Graphene dimer-based nano-antenna scattering direction modulation method and device

Abstract

The application belongs to the technical field of light manipulation, and provides a graphene dimer-based nano-antenna scattering direction regulation method and device, wherein a plane electromagnetic wave with a preset electric field amplitude and electric field direction is irradiated to a dimer nano-antenna; the dimer nano-antenna is composed of a dielectric particle nanodimer system with different radii wrapped by two nonlinear graphenes; more parameters can be introduced, the required light intensity energy of incident light can be effectively reduced, damage of the nano-antenna caused by high temperature can be avoided, and the adjustability is higher, so that the properties of electromagnetic waves can be more flexibly controlled, and more functions can be realized.

Description

Method and device for controlling the scattering direction of nanoantennas based on graphene dimers Technical Field

[0001] This invention belongs to the field of optical manipulation technology, and particularly relates to a method and device for controlling the scattering direction of nano-antennas based on graphene dimers. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Controlling the direction of electromagnetic wave scattering plays an important role in the design of all-optical devices such as nanoantennas, sensors, and memory.

[0004] Typically, when a nanosphere has the same dielectric constant and magnetic permeability, its backscattering can completely disappear. This is because, under electromagnetic radiation, the electric and magnetic multipole moments of the nanosphere completely cancel each other out in the backscattered far-field, thus inducing one-way scattering. However, it is almost impossible to find single-particle materials in nature that meet these conditions. High-dielectric particles (such as silicon particles) can induce magnetic dipole moments, but their electric and magnetic resonance frequencies are different. One-way scattering can only be achieved when the electric and magnetic dipole moments produce the same amount of radiation energy at the same frequency. Researchers have also tried many other structures to adjust the overlap of electric and magnetic resonances, but all of these methods have proven challenging.

[0005] Besides utilizing electrode resonance and magnetic pole resonance, in order to design a dimer structure so that the far-field radiation generated by the electric dipole moments of the two particles cancels each other out, thereby achieving unidirectional scattering, researchers have tried to use subwavelength heterodimeric structures, such as dimer systems composed of metal particles and dielectric particles. In the long-wavelength limit, the magnetic dipole moment induced by these particles can be ignored, and at certain frequencies, the far-field radiation generated by their electric dipole moments can cancel each other out in the forward or backward direction. For example, YSKivsha et al. proposed that a nanodimeric antenna composed of nonlinear silver-silicon particles can achieve adjustable scattering direction, and arbitrary switching of radiation modes can be achieved by changing the incident field intensity (adding a Gaussian signal).

[0006] However, the experimental fabrication of heterostructures remains challenging, hindering mass production. Subsequently, AAPotapov also achieved unidirectional scattering using a dimer structure composed of only one noble metal (gold). However, the inherently high ohmic loss of metals and their low tunability limit the quality of plasmon resonances to some extent. Furthermore, traditional metal-dielectric models, based on classical electromagnetic theory and the Drude model, neglect quantum effects of metals at the nanoscale, thus failing to accurately describe the optical properties of the metal sphere. Additionally, this study did not consider the inherent nonlinear effects of metals or their time-evolving dynamic scattering properties.

[0007] In addition, previous studies have been based on the manipulation of dimer nanoantennas of dielectric particles with the same radius, which introduces few parameters, has poor tunability, and is not convenient for more flexible control of the properties of electromagnetic waves. At the same time, if the incident light energy is relatively high, the nanoantenna is easily damaged due to high temperature, resulting in poor tunability and difficulty in flexibly controlling the properties of electromagnetic waves. Summary of the Invention

[0008] To address at least one of the technical problems mentioned above, this invention provides a method and apparatus for controlling the scattering direction of a nano-antenna based on graphene dimers. This method can introduce more parameters, effectively reduce the light intensity energy required for incident light, avoid damage to the nano-antenna caused by high temperatures, and has higher tunability. This allows it to more flexibly control the properties of electromagnetic waves and achieve more functions.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] The first aspect of this invention provides a method for controlling the scattering direction of a graphene dimer-based nanoantenna, comprising the following steps:

[0011] A plane electromagnetic wave with a preset electric field amplitude and direction is applied to the dimer nanoantenna; wherein, the dimer nanoantenna is composed of two nonlinear graphene-encapsulated dielectric particle nanodimer systems with different radii;

[0012] A set of nonlinear equations is used to calculate the electric dipole moment of two particles with different radii constituting the dimer nanoantenna as a function of time. The set of nonlinear equations describes the dynamic scattering characteristics of the dielectric particle dimer nanoantenna with different radii under external plane wave excitation.

