Multi-frequency and multi-port terahertz source generation method based on stimulated amplified coherent emission

Abstract

The present invention provides a multi-frequency, multi-port terahertz source generation method based on stimulated amplification of coherent radiation, comprising: obtaining free electrons emitted by an electron emission source and accelerating the free electrons to a set speed; initially clustering the accelerated free electrons under the action of an external pump source to form primary electron clusters; interacting the primary electron clusters with a clustering grating to generate coherent electromagnetic radiation to achieve electron clustering; based on the interaction of the coherent electromagnetic radiation with the radiation grating in a resonant cavity structure to form stimulated amplified coherent electromagnetic radiation, the electron clustering is enhanced, the size of the electron clusters is reduced, and high-density periodic clustered electron clusters are obtained; the periodic clustered electron clusters interact with the radiation grating to generate high-order frequency-doubled coherent electromagnetic radiation signals, which are output from a port, the terminal window containing a diamond window, and the output waveguide connected to the resonant cavity. The present invention solves the problems of existing small-scale terahertz electronic devices operating at room temperature that are difficult to increase the frequency and effectively compress the radiation linewidth.

Description

Technical Field

[0001] The present invention relates to the field of signal processing technology, and in particular to a method for generating a multi-frequency multi-port terahertz source based on stimulated amplified coherent radiation. Background Art

[0002] Terahertz (1THz=10 12 Terahertz (THz) waves refer to electromagnetic waves with frequencies in the 0.1THz-10 THz frequency range. Terahertz waves have strong penetrability and can be used in the field of security detection. In addition, the photon energy of terahertz waves is low and the coherence is good, which has important application value in the fields of communication, medical treatment, detection, etc. Terahertz technology is considered to be one of the most important technologies of the future. Smith-Purcell radiation (SPR) refers to the electromagnetic radiation generated when a DC electron beam flies over the surface of a periodic grating. By designing the parameters of the electron beam and the grating period, the output of electromagnetic waves with a specific wavelength and a specific angle can be achieved. Stimulated SPR refers to the generation of SPR by free electrons under the action of external pumping, realizing the interaction between electromagnetic waves and electron beams, and realizing the positive feedback process of energy interaction. In this process, the DC electron beam will form periodic clusters of electrons, carrying rich high-order harmonic frequency components. The high-order frequency-doubled THz radiation can be further extracted through the small-period grating. When electrons are clustered into a single electron cluster whose spatial length is smaller than the radiation wavelength, the interaction between the electron cluster and the grating structure will produce electromagnetic radiation with enhanced intensity. This radiation is called coherent SPR, which has an enhanced radiation effect and is considered to be the most effective way to realize a radiation light source. It also has the characteristics of a narrowed spectral linewidth, realizing a high-intensity THz radiation source.

[0003] Currently, miniaturized free-electron THz radiation devices face the challenge of increasing their frequency. Coherent SPR is coherent electromagnetic radiation generated by periodic clusters of electrons flying across a grating surface. High-order frequency-doubled radiation based on coherent SPR is expected to increase the radiation frequency. Although high-frequency THz coherent SPR has been achieved in electron accelerators, achieving high-frequency coherent SPR in miniaturized devices remains a major challenge. In addition, the generation of THz waves is susceptible to factors such as precision machining and assembly, micro-electron beam forming and focusing, and high-efficiency extraction and output of terahertz signals. The radiation linewidth is difficult to effectively compress, and the linewidth generally exceeds the MHz limit. Summary of the Invention

[0004] The present invention provides a method for generating a multi-frequency and multi-port terahertz source based on stimulated amplified coherent radiation, which is used to solve the problems that the frequency of existing miniaturized terahertz electronic devices operating at room temperature is difficult to increase and the radiation linewidth cannot be effectively compressed.

[0005] The present invention provides a method for generating a multi-frequency and multi-port terahertz source based on stimulated amplified coherent radiation, comprising:

[0006] Obtaining free electrons emitted by a preset electron emission source, and accelerating the free electrons to a set speed;

[0007] The accelerated free electrons are initially clustered under the action of an external pump source to form primary electron clusters;

[0008] The primary electron clusters after preliminary clustering interact with the clustering grating to generate coherent electromagnetic radiation to achieve electron clustering;

[0009] Based on the coherent electromagnetic radiation forming stimulated amplified coherent electromagnetic radiation with the radiation grating in the preset resonant cavity structure, the electron clustering is enhanced, the size of the electron cluster is reduced, and a high-density periodic clustered electron cluster is obtained;

[0010] The periodic clustered electron clusters interact with the radiation grating to generate corresponding high-order frequency-doubled coherent electromagnetic radiation signals. The high-order frequency-doubled coherent radiation is output from the port. The end window contains a diamond window and is connected to the resonant cavity through an output waveguide.

