Terahertz frequency comb generation method, device, electronic device and storage medium

Abstract

The present invention provides a terahertz frequency comb generation method, device, electronic device, and storage medium. The terahertz frequency comb generation method is applied to a radiating device, which is generated based on stimulated amplified coherent Smith-Purcell radiation. The terahertz frequency comb generation method includes: obtaining a multi-frequency signal, wherein the multi-frequency signal is a signal including a first frequency and a second frequency, the first frequency being a terahertz frequency, and the second frequency being a modulation frequency; injecting the multi-frequency signal into the radiating device, and obtaining new frequency components based on the nonlinear intermodulation distortion effect of the radiating device when the radiating device is in a saturated gain state, wherein the new frequency components are frequency components generated by the multi-frequency signal under the action of intermodulation and present in the evanescent field spectrum surrounding the electron; and generating a terahertz frequency comb based on the new frequency components, wherein the frequency interval of the terahertz frequency comb is the same as the modulation frequency. The present invention ensures that the generated terahertz frequency comb has continuous tunability.

Description

Technical Field

[0001] The present invention relates to the field of terahertz radiation technology, and in particular to a terahertz frequency comb generation method, device, electronic equipment and storage medium. Background Art

[0002] Terahertz (THz) waves are electromagnetic waves with frequencies between 0.1THz and 10THz, corresponding to wavelengths between 3mm and 30μm. Located between infrared and microwaves, THz waves possess unique properties not found in other wavelengths.

[0003] A frequency comb is a spectral structure composed of a series of discrete, stably spaced frequency components. Its ultra-high frequency stability makes it crucial for applications such as precision spectroscopy, communications, timing, molecular fingerprinting, and distance measurement. Terahertz frequency combs were developed because terahertz waves cover the vibrational and rotational energy levels of many macromolecules and exhibit unique absorption spectra.

[0004] Current terahertz frequency comb generation methods are primarily optical and optoelectronic. These methods often lack continuous tunability and are complex, making them inconvenient to operate. Summary of the Invention

[0005] The present invention provides a terahertz frequency comb generation method, device, electronic device and storage medium, which are used to solve the defects of the terahertz frequency comb generated in the prior art, such as the lack of continuous tunability, high complexity of the generation process, and inconvenience in practical operation. The present invention ensures that the generated terahertz frequency comb has continuous tunability, and the process of generating the terahertz frequency comb is simple and easy to operate.

[0006] The present invention provides a terahertz frequency comb generation method, which is applied to a radiation device, wherein the radiation device is obtained based on stimulated amplified coherent Smith-Purcell radiation, and the terahertz frequency comb generation method comprises: obtaining a multi-frequency signal, wherein the multi-frequency signal is a signal including a first frequency and a second frequency, the first frequency is a terahertz frequency, and the second frequency is a modulation frequency; injecting the multi-frequency signal into the radiation device, and when the radiation device is in a saturated gain state, obtaining a new frequency component based on the nonlinear intermodulation distortion effect of the radiation device, wherein the new frequency component is a frequency component generated by the multi-frequency signal under the action of intermodulation and existing in the evanescent field spectrum around electrons; generating a terahertz frequency comb based on the new frequency component, wherein the frequency interval of the terahertz frequency comb is the same as the modulation frequency.

[0007] According to a terahertz frequency comb generation method provided by the present invention, obtaining a multi-frequency signal specifically includes: obtaining a single-frequency pump wave, wherein the pump frequency of the single-frequency pump wave is the terahertz frequency; determining the modulation frequency; modulating the single-frequency pump wave according to the modulation frequency to obtain a modulated pump signal, and using the modulated pump signal as the multi-frequency signal.

[0008] According to a terahertz frequency comb generation method provided by the present invention, the new frequency component is obtained based on the nonlinear intermodulation distortion effect of the radiating device, specifically comprising: based on the nonlinear intermodulation distortion effect of the radiating device, exciting the terahertz frequency and the modulation frequency in the multi-frequency signal to undergo intermodulation to obtain high-order frequency harmonic components and intermodulation components; using the high-order frequency harmonic components and the intermodulation components as the new frequency components, wherein the high-order frequency harmonic components are frequency components formed according to integer multiples of the terahertz frequency, and the intermodulation components are frequency components formed on both sides of the high-order frequency harmonic components with the high-order frequency harmonic components as the center under the intermodulation effect.

[0009] According to a terahertz frequency comb generation method provided by the present invention, the radiation device includes a primary grating structure and a secondary grating structure, wherein the first period of the primary grating structure is determined according to the pump frequency, and the second period of the secondary grating structure is determined according to the first period; generating a terahertz frequency comb based on the new frequency component specifically includes: based on the new frequency component, by exciting the surface local electromagnetic field of the primary grating structure, the electrons emitted by the radiation device are clustered to obtain clustered electron clusters; based on the secondary grating structure, new frequency components are extracted from the evanescent field around the clustered electron clusters to generate radiation containing the new frequency components; based on the radiation containing the new frequency components, a terahertz frequency comb is generated.

[0010] According to a terahertz frequency comb generation method provided by the present invention, the first period of the primary grating structure is determined according to the pump frequency and is implemented using the following formula:

[0011] f p =v / L1

[0012] Wherein, L1 represents the first period; f p represents the pump frequency; v represents the flying speed of the electrons emitted by the radiation device.

[0013] According to a terahertz frequency comb generation method provided by the present invention, the second period of the secondary grating structure is determined according to the first period, and is implemented using the following formula:

[0014] L2=L1 / n(n=1,2,3…)

[0015] Wherein, L1 represents the first period; L2 represents the second period, and n represents a positive integer.