[0013] The dipole scattering intensity of the dielectric particle dimer nanoantennas with different radii is calculated based on the nonlinear equations.

[0014] By adjusting the parameters of the dimer nanoantenna and the frequency of the incident electric field, the electric dipole moments of the dimer nanoantenna interaction can generate a preset phase difference, thus achieving unidirectional scattering.

[0015] Based on the scattering intensity of nanoantennas composed of dielectric particles of different radii, Gaussian pulses are superimposed on the incident background electric field to allow the scattering state of the nanoantenna to arbitrarily switch between omnidirectional scattering and backscattering.

[0016] A second aspect of the present invention provides a nano-antenna scattering direction modulation device based on graphene dimers, comprising:

[0017] The first calculation module is used to irradiate the dimer nanoantenna with a plane electromagnetic wave of a preset electric field amplitude and direction; wherein, the dimer nanoantenna is composed of two nonlinear graphene-encapsulated dielectric particle nanodimer systems of different radii; the module calculates a set of nonlinear equations for the evolution of the electric dipole moments of the two particles of different radii constituting the dimer nanoantenna over time, and the set of nonlinear equations describes the dynamic scattering characteristics of the dielectric particle dimer nanoantenna of different radii under the excitation of the plane wave;

[0018] The second calculation module is used to calculate the dipole scattering intensity of the dielectric particle dimer nanoantennas with different radii based on the nonlinear equations.

[0019] The parameter adjustment module is used to adjust the parameters of the dimer nanoantenna and the frequency of the incident electric field to generate a preset phase difference in the electric dipole moments of the dimer nanoantenna interaction, thereby achieving unidirectional scattering.

[0020] The scattering state switching module is used to switch the scattering state of a nanoantenna composed of dielectric particles of different radii arbitrarily between omnidirectional scattering and backscattering by superimposing a Gaussian pulse on the incident background electric field, based on the scattering intensity of the nanoantenna.

[0021] A third aspect of the present invention provides a computer-readable storage medium.

[0022] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps in the above-described method for controlling the scattering direction of a graphene dimer-based nanoantenna.

[0023] A fourth aspect of the present invention provides a computer device.

[0024] A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps in the graphene dimer-based nanoantenna scattering direction modulation method described above.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] This invention employs a dimer composed of two graphene-coated dielectric particles. Compared to a graphene-coated dielectric dimer, this allows for the introduction of more parameters, such as the graphene conductivity σ of particle two. L Photoelectron relaxation time τ and electron Fermi velocity E F Therefore, it has higher adjustability, which allows it to control the properties of electromagnetic waves more flexibly and achieve more functions.

[0027] Existing technology models require relatively high incident light energy, while this invention can effectively reduce the incident light intensity energy, avoiding damage to the nanoantenna caused by high temperatures. Therefore, it offers greater tunability, enabling more flexible control over the properties of electromagnetic waves and achieving more functions.

[0028] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0029] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0030] Figure 1 is a flowchart of the method for controlling the scattering direction of a nano-antenna based on graphene dimer provided in an embodiment of the present invention;

[0031] Figure 2 is a model diagram of the dimer nanoantenna provided in an embodiment of the present invention and a reference diagram of a specific implementation scheme;

[0032] Figure 3(a) is a graph showing the dimensionless electric dipole moment of the two dimer particles in this invention as a function of the incident plane wave frequency, where curve 2 represents graphene-encapsulated particle 1 and curve 1 represents graphene-encapsulated particle 2.