[0011] According to a multi-frequency multi-port terahertz source generation method based on stimulated amplified coherent radiation provided by the present invention, the method of obtaining free electrons emitted by a preset electron emission source and accelerating the free electrons to a set speed specifically includes:

[0012] The electron emission source generates an electron beam with a set beam spot size and current according to a set operating frequency;

[0013] Accelerate the electrons in the electron beam to the set speed required for device operation.

[0014] According to a multi-frequency multi-port terahertz source generation method based on stimulated amplified coherent radiation provided by the present invention, the accelerated free electrons are initially clustered under the action of an external pump source to form primary electron clusters, specifically comprising:

[0015] The pump source generates a pump signal which is input into the resonant cavity to excite a periodic electromagnetic field on the surface of the preset clustered grating structure;

[0016] The frequency range of the pump signal covers the microwave and terahertz bands, and performs preliminary clustering of DC electrons to form primary electron clusters.

[0017] According to a method for generating a multi-frequency multi-port terahertz source based on stimulated amplification of coherent radiation provided by the present invention, the method comprises:

[0018] Adjusting the resonance mode by designing and optimizing the period, height, and width parameters of the cluster grating;

[0019] After the initial clustering, the primary electrons interact with the clustering grating structure to produce coherent electromagnetic radiation;

[0020] The pump source and the coherent electromagnetic radiation signal form a periodic electromagnetic field on the surface of the clustering grating to modulate the electron energy and realize electron clustering.

[0021] According to the present invention, a multi-frequency, multi-port terahertz source generation method based on stimulated amplification of coherent radiation is provided. The method forms stimulated amplification of coherent electromagnetic radiation with a radiation grating in a preset resonant cavity structure, while enhancing electron clustering and reducing the size of electron clusters to obtain high-density periodically clustered electron clusters. The method specifically includes:

[0022] Setting the period, height and width parameters of the radiation grating to determine the corresponding resonance mode;

[0023] Based on the resonance model, the interaction between periodically clustered electrons and the radiating grating structure generates corresponding high-order frequency-doubled coherent electromagnetic radiation signals, outputs high-order frequency-doubled coherent electromagnetic radiation, and at the same time enhances electron clustering and reduces the size of electron clusters. The clustered electron clusters generate stronger coherent electromagnetic radiation, forming a positive feedback process of energy interaction between electron clustering and coherent electromagnetic radiation, namely the stimulated coherent electromagnetic radiation process, to obtain high-density periodically clustered electron clusters.

[0024] The present invention also provides a multi-frequency multi-port terahertz source generation system based on stimulated amplified coherent radiation, the system comprising:

[0025] An electron acquisition module, configured to acquire free electrons emitted by a preset electron emission source and accelerate the free electrons to a set speed;

[0026] The preliminary clustering module is used to perform preliminary clustering of the accelerated free electrons under the action of an external pump source to form primary electron clusters;

[0027] A deep clustering module is used to interact the primary electron clusters after preliminary clustering with the clustering grating to generate coherent electromagnetic radiation to achieve electron clustering;

[0028] A high-order frequency doubling module is used to form stimulated amplified coherent electromagnetic radiation based on the coherent electromagnetic radiation and the radiation grating in a preset resonant cavity structure, while enhancing electron clustering, reducing the size of electron clusters, and obtaining high-density periodic clustered electron clusters;

[0029] The output module is used for the interaction between the periodic clustered electron clusters and the radiation grating to generate corresponding high-order frequency-doubled coherent electromagnetic radiation signals. The high-order frequency-doubled coherent radiation is output from the port. The end window contains a diamond window and is connected to the resonant cavity through an output waveguide.

[0030] The present invention also provides a multi-frequency multi-port terahertz source generation device based on stimulated amplified coherent radiation, comprising:

[0031] Electron emission sources, resonant cavities, pump sources, cluster gratings and radiation gratings;

[0032] The resonant cavity is an oxygen-free copper tube, and the electron emission source is installed at the end of the resonant cavity to emit free electrons into the resonant cavity;

[0033] The pump source is arranged on the outer side of the resonant cavity, and transmits a pump signal into the resonant cavity through the pump source;

[0034] The clustering grating is arranged at the inner edge of the resonant cavity close to the electron emission source, and the radiation grating is arranged at the inner edge of one end of the resonant cavity away from the electron emission source.

[0035] According to the present invention, a multi-frequency multi-port terahertz source generation device based on stimulated amplified coherent radiation further includes: a magnetic ring is provided on each circle of the resonant cavity, the magnetic ring surrounds the oxygen-free copper tube of the resonant cavity, and the magnetic field generated by the magnetic ring is used to focus the electron beam;

[0036] A periodic pole shoe structure is wrapped around the cylindrical outer surface of the oxygen-free copper tube, and a periodic magnetic ring for focusing the electron beam is assembled through the pole shoe structure. A periodic permanent magnet focusing system is composed of multiple periodic magnetic rings. The magnetic rings are arranged in a manner of axial magnetization repulsion, and the magnetic induction intensity at the center of the magnetic ring presents a sinusoidal distribution curve along the direction of electron flight.