[0016] The present invention also provides a terahertz frequency comb generation device, and the terahertz frequency comb generation method is applied to a radiation device, wherein the radiation device is obtained based on stimulated amplified coherent Smith-Parcell radiation, and the terahertz frequency comb generation device includes: a first module, used to obtain a multi-frequency signal, wherein the multi-frequency signal is a signal including a first frequency and a second frequency, the first frequency is a terahertz frequency, and the second frequency is a modulation frequency; a second module, used to inject the multi-frequency signal into the radiation device, and when the radiation device is in a saturated gain state, based on the nonlinear intermodulation distortion effect of the radiation device, obtain a new frequency component, wherein the new frequency component is a frequency component generated by the multi-frequency signal under the action of intermodulation and exists in the evanescent field spectrum around the electron; a third module, used to generate a terahertz frequency comb based on the new frequency component, wherein the frequency interval of the terahertz frequency comb is the same as the modulation frequency.

[0017] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the terahertz frequency comb generation method as described above is implemented.

[0018] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any of the above-described terahertz frequency comb generation methods.

[0019] The present invention also provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the computer program implements any of the above-described terahertz frequency comb generation methods.

[0020] The terahertz frequency comb generation method, device, electronic device and storage medium provided by the present invention are applied to a radiating device obtained based on stimulated amplified coherent Smith-Purcell radiation. By injecting a multi-frequency signal into the radiating device and, when the radiating device is in a saturated gain state, a new frequency component is obtained based on the nonlinear intermodulation distortion effect of the radiating device, and then a terahertz frequency comb is generated based on the new frequency component. This realizes the use of the intermodulation distortion effect to obtain a terahertz frequency comb through the radiating device, so that the frequency interval of the terahertz frequency comb is the same as the modulation frequency, thereby ensuring that the generated terahertz frequency comb has continuous tunability, and the process of generating the terahertz frequency comb is simple and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to 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.

[0022] Figure 1 1 is a flow chart of the terahertz frequency comb generation method provided by the present invention;

[0023] Figure 2 It is a schematic structural diagram of the radiation device provided by the present invention;

[0024] Figure 3 It is a schematic diagram of the process of obtaining multi-frequency signals provided by the present invention;

[0025] Figure 4 This is a schematic diagram of a process for obtaining new frequency components based on the nonlinear intermodulation distortion effect of a radiation device provided by the present invention;

[0026] Figure 5 This is a schematic diagram of a process for generating a terahertz frequency comb based on a new frequency component provided by the present invention;

[0027] Figure 6 Schematic diagram of generating a terahertz frequency comb near the frequency tripled 1.02 THz at different modulation depths provided by the present invention;

[0028] Figure 7 Schematic diagram of generating a terahertz frequency comb near the tripled frequency of 1.02 THz at different modulation frequencies provided by the present invention;

[0029] Figure 8 Schematic diagram of the structure of the terahertz frequency comb generating device provided by the present invention;

[0030] Figure 9 It is a structural schematic diagram of the electronic device provided by the present invention.

[0031] Reference numerals:

[0032] 10: Radiation device; 1: Electron emission source;

[0033] 2: Pump signal; 3: First-stage resonant cavity structure;

[0034] 4: First-order grating structure; 5: Second-order resonant cavity structure;

[0035] 6: Secondary grating structure; 7: Radiation signal;

[0036] 8: Magnetic ring structure; 9: Electron collector. DETAILED DESCRIPTION

[0037] 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 of the embodiments of the present invention, not all of them. 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.

[0038] The terahertz frequency comb generation method provided by this invention utilizes nonlinear intermodulation distortion in power amplifier devices as a technical means to generate a terahertz frequency comb in a terahertz radiator (corresponding to a radiating device) based on stimulated amplified coherent Smith-Purcell Radiation (SPR). By utilizing the nonlinear intermodulation distortion effect to generate the terahertz frequency comb, the generated terahertz frequency comb is continuously tunable, and the generation process is simple and easy to operate.

[0039] Intermodulation distortion refers to the phenomenon in which, when multi-frequency signals are injected into a nonlinear device, the multiple frequencies interact with each other to produce new frequency components due to the nonlinear characteristics of the device, thus interfering with the device's operation. In traditional vacuum electron source devices, especially traveling wave tube power amplifiers, intermodulation distortion is often considered one of the key interference factors affecting device and system performance, so efforts are often made to avoid this interference. However, in the present invention, intermodulation distortion is not considered interference. Instead, it is proposed to utilize this effect of nonlinear intermodulation distortion to generate a terahertz frequency comb in a vacuum electron terahertz radiation device (corresponding radiation device).

[0040] In order to further introduce the terahertz frequency comb generation method provided by the present invention, the following embodiments will be used for illustration.

[0041] In an exemplary embodiment of the present invention, a terahertz frequency comb generation method may be applied to a radiation device, wherein the radiation device is obtained based on stimulated amplified coherent Smith-Purcell radiation.

[0042] Figure 2 It is a schematic structural diagram of the radiation device provided by the present invention.

[0043] Combine Figure 2 It can be seen that the radiation device 10 may include an electron emission source 1, a primary resonant cavity structure 3, a primary grating structure 4, a secondary resonant cavity structure 5, a secondary grating structure 6, a magnetic ring structure 8 and an electron collector 9.

[0044] The electron emission source 1 can be used to emit an electron beam, which flies through the primary resonant cavity structure 3 and the secondary resonant cavity structure 5 and is finally recovered by the electron collector 9.

[0045] The pump signal 2 is a modulated multi-frequency signal. In one example, the pump signal 2 may include a pump frequency f p and modulation frequency f m In the application process, the pump signal 2 can be injected into the first-level resonant cavity structure 3, and the pump frequency f p The vertical resonance mode in the primary resonant cavity structure 3 is excited, a periodic electromagnetic field is generated on the surface of the primary grating structure 4, and the DC electrons are preliminarily clustered.