[0033] Figure 3(b) is a graph showing the ratio of backscattering to forward scattering of the dimer nanoantenna in this invention as a function of the incident plane wave frequency. The inset is a graph showing the far-field scattering of the nanoantenna at the marked frequency.

[0034] Figure 4 shows the evolution of the backscattering and forward scattering ratios of the dimer nanoantenna in this invention over time under an applied Gaussian signal. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0036] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0037] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0038] To address the technical problems mentioned in the background section of this invention, this invention selects graphene as a material to replace metal materials. Experimentally, near-field scattering microscopy and nano-imaging methods have demonstrated that graphene can also excite plasmon resonances. By using Kerr-type nonlinear graphene to encapsulate two dielectric particle dimers of different radii, and adjusting the structural parameters and the frequency of the incident electric field, a suitable phase difference is generated between the interacting electric dipole moments, achieving unidirectional scattering. Furthermore, by superimposing a Gaussian pulse on the incident background electric field, dynamic switching between two scattering modes (backscattering and omnidirectional scattering) is achieved. The graphene-encapsulated dielectric particle model considers the interaction between the dielectric particles and graphene; its resonance frequency is related to multiple parameters, resulting in higher tunability. Moreover, compared to metal materials, graphene has a higher plasmon resonance frequency, thus requiring a shorter response time for direction switching.

[0039] Example 1

[0040] This invention addresses the limitations of existing technologies by providing a method for controlling the scattering directionality of tunable nonlinear nanoantennas based on quasi-static theory and dispersion relation theory. It utilizes a dimer nanoantenna composed of a nano-dimer system containing dielectric particles of different radii encapsulated by two nonlinear graphene layers. By studying its dynamic scattering characteristics, the scattering direction can be tunable over time. This has significant application value in signal detection and information transmission for nanodevices.

[0041] As shown in Figure 1, this embodiment provides a method for controlling the scattering direction of a nano-antenna based on graphene dimers, including the following steps:

[0042] Step 1: Apply a pre-defined planar electromagnetic wave with a preset electric field amplitude and direction to the dimer nanoantenna; wherein the dimer nanoantenna is composed of two nonlinear graphene-encapsulated dielectric particle nanodimer systems with different radii.

[0043] Step 2: Calculate the nonlinear equations for the evolution of the electric dipole moments of the two particles with different radii constituting the dimer nanoantenna over time. The nonlinear equations describe the dynamic scattering characteristics of the dielectric particle dimer nanoantenna with different radii under external plane wave excitation.

[0044] Step 3: Calculate the dipole scattering intensity of the dielectric particle dimer nanoantennas with different radii based on the nonlinear equations.

[0045] Step 4: By adjusting the parameters of the dimer nanoantenna and the frequency of the incident electric field, the electric dipole moments of the dimer nanoantenna interaction generate a preset phase difference, achieving unidirectional scattering.

[0046] Step 5: Based on the scattering intensity of the nanoantenna composed of dielectric particles of different radii, a Gaussian pulse is superimposed on the incident background electric field to allow the scattering state of the nanoantenna to arbitrarily switch between omnidirectional scattering and backscattering.

[0047] The following describes the process further with specific examples.

[0048] A plane electromagnetic wave is incident on a nonlinear nanoantenna. The incident plane electromagnetic wave is incident along the z-direction, and the amplitude of the applied electric field is E. (ex) electric field E i The polarization direction is along the x-direction, and it takes the following form: E i =E0e ikz-iωt E x Where E0,k,ω,t are the applied field frequency, incident electric field intensity, background material wave vector, and time, respectively.

[0049] Since the thickness of a single layer of graphene is only the diameter of a single atom, the thickness of the graphene layer is ignored here, and it is considered equivalent to a two-dimensional uniform conductive film. Furthermore, the surface conductivity of graphene exhibits Kerr-type nonlinearity, i.e., σ = σ L +σ (3) |E in | 2 , where σ L and σ (3) E represents the linear and third-order nonlinear terms of the electrical conductivity of graphene. in This represents the local field of the graphene layer.