[0037] According to the present invention, a multi-frequency multi-port terahertz source generating device based on stimulated amplified coherent radiation further includes:

[0038] An electron collector is adjacent to the magnetic ring and is disposed at the end of the resonant cavity. The electrons that have interacted with the clustering grating and the radiation grating are collected by the electron collector.

[0039] The present invention provides a multi-frequency, multi-port terahertz source generation method based on stimulated amplified coherent radiation. This method achieves high-order frequency-doubled terahertz radiation through a stimulated coherent electromagnetic radiation mechanism. Free electrons are initially clustered under the action of an external pump source, then interact with corresponding clustering gratings to generate coherent electromagnetic radiation. This stimulated amplified coherent electromagnetic radiation forms in a resonant cavity structure, resulting in high-density periodic clusters of electrons. This effectively reduces the requirements for the electron source, particularly the current and beam focusing requirements. Furthermore, the clustering frequency of the obtained periodic electron clusters and their high-order frequency-doubled components are determined solely by the frequency of the pump wave, effectively avoiding operating frequency drift and spectrum broadening caused by operating voltage jitter. High-order frequency-doubled radiation is achieved. The multi-frequency radiation grating design allows for the extraction of rich high-order frequency-doubled information, and the radiation power can be adjusted according to the structural design and electron source parameters. This solves the problem of extracting different high-order frequency-doubled radiation at different angles. Furthermore, it fully extracts the radiation energy, improving the overall energy utilization of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0041] Figure 1 This is one of the flow charts of a method for generating a multi-frequency and multi-port terahertz source based on stimulated amplified coherent radiation provided by the present invention;

[0042] Figure 2 This is the second flow chart of a method for generating a multi-frequency and multi-port terahertz source based on stimulated amplified coherent radiation provided by the present invention;

[0043] Figure 3 This is the third flow chart of a method for generating a multi-frequency and multi-port terahertz source based on stimulated amplified coherent radiation provided by the present invention;

[0044] Figure 4 This is the fourth flow chart of a method for generating a multi-frequency and multi-port terahertz source based on stimulated amplified coherent radiation provided by the present invention;

[0045] Figure 5 This is the fifth flow chart of a method for generating a multi-frequency and multi-port terahertz source based on stimulated amplified coherent radiation provided by the present invention;

[0046] Figure 6 This is a schematic diagram of module connections of a multi-frequency, multi-port terahertz source generation system based on stimulated amplified coherent radiation provided by the present invention;

[0047] Figure 7 This is a schematic structural diagram of a terahertz source generating device provided by the present invention;

[0048] Figure 8 Schematic diagram of the dispersion curve formed by the resonant cavity and cluster grating structure provided by the present invention;

[0049] Figure 9 This is a schematic diagram of energy changes in the interaction between the DC electron beam and the cluster grating structure provided by the present invention;

[0050] Figure 10 Schematic diagram of the electron density spatial distribution after energy modulation provided by the present invention;

[0051] Figure 11 It is a schematic diagram of the overall structure of an exemplary multi-frequency device provided by the present invention.

[0052] Reference numerals:

[0053] 1: Electron emission source; 2: Resonant cavity; 3: Pump source; 4: Cluster grating; 5: Radiation grating; 6: High-order frequency-doubled coherent electromagnetic radiation signal; 7: Magnetic ring; 8: Electron collector;

[0054] 110: electron acquisition module; 120: preliminary clustering module; 130: deep clustering module; 140: high-order frequency multiplication module; 150: output module. DETAILED DESCRIPTION

[0055] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0056] The following combination Figure 1-Figure 5 The present invention describes a method for generating a multi-frequency and multi-port terahertz source based on stimulated amplified coherent radiation, comprising:

[0057] S100, obtaining free electrons emitted by a preset electron emission source 1, and accelerating the free electrons to a set speed;

[0058] S200, the accelerated free electrons are initially clustered under the action of an external pump source 3 to form a primary electron cluster;

[0059] S300, the primary electron clusters after preliminary clustering interact with the clustering grating 4 to generate coherent electromagnetic radiation to achieve electron clustering;

[0060] S400, based on the coherent electromagnetic radiation forming stimulated amplified coherent electromagnetic radiation with the radiation grating 5 in the preset resonant cavity 2 structure, while enhancing electron clustering, reducing the size of electron clusters, and obtaining high-density periodic clustered electron clusters;

[0061] S500, the periodic clustered electron clusters interact with the radiation grating to generate corresponding high-order frequency-doubled coherent electromagnetic radiation signals, the high-order frequency-doubled coherent radiation is output from the port, the end window contains a diamond window, and is connected to the resonant cavity through an output waveguide.

