Radiation device based on free electron driving

Abstract

The invention provides a radiation device based on free electron driving. The radiation device comprises an electron beam injection module, a topological dielectric chain and an output port. The electron beam injection module injects a free electron beam into a preset moving track. A plurality of dielectric parts are arranged on the topological dielectric chain in the moving track direction, and electron beam energy is injected at the head end of the chain, directionally transmitted in an energy transmission channel formed in the chain and gathered at the tail end of the chain by regulating and controlling geometric structure parameters of the dielectric parts. The output port extracts electron beam energy and converts the electron beam energy into directional radiation signals to be output. The device is simple in structure, and stable and controllable one-way narrow-band radiation output can be realized under the condition that the structure is kept compact.

Description

Technical Field

[0001] This invention relates to the field of free electron radiation and micro / nano photonic devices, and particularly to a radiation device based on free electron drive. Background Technology

[0002] When a free electron beam moves near a dielectric or periodic structure, its following electric field exchanges energy with the local electromagnetic modes in the structure, producing Cherenkov radiation, Smith-Purcell radiation, and so on. These devices are widely used in the terahertz and mid-infrared frequency bands, but they generally suffer from weak output directionality. Summary of the Invention

[0003] This invention provides a radiation device based on free electron drive to overcome the weakness of traditional free electron radiation sources in terms of directionality. The device of this invention has a simple structure, controllable manufacturing requirements, can be efficiently excited by a free electron beam, and can transmit energy to the output end in a single direction.

[0004] This invention provides a radiation device based on free electron drive, comprising: an electron beam injection module for injecting a free electron beam into a preset operating trajectory; a topological dielectric chain disposed on the output side of the electron beam injection module, for arranging multiple dielectric elements along the operating trajectory direction, and for injecting electron beam energy at the beginning of the chain by adjusting the geometric parameters of the dielectric elements, for directional transmission of energy through an energy transmission channel formed within the chain, and for focusing at the end of the chain; and an output port disposed at the end of the topological dielectric chain for extracting electron beam energy and converting it into a directional radiation signal output.

[0005] According to the present invention, a radiation device based on free electron drive is provided, wherein the topological dielectric chain is disposed on a substrate and a protective layer is covered on the topological dielectric chain.

[0006] According to the present invention, a radiation device based on free electron drive is provided, wherein the energy of the free electron beam is 10keV-5MeV, and the lateral dimension is... .

[0007] According to the present invention, a radiation device based on free electron drive is provided, wherein the dielectric material used is at least one of Si, Si3N4, GaAs and LiNbO3.

[0008] According to the present invention, a radiation device based on free electron drive is provided, wherein the output port adopts a gradient waveguide, a subwavelength grating, or a micro-antenna structure.

[0009] According to the present invention, a radiation device based on free electron drive includes geometric parameters including alternating spacing between dielectric components; a topological dielectric chain is used to form a periodic distribution of strong and weak coupling by adjusting the alternating spacing to form the energy transmission channel; when the free electron beam runs along the side of the topological dielectric chain, the follower electric field interacts with the energy transmission channel to cause the electron beam energy to be directionally transmitted in the energy transmission channel.

[0010] According to the present invention, a radiation device based on free electron drive includes a lateral gap between the free electron beam and the topological dielectric chain as its geometric parameters; the topological dielectric chain is used to adjust the excitation intensity of the near-field electron beam on the chain head end by adjusting the lateral gap, so that the electron beam energy is injected at the chain head end.

[0011] According to the present invention, a radiation device based on free electron drive is provided, wherein the lateral gap is... .

[0012] According to the present invention, a radiation device based on free electron drive is provided, wherein the dielectric element is a dielectric sphere; the radius of the dielectric sphere in the infrared band is... The radius in the terahertz band is .

[0013] According to the present invention, a radiation device based on free electron drive is provided, wherein the alternating spacing includes at least a first spacing and a second spacing; the alternating spacing satisfies the following relationship: ; Wherein, d1 is the first spacing, d2 is the second spacing, and R is the radius of the dielectric sphere.