[0050] When the photon energy is much lower than the Fermi level, intraband transport is much smaller than interband transport, so intraband transport is ignored. The conductivity of linear graphene can be expressed in the form of the Drude model as follows:

[0051]

[0052] The third-order nonlinear conductivity coefficient is:

[0053]

[0054] In the formula, e, E F v F , respectively, are Planck's constant, relaxation time of in-band transition, Fermi level of electron, and Fermi velocity.

[0055] First, write the expressions for the electric dipole moments p1 and p2 of the two spherical dimer particles in the Fourier transform:

[0056]

[0057] The polarizability of graphene-encapsulated dielectric nanoparticles is:

[0058]

[0059] Where a 1,2 Let ε1 and ε2 be the radii of the two particles, respectively. h ε0 represents the dielectric constant of the internal medium of the graphene, the relative dielectric constant of the background material, and the dielectric constant in a vacuum; c represents the speed of light in a vacuum; and d represents the distance between the two particles.

[0060] The electric dipole interaction between particles is as follows:

[0061]

[0062] The subscripts m and n represent the electric dipole interaction between the m-th particle and the n-th particle, where d is the center-to-center distance between the two particles. This represents the unit vector pointing from the center of the m-th particle to the center of the n-th particle.

[0063] At terahertz frequencies, the nonlinear phase of the electrical conductivity on the graphene surface is very weak, much smaller than the linear portion, i.e., σ0 (3) |E in | 2 <<σ L ;

[0064] Therefore, near the resonant frequency ω0, for Decompose the terms, retaining only the first-order terms containing the time derivative:

[0065]

[0066] The resonant frequency is Δω is the difference between the actual frequency and the resonant frequency.

[0067] Then, substituting equation (4) into equation (1), we can obtain the nonlinear equations concerning the electric dipole moment of the dimer spherical particles:

[0068]

[0069] in, and It is a dimensionless electric dipole moment and incident electric field that evolve and normalize over time. It is the dipole interaction factor between the two particles. For the heat loss and radiation loss of the dimer, τ=ω0t is the normalized dimensionless time, Ω 1,2 =(ω-ω 01,02 ) / ω 01,02 The detuning amount between the driving frequency and the resonant frequency;

[0070] It should be noted that, in order to simplify the equation, dimensionless variables are used here.

[0071] Characterize the dispersion of the system.

[0072] Equation (5) describes the dynamic scattering characteristics of this dimer nanoantenna under external plane wave excitation at frequency ω.

[0073] It is particularly noteworthy that when the time-varying term is removed, formula (5) becomes:

[0074]

[0075] This describes the static scattering characteristics of the dimer nanoantenna, where E is the static amplitude of the applied electric field.

[0076] At this point, at certain frequencies, the electric dipole moments P1 and P2 of the two spherical particles will have three solutions, including two steady-state solutions and one unsteady-state solution. Therefore, as long as the frequency is fixed near the resonant frequency ω0, the electric dipole moment of the spherical particles will exhibit a so-called bistable state under the excitation of an applied electric field E0.

[0077] To achieve directional control of the scattering of these dimer particles, we will now analyze their dipole scattering. Since the particle size is much smaller than the incident wavelength, this embodiment uses a quasi-static approximation and only considers dipole scattering.

[0078] The scattering intensity of the nanoantenna composed of dimer particles is:

[0079]

[0080] in θ and θ are the azimuth and polar angles in spherical coordinates, and ΔΨ is the phase difference between the two electric dipoles.

[0081] Therefore, it can be seen from equation (7) that the scattering of this nanoantenna will also exhibit a bistable state.

[0082] The ratio of backscattering to forward scattering is defined as follows:

[0083] By adjusting the geometric parameters of the nanoantenna and the conductivity parameters of the nonlinear graphene, two steady states, distinguishable by detecting the scattering signal, exist at a fixed frequency. For example, one steady state is all-directional scattering (l = 0 dB), and the other is backscattering (l > 20 dB). By adjusting the applied electric field with an applied Gaussian signal, the scattering state of the nanoantenna can be controlled, achieving arbitrary switching between all-directional and backscattering.