[0062] The multi-frequency, multi-port design extracts a wealth of high-order frequency harmonics information one by one, and the radiation power can be adjusted according to the structural design and electron source parameters. On the one hand, this solves the problem of extracting different high-order frequency harmonics at different angles; on the other hand, it fully extracts the radiation energy, improving the overall energy utilization of the device. The grating structure can be changed according to the different application scenarios of the device to extract radiation of different high-order frequency harmonics.

[0063] In this invention, high-order frequency-doubled terahertz (THz) radiation is achieved through a stimulated coherent SPR mechanism. Free electrons are initially clustered by an external pump source 3, then interact with the corresponding clustering grating 4 to generate coherent SPR. This stimulated amplified coherent SPR forms within the resonant cavity 2, resulting in high-density, periodic clusters of electrons. The signal transmitted by the grating structure contains abundant high-order frequency-doubled information. This high-order frequency-doubled signal can be extracted through the radiation grating 5, yielding high-intensity, highly coherent, and high-frequency-doubled THz radiation.

[0064] Smith-Purcell radiation (SPR) refers to the electromagnetic radiation generated when a DC electron beam flies over the surface of a periodic grating. The wavelength of the radiation is:

[0065]

[0066] Where λ is the radiation wavelength, L is the grating period, v is the electron velocity, c is the speed of light, θ is the electromagnetic radiation angle, and m is the SPR order. By designing the parameters of the electron beam and the grating period, electromagnetic wave output of a specific wavelength and angle can be achieved.

[0067] For radiation gratings 5 ​​of the same structural dimensions, the radiation angles, radiation intensities, and radiation linewidths of different high-order frequency-doubled radiations are all different, which brings certain difficulties to the extraction and utilization of different high-order frequency-doubled radiations. In the present invention, through the cascade design of multiple sections of radiation gratings 5, the rich high-order frequency-doubled information can be extracted one by one, and the radiation power can be adjusted according to the structural design and electron source parameters. On the one hand, the problem of extracting different high-order frequency-doubled radiation angles is solved; on the other hand, the radiation energy is fully extracted, improving the overall energy utilization rate of the device. The grating structure can be changed according to the different application scenarios of the device to extract radiation of different high-order frequency-doubled radiation.

[0068] Obtaining free electrons emitted by a preset electron emission source 1 and accelerating the free electrons to a set speed specifically includes:

[0069] S101, the electron emission source 1 generates an electron beam with a set beam spot size and current according to a set operating frequency;

[0070] S102, accelerating the electrons in the electron beam to a set speed required for device operation.

[0071] refer to Figure 7 The present invention also provides a resonant cavity 2 structure, the material of which is oxygen-free copper, which has high thermal conductivity, electrical conductivity and anti-magnetic interference characteristics, and processes the grating structure and resonant structure used for electron clustering and frequency doubling radiation inside the oxygen-free copper tube.

[0072] The electron emission source 1 can adjust the frequency according to actual working frequency requirements to meet actual application needs.

[0073] The accelerated free electrons are initially clustered under the action of the external pump source 3 to form primary electron clusters, specifically including:

[0074] S201, generating a pump signal through the pump source 3 and inputting it into the resonant cavity 2, thereby exciting a periodic electromagnetic field on the surface of the preset cluster grating 4 structure;

[0075] S202 , the frequency range of the pump signal covers the microwave and terahertz bands, and the DC electrons are preliminarily clustered to form primary electron clusters.

[0076] In the present invention, the pump source 3 is 0.1 THz, and the dispersion curve formed by the resonant cavity 2 and the cluster grating 4 structure is as follows: Figure 8 As shown in the figure, the electron beam energy is 22keV and the current is 50mA. The external pump signal excites a vertical resonant mode within the structure, with the corresponding group velocity being zero and the phase velocity approaching infinity. The marked points represent the 0.1THz vertical resonant mode within the waveguide excited by the clustered electrons.

[0077] When a THz wave impinges on a metallic grating, it excites a surface electromagnetic mode (EM) within the grating, generating a localized field between the grating slits. The dispersion relation of this surface electromagnetic mode is similar to that of surface plasmon polaritons (SPPs) in visible light, leading to the term "artificial SPPs." First, the localized field formed between the grating slits modulates the spatial density of the flying DC electron beam, generating periodic electron clusters at the THz clustering frequency. A THz wave with frequency fp and polarization along the z-direction perpendicularly pumps the metallic copper grating structure, generating an in-phase localized electric field (Ez) between the grating slits. This electric field, Ez, oscillates at fp and periodically varies with the pump wave. When a DC electron beam flies across the metallic grating structure in the +z direction, and the electron's velocity matches the phase variation of the THz pump wave, the in-phase localized electric field clusters the DC electrons. During the clustering process, the pump signal oscillates at exactly one frequency for each grating period L1, satisfying the relationship fp = v / L1. External pump signal power levels of 1mW to 1W are applicable, while electron beam energy ranges from 10 to 30keV, beam spot diameters from 100 to 120μm, and beam currents from 10 to 50mA.