[0014] The present invention provides a radiation device based on free electron drive. The device has a simple structure and can achieve stable and controllable unidirectional narrowband radiation output while maintaining a compact structure. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in this 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 some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of a radiation device based on free electron drive provided by the present invention.

[0017] Figure 2This is a schematic diagram of a radiation device based on free electron drive provided by the present invention.

[0018] Figure 3 This is a schematic diagram of the energy distribution of an equally spaced microsphere chain structure.

[0019] Figure 4 This is a schematic diagram of the energy distribution of an alternating spacing microsphere chain structure.

[0020] Figure 5 This is a schematic diagram of the radiation directionality of the microsphere chain structure.

[0021] Figure 6 This is a schematic diagram of the radiation spectrum of the microsphere chain structure.

[0022] Figure 7 This is a schematic diagram illustrating the stability of the microsphere chain structure under geometric deviations. Detailed Implementation To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this 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 this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0024] When a free electron beam moves near a dielectric or periodic structure, its following electric field exchanges energy with local electromagnetic modes within the structure, producing Cherenkov radiation, Smith-Purcell radiation, and other similar phenomena. These devices are widely used in the terahertz and mid-infrared bands, but they generally suffer from: weak output directionality; typically broad spectrum; sensitivity to structural errors; and low efficiency due to the easy coupling of electron beam energy into non-target modes. In particular, periodic structures contain numerous phantoms and bleed channels, making it impossible for the electron beam to focus on exciting modes in a specific direction.

[0025] Microspheres possess significant multipolar scattering characteristics, including electric and magnetic dipoles, and exhibit rich local field directions, making them easy to match with the near-field of an electron beam. This invention provides a radiation device based on free electron drive, utilizing an edge transmission channel formed by alternating-spacing microsphere chains. Direct excitation by a free electron beam allows energy to be automatically transmitted along a single direction after electron injection, unaffected by local defects or manufacturing deviations, while simultaneously outputting a narrow spectrum and strong directionality.

[0026] Please refer to Figure 1 , Figure 1 This is a schematic diagram of a radiation device based on free electron drive, provided by the present invention.

[0027] Please refer to Figure 2 , Figure 2This is a schematic diagram of a radiation device based on free electron drive, provided by the present invention.

[0028] This invention provides a radiation device based on free electron drive, comprising: an electron beam injection module 1 for injecting a free electron beam into a preset running trajectory; a topological dielectric chain 2, disposed on the output side of the electron beam injection module 1, for arranging multiple dielectric elements along the running trajectory direction, and by adjusting the geometric structural parameters of the dielectric elements, allowing electron beam energy to be injected at the beginning of the chain, directionally transmitted through an energy transmission channel formed within the chain, and concentrated at the end of the chain; and an output port 3, disposed at the end of the topological dielectric chain 2, for extracting electron beam energy and converting it into a directional radiation signal output.

[0029] This invention provides a microstructure radiation device with a simple structure, controllable processing requirements, efficient excitation by a free electron beam, and the ability to transmit energy to the output end in a single direction. The device includes an electron beam injection module 1, a topological dielectric chain 2, and an output port 3. The electron beam injection module 1 provides a free electron beam, which, after shaping, travels along a specific trajectory (preset trajectory). The electron beam passes parallel to one side of the topological dielectric chain 2 (topological microsphere chain), maintaining a certain gap with the chain. The topological dielectric chain 2 is composed of multiple dielectric elements (dielectric microspheres) with high refractive index, arranged along the direction of the trajectory (one-dimensional direction), and possessing alternating spacing characteristics to form topological edge states. For example, the distance between the microspheres is arranged in a "near-far-near-far" manner, resulting in varying interaction strengths between adjacent microspheres. This alternating strong and weak coupling method naturally creates a localized energy transmission channel at one end of the chain. This channel has the following characteristics: energy is mainly concentrated near the very end of the chain; energy propagates along a fixed direction within the chain, rather than bidirectionally; and the transmission direction remains unchanged even if a small number of microspheres are missing or the spacing is off. When the electron beam travels near the microsphere chain, its follow-up electric field interacts with the resonant modes of the microspheres near their operating frequency. When the electron beam velocity is sufficiently close to the equivalent propagation velocity of this fixed-direction channel in the microsphere chain, the electron beam energy will preferentially be injected into the channel in that direction, rather than being dispersed into other modes. Ultimately, the energy transmitted along the chain is concentrated and directed to the output port 3 at the end of the chain, thereby achieving "automatic energy selection" and generating strong directional radiation. This achieves the effect of "automatic energy selection" and ultimately concentrating it at the output port at the end of the chain. The output port 3, located at the end of the chain, can be a graded waveguide, a subwavelength grating, or a micro-antenna structure, used to extract unidirectional electron beam energy and convert it into a directional electromagnetic radiation signal output.