[0084] The aforementioned technological advantage lies in the fact that, by adjusting the geometric parameters of the nanoantenna and the conductivity parameters of the nonlinear graphene, two steady states, distinguishable by detecting the scattering signal, exist at a fixed frequency. For example, one steady state is all-directional scattering (l = 0 dB), and the other is backscattering (l > 20 dB). By adjusting the applied electric field using an applied Gaussian signal, the scattering state of the nanoantenna can be controlled, achieving arbitrary switching between all-directional and backscattering.

[0085] In this embodiment of the invention, the particle radii selected are R1 = 100 nm and R2 = 80 nm. Within the research frequency range, their dielectric constant is ε = 2.15, and the center-to-center distance between the two particles is d = 300 nm. In this invention, due to the introduction of the dipole approximation theory, the distance between the surfaces of the two particles, s = d - R2 - R1, must be greater than min{R2; R1}.

[0086] This embodiment selects E F =0.9eV, τ=0.3ps. If the entire system is placed in air, then the dielectric constant of the background medium is ε. h =1. See Appendix 2 for the design drawing of the entire device.

[0087] Numerical calculations were performed using Mathematica software, and the obtained data were plotted using Origin software to visually reflect the law of directional control of the nanoantenna.

[0088] Referring to Figures 3(a)-3(b), the static scattering properties of the antenna are analyzed first.

[0089] When a monochromatic plane wave is applied to the dimer system, the electric field strength is 1.5 W / cm. 2 .

[0090] The electric dipole moments of the two particles in the range of 230 THz to 270 THz were calculated using Mathematica software. Then, according to equation (7), the ratio of backscattering to all-directional scattering of the nanoantenna was obtained using the electric dipole moments of the two particles. Due to the introduction of the nonlinear conductivity of graphene, the electric dipole moment and the backscattering-forward scattering ratio will have three values ​​in certain frequency ranges. The upper and lower branches are steady states, while the middle branch is an unsteady state, which is the so-called "bistable".

[0091] Referring to Figure 3(b), an optimal frequency (ω=255THz) can be found where the two steady states of the backscattering ratio reach 33dB and 0dB, respectively. This means that under plane wave illumination at the same frequency, there may be two scattering states, namely backscattering and all-directional scattering. The far-field scattering diagram is shown in the inset.

[0092] Next, we will consider the dynamic evolution of this system.

[0093] Referring to Figure 4, based on the optimal frequency obtained from the above process, the applied frequency to the dimer system is 255 THz, and the electric field strength is 1.5 W / cm. 2 A monochromatic plane wave, the signal of which is generated by a laser, with its intensity gradually increasing from 0 to 1.5 W / cm². 2 (See the solid black line in Figure 3).

[0094] Around t = 12.5 ps, an applied Gaussian signal causes a rapid change in the electric field strength before it returns to its original value. At this point, the backscattering-to-forward scattering ratio of the nanoantenna jumps rapidly from 33 dB to 0 dB, meaning the scattering state changes from backscattering to omnidirectional scattering. Around t = 33.4 ps, a second applied Gaussian signal causes another rapid change in the electric field strength before it returns to its original value. This time, the backscattering-to-forward scattering ratio of the nanoantenna jumps rapidly from 0 dB to its original value of 33 dB, meaning the scattering state changes from omnidirectional scattering to backscattering. Therefore, by applying Gaussian signals of different amplitudes and phases, the arbitrary transition between omnidirectional and backscattering of the nanoantenna can be controlled.

[0095] In conclusion, the following conclusions can be drawn:

[0096] The scattering direction reversal time achieved with the nanoantenna is approximately 2.32 ps, exhibiting an extremely short response time; the required external electric field strength in this invention is 1.5 W / cm². 2 This power level, when applied to metallic materials, could potentially burn the surface of the metal particles. This invention pioneers the use of graphene-encapsulated dielectric materials to replace metal particles, thereby controlling the scattering direction and preventing damage to the nano-antennas caused by excessively high external electric field strength. The graphene material can support a maximum power of 100 W / cm². 2The applied electric field strength; the structure of graphene-encapsulated dielectric material has higher tunability. Not only can we control the wavelength range required in our practical applications by adjusting its geometric parameters and changing the dielectric material, but we can also adjust the conductivity parameters of the linear graphene, such as the chemical formula and relaxation time.