[0046] When the radiation device 10 operates in a saturated gain state, the pump frequency f p and modulation frequency f m There will be cross-modulation between them, producing a series of shapes like xf p ±yf m (x, y = 0, 1, 2, 3...) new frequency components, these new frequency components will also cluster the DC electrons.

[0047] The first-level resonant cavity structure 3 can be used to generate a vertical resonant mode and amplify the pump frequency f in the pump signal 2. p The power and intensity of the stimulated coherent Smith-Purcell radiation produced by the initial clustered electrons are enhanced.

[0048] For the primary grating structure 4, the interaction between the preliminary clustered electrons and the primary grating structure 4 can generate stimulated coherent Smith-Purcell radiation, which can also excite the vertical resonant mode in the primary resonant cavity structure 3, generating a periodic electromagnetic field on the surface of the primary grating structure 4, thereby enhancing the electron clustering. In one example, the period L1 of the primary grating structure 4, the electron velocity v, and the pump frequency f in the pump signal 2 are p Satisfy the relationship f p =v / L1.

[0049] The secondary resonant cavity structure 5 can be used to generate a vertical resonant mode and enhance the intensity of high-order frequency-harmonic coherent Smith-Purcell radiation.

[0050] For the secondary grating structure 6, when the radiation device 10 works in the saturated gain state, the periodic clustered electrons interact with the secondary grating structure 6, which can improve the f p While extracting the high-order harmonic components (corresponding to the high-order harmonic components), the newly generated frequency components on both sides (corresponding to the intermodulation components) are also extracted, and finally a high-order harmonic coherent Smith-Purcell radiation signal 7 carrying the terahertz frequency comb is generated. Among them, the high-order harmonic coherent Smith-Purcell radiation signal 7 carrying the terahertz frequency comb has a radiation signal spectrum with the pump frequency f pThe high-order frequency of the center generates a series of equal frequency intervals f on both sides. m The radiation peaks of the terahertz frequency comb can be formed. It can be understood that the formed terahertz frequency comb has continuous tunability, wherein the repetition frequency of the terahertz frequency comb (also known as the frequency interval of the terahertz frequency comb) can be changed according to the change of the modulation frequency, thereby achieving continuous tunability of the terahertz frequency comb.

[0051] In one example, the period L2 of the secondary grating structure 6 and the period L1 of the primary grating structure 4 satisfy L2 = L1 / n (n = 1, 2, 3 . . . ).

[0052] The magnetic ring structure 8 can be used to focus the electron beam. For example, the magnetic ring structure 8 is wrapped around the outside of the radiation device 10 structure to reduce the diffusion of electrons during flight.

[0053] The electron collector 9 can be used to collect the electron beam emitted by the electron emission source 1 and after passing through the primary resonant cavity structure 3 and the secondary resonant cavity structure 5 .

[0054] Figure 1 It is a flow chart of the terahertz frequency comb generation method provided by the present invention.

[0055] The following will be combined Figure 1 The process of the terahertz frequency comb generation method is described.

[0056] In an exemplary embodiment of the present invention, Figure 1 It can be seen that the terahertz frequency comb generation method may include steps 110 to 130, and each step will be introduced below.

[0057] In step 110 , a multi-frequency signal is acquired, wherein the multi-frequency signal is a signal including a first frequency and a second frequency, the first frequency is a terahertz frequency, and the second frequency is a modulation frequency.

[0058] In one embodiment, the first frequency in the multi-frequency signal may be a terahertz frequency. It will be appreciated that the inclusion of the terahertz frequency in the multi-frequency signal results in a terahertz-level frequency comb. The second frequency may be a modulation frequency. The magnitude of the modulation frequency affects the frequency spacing of the generated terahertz frequency comb.

[0059] In one example, the frequency value of the first frequency may be greater than the frequency value of the second frequency.

[0060] In step 120, a multi-frequency signal is injected into the radiating device, and when the radiating device is in a saturated gain state, a new frequency component is obtained based on the nonlinear intermodulation distortion effect of the radiating device, wherein the new frequency component is a frequency component generated by the multi-frequency signal under the action of intermodulation and exists in the evanescent field spectrum around the electron.

[0061] In one embodiment, when multi-frequency signals are injected into a radiating device, and the radiating device operates at saturated gain, the input multi-frequency signals interact (e.g., intermodulation), generating a series of new intermodulation frequency components (corresponding to new frequency components) at equal frequency intervals. These intermodulation frequency components act on electron clusters and appear in the evanescent field spectrum surrounding the electrons.

[0062] In step 130 , a terahertz frequency comb is generated based on the new frequency component, wherein the frequency interval of the terahertz frequency comb is the same as the modulation frequency.

[0063] In one embodiment, a terahertz frequency comb with the same frequency spacing as the modulation frequency can be generated based on the new frequency components present in the evanescent field spectrum surrounding the electron. Because the modulation frequency can be continuously adjusted based on actual conditions, the frequency spacing of the terahertz frequency comb can be adjusted accordingly, ensuring continuous tunability of the generated terahertz frequency comb.

[0064] The terahertz frequency comb generation method provided by the present invention is applied to a radiating device obtained based on stimulated amplified coherent Smith-Purcell radiation. By inputting a multi-frequency signal into the radiating device and, when the radiating device is in a saturated gain state, a new frequency component is obtained based on the nonlinear intermodulation distortion effect of the radiating device, and then a terahertz frequency comb is generated based on the new frequency component. This realizes the use of the intermodulation distortion effect to obtain a terahertz frequency comb through the radiating device, so that the frequency interval of the terahertz frequency comb is the same as the modulation frequency, thereby ensuring that the generated terahertz frequency comb has continuous tunability, and the process of generating the terahertz frequency comb is simple and easy to operate.