[0078] Lowering the radiation frequency places even more stringent demands on the electron source: the electron beam diameter must be small enough to ensure close proximity to the interacting structure to generate a radiation field; and the electron beam current intensity must be high enough to achieve the gain condition for stimulated emission. As the radiation frequency continues to increase, the electron beam diameter must be reduced to tens of microns, often requiring focusing with a strong magnetic field. Furthermore, as the electron beam diameter decreases, the Coulomb repulsion effect intensifies, making it difficult to maintain a current intensity above the current threshold for stimulated emission.

[0079] The present invention utilizes an external pump source 3 to initiate the initial clustering of free electrons. During this process, the Coulomb repulsion effect is weakened, and the requirements for electron beam spot focus are reduced. After initial clustering, the electron beam interacts with the clustering grating 4 to generate coherent SPR signals. This stimulated amplification of the coherent SPR signals is achieved within the resonant cavity 2 structure, resulting in high-density, periodically clustered electron clusters. This method effectively reduces the requirements for the electron source, particularly the current and beam spot focus.

[0080] The primary electron clusters after preliminary clustering interact with the clustering grating 4 to generate coherent electromagnetic radiation to achieve electron clustering, specifically including:

[0081] S301, adjusting the resonance mode by designing and optimizing the period, height, and width parameters of the cluster grating 4;

[0082] S302, the primary electron clusters after preliminary clustering interact with the clustering grating 4 structure to generate coherent electromagnetic radiation;

[0083] S303, the pump source 3 and the coherent electromagnetic radiation signal form a periodic electromagnetic field on the surface of the clustering grating 4 to modulate the electron energy to achieve electron clustering.

[0084] Initially clustered electrons flying across the surface of clustering grating 4 can stimulate a coherent SPR with a resonant frequency fp perpendicular to the y-axis, further enhancing the density modulation of the pre-clustered electrons. The enhanced density modulation of the clustered electrons further stimulates the generation of an enhanced coherent SPR. This cycle repeats, with the enhanced density modulation of the clustered electrons and the enhanced coherent SPR forming a positive feedback loop until the electron clustering reaches an optimal stable state, similar to the "stimulated amplification" phenomenon in lasers. During this positive feedback process, the coherent SPR continuously clusters electrons. The generation of the coherent SPR is due to the excitation of the pre-clustered electrons, so this electron clustering process is called pre-clustered electron-induced stimulated coherent SPR clustering. In this example, the corresponding L1 is 0.836 mm, and the grating period N1 of clustering grating 4 is 64. Figure 9 This is the energy change during the interaction between the DC electron beam and the clustering grating 4. It can be observed that as the two interact, the clustering of the electron beam gradually tends to the "optimal clustering" (the slope of the energy and spatial position gradually becomes "upright"). Figure 10 The spatial distribution of electron density along the flight direction of the electron beam is shown in Figure 2. DC electrons form periodic electron clusters in space, and the density peak value within a single electron cluster increases significantly compared to the initial value. Figure 7 In the middle, a high-order frequency-doubled coherent electromagnetic radiation signal 6 is output, and the end window contains a diamond window, which is connected to the oxygen-free copper material through an output waveguide.

[0085] The present invention effectively avoids operating frequency drift and spectrum broadening caused by operating voltage fluctuations. The electron gun operating voltage typically fluctuates by hundreds of volts, which can cause operating frequency drift and broaden the coherent radiation spectrum linewidth. The clustering frequency of the periodic electron clusters obtained in the present invention, as well as its higher-order harmonic components, are determined solely by the frequency of the pump wave. This characteristic prevents radiation frequency drift caused by voltage fluctuations, resulting in only a small shift in the radiation angle without broadening the coherent radiation spectrum linewidth. Consequently, the output signal is stable and unaffected by electron beam voltage fluctuations.

[0086] Based on the coherent electromagnetic radiation forming stimulated amplified coherent electromagnetic radiation with the radiation grating 5 in the preset resonant cavity 2 structure, the electron clustering is enhanced, the size of the electron cluster is reduced, and a high-density periodic clustered electron cluster is obtained, specifically including:

[0087] S401, setting the period, height, and width parameters of the radiation grating 5 to determine the corresponding resonance mode;

[0088] S402. Based on the resonant model, the periodic clustering of electrons and the radiation grating 5 structure interact to generate corresponding high-order frequency-doubled coherent electromagnetic radiation signals, output high-order frequency-doubled coherent electromagnetic radiation, and at the same time enhance electron clustering and reduce the size of electron clusters. The clustered electron clusters generate stronger coherent electromagnetic radiation, forming a positive feedback process of energy interaction between electron clustering and coherent electromagnetic radiation, that is, a stimulated coherent electromagnetic radiation process, to obtain high-density periodic clustered electron clusters.