[0030] The beneficial effects of this invention are as follows: The alternating-spacing microsphere chains used in this invention, by introducing a periodic combination of "strong coupling and weak coupling" in the structure, naturally form a fixed-direction energy transmission path. When a free electron beam grazes near the chain side, its follower electric field is more easily absorbed and drawn by this transmission path, thereby enabling the electron energy to automatically concentrate at one end of the chain, rather than diffusing to both sides simultaneously.

[0031] This structural energy bias makes the present invention significantly superior to equidistant chains or conventional periodic structures in terms of radiation directionality, energy concentration, and operational stability. Radiation output is more likely to exhibit a single dominant direction, and energy is not randomly distributed within the chain; the operating frequency is also more concentrated and less susceptible to multimode interference.

[0032] Furthermore, because the energy transmission direction is determined by the "strong-weak coupling relationship" rather than by the absolute size or precise spacing of the microspheres, this invention is insensitive to processing deviations, local defects, and slight positional errors. Even with some geometric offset or missing individual microspheres, the energy deflection and output direction remain stable, making the device more reliable in actual manufacturing and application.

[0033] This invention solves the problems of insufficient directionality, unstable spectrum, and sensitivity to defects in traditional free electron radiation sources by using a simple and feasible geometric structure, and can achieve stable and controllable unidirectional narrowband radiation output while maintaining a compact structure.

[0034] As a preferred embodiment, the geometric parameters include alternating spacing between dielectric components; a topological dielectric chain 2, used to form a periodic distribution of strong and weak coupling by adjusting the alternating spacing, thus forming an energy transmission channel; when the free electron beam runs along the side of the topological dielectric chain 2, the follower electric field interacts with the energy transmission channel, so that the electron beam energy is directionally transmitted in the energy transmission channel.

[0035] As a preferred embodiment, the geometric parameters also include a lateral gap between the free electron beam and the topological dielectric chain 2; the topological dielectric chain 2 is used to adjust the excitation intensity of the near field of the electron beam on the chain head end by adjusting the lateral gap, so that the electron beam energy is injected at the chain head end.

[0036] In this embodiment, when the electron beam sweeps along one side of the topological dielectric chain 2 of the device, a preset lateral gap d is maintained between the electron beam and the topological dielectric chain 2. This gap is a geometric parameter of the device, used to control the excitation intensity of the electron beam in the near field on the first microsphere in the chain, so that the energy carried by the electron beam can be effectively coupled into the topological dielectric chain 2 without causing contact or scattering loss.

[0037] The topological dielectric chain 2 of the device of the present invention is composed of multiple dielectric microspheres. The center-to-center distance between adjacent microspheres is alternately set in a sequence of alternating spacings (first spacing d1 and second spacing d2), where both the first spacing d1 and the second spacing d2 are preset geometric parameters. Due to the difference between the first spacing d1 and the second spacing d2, the coupling strength between adjacent microspheres exhibits a periodic distribution of "strong-weak-strong-weak," thereby forming an energy transmission path (channel) with directional bias within the chain. After the electron beam injects energy at the head of the chain, the energy will automatically propagate preferentially along the direction of stronger coupling, rather than diffusing evenly to both sides.