[0065] In order to further introduce the terahertz frequency comb generation method provided by the present invention, the following Figure 3 Provide explanation.

[0066] Figure 3 It is a schematic diagram of the process of obtaining multi-frequency signals provided by the present invention.

[0067] In an exemplary embodiment of the present invention, Figure 3 It can be seen that acquiring the multi-frequency signal may include steps 310 to 330, and each step will be described below.

[0068] In step 310 , a single-frequency pump wave is acquired, wherein the pump frequency of the single-frequency pump wave is a terahertz frequency.

[0069] In step 320, the modulation frequency is determined.

[0070] In step 330 , the single-frequency pump wave is modulated according to the modulation frequency to obtain a modulated pump signal, and the modulated pump signal is used as a multi-frequency signal.

[0071] In one embodiment, the modulated pump signal (corresponding to the modulated pump signal) may include a pump frequency f p and modulation frequency f m , which is expressed as a multi-frequency signal. In one example, a single-frequency pump wave can be modulated according to a modulation frequency to obtain a modulated pump signal, wherein the modulated pump signal is a multi-frequency signal.

[0072] In the application process, the multi-frequency signal (corresponding to the modulated pump signal) is injected into the radiating device. When the radiating device works in the saturated gain state, due to the nonlinear intermodulation distortion effect, the injected pump frequency f p and modulation frequency f m There is a cross-modulation between them, which can produce a series of shapes like xf p ±yf m (x, y = 0, 1, 2, 3 ...) new frequency components. The new frequency components may exist in the spectrum of the evanescent field around the electron.

[0073] It should be noted that due to the existence of saturation gain of the radiating device, the amplified signal will be distorted, thereby introducing new frequency components. This nonlinear process can be expressed by formula (1):

[0074]

[0075] Among them, E amplify Represents the amplified signal, v0 represents the input signal, a n Represents the coefficients of each higher-order term.

[0076] When the input is a multi-frequency signal, such as a modulated pump signal, the input signal v0 can be expressed by formula (2):

[0077] v0=Acosω p t(1+mcosω m t) (2)

[0078] Among them, ω p =2πf p and ω m =2πf m , f p represents the pump frequency, f m represents the modulation frequency, and m represents the modulation depth.

[0079] Substitute formula (2) into formula (1). To simplify the calculation, only the first two terms are expanded to obtain the following formula (3):

[0080]

[0081] As can be seen from Equation (3), the expanded term generates a series of frequency components, as shown in Equation (4). These new frequency components are generated by the interaction between the pump frequency and the modulation frequency and are called intermodulation products. This nonlinear process that occurs when multi-frequency signals are transmitted in a coherent Smith-Purcell radiator is called intermodulation distortion.

[0082] xω p ±yω m x, y=0,1,2,3… (4)

[0083] Furthermore, based on the intermodulation effect, the double frequency component 2ω p (corresponding to 2f p ) produces 2ω on both sides p -2ω m , 2ω p -ω m , 2ω p +ω m , 2ω p +2ω m , where the frequency interval between adjacent components is ω m (corresponding to f m ).

[0084] It should be noted that formula (3) only expands the first and second power terms. Further expansion of higher power terms will result in 2ω p More frequency components are obtained on both sides, and the frequency interval between adjacent components is ω m If the high-order terms are expanded, the triple frequency component 3ω p , the fourth frequency component 4ω p Even near the higher-order harmonic components, there will be a series of equally spaced intermodulation frequency components, which constitute the terahertz frequency comb. Among them, the frequency interval of the terahertz frequency comb is ω m .

[0085] The impact of intermodulation distortion on electrons is also reflected in changes in their spatial clustering. When a single-frequency signal is injected into a coherent Smith-Purcell radiator, electrons cluster according to the pump signal frequency, and the frequency components of the evanescent field surrounding the electrons are equal to integer multiples of the pump signal frequency. When multi-frequency signals are injected into a coherent Smith-Purcell radiator, electrons cluster not only according to the pump signal frequency but also according to a series of new frequencies generated by intermodulation distortion. Ultimately, the electrons form a new cluster distribution in space. The frequency components generated by intermodulation distortion appear in the evanescent field surrounding the electrons. While using a second-stage small-period grating to extract higher-order frequency harmonic components, the intermodulation frequency components are also extracted, ultimately forming a terahertz frequency comb in the radiation output spectrum.

[0086] It should be noted that in this embodiment, a terahertz frequency comb can be generated based on a miniaturized vacuum electron terahertz source radiation device (corresponding radiation device). However, compared to the current generation of terahertz frequency combs using large high-energy electron storage ring devices, this application can reduce the size of the device generating the terahertz frequency comb and increase its portability, thus ensuring the simplicity and ease of operation of the terahertz frequency comb generation process.

[0087] Figure 4 The present invention provides a flow chart of obtaining new frequency components based on the nonlinear intermodulation distortion effect of a radiation device.

[0088] The following will be combined Figure 4 The process of obtaining new frequency components based on the nonlinear intermodulation distortion effect of radiating devices is explained.

[0089] In an exemplary embodiment of the present invention, Figure 4 It can be seen that, based on the nonlinear intermodulation distortion effect of the radiating device, obtaining the new frequency component may include step 410 and step 420, and each step will be described below.

[0090] In step 410, based on the nonlinear intermodulation distortion effect of the radiation device, the terahertz frequency and the modulation frequency in the multi-frequency signal are excited to intermodulate, thereby obtaining high-order frequency harmonic components and intermodulation components.

