A kind of too hereby wave radiation source with oval groove optical grating constructionTechnical field
The present invention relates to vacuum electronics Terahertz Technology field more particularly to a kind of oval groove optical grating construction Smith-Purcell effect THz wave radiation source.
Background technique
Terahertz (Terahertz, abbreviation THz) wave is a kind of electromagnetism between far infrared light wave and microwave and millimeter waveRadiation, frequency (1THz=10 from 100GHz to 10THz12Hz), corresponding wavelength is from 3 millimeters to 30 micron, and THz wave is in electromagnetismOccupy very special position in wave frequency spectrum, special performance gives communication, radar, electronic countermeasure, ELECTROMAGNETIC WEAPON, astronomy, medicineThe fields such as imaging, non-destructive testing, safety inspection bring profound influence.Nowadays THz technology has been used for material, life sectionIn the researchs such as, communication, agricultural and national security, multiple research fields interdisciplinary are formd.However, one urgently to be resolvedDoes is problem: how to obtain a high power, compact adjustable room temperature THz wave radiation source? because either from electricity or opticsAngle, there are a limit all near THz frequency for common opto-electronic device: electronic device be difficult to be higher than this THz frequencyRate, optical device are difficult to lower than this THz frequency.Therefore seek effective ways, explore the high performance THz amplitude of new mechanism developmentThe source of penetrating is very necessary, and is being applied of both military and civilian with important strategic importance to promotion THz wave.
There are many ways to can be used as THz emission source at present, mainly include the following categories: semiconductor THz wave radiation source is (such asTHz-QCL etc.)；THz generator based on photonics；Utilize THz wave radiation source (including the THz vacuum device, electricity of free electronSub- cyclotron maser and free-electron laser)；THz radiation source etc. based on high energy acclerator.THz-QCL radiation source is due to by poleThe limitation of low temperature becomes its widely applied barrier, and the power of the source the THz output based on photonics is lower, and is added based on high energyFor the THz radiation source of fast device due to needing huge accelerator, being widely applied includes also receiving in the application of military fieldGreatly limitation.In THz radiation source, the coherent radiation phenomenon based on Smith-Purcell (SP) effect causes scientistExtensive research interest and government highest attention, be more active one of research field in the world at present.Its principle isWhen moving using electronics note close to grating upper surface, the radiation of millimeter wave far infrared band is generated, the frequency of radiation is with viewing angleThe variation of degree and change, referred to as SP effect.When continuous electronic note is with the interaction of grating surface slow wave and when clustering, SP radiation just becomesAt stronger coherent radiation.Representative device based on this coherent radiation has SP effect free electron laser (free-electronLasers, abbreviation FELs).Relatively traditional FELs, SP-FELs have the advantages such as compact, adjustable, high-power, therefore it becomesOne hot research field of vacuum electronics THz radiation source.
1998, the optical grating construction that Urata et al. is 0.17mm using the continuous electronic note drive cycle of 30-50keV led toCrossing Beam and wave interaction makes electronics infuse clustering, the superradiance phenomenon of SP effect has been observed in an experiment, to the SP of Development of NovelFELs has great importance.Optical grating construction uses rectangular channel metal grating in experiment, this structure dispersion is very strong and work is being returnedWhen wavy state, need biggish electric current could starting of oscillation.2005, it was 15MeV's that MIT group, which generates energy using linear accelerator,Preparatory clustering electron beam group, carrys out drive cycle with this for the grating of 1cm, observed THz wave on 90 ° of directions.It is adopted in experimentUse stepped grating as Beam and wave interaction structure, advantage is to improve efficiency, but the electron beam group for generating preparatory clustering needsHuge accelerator is wanted, its extensive use is limited.
Summary of the invention
(1) technical problems to be solved
In view of above-mentioned technical problem, the present invention provides a kind of oval groove optical grating construction Smith-Purcell effect THz wavesCoherent source.