[0089] On the basis of obtaining a periodic electron cluster with a cluster frequency of 0.1THz, the first radiation grating 5 with a period p1 = L1 / 3 = 278μm interacts with the electron cluster to generate 0.3THz tripled frequency coherent SPR radiation. The period length of the second radiation grating 5 is p2 = L1 / 4 = 210μm (to extract the quadruple frequency coherent SPR radiation), and the period length of the third radiation grating 5 is p3 = L1 / 5 = 168μm (to extract the quintuple frequency coherent SPR radiation). The overall structure of the device is as follows: Figure 11 shown.

[0090] The above process in this invention uses a 0.1 THz pump source 3, a 22 keV electron emission source 1, and triple, quadruple, and quintuple frequency radiation extraction as examples. If the input frequency of pump source 3 is changed to a microwave signal or other THz frequency band signal, by adjusting the structure of cluster grating 4 and resonant cavity 2, coherent SPR signals generated by stimulated amplification of microwave or other THz frequencies can also be achieved. Furthermore, by optimizing the design of radiation grating 5, other higher-order frequency-doubled signals can be generated.

[0091] The present invention solves the problem of extracting different high-order frequency harmonic radiation at different angles, and realizes the output of multiple frequencies; taking the pump source 3 as 0.1THz as an example, for the third-order frequency harmonic radiation grating 5, it can be obtained from formula (1-1) that the radiation angles θ=90° and θ=28° meet the orders n=3 and n=4 of the frequency harmonic components in the evanescent field, and combined with the structure of the resonant cavity 2, only the vertical port is convenient for extracting radiation of the corresponding order. In this patent, the design of the multi-order frequency harmonic radiation grating 5 can extract rich high-order frequency harmonic information, and the radiation power can be adjusted according to the structural design and electron source parameters. On the one hand, it solves the problem of extracting different high-order frequency harmonic radiation at different angles; on the other hand, it fully extracts the radiation energy, improving the overall energy utilization of the device.

[0092] refer to Figure 6 The present invention also discloses a multi-frequency multi-port terahertz source generation system based on stimulated amplified coherent radiation, the system comprising:

[0093] The electron acquisition module 110 is used to acquire free electrons emitted by the preset electron emission source 1 and accelerate the free electrons to a set speed;

[0094] The preliminary clustering module 120 is used to perform preliminary clustering of the accelerated free electrons under the action of the external pump source 3 to form primary electron clusters;

[0095] The deep clustering module 130 is used to interact the initially clustered primary electron clusters with the clustering grating 4 to generate coherent electromagnetic radiation to achieve electron clustering;

[0096] The high-order frequency multiplication module 140 is used to form stimulated amplified coherent electromagnetic radiation based on the coherent electromagnetic radiation and the radiation grating 5 in the preset resonant cavity 2 structure, while enhancing electron clustering, reducing the size of electron clusters, and obtaining high-density periodic clustered electron clusters;

[0097] Output module 150, the periodic clustered electron clusters interact with the radiation grating to generate corresponding high-order frequency-doubled coherent electromagnetic radiation signals, and the high-order frequency-doubled coherent radiation is output from the port. The end window contains a diamond window and is connected to the resonant cavity through an output waveguide.

[0098] The electron emission source 1 in the electron acquisition module 110 generates an electron beam with a set beam spot size and current according to the operating frequency of the device;

[0099] Accelerate the electrons in the electron beam to the set speed required for device operation.

[0100] The preliminary clustering module 120 generates a pump signal through the pump source 3 and inputs it into the resonant cavity 2, thereby exciting a periodic electromagnetic field on the surface of the preset clustering grating 4 structure;

[0101] The frequency range of the pump signal covers the microwave and terahertz bands, and performs preliminary clustering of DC electrons to form primary electron clusters.

[0102] The deep clustering module 130 adjusts the resonance mode by designing and optimizing the period, height, and width parameters of the clustering grating 4;

[0103] After the initial clustering, the primary electron cluster electrons interact with the clustering grating 4 structure to produce coherent electromagnetic radiation;

[0104] The pump source 3 and the coherent electromagnetic radiation signal form a periodic electromagnetic field on the surface of the clustering grating 4 to modulate the electron energy and realize electron clustering.

[0105] The high-order frequency multiplication module 140 sets the period, height, and width parameters of the radiation grating 5 to determine the corresponding resonance mode;

[0106] Based on the resonance model, the interaction between the periodic clustered electrons and the radiation grating 5 structure generates a corresponding high-order frequency-doubled coherent electromagnetic radiation signal, outputs high-order frequency-doubled coherent electromagnetic radiation, and at the same time enhances electron clustering and reduces the size of electron clusters. The clustered electron clusters generate stronger coherent electromagnetic radiation, forming a positive feedback process of energy interaction between electron clustering and coherent electromagnetic radiation, that is, a stimulated coherent electromagnetic radiation process, to obtain high-density periodic clustered electron clusters.