[0091] In one embodiment, the pump frequency f is continuously set to the terahertz frequency. p , modulation frequency f m Take the example of 2f as an example. Under the effect of the nonlinear intermodulation distortion of the radiation device, the terahertz frequency and the modulation frequency of the multi-frequency signal entering the radiation device can be stimulated to intermodulate to generate high-order frequency components and intermodulation components. Among them, the high-order frequency components can be understood as frequency components formed according to the integer multiples of the terahertz frequency. For example, 2f p The frequency component of 3f p The frequency component of nf p The frequency components of , where n represents a positive integer. The intermodulation components can be understood as the frequency components formed on both sides of the high-order frequency components under the action of intermodulation with the high-order frequency components as the center. Among them, the frequency interval of the generated intermodulation components is f m .

[0092] In step 420, the high-order frequency harmonic components and the intermodulation components are used as new frequency components, wherein the high-order frequency harmonic components are frequency components formed according to integer multiples of the terahertz frequency, and the intermodulation components are frequency components formed on both sides of the high-order frequency harmonic components with the high-order frequency harmonic components as the center under the action of intermodulation.

[0093] In one embodiment, the obtained high-order frequency harmonic components and intermodulation components can be used as new frequency components to generate a terahertz frequency comb based on the new frequency components.

[0094] It should be noted that the new frequency component may correspond to the frequency component described in formula (4).

[0095] In order to further introduce the terahertz frequency comb generation method provided by the present invention, the following Figure 5 Provide explanation.

[0096] Figure 5 It is a schematic diagram of the process of generating a terahertz frequency comb based on the new frequency component provided by the present invention.

[0097] In an exemplary embodiment of the present invention, the radiation device may include a primary grating structure (corresponding to Figure 2 4) and the secondary grating structure (corresponding to Figure 2 6), wherein the first period of the primary grating structure is determined according to the pump frequency, and the second period of the secondary grating structure is determined according to the first period.

[0098] Combine Figure 5 It can be seen that generating a terahertz frequency comb based on the new frequency component may include steps 510 to 530, and each step will be introduced below.

[0099] In step 510, based on the new frequency component, the electrons emitted by the radiation device are clustered by exciting the surface local electromagnetic field of the primary grating structure to obtain clustered electron clusters.

[0100] In step 520, based on the secondary grating structure, new frequency components in the evanescent field around the clustered electron cluster are extracted to generate radiation containing the new frequency components.

[0101] In step 530 , a terahertz frequency comb is generated based on the radiation containing the new frequency components.

[0102] In one embodiment, the pump frequency f is continuously set to the terahertz frequency. p , modulation frequency f m For example, injecting a multi-frequency signal into a radiation device can generate new frequency components. Furthermore, these new frequency components excite the electromagnetic field on the surface of the primary grating structure, clustering DC electrons. These DC electrons are emitted by the radiation device's electron emission source.

[0103] Among them, DC electrons are pumped at the pump frequency f pIn addition to clustering, the electrons will also cluster according to a series of newly generated frequency components. Under the joint action of all frequencies, the electrons form a new periodic cluster distribution in the free space, which in turn causes the spectrum of the evanescent field around the electrons to carry the new frequency components. The secondary grating structure is used to extract the f in the evanescent field around the electrons (or clustered electrons). p When high-order harmonic components of a signal are extracted to produce coherent Smith-Purcell radiation (corresponding to high-order harmonic components), new frequency components (corresponding to intermodulation components) distributed continuously on both sides of the signal are also extracted, thereby ultimately generating radiation containing new frequency components. In one example, radiation containing new frequency components can be considered to contain part or all of the new frequency components.

[0104] Furthermore, a terahertz frequency comb can be generated based on the radiation containing the new frequency components. The terahertz frequency comb has equal frequency intervals f m .

[0105] In another exemplary embodiment of the present invention, the first period of the primary grating structure is determined according to the pump frequency, which can be implemented using the following formula (5):

[0106] f p =v / L1 (5)

[0107] Wherein, L1 represents the first cycle; f p represents the pump frequency; v represents the flight speed of electrons emitted by the radiation device.

[0108] In another exemplary embodiment of the present invention, the second period of the two-stage grating structure is determined according to the first period, which can be implemented using the following formula (6):

[0109] L2=L1 / n(n=1,2,3…) (6)

[0110] Wherein, L1 represents the first period; L2 represents the second period, and n represents a positive integer.

[0111] Taking the generation of a terahertz frequency comb near 1 THz as an example, the following will specifically demonstrate the terahertz frequency comb generation method provided by the present invention in combination with numerical calculations.

[0112] Figure 6 It is a schematic diagram of generating a terahertz frequency comb near the frequency tripling of 1.02 THz at different modulation depths provided by the present invention.

[0113] Now let the pump signal frequency ω in the multi-frequency signal be p =2πf p Select 0.34THz and modulate it. The modulation frequency ω m =2πf mThey are selected as 100kHz, 500kHz and 1MHz respectively, the modulation depth m is selected as a value between 0-1, and the signal amplitude A is set to 1.

[0114] Substitute the modulated signal into formula (1) and observe the terahertz frequency comb phenomenon generated near the triple frequency component 1.02THz. The coefficients a of each high-order term are n All are set to 1, and the formula (1) is numerically expanded and calculated using MATLAB software, with n being 75.

[0115] Fixed modulation frequency f m =100kHz, observe the frequency components near the third frequency at different modulation depths, the results are as follows Figure 6 As shown in the figure, it can be clearly seen that: first, a series of equally spaced frequency components are generated around the frequency of 1.02THz, forming a terahertz frequency comb; second, as the modulation depth increases, the number of comb teeth continues to increase, and the spectrum range covered by the frequency comb continues to expand; third, the frequency interval between adjacent comb teeth is measured to be 100kHz, which is consistent with the f m The modulation frequencies are equal.