[0038] The near field of the electron beam contains multiple spatial components, some of which have propagation velocities close to the energy transfer velocity within the microsphere chain, thus enabling more efficient energy coupling. By adjusting the geometric relationships of the lateral gap d, the first spacing d1, and the second spacing d2, the device of this invention allows the energy of the electron beam to be stably injected into the chain and continuously transmitted in a single direction within the chain, ultimately being converted into a directional electromagnetic radiation signal at the output port 3 at the end of the chain.

[0039] Since the lateral gap d, the first spacing d1, and the second spacing d2 are all fixed geometric parameters, their strong and weak coupling relationships are directly determined by the microsphere chain layout. Therefore, the device has good tolerance for processing errors such as microsphere size deviation and arrangement deviation, and the energy transmission within the chain will not become unstable due to the size or positional displacement of individual microspheres. The device of this invention not only realizes unidirectional energy transmission but also significantly improves energy coupling efficiency, transmission stability, and output directionality.

[0040] In a preferred embodiment, the topological dielectric chain 2 is disposed on the substrate, and a protective layer is covered on the topological dielectric chain 2.

[0041] The choice of substrate needs to consider its mechanical stability, optical transparency, and compatibility with the dielectric microsphere material. In this embodiment, the topological dielectric chain 2 can be fixed on a silicon or quartz substrate. Silicon (Si) has good mechanical strength and thermal stability and is widely used in micro-nano fabrication, making it suitable for various optical devices. Quartz (SiO2) has high optical transparency, low absorption loss, and good chemical stability, making it suitable for applications requiring high optical performance.

[0042] The substrate provides stable physical support for the topological dielectric chain 2, preventing displacement or deformation of the microspheres during processing and use. In some cases, the substrate can provide optical isolation to prevent interference from the external environment on energy transfer within the microsphere chain. For high-power applications, the thermal conductivity of the substrate material can effectively manage heat and prevent overheating of the device.

[0043] The topological dielectric chain 2 needs to be firmly fixed to the substrate to ensure the stability of its structure. Fixing methods include: Chemical bonding: Microspheres are bonded to the substrate surface through chemical reactions. For example, chemical reagents such as silane coupling agents are used to form chemical bonds between the microsphere surface and the substrate surface, thereby achieving strong fixation.

[0044] Physical adsorption: Microspheres are adsorbed onto the substrate surface using van der Waals forces or electrostatic forces. This method is typically suitable for substrates with specially treated surfaces, such as those enhanced by plasma treatment or chemical modification to improve surface adsorption capacity.

[0045] Micro / nano fabrication technology: This method involves pre-fabricating microsphere fixation sites on a substrate using micro / nano fabrication techniques such as photolithography and etching, and then precisely placing the microspheres onto these sites. This method enables high-precision fixation and is suitable for applications requiring high structural accuracy.

[0046] The protective layer material covering the topological dielectric chain 2 needs to possess good optical transparency, chemical stability, and mechanical strength. Examples of suitable protective layer materials include: Silicon dioxide (SiO2): It has high optical transparency, low absorption loss and good chemical stability, making it suitable for use as an optical protective layer.

[0047] Silicon nitride (Si3N4): It has high hardness, good chemical stability and certain optical transparency, making it suitable for protective layers that require high mechanical strength.

[0048] Polymer materials, such as polymethyl methacrylate (PMMA), have good flexibility and optical transparency, making them suitable for applications requiring a lightweight protective layer.

[0049] The protective layer protects the topological dielectric chain 2 from external environmental factors (such as humidity and chemical corrosion), extending the device's lifespan. By adjusting the thickness and refractive index of the protective layer, the device's optical performance can be optimized, such as reducing reflection loss and increasing transmittance. It also provides additional mechanical strength to prevent physical damage to the microspheres during use.

[0050] As a preferred embodiment, the energy of the free electron beam is 10keV-5MeV, and the lateral dimension is... .

[0051] The electron beam injection module 1 can be a field emission electron gun, a thermionic emission electron gun, or a transmission electron microscope electron source.

[0052] Field emission electron guns use a strong electric field to emit electrons from the tip of a metal or conductive material. Their working principle is based on the quantum tunneling effect; when a sufficiently high electric field is applied, electrons can overcome the potential barrier and escape from the surface of the emitter.