[0107] The multi-frequency, multi-port terahertz source generation system based on stimulated amplified coherent radiation provided by the present invention realizes high-order frequency-doubled terahertz radiation through the stimulated coherent electromagnetic radiation mechanism. Free electrons are initially clustered under the action of an external pump source 3, and then interact with the corresponding clustering grating 4 to generate coherent electromagnetic radiation. Stimulated amplified coherent electromagnetic radiation is formed in the resonant cavity 2 structure, and high-density periodic clustered electron clusters are obtained, which effectively reduces the requirements for the electron source, especially the requirements for current and beam spot focusing. In addition, the clustering frequency of the obtained periodic electron clusters and their high-order frequency-doubled components are only determined by the frequency of the pump wave, effectively avoiding the operating frequency drift and spectrum broadening caused by the operating voltage jitter, and realizing high-order frequency-doubled radiation.

[0108] refer to Figure 8 The present invention also discloses a multi-frequency multi-port terahertz source generating device based on stimulated amplified coherent radiation, comprising:

[0109] Electron emission source 1, resonant cavity 2, pump source 3, cluster grating 4 and radiation grating 5;

[0110] The resonant cavity 2 is an oxygen-free copper tube, and the electron emission source 1 is installed at the end of the resonant cavity 2 to emit free electrons into the resonant cavity 2;

[0111] The pump source 3 is arranged on the outer side of the resonant cavity 2, and the pump signal is emitted into the resonant cavity 2 through the pump source 3;

[0112] The clustering grating 4 is arranged at the inner edge of the resonant cavity 2 close to the electron emission source 1 , and the radiation grating 5 is arranged at the inner edge of the resonant cavity 2 away from the electron emission source 1 .

[0113] A magnetic ring 7 is provided around the resonant cavity 2. The magnetic ring 7 surrounds the oxygen-free copper tube of the resonant cavity 2 and focuses the electron beam through the magnetic field generated by the magnetic ring 7.

[0114] A periodic pole shoe structure is wrapped around the cylindrical outer surface of an oxygen-free copper tube. Periodic magnetic rings are assembled through these pole shoe structures to focus the electron beam. Multiple periodic magnetic rings form a periodic permanent magnet focusing system. The rings are arranged in a manner that magnetizes them axially, with their repulsive properties. The magnetic flux density at the center of the rings exhibits a sinusoidal distribution along the direction of electron flight. The periodic permanent magnet focusing system provides magnetic flux density in the direction of flight. A suitable magnetic flux density offsets the divergent force of space charge, preventing electron beam diffusion during flight and achieving a converging effect. The electron beam moves axially under this magnetic flux density, significantly reducing collisions with the grating structure caused by electron diffusion, thereby improving electron utilization efficiency.

[0115] An electron collector 8 is also provided. The electron collector 8 is adjacent to the magnetic ring 7 and is arranged at the end of the resonant cavity 2. The electrons that have interacted with the cluster grating 4 and the radiation grating 5 are collected by the electron collector 8. The electrons that have interacted with the grating are collected by the electron collector 8, and the electron energy is recovered by a step-down collection method. High-order frequency-doubled coherent electromagnetic radiation is output through a frequency-doubled output window. The window contains a diamond window and is connected to the oxygen-free copper material through an output waveguide.

[0116] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A multi-frequency multi-port terahertz source generation device based on stimulated amplified coherent radiation, characterized in that: include: Electron emission sources, resonant cavities, pump sources, cluster gratings and radiation gratings; The resonant cavity is an oxygen-free copper tube, and the electron emission source is installed at the end of the resonant cavity to emit free electrons into the resonant cavity; The pump source is arranged on the outer side of the resonant cavity, and transmits a pump signal into the resonant cavity through the pump source; The clustering grating is arranged at the inner edge of the resonant cavity close to the electron emission source, and the radiation grating is arranged at the inner edge of the resonant cavity away from the electron emission source; A magnetic ring is provided in one circle of the resonant cavity, and the magnetic ring surrounds the oxygen-free copper tube of the resonant cavity, and the magnetic field generated by the magnetic ring is used to focus the electron beam; A periodic pole shoe structure is wrapped around the cylindrical outer surface of the oxygen-free copper tube, and a periodic magnetic ring for focusing the electron beam is assembled through the pole shoe structure. A periodic permanent magnet focusing system is composed of multiple periodic magnetic rings. The magnetic rings are arranged in a manner of axial magnetization repulsion, and the magnetic induction intensity at the center of the magnetic ring presents a sinusoidal distribution curve along the direction of electron flight.

2. The multi-frequency multi-port terahertz source generation device based on stimulated amplified coherent radiation according to claim 1, characterized in that: Also includes: An electron collector is adjacent to the magnetic ring and is disposed at the end of the resonant cavity. The electrons that have interacted with the clustering grating and the radiation grating are collected by the electron collector.