[0116] In one example, a single-frequency pump wave may be modulated according to a preset modulation depth and a modulation frequency to obtain a modulated pump signal, and the modulated pump signal may be used as a multi-frequency signal.

[0117] Among them, the preset modulation depth can be greater than the depth threshold. In the present invention, there is no specific limitation on the preset modulation depth and the depth threshold, which can be adjusted according to actual conditions. In one example, the maximum value of the preset modulation depth can be 1.

[0118] The results show that after the modulated pump signal is injected into the radiating device, a terahertz frequency comb phenomenon appears in the radiation spectrum under the action of intermodulation distortion, and the frequency interval of the generated terahertz frequency comb is consistent with the modulation frequency, thereby ensuring that the terahertz frequency comb can achieve continuous tunability according to the change of the modulation frequency.

[0119] Figure 7 It is a schematic diagram of generating a terahertz frequency comb near the tripled frequency 1.02 THz at different modulation frequencies provided by the present invention.

[0120] In one example, the modulation depth m is fixed at 0.5, and the frequency components near the triple frequency at different modulation frequencies are observed. The results are as follows: Figure 7 As shown in the figure, we can see that: first, the terahertz frequency comb phenomenon is also generated around 1.02 THz under different modulation frequencies; second, the frequency spacing between adjacent comb teeth is always equal to the modulation frequency, that is, the modulation frequency determines the frequency spacing between adjacent comb teeth, and the comb tooth spacing can be tuned by changing the modulation frequency.

[0121] Compared with the optical generation method that depends on the MHz-level repetition frequency of the mode-locked laser, the terahertz frequency comb generation method provided by the present invention can achieve a comb tooth frequency spacing as low as kHz or even smaller, and the comb tooth spacing has flexible tunability.

[0122] In summary, using the generation of a terahertz frequency comb near 1 THz as an example, calculation results demonstrate that the terahertz frequency comb generation method provided by the present invention can effectively generate a terahertz frequency comb phenomenon in the radiation spectrum. It is important to note that the present invention not only generates a terahertz frequency comb near 1 THz but also can generate terahertz frequency combs of any frequency by varying the pump signal frequency and modulation frequency to extract higher-order harmonic components of different orders.

[0123] The terahertz frequency comb generation method provided by the present invention has the following advantages:

[0124] (1) Different from the traditional vacuum electronics which regards the nonlinear intermodulation distortion effect as an interference factor of the device, the present invention innovatively proposes to utilize the intermodulation distortion to generate a terahertz frequency comb in the radiation output spectrum of the vacuum electron terahertz radiation device (corresponding radiation device).

[0125] (2) This invention proposes injecting multi-frequency signals into a terahertz radiator (corresponding to a radiating device) based on stimulated amplified coherent Smith-Purcell radiation, utilizing the device's inherent nonlinear characteristics to generate a terahertz frequency comb. Compared to currently reported terahertz frequency combs generated in large storage ring devices, the miniaturized radiating device in this invention is reduced in size by nearly four orders of magnitude, significantly improving its portability.

[0126] (3) In the terahertz frequency comb generation method proposed in this invention, the number of comb teeth can be increased to dozens by increasing the modulation depth, thereby expanding the spectrum coverage. Compared with the number of comb teeth generated by the terahertz frequency combs currently reported in miniaturized solid-state electronic terahertz radiation sources, the number of comb teeth obtained in this invention is increased by one order of magnitude.

[0127] (4) The frequency spacing between adjacent teeth of the terahertz frequency comb generated by the present invention is entirely dependent on the modulation frequency, which means that the spacing between adjacent teeth can be reduced to the kHz level or even narrower. At the same time, this spacing is tunable, which is an advantage that other generation methods cannot match. Compared with the MHz-level comb spacing obtained by current optical methods and the 864kHz comb spacing generated in high-energy electron storage rings, the comb spacing of the terahertz frequency comb in the present invention can reach 100kHz, indicating that the resolution of the terahertz frequency comb achieved can reach the hundreds of kHz level, greatly improving the measurement accuracy.

[0128] According to the above description, the terahertz frequency comb generation method provided by the present invention is applied to a radiating device obtained based on stimulated amplified coherent Smith-Purcell radiation. By injecting a multi-frequency signal into the radiating device, and when the radiating device is in a saturated gain state, a new frequency component is obtained based on the nonlinear intermodulation distortion effect of the radiating device, and then a terahertz frequency comb is generated based on the new frequency component. This realizes the use of the intermodulation distortion effect to obtain a terahertz frequency comb through the radiating device, so that the frequency interval of the terahertz frequency comb is the same as the modulation frequency, thereby ensuring that the generated terahertz frequency comb has continuous tunability, and the process of generating the terahertz frequency comb is simple and easy to operate.

[0129] Based on the same concept, the present invention also provides a terahertz frequency comb generating device.

[0130] The terahertz frequency comb generating device provided by the present invention is described below. The terahertz frequency comb generating device described below and the terahertz frequency comb generating method described above can refer to each other.

[0131] Figure 8 It is a structural schematic diagram of the terahertz frequency comb generating device provided by the present invention.

[0132] In an exemplary embodiment of the present invention, the terahertz frequency comb generation device can be applied to a radiation device, wherein the radiation device is obtained based on stimulated amplified coherent Smith-Purcell radiation. Figure 8 It can be seen that the terahertz frequency comb generation device can include a first module 810 to a third module 830, and each module will be introduced below.