(2) technical solution
According to an aspect of the invention, there is provided a kind of have oval groove optical grating construction terahertz radiation source, spySign is, comprising:
Gun cathode, the cathode are used to emit the electronics note of certain speed；
Electronics infuses collector, is set to the face position of the gun cathode, the gun cathode and the electronicsIt infuses and forms Beam and wave interaction area between collector；
Oval groove optical grating construction is set in the Beam and wave interaction area；
Electron beam channel is set to the interposition of oval groove optical grating construction upper surface along the exit direction of electronics noteIt sets, it is vertical with the oval groove and parallel with the electronics note that the gun cathode is launched；
Plate is set to the position directly above of the oval groove optical grating construction, the opening parallel with the oval groove；
Wherein, the electronics note of the gun cathode transmitting passes through the electron beam channel, with the oval groove grating knotConfiguration interaction generate clustering electron beam group, and then generate the THz wave based on relevant Smith-Purcell effect, it is described tooHertz wave carries out energy by the plate and collects, and realizes that power amplification and growth rate improve, and passes through the electricity of interacting formationsSon note is collected by electronics note collector.
(3) beneficial effect
It can be seen from the above technical proposal that oval groove optical grating construction Smith-Purcell effect THz wave radiation of the present inventionSource has the advantages that
(1) it using periodical oval groove grating as Beam and wave interaction structure, not only reduces the dispersion of structure simultaneously but also dropsStarting oscillation current when low backward wave work is conducive to the generation of electronics note clustering and coherent radiation, to be conducive to THz wave radiationThe extensive use in source；
(2) by the way that electron beam channel to be partially submerged into optical grating construction, electronics note is reduced to the distance of grating, is enhancedBeam and wave interaction, while THz wave radiation intensity is improved, it is advantageously implemented high power, miniaturization, the densification of radiation source, is droppedThe low development cost of device；
(3) energy for being radiated open space is converged by being located at the plate (metal plate or dielectric-slab) right above gratingCollection, is advantageously implemented the collection and output of radiation.
Detailed description of the invention
Fig. 1 is the too hereby wave radiation source three dimensional structure diagram in the present invention with oval groove optical grating construction；
Fig. 2 is the too hereby wave radiation source overall structure diagram in the present invention with oval groove optical grating construction；
Fig. 3 is electron beam channel schematic cross-section in the present invention.
[main element symbol description of the present invention]
1- gun cathode；2- electronics note；
3- electronics infuses collector；4- oval groove optical grating construction；
5- plate (metal plate or dielectric-slab)；6- electron beam channel.
Specific embodiment
To make the objectives, technical solutions, and advantages of the present invention clearer, below in conjunction with specific embodiment, and referenceAttached drawing, the present invention is described in more detail.
It should be noted that similar or identical part all uses identical figure number in attached drawing or specification description.It is attachedThe implementation for not being painted or describing in figure is form known to a person of ordinary skill in the art in technical field.In addition, though thisText can provide the demonstration of the parameter comprising particular value, it is to be understood that parameter is equal to corresponding value without definite, but can connectIt is similar to be worth accordingly in the error margin or design constraint received.In addition, the direction term mentioned in following embodiment, such as"upper", "lower", "front", "rear", "left", "right" etc. are only the directions with reference to attached drawing.Therefore, the direction term used be forExplanation is not intended to limit the invention.
The present invention provides a kind of oval groove optical grating construction Smith-Purcell effect THz wave radiation sources.The THz amplitudeSource to be penetrated using periodical oval groove optical grating construction, electron beam channel is partially submerged into grating, electronics note passes through electron beam channel,Surface slow wave interaction with grating generates the SP radiation for being located at THz frequency range, and will be radiated by plate (metal or medium)Energy to open space collects, and is realized and is exported by coupled structure in optical grating construction end.The structure reduces dispersion and realShow that frequency is adjustable to be collected with energy.