3. A method for generating a multi-frequency and multi-port terahertz source based on stimulated amplified coherent radiation, characterized in that: The multi-frequency multi-port terahertz source generating device based on stimulated amplified coherent radiation as claimed in claim 1 or 2 comprises: Obtaining free electrons emitted by a preset electron emission source, and accelerating the free electrons to a set speed; The accelerated free electrons are initially clustered under the action of an external pump source to form primary electron clusters; The primary electron clusters after preliminary clustering interact with the clustering grating to generate coherent electromagnetic radiation to achieve electron clustering; Based on the coherent electromagnetic radiation forming stimulated amplified coherent electromagnetic radiation with the radiation grating in the preset resonant cavity structure, the electron clustering is enhanced, the size of the electron cluster is reduced, and a high-density periodic clustered electron cluster is obtained; The periodic clustered electron clusters interact with the radiation grating to generate corresponding high-order frequency-doubled coherent electromagnetic radiation signals, and the high-order frequency-doubled coherent radiation is output from the port. The end window contains a diamond window and is connected to the resonant cavity through an output waveguide. The step of obtaining free electrons emitted by a preset electron emission source and accelerating the free electrons to a set speed specifically includes: The electron emission source generates an electron beam with a set beam spot size and current according to a set operating frequency; Accelerate the electrons in the electron beam to the set speed required for device operation.

4. The method for generating a multi-frequency multi-port terahertz source based on stimulated amplified coherent radiation according to claim 3, characterized in that: The accelerated free electrons are initially clustered under the action of an external pump source to form primary electron clusters, specifically including: The pump source generates a pump signal which is input into the resonant cavity to excite a periodic electromagnetic field on the surface of the preset clustered grating structure; The frequency range of the pump signal covers the microwave and terahertz bands, and performs preliminary clustering of DC electrons to form primary electron clusters.

5. The method for generating a multi-frequency multi-port terahertz source based on stimulated amplified coherent radiation according to claim 3, characterized in that: The method of causing the initially clustered primary electron clusters to interact with the clustering grating to generate coherent electromagnetic radiation to achieve electron clustering specifically includes: Adjusting the resonance mode by designing and optimizing the period, height, and width parameters of the cluster grating; After the initial clustering, the primary electrons interact with the clustering grating structure to produce coherent electromagnetic radiation; The pump source and the coherent electromagnetic radiation signal form a periodic electromagnetic field on the surface of the clustering grating to modulate the electron energy and realize electron clustering.

6. The method for generating a multi-frequency multi-port terahertz source based on stimulated amplified coherent radiation according to claim 3, characterized in that: Based on the coherent electromagnetic radiation forming stimulated amplified coherent electromagnetic radiation with the radiation grating in the preset resonant cavity structure, electron clustering is enhanced, the size of the electron cluster is reduced, and high-density periodic clustered electron clusters are obtained, specifically including: Setting the period, height and width parameters of the radiation grating to determine the corresponding resonance mode; Based on the resonance model, the interaction between periodically clustered electrons and the radiating grating structure generates corresponding high-order frequency-doubled coherent electromagnetic radiation signals, outputs high-order frequency-doubled coherent electromagnetic radiation, and at the same time enhances electron clustering and reduces the size of electron clusters. The clustered electron clusters generate stronger coherent electromagnetic radiation, forming a positive feedback process of energy interaction between electron clustering and coherent electromagnetic radiation, namely the stimulated coherent electromagnetic radiation process, to obtain high-density periodically clustered electron clusters.

7. A multi-frequency multi-port terahertz source generation system based on stimulated amplified coherent radiation, characterized in that: The multi-frequency multi-port terahertz source generating device based on stimulated amplified coherent radiation according to claim 1 or 2, wherein the system comprises: An electron acquisition module, used to acquire free electrons emitted by a preset electron emission source and accelerate the free electrons to a set speed; The preliminary clustering module is used to perform preliminary clustering of the accelerated free electrons under the action of an external pump source to form primary electron clusters; A deep clustering module is used to interact the initially clustered primary electron clusters with the clustering grating to generate coherent electromagnetic radiation to achieve electron clustering; A high-order frequency doubling module is used to form stimulated amplified coherent electromagnetic radiation based on the coherent electromagnetic radiation and the radiation grating in a preset resonant cavity structure, while enhancing electron clustering, reducing the size of electron clusters, and obtaining high-density periodic clustered electron clusters; An output module, used for the interaction between the periodic clustered electron clusters and the radiation grating to generate a corresponding high-order frequency-doubled coherent electromagnetic radiation signal, the high-order frequency-doubled coherent radiation is output from the port, the end window contains a diamond window, and is connected to the resonant cavity through an output waveguide; The step of obtaining free electrons emitted by a preset electron emission source and accelerating the free electrons to a set speed specifically includes: The electron emission source generates an electron beam with a set beam spot size and current according to a set operating frequency; Accelerate the electrons in the electron beam to the set speed required for device operation.

Images