[0133] The first module 810 may be configured to acquire a multi-frequency signal, wherein the multi-frequency signal is a signal including a first frequency and a second frequency, the first frequency being a terahertz frequency and the second frequency being a modulation frequency;

[0134] The second module 820 may be configured to inject the multi-frequency signal into the radiating device, and obtain a new frequency component based on the nonlinear intermodulation distortion effect of the radiating device when the radiating device is in a saturated gain state, wherein the new frequency component is a frequency component generated by the multi-frequency signal under the intermodulation effect and existing in the evanescent field spectrum around the electron;

[0135] The third module 830 may be configured to generate a terahertz frequency comb based on the new frequency component, wherein the frequency interval of the terahertz frequency comb is the same as the modulation frequency.

[0136] In an exemplary embodiment of the present invention, the first module 810 may acquire the multi-frequency signal in the following manner:

[0137] obtaining a single-frequency pump wave, wherein the pump frequency of the single-frequency pump wave is a terahertz frequency;

[0138] Determine the modulation frequency;

[0139] The single-frequency pump wave is modulated according to the modulation frequency to obtain a modulated pump signal, and the modulated pump signal is used as a multi-frequency signal.

[0140] In an exemplary embodiment of the present invention, the second module 820 may obtain the new frequency component based on the nonlinear intermodulation distortion effect of the radiation device in the following manner:

[0141] Based on the nonlinear intermodulation distortion effect of the radiation device, the terahertz frequency and the modulation frequency in the multi-frequency signal are stimulated to intermodulate, and high-order frequency harmonic components and intermodulation components are obtained;

[0142] The high-order frequency harmonic components and intermodulation components are taken as new frequency components, wherein the high-order frequency harmonic components are frequency components formed according to integer multiples of the terahertz frequency, and the intermodulation components are frequency components formed on both sides of the high-order frequency harmonic components with the high-order frequency harmonic components as the center under the action of intermodulation.

[0143] In an exemplary embodiment of the present invention, the radiation device may include a primary grating structure and a secondary grating structure, wherein a first period of the primary grating structure may be determined according to a pumping frequency, and a second period of the secondary grating structure may be determined according to the first period;

[0144] The third module 830 can generate a terahertz frequency comb based on the new frequency components in the following manner:

[0145] Based on the new frequency component, the electrons emitted by the radiation device are clustered by exciting the local electromagnetic field on the surface of the first-order grating structure to obtain clustered electron clusters;

[0146] Based on the secondary grating structure, new frequency components are extracted from the evanescent field around the clustered electron clusters, generating radiation containing new frequency components.

[0147] Based on the radiation containing the new frequency components, a terahertz frequency comb is generated.

[0148] In an exemplary embodiment of the present invention, the third module 830 may use the following formula (7) to determine the first period of the primary grating structure according to the pump frequency:

[0149] f p =v / L1 (7)

[0150] Wherein, L1 represents the first cycle; f p represents the pump frequency; v represents the flight speed of electrons emitted by the radiation device.

[0151] In an exemplary embodiment of the present invention, the third module 830 may use the following formula (8) to determine the second period of the secondary grating structure according to the first period:

[0152] L2=L1 / n(n=1,2,3…) (8)

[0153] Wherein, L1 represents the first period; L2 represents the second period, and n represents a positive integer.

[0154] Figure 9 An example of a physical structure diagram of an electronic device is shown below. Figure 9 As shown, the electronic device may include: a processor (processor) 910, a communication interface (Communications Interface) 920, a memory (memory) 930 and a communication bus 940, wherein the processor 910, the communication interface 920, and the memory 930 communicate with each other through the communication bus 940. The processor 910 can call the logic instructions in the memory 930 to execute the terahertz frequency comb generation method, which is applied to a radiating device, wherein the radiating device is obtained based on stimulated amplified coherent Smith-Purcell radiation, and the terahertz frequency comb generation method includes: obtaining a multi-frequency signal, wherein the multi-frequency signal is a signal including a first frequency and a second frequency, the first frequency is a terahertz frequency, and the second frequency is a modulation frequency; injecting the multi-frequency signal into the radiating device, and when the radiating device is in a saturated gain state, obtaining a new frequency component based on the nonlinear intermodulation distortion effect of the radiating device, wherein the new frequency component is a frequency component generated by the multi-frequency signal under the action of intermodulation and exists in the evanescent field spectrum around the electron; based on the new frequency component, generating a terahertz frequency comb, wherein the frequency interval of the terahertz frequency comb is the same as the modulation frequency.

[0155] In addition, the logic instructions in the above-mentioned memory 930 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0156] On the other hand, the present invention also provides a computer program product, which includes a computer program, which can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the terahertz frequency comb generation method provided by the above methods. The terahertz frequency comb generation method is applied to a radiation device, wherein the radiation device is obtained based on stimulated amplified coherent Smith-Parcell radiation, and the terahertz frequency comb generation method includes: obtaining a multi-frequency signal, wherein the multi-frequency signal is a signal including a first frequency and a second frequency, the first frequency is the terahertz frequency, and the second frequency is the modulation frequency; injecting the multi-frequency signal into the radiation device, and when the radiation device is in a saturated gain state, obtaining a new frequency component based on the nonlinear intermodulation distortion effect of the radiation device, wherein the new frequency component is a frequency component generated by the multi-frequency signal under the action of intermodulation and exists in the evanescent field spectrum around the electron; based on the new frequency component, generating a terahertz frequency comb, wherein the frequency interval of the terahertz frequency comb is the same as the modulation frequency.