[0053] Thermionic electron guns work by heating an emitter (usually a tungsten filament) to a high temperature, thus giving electrons enough energy to escape from the surface. Their working principle is based on a thermal excitation mechanism.

[0054] A transmission electron microscope (TEM) electron source is a high-precision electron beam generating device that can provide a high-precision electron beam, suitable for applications requiring high resolution and high energy density.

[0055] As a preferred embodiment, the refractive index material used in the dielectric element is at least one of Si, Si3N4, GaAs, and LiNbO3.

[0056] The dielectric microspheres of this invention can be fabricated using a variety of high refractive index materials such as silicon, silicon nitride, gallium arsenide, and lithium niobate, and the electron beam energy range covers a variety of application scenarios from low energy to high energy.

[0057] By adjusting the combination of microsphere radius and spacing, this invention can be applied to different frequency bands such as terahertz and mid-infrared, and has good scalability.

[0058] Silicon (Si) has a high refractive index (approximately 3.4-3.5) in the infrared band, which effectively enhances the localization effect of light. It also exhibits low absorption loss in the infrared band, making it suitable for optical devices. Silicon materials have mature technologies in the field of micro- and nano-fabrication. For example, high-purity silicon microspheres can be prepared using techniques such as chemical vapor deposition (CVD) or sol-gel methods. The high refractive index allows silicon microspheres to efficiently couple with the follower electric field of a free electron beam in optical resonance mode, improving energy injection efficiency. Low absorption loss ensures efficient energy transfer within the microsphere chain, reducing energy loss. Mature processing technologies result in low manufacturing costs for silicon microspheres, making them suitable for large-scale production and application.

[0059] Silicon nitride (Si3N4) has a refractive index of approximately 2.0-2.2, making it suitable for optical devices. It exhibits good chemical stability and corrosion resistance, making it suitable for various operating environments. Its excellent transparency across the visible to infrared spectrum makes it suitable for applications in multiple frequency bands. For example, silicon nitride microspheres can be fabricated using techniques such as chemical vapor deposition (CVD) or magnetron sputtering. The high refractive index and broad spectral transparency of silicon nitride microspheres enable efficient optical resonance across multiple frequency bands, adapting to diverse application scenarios. Its excellent chemical stability ensures stable performance even in complex operating environments. Mature fabrication technologies enable high-precision microsphere manufacturing, guaranteeing device performance and reliability.

[0060] Gallium arsenide (GaAs) has a refractive index of approximately 3.4-3.6, similar to silicon, which effectively enhances the localization effect of light. Its high electron mobility makes it suitable for high-power and high-frequency applications, and it can withstand large current densities. It exhibits low absorption loss in the infrared band, making it suitable for optical devices. For example, high-purity gallium arsenide microspheres can be fabricated using techniques such as molecular beam epitaxy (MBE) or metal-organic chemical vapor deposition (MOCVD). The high refractive index and low absorption loss of gallium arsenide microspheres enable efficient coupling of free electron beam energy in optical resonance mode, improving energy injection efficiency. The high electron mobility allows gallium arsenide microspheres to withstand large current densities, making them suitable for high-power and high-frequency applications. Excellent optical properties ensure efficient energy transfer within the microsphere chain, reducing energy loss.

[0061] Lithium niobate (LiNbO3) has a refractive index of approximately 2.2-2.3, making it suitable for optical devices. It exhibits a significant electro-optic effect, allowing its optical properties to be modulated by an electric field, making it suitable for dynamically controlled optical devices. It also has low absorption loss in the infrared band, further enhancing its suitability for optical applications. For example, high-purity lithium niobate microspheres can be prepared using techniques such as chemical vapor deposition (CVD) or sol-gel methods. The high refractive index and low absorption loss of lithium niobate microspheres enable efficient coupling of free electron beam energy in optical resonance mode, improving energy injection efficiency. The electro-optic effect allows for dynamic modulation of the optical properties of lithium niobate microspheres using an external electric field, making it suitable for applications requiring dynamic modulation. Excellent optical properties ensure efficient energy transfer within the microsphere chain, reducing energy loss.