In an exemplary embodiment of the present invention, a kind of oval groove optical grating construction Smith-Purcell effect is providedAnswer THz wave radiation source.Fig. 1 is the structural schematic diagram according to THz wave radiation of embodiment of the present invention source.Please refer to Fig. 1, the present embodimentOval groove optical grating construction Smith-Purcell effect THz wave radiation source includes: gun cathode 1, electronics note 2, electronics note collectionPole 3, oval groove optical grating construction 4, plate (metal or dielectric-slab) 5 and oval electron beam channel 6.
Individually below to each group of the present embodiment oval groove optical grating construction Smith-Purcell effect THz wave radiation sourceAt being partially described in detail.
The gun cathode 1 is used to emit the electronics note 2 of certain voltage.Wherein, gun cathode can be by band-likeAny one shape such as note, round and ellipse is constituted.Corresponding thereto, Electron Beam Shape is also possible to band-like (i.e. planeShape), any one shape such as round and ellipse.
The electronics infuses collector 5, is set to the face position of gun cathode 1, for collecting and the oval groove lightElectronics note after interaction occurs for 4 surface of grid structure, forms Beam and wave interaction between gun cathode and electronics note collectorArea.
The oval groove optical grating construction 4, is set in Beam and wave interaction area, is periodic grating structure, and grating slotIt is for the oval groove of ellipse.Wherein, oval groove can be the media slot of vacuum tank and the certain dielectric constant of filling, this structure canTo weaken the influence of dispersion, when working in backward wave state, the starting oscillation current of structure can be effectively reduced.The oval groove gratingStructure is periodic structure, and metal is used to be made.
The electron beam channel 6, the exit direction along electronics note are set in oval groove optical grating construction upper surfaceBetween position (i.e.), it is vertical with oval groove, it is parallel with the electronics note that gun cathode is launched.6 part of electron beam channel is embeddingEnter in the oval groove optical grating construction.Wherein, corresponding with Electron Beam Shape, electron beam channel shape be also possible to it is band-like,Any one shape such as round and ellipse, the transmission for electronics note.
The plate 5 is set to the position directly above of optical grating construction, parallel with oval groove.Wherein, plate can be metalPlate or dielectric-slab with certain dielectric constant, for collecting the energy for being radiated open space.
The electronics note that the gun cathode 1 emits passes through electron beam channel 6, interacts with oval groove optical grating construction 4Clustering electron beam group, the THz wave of the electron beam group excitation Smith-Purcell effect of clustering are generated, THz wave passes through the plate5 collect, and realize that power amplification and growth rate improve, and realize THz wave output by the coupled structure of end, by mutualElectronics note after effect is collected by collector.
It should be understood that this structure may be implemented by adjusting operating voltage of the external load on gun cathode 1Work wave band or the backward wave section of being expert at.The frequency of radiation is different with the difference of viewing angle, realizes the present embodiment THz wave radiationThe frequency in source is adjustable.
The present embodiment oval groove optical grating construction Smith-Purcell effect THz wave radiation source not only realizes THz signalIt generates, but also realizes the enhancing of Beam and wave interaction by oval groove, distance needed for infusing clustering so as to shorten electronics,Reduce the development difficulty of electron-optical system.
In addition, the above-mentioned definition to each element is not limited in the various specific structures or shape mentioned in embodiment,Those skilled in the art can replace with simply being known to it.
In conclusion the present invention provides a kind of oval groove optical grating construction Smith-Purcell effect THz wave radiation source.It shouldTHz wave radiation source note-as interacting formations, is realized by the way that electron beam channel to be partially submerged into grating using oval groove gratingThe enhancing of wave interaction and the generation of periodical electron beam group had both realized THz wave to generate relevant THz wave radiation sourceIt generates and realizes that THz wave frequency rate is adjustable, is conducive to the extensive use in THz wave radiation source again simultaneously.
The technical concepts and features of above-described embodiment only to illustrate the invention, its object is to allow person skilled in the artScholar cans understand the content of the present invention and implement it accordingly, and it is not intended to limit the scope of the present invention.It is all of the inventionWithin spirit and principle, any modification, equivalent substitution, improvement and etc. done be should be covered by the protection scope of the present invention.