameters of the nanopores in the metal horseshoe-shaped nanopore array are 76 nm, 95 nm, and 114 nm, respectively. The lengths of the internal rod-shaped structures are 48 nm, 60 nm, and 72 nm, respectively, and the widths are 32 nm, 40 nm, and 52 nm, respectively. The pore thickness is 150 nm.

6. The method for manipulating sub-100 nanometer particles based on near-field optics according to claim 1, characterized in that, The three-layer structure includes a liquid environment, a substrate, and a micro / nano structure and an adjacent film layer. The liquid environment is made of water with a low refractive index and no damage. The substrate is made of silicon dioxide with a high refractive index and no damage. The micro / nano structure and the adjacent film layer are made of gold and copper. The thermal field originates from the absorption and loss of light by the gold layer. A copper film layer is added between the gold and the substrate.

7. The method for manipulating sub-100 nanometer particles based on near-field optics according to claim 1, characterized in that, The motion of the particles simultaneously considers the multi-physics field coupling effects, including optical force, thermophoretic force, liquid drag force, and Brownian motion, which are applied to the particles in the form of direct forces.

8. The method for manipulating sub-100 nanometer particles based on near-field optics according to claim 1, characterized in that, The preset lighting strategy includes a combination of different parameters such as laser power density, switching speed of different wavelength lasers, and illumination duration duty cycle. Adjusting the preset lighting strategy enables adjustments to the long-distance transmission and sorting process.

9. The method for manipulating sub-100 nanometer particles based on near-field optics according to claim 1, characterized in that, The method is applicable to the manipulation and sorting of thermophilic polystyrene particles with a particle size of 40-100nm, a quantity of more than 99 particles, and modified with SDS. The center-to-center spacing of the various particle size groups obtained by sorting is greater than or equal to 20μm.

10. The method for manipulating sub-100 nanometer particles based on near-field optics according to claim 1, characterized in that, The width of the metal horseshoe-shaped nanopore array structure in the y-direction perpendicular to the transmission direction is greater than one period of the array structure, and the length in the x-direction of the transmission direction is greater than 200 periods of the array structure.

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