[0062] As a preferred embodiment, output port 3 adopts a gradient waveguide, subwavelength grating, or microantenna structure.

[0063] This invention provides an output port 3, such as a graded waveguide, subwavelength grating, or microantenna device, at the end of the topological dielectric chain 2. This allows for the efficient extraction of energy transmitted along the chain and further forms a far-field radiation output with a clear direction and stable waveform. This output method avoids random energy dispersion at the chain end, improving the radiation efficiency and directional controllability of the device.

[0064] A graded waveguide is a waveguide structure whose structural parameters (such as width and height) gradually change along the propagation direction. Its main function is to gradually focus or diffuse the energy transmitted in a microsphere chain to achieve efficient energy conversion and radiation. Graded waveguides can flexibly adjust the direction and intensity of energy transmission, making them suitable for applications requiring high directionality and efficiency. Furthermore, their structure is relatively simple and easy to integrate with microsphere chains.

[0065] A subwavelength grating is a periodic structure with a period smaller than the operating wavelength. This structure can convert incident light or transmitted energy into radiation in a specific direction through diffraction. A subwavelength grating consists of a series of periodically arranged microstructures, which can be nanoscale pillars, holes, or other shapes. Subwavelength gratings exhibit highly directional and selective radiation characteristics, enabling narrowband radiation output. Furthermore, their compact structure makes them easy to integrate into micro / nano photonic devices, making them suitable for applications with high requirements for radiation direction and spectrum.

[0066] A microantenna is a miniaturized antenna structure capable of efficiently radiating electromagnetic energy to the far field. Its operating principle is similar to that of a traditional antenna, but its size is reduced to the micro-nano scale to meet the application requirements of micro-nano photonic devices. Microantennas can adopt various structural forms, such as dipole antennas and loop antennas. Microantennas possess high radiation efficiency and good directivity control capabilities, making them suitable for applications requiring high efficiency and high directivity radiation. Their diverse structures allow for flexible design and optimization according to specific needs, and they are easily integrated with other micro-nano photonic devices.

[0067] As a preferred embodiment, the lateral clearance is .

[0068] In a preferred embodiment, the dielectric element is a dielectric sphere; the radius of the dielectric sphere in the infrared band is... The radius in the terahertz band is .

[0069] In a preferred embodiment, the alternating spacing includes at least a first spacing and a second spacing; the alternating spacing satisfies the following relationship: ; Where d1 is the first spacing, d2 is the second spacing, and R is the radius of the dielectric sphere.

[0070] The center-to-center spacing of adjacent dielectric spheres (microspheres) alternates according to a first spacing d1 and a second spacing d2, forming a one-dimensional alternating coupled chain of microspheres. The alternating spacing is defined as follows: If the center position of the i-th microsphere is X i ,but: , In this invention, the first spacing d1 The second spacing is d2. The alternating spacing between the dielectric spheres is arranged in a repeating pattern of "d1-d2-d1-d2…". Here, d1 corresponds to "stronger coupling" and d2 corresponds to "weaker coupling".

[0071] The device design of this invention considers a selective energy coupling mechanism of the electron beam. When a free electron beam sweeps along the side of the microsphere chain, its follow-up electric field interacts with the localized propagation channel formed inside the microsphere chain. When the electron beam velocity is close to the equivalent propagation velocity of this propagation channel, electron energy will preferentially be injected into this fixed-direction channel in the chain, rather than entering other non-directional propagation modes, thereby achieving directional energy injection and transmission. This coupling method relies on the microsphere chain structure, rather than complex external control, and is repeatable and designable.

[0072] The following embodiments illustrate the structural configuration and parameter range of this device, aiming to demonstrate its feasibility under different materials, sizes, and application scenarios. All parameters are adjustable structural parameters and can be optimized according to application requirements.

[0073] For the terahertz band implementation, the chain length is 50 (number of Si microspheres), and the microsphere radius is... In an alternating spacing arrangement, the first segment of spacing The second segment spacing (Approximately 0.8R and 1.2R respectively); electron beam energy 100keV, initial transverse dimension approximately Vacuum channel gap between microsphere chains .