[0157] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to execute the terahertz frequency comb generation method provided by the above-mentioned methods, wherein the terahertz frequency comb generation method is applied to a radiation device, wherein the radiation device is obtained based on stimulated amplified coherent Smith-Passell radiation, and the terahertz frequency comb generation method includes: obtaining a multi-frequency signal, wherein the multi-frequency signal is a signal including a first frequency and a second frequency, the first frequency is the terahertz frequency, and the second frequency is the modulation frequency; injecting the multi-frequency signal into the radiation device, and when the radiation device is in a saturated gain state, obtaining a new frequency component based on the nonlinear intermodulation distortion effect of the radiation device, wherein the new frequency component is a frequency component generated by the multi-frequency signal under the action of intermodulation and existing in the evanescent field spectrum around the electron; generating a terahertz frequency comb based on the new frequency component, wherein the frequency interval of the terahertz frequency comb is the same as the modulation frequency.

[0158] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0159] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, or of course, by hardware. Based on this understanding, the essence of the above technical solution or the part that contributes to the existing technology can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or certain parts of the embodiments.

[0160] It should be further understood that, although operations are described in a particular order in the accompanying drawings in the embodiments of the present invention, this should not be construed as requiring that the operations be performed in the particular order shown or in a serial order, or that all of the operations shown be performed to obtain the desired results. In certain circumstances, multitasking and parallel processing may be advantageous.

[0161] 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 terahertz frequency comb generation method, characterized in that: The terahertz frequency comb generation method is applied to a radiation device, wherein the radiation device is obtained based on stimulated amplified coherent Smith-Purcell radiation, and the terahertz frequency comb generation method includes: Acquire a multi-frequency signal, wherein the multi-frequency signal is a signal including a first frequency and a second frequency, the first frequency is a terahertz frequency, and the second frequency is a modulation frequency; Injecting the multi-frequency signal into the radiating device, and obtaining a new frequency component based on the nonlinear intermodulation distortion effect of the radiating device when the radiating device is in a saturated gain state, wherein the new frequency component is a frequency component generated by the multi-frequency signal under the intermodulation effect and exists in the evanescent field spectrum around the electron; A terahertz frequency comb is generated based on the new frequency component, wherein the frequency interval of the terahertz frequency comb is the same as the modulation frequency.

2. The terahertz frequency comb generation method according to claim 1, characterized in that: The acquiring of the multi-frequency signal specifically includes: Acquiring a single-frequency pump wave, wherein the pump frequency of the single-frequency pump wave is the terahertz frequency; determining the modulation frequency; The single-frequency pump wave is modulated according to the modulation frequency to obtain a modulated pump signal, and the modulated pump signal is used as the multi-frequency signal.

3. The terahertz frequency comb generation method according to claim 1, characterized in that: The obtaining of a new frequency component based on the nonlinear intermodulation distortion effect of the radiating device specifically includes: Based on the nonlinear intermodulation distortion effect of the radiation device, the terahertz frequency and the modulation frequency in the multi-frequency signal are stimulated to intermodulate to obtain high-order frequency harmonic components and intermodulation components; The high-order frequency harmonic component and the intermodulation component are used as the new frequency component, wherein the high-order frequency harmonic component is a frequency component formed according to an integer multiple of the terahertz frequency, and the intermodulation component is a frequency component formed on both sides of the high-order frequency harmonic component with the high-order frequency harmonic component as the center under the action of the intermodulation.

4. The terahertz frequency comb generation method according to claim 2, characterized in that: The radiation device includes a primary grating structure and a secondary grating structure, wherein a first period of the primary grating structure is determined according to the pump frequency, and a second period of the secondary grating structure is determined according to the first period; Generating a terahertz frequency comb based on the new frequency component specifically includes: Based on the new frequency component, the electrons emitted by the radiation device are clustered by exciting the surface local electromagnetic field of the primary grating structure to obtain clustered electron clusters; extracting new frequency components from the evanescent field around the clustered electron cluster based on the secondary grating structure, and generating radiation containing the new frequency components; A terahertz frequency comb is generated based on the radiation containing the new frequency components.

5. The terahertz frequency comb generation method according to claim 4, characterized in that: The first period of the primary grating structure is determined according to the pump frequency and is implemented using the following formula: f p =v / L1 Wherein, L1 represents the first period; f p represents the pump frequency; v represents the flying speed of the electrons emitted by the radiation device.

6. The terahertz frequency comb generation method according to claim 4, characterized in that: The second period of the secondary grating structure is determined according to the first period and is implemented using the following formula: L2=L1 / n(n=1,2,3…) Wherein, L1 represents the first period; L2 represents the second period, and n represents a positive integer.

7. A terahertz frequency comb generating device, characterized in that: The terahertz frequency comb generation device is applied to a radiation device, wherein the radiation device is obtained based on stimulated amplified coherent Smith-Purcell radiation, and the terahertz frequency comb generation device includes: A first module is configured to acquire a multi-frequency signal, wherein the multi-frequency signal is a signal including a first frequency and a second frequency, the first frequency is a terahertz frequency, and the second frequency is a modulation frequency; a second module, configured to inject the multi-frequency signal into the radiating device, and obtain a new frequency component based on the nonlinear intermodulation distortion effect of the radiating device when the radiating device is in a saturated gain state, wherein the new frequency component is a frequency component generated by the multi-frequency signal under the intermodulation effect and existing in the evanescent field spectrum around the electron; The third module is configured to generate a terahertz frequency comb based on the new frequency component, wherein the frequency interval of the terahertz frequency comb is the same as the modulation frequency.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the terahertz frequency comb generation method according to any one of claims 1 to 6 is implemented.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the terahertz frequency comb generation method according to any one of claims 1 to 6 is implemented.

10. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the terahertz frequency comb generation method according to any one of claims 1 to 6 is implemented.

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