[0097] Example 2

[0098] This embodiment provides a nano-antenna scattering direction modulation device based on graphene dimers, including:

[0099] The first calculation module is used to irradiate the dimer nanoantenna with a plane electromagnetic wave of a preset electric field amplitude and direction; wherein, the dimer nanoantenna is composed of two nonlinear graphene-encapsulated dielectric particle nanodimer systems of different radii; the module calculates a set of nonlinear equations for the evolution of the electric dipole moments of the two particles of different radii constituting the dimer nanoantenna over time, and the set of nonlinear equations describes the dynamic scattering characteristics of the dielectric particle dimer nanoantenna of different radii under the excitation of the plane wave;

[0100] The second calculation module is used to calculate the dipole scattering intensity of the dielectric particle dimer nanoantennas with different radii based on the nonlinear equations.

[0101] The parameter adjustment module is used to adjust the parameters of the dimer nanoantenna and the frequency of the incident electric field to generate a preset phase difference in the electric dipole moments of the dimer nanoantenna interaction, thereby achieving unidirectional scattering.

[0102] The scattering state switching module is used to switch the scattering state of a nanoantenna composed of dielectric particles of different radii arbitrarily between omnidirectional scattering and backscattering by superimposing a Gaussian pulse on the incident background electric field, based on the scattering intensity of the nanoantenna.

[0103] Example 3

[0104] This embodiment provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps in the graphene dimer-based nanoantenna scattering direction modulation method described in Embodiment 1.

[0105] Example 4

[0106] This embodiment provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the steps in the method for controlling the scattering direction of a nano-antenna based on graphene dimers as described in Embodiment 1.

[0107] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of hardware embodiments, software embodiments, or embodiments combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage and optical storage) containing computer-usable program code.

[0108] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in one or more blocks of the flowchart illustrations and / or one or more blocks of the block diagrams.

[0109] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means that implement the functions specified in one or more flowcharts and / or one or more block diagrams.

[0110] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, such that the instructions, which execute on the computer or other programmable apparatus, provide steps for implementing the functions specified in one or more flowcharts and / or one or more block diagrams.

[0111] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0112] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for controlling the scattering direction of a nanoantenna based on graphene dimers, characterized in that, The process includes the following steps: irradiating a dimer nanoantenna with a pre-defined electric field amplitude and direction using a plane electromagnetic wave; wherein the dimer nanoantenna is composed of two nonlinear graphene-encapsulated dielectric particle nanodimer systems of different radii; calculating a set of nonlinear equations describing the time-dependent evolution of the electric dipole moments of the two particles with different radii constituting the dimer nanoantenna, the nonlinear equations describing the dynamic scattering characteristics of the dielectric particle dimer nanoantennas of different radii under plane wave excitation; calculating the dipole scattering intensity of the dielectric particle dimer nanoantennas of different radii based on the nonlinear equations; adjusting the parameters of the dimer nanoantenna and the frequency of the incident electric field to generate a pre-defined phase difference in the interacting electric dipole moments of the dimer nanoantennas, achieving unidirectional scattering; and, based on the scattering intensity of the nanoantennas composed of dielectric particles of different radii, superimposing a Gaussian pulse on the incident background electric field to allow the scattering state of the nanoantenna to arbitrarily switch between omnidirectional and backscattering.

2. The method for controlling the scattering direction of a nano-antenna based on graphene dimers as described in claim 1, characterized in that, The method of adjusting the scattering intensity of the nanoantenna composed of dielectric particles of different radii by superimposing a Gaussian pulse on the incident background electric field to allow the scattering state of the nanoantenna to arbitrarily switch between all-directional scattering and backscattering includes: adjusting the geometric parameters of the nanoantenna and the nonlinear graphene conductivity parameters so that at a certain fixed frequency, the type of scattering is determined by the value of the ratio of backscattering to forward scattering.