[0074] For the mid-infrared band embodiment, the chain length is 100 (number of Si3N4 microspheres), and the microsphere radius is... In an alternating spacing arrangement, the first segment of spacing The second segment spacing (Approximately 0.75R and 1.25R respectively); electron beam energy 200keV, initial transverse dimension approximately The gap between the inter-chain vacuum channels is approximately .

[0075] In applications requiring high current and high electron beam energy density, the chain length is 30 (number of GaAs microspheres), and the microsphere radius... In an alternating spacing arrangement, the first segment of spacing The second segment spacing (Approximately 0.85R and 1.1R respectively); electron beam energy 1MeV, initial lateral dimension approximately The gap between the inter-chain vacuum channels is approximately .

[0076] The device of this invention provides an energy conversion path for electron beams that is simple in structure, directional, and spectrally stable. It can be widely used in: narrowband radiation sources; chip-level photoelectric conversion units; directional excitation modules in detection, imaging, and communication systems; and has good integration potential and engineering application prospects.

[0077] Given that the equidistant microsphere chain structure is a uniformly coupled structure, energy will naturally diffuse to both sides simultaneously regardless of whether photoexcitation or electron beam excitation is used. The coupling strength between each microsphere and its adjacent microspheres is exactly the same, and there is no obvious preference in the transmission direction, resulting in a "left-right splitting" diffusion behavior of energy along the chain. This structure is also very sensitive to dimensional and positional errors in actual manufacturing. Even slight defects in a few microspheres can disrupt the coupling phase within the chain, leading to significant overall energy attenuation and poorer directionality, making it difficult to achieve effective unidirectional transmission and stable output.

[0078] This invention not only designs a microsphere chain structure but also optimizes the spacing design. The invention employs an alternating spacing microsphere chain structure, creating a periodic structure of "strong coupling-weak coupling-strong coupling" between adjacent microspheres. This feature is independent of the specific material or size of the microspheres; as long as d1≠d2 and the sequence is fixed, a stable energy bias can be formed. This slight geometrical breaking of symmetry causes the energy coupling path to automatically favor the strongly coupled side, naturally forming a directional transmission channel at one end of the chain where energy is more easily concentrated and output, approximating a "unidirectional bias." When the electron beam sweeps along one side of the chain, because the strength of its near-field interaction with the microsphere chain corresponds precisely to the "strong-weak" coupling sequence in the chain, the injected energy naturally flows along this bias channel towards one end of the chain, rather than diffusing evenly to both sides, reducing backpropagation. More importantly, the coupling relationship of each unit in the alternating spacing structure is geometrically "fixed." Directional transmission is determined by the "strength of coupling," not by absolute spacing or precise geometric dimensions. Therefore, when local dimensional errors, spacing deviations, or missing microspheres occur in the chain, this strong-weak relationship is not disrupted, and energy can still be stably transmitted along the bias direction. This is why the device of this invention exhibits good stability and defect tolerance. This invention still possesses significant directional maintenance capability under manufacturing errors, local defects, or external disturbances, demonstrating strong resistance to deviation.

[0079] Please refer to Figure 3 , Figure 3 This is a schematic diagram of the energy distribution of an equally spaced microsphere chain structure.

[0080] Please refer to Figure 4 , Figure 4 This is a schematic diagram of the energy distribution of an alternating spacing microsphere chain structure.

[0081] In a microsphere chain structure with equal spacing, energy diffuses simultaneously along both sides of the chain, making directional propagation difficult. In a microsphere chain structure with alternating spacing, energy is concentrated and transported along a specific direction within the chain and accumulates at the chain ends. Even with local microsphere defects or spacing deviations, stable directional characteristics can still be maintained.

[0082] Please refer to Figure 5 , Figure 5 This is a schematic diagram of the radiation directionality of the microsphere chain structure.