3. The method for controlling the scattering direction of a nano-antenna based on graphene dimers as described in claim 2, characterized in that, The method of determining the type of scattering by the ratio of backscattering to forward scattering includes: if the ratio of backscattering to forward scattering is equal to 0 dB, it is omnidirectional scattering; if the ratio of backscattering to forward scattering is greater than a set threshold, it is backscattering.

4. The method for controlling the scattering direction of a nano-antenna based on graphene dimers as described in claim 1, characterized in that, In the dielectric nanodimers with different radii, the polarizability of the graphene-encapsulated dielectric nanoparticles is: Among them, a 1,2 Let ε1 and ε2 be the radii of the two particles, respectively. h ε0 represents the dielectric constant of the internal medium of the graphene, the relative dielectric constant of the background material, and the dielectric constant in vacuum; c represents the speed of light in vacuum; d represents the distance between the two particles; i represents the imaginary unit; σ 1,2 Let be the conductivity of the two particles, and k be the wave vector.

5. The method for controlling the scattering direction of a nanoantenna based on graphene dimers as described in claim 1, characterized in that, The nonlinear equation system is as follows: In the formula, P 1,2 E is the dimensionless electric dipole moment and incident electric field, normalized over time, and γ is the electric dipole moment and incident electric field, respectively. 1,2 For the heat loss and radiation loss of the dimer, ω 01,02 Where σ is the resonant frequency (3) a is a third-order nonlinear term of the electrical conductivity of graphene. 1,2 τ represents the polarizability of the graphene-encapsulated dielectric nanoparticles, and τ is the normalized dimensionless time. Characterizing the dispersion of the system, Ω 1,2 ε1, ε are the detuning factors between the driving frequency and the resonant frequency. h ε0 represents the dielectric constant of the internal medium of graphene, the relative dielectric constant of the background material, and the dielectric constant in vacuum, respectively.

6. The method for controlling the scattering direction of a nano-antenna based on graphene dimers as described in claim 1, characterized in that, The dipole scattering intensity of the dielectric particle dimer nanoantennas with different radii is: In the formula, θ and y are the azimuth and polar angles of spherical coordinates, ΔΨ is the phase difference between the two electric dipoles, p1 is the electric dipole moment of the dielectric material particle with the first radius evolving over time, and p2 is the electric dipole moment of the dielectric material particle with the second radius evolving over time.

7. The method for controlling the scattering direction of a nanoantenna based on graphene dimers as described in claim 1, characterized in that, The time-evolution term has been removed from the nonlinear equations, which describe the static scattering characteristics of this dimer nanoantenna.

8. A nano-antenna scattering direction modulation device based on graphene dimer, characterized in that, include: The first calculation module is used to irradiate the dimer nanoantenna with a plane electromagnetic wave of a preset electric field amplitude and direction; wherein the dimer nanoantenna is composed of two nonlinear graphene-encapsulated dielectric particle nanodimer systems of different radii; and to calculate the nonlinear equations of the evolution of the electric dipole moments of the two particles of different radii constituting the dimer nanoantenna over time, wherein the nonlinear equations describe the dynamic scattering characteristics of the dielectric particle dimer nanoantenna of different radii under the excitation of the plane wave; the second calculation module is used to calculate the dipole scattering intensity of the dielectric particle dimer nanoantenna of different radii based on the nonlinear equations. The parameter adjustment module is used to adjust the parameters of the dimer nanoantenna and the frequency of the incident electric field to generate a preset phase difference in the electric dipole moments of the dimer nanoantenna interaction, thereby achieving unidirectional scattering. The scattering state switching module is used to switch the scattering state of the nanoantenna arbitrarily between omnidirectional scattering and backscattering by superimposing a Gaussian pulse on the incident background electric field according to the scattering intensity of the nanoantenna composed of dielectric particles of different radii.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps in the method for controlling the scattering direction of a graphene dimer-based nanoantenna as described in any one of claims 1-7.

10. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps in the method for controlling the scattering direction of a nano-antenna based on graphene dimers as described in any one of claims 1-7.

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