[0083] The radiative energy of the equally spaced microsphere chain structure is dispersed in multiple directions (blue curve). The radiation of the alternating-spaced microsphere chain structure exhibits a single main direction (red curve) due to the deflected energy transfer within the chain, thus enhancing its directivity.

[0084] Please refer to Figure 6 , Figure 6 This is a schematic diagram of the radiation spectrum of the microsphere chain structure.

[0085] Equally spaced microsphere chains are prone to multimode superposition, leading to increased spectral width. In microsphere chains with alternating spacing, energy is mainly injected into a single transmission path, resulting in a more concentrated output spectrum and a more prominent main peak.

[0086] Please refer to Figure 7 , Figure 7 This is a schematic diagram illustrating the stability of the microsphere chain structure under geometric deviations.

[0087] In the case of microsphere chain structures with equal spacing, the radiation direction is prone to significant shift when there are errors in microsphere size or spacing deviations. In contrast, microsphere chain structures with alternating spacing, because they rely on the strength of coupling rather than absolute size, can maintain the stability of the output direction even with certain geometric deviations.

[0088] The problem with equally spaced microsphere chain structures lies in their coupling symmetry, uncontrollable orientation, and sensitivity to defects. Alternating-spacing microsphere chain structures, however, break this coupling symmetry, "guiding" energy to concentrate at one end of the chain. This fundamentally changes the way energy propagates within the microsphere chain, achieving unidirectional stable transmission and controllable output—features impossible with traditional structures. These characteristics stem from a defined geometric structure, rather than a theoretical model, thus possessing excellent feasibility and engineering applicability.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A radiation device based on free electron drive, characterized in that, include: The electron beam injection module is used to inject a free electron beam into a preset running trajectory; A topological dielectric chain is disposed on the output side of the electron beam injection module. It is used to arrange multiple dielectric elements along the running trajectory direction. By adjusting the geometric structural parameters of the dielectric elements, electron beam energy is injected at the beginning of the chain, the energy transmission channel formed in the chain is directionally transmitted, and the energy is concentrated at the end of the chain. An output port, located at the end of the topological dielectric chain, is used to extract electron beam energy and convert it into a directional radiation signal output.

2. The radiation device based on free electron drive according to claim 1, characterized in that, The topological dielectric chain is disposed on the substrate, and a protective layer is covered on the topological dielectric chain.

3. The radiation device based on free electron drive according to claim 1, characterized in that, The free electron beam has an energy of 10keV-5MeV and a lateral dimension of [missing information]. .

4. The radiation device based on free electron drive according to claim 1, characterized in that, The dielectric material used is at least one of Si, Si3N4, GaAs, and LiNbO3.

5. The radiation device based on free electron drive according to claim 1, characterized in that, The output port adopts a gradient waveguide, subwavelength grating, or micro-antenna structure.

6. The radiation device based on free electron drive according to any one of claims 1 to 5, characterized in that, The geometric parameters include the alternating spacing between dielectric components; The topological dielectric chain is used to form a periodic distribution of strong and weak coupling by adjusting the alternating spacing, thereby forming the energy transmission channel. When the free electron beam runs along the side of the topological dielectric chain, the follower electric field interacts with the energy transmission channel to cause the electron beam energy to be directionally transmitted in the energy transmission channel.

7. The radiation device based on free electron drive according to claim 6, characterized in that, The geometric parameters also include the lateral gap between the free electron beam and the topological dielectric chain; The topological dielectric chain is used to adjust the excitation intensity of the electron beam near field on the chain head end by controlling the lateral gap, so that the electron beam energy is injected at the chain head end.

8. The radiation device based on free electron drive according to claim 7, characterized in that, The lateral clearance is .

9. The radiation device based on free electron drive according to claim 6, characterized in that, The dielectric element is a dielectric sphere; the radius of the dielectric sphere in the infrared band is... The radius in the terahertz band is .

10. The radiation device based on free electron drive according to claim 9, characterized in that, The alternating spacing includes at least a first spacing and a second spacing; The alternating spacing satisfies the following relationship: ； Wherein, d1 is the first spacing, d2 is the second spacing, and R is the radius of the dielectric sphere.

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