CN109950777A - Double frequency terahertz emission source based on dirac semimetal surface plasma wave - Google Patents
Double frequency terahertz emission source based on dirac semimetal surface plasma wave Download PDFInfo
- Publication number
- CN109950777A CN109950777A CN201910281219.6A CN201910281219A CN109950777A CN 109950777 A CN109950777 A CN 109950777A CN 201910281219 A CN201910281219 A CN 201910281219A CN 109950777 A CN109950777 A CN 109950777A
- Authority
- CN
- China
- Prior art keywords
- surface plasma
- wave
- plasma wave
- dirac
- terahertz emission
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
Abstract
The invention discloses a kind of double frequency terahertz emission sources based on dirac semimetal surface plasma wave, it includes to cover the medium substrate with buffer layer by dirac half metal film, the surface plasma wave of moving electron both of which from film surface skims over excitation, when buffer layer dielectric constant is lower than substrate dielectric constant, both of which can be converted into substrate the Cherenkov's terahertz emission that is concerned with, the radiosity enhances two to three orders of magnitude by surface plasma wave, the present invention, which can be used for developing, has working and room temperature, it is high-power, cover the double frequency coherent THz radiation source of entire Terahertz frequency range.
Description
Technical field
The invention belongs to radiation source field of engineering technology, are related to a kind of based on dirac semimetal surface plasma wave
Double frequency terahertz emission source, specifically a kind of double frequency that can be used for the systems such as terahertz imaging, safety check and communication is relevant
Terahertz emission source.
Background technique
THz wave is being between microwave and infrared ray in electromagnetic spectrum.THz wave has many unique properties,
Firstly, its photon energy is low, lower than the bond energy of various chemical bonds, it can be used for the lossless safety inspection to human body and various organisms
It surveys.Secondly, Terahertz wavelength is longer than visible wavelength, smog etc. can be had an X-rayed, and to many substances (ceramics, fat, carbon
Plate, cloth, plastics) penetrability it is fine.Further more, Terahertz spectral bandwidth is very wide, it can be used for high-speed radiocommunication.Also, it is big
The vibration of most large biological molecules and rotational energy level are located at terahertz wave band, can detecte these molecules using tera-hertz spectra
Fingerprint characteristic spectrum.Based on these characteristics, Terahertz has important in fields such as safety detection, imaging, biomedicine, wireless telecommunications
Application.In recent years, Terahertz Technology at home and abroad all starts one research boom, and a core key for pushing it to develop is asked
Topic is terahertz emission source.
Currently, terahertz emission source relies primarily on two methods, electronics and photonics method.However they in frequency and
Two aspect of power faces huge challenge.Electronics cosmogony includes solid-state electronic cosmogony and vacuum electronic cosmogony.Based on semiconductor device
The solid-state electronic cosmogony of part operates mainly in Terahertz low-frequency range, such as 0.1THz-0.5THz, but this kind of device is limited to electronics
Transition time between semiconductor junction has high-frequency cut-off characteristic, and as working frequency increases, the fast prompt drop of radiant power
It is low.In 0.1THz-0.2THz, up to several hundred milliwatts, and when frequency is increased to 0.4THz, output power is reduced to several output power
Hundred microwatts.Vacuum electron device refers mainly to gyrotron, backward wave tube, klystron and travelling-wave tubes etc. by electronics note and slow-wave structure phase
The vacuum device of net energy output is realized in interaction.The working frequency of vacuum electron device and the size of slow-wave structure are at anti-
Than however as increasing for working frequency, the processing of slow-wave structure is more and more difficult.Current certain vacuum electron devices, are such as returned
The working frequency of coil, backward wave tube etc. can reach 1THz, but its output power declines rapidly as frequency increases.Photonics
Method rely primarily on femto-second laser pulse driving optical frequency under conversion generate, but this method generate terahertz emission its effect
Rate, output power are all relatively low.The swift and violent quantum cascade laser of latest developments operates mainly in Terahertz high band, be difficult by
Frequency is reduced to 1THz hereinafter, and also reducing as frequency reduces output power.In order to inhibit quantum ambient noise, the radiation
Source needs work under cryogenic.Therefore, exploitation, which covers the high power terahertz emission source of entire Terahertz frequency range, is still
One challenge outstanding.
Dirac semimetal is a kind of completely new peculiar Topological Quantum material.The body of this material has electronically formed three-dimensional
Dirac wimble structure, it is possible to regard " three-dimensional graphene " as.Similar with graphene, dirac semimetal can be with support matrix
Surface plasma wave (SPPs).Also the frequency with SPPs is in Terahertz to middle infrared band simultaneously, extremely strong locality and
Extremely low propagation loss, SPPs can be by adjusting applying bias voltages or chemical doping come the advantages that tuning.Compared to graphite
Alkene, since crystal symmetry is protected so that electronics therein has higher mobility in dirac semimetal.This will make Di La
Gram semimetal SPPs has lower inherent loss.Meanwhile dirac semimetal body material is one more than graphene two-dimensional structure
Dimension, it may be constructed plasma grating, and therefore, dirac semimetal can not only support conventional surface plasma wave
It can also support housing surface plasma wave.Currently, being also concentrated mainly on it to the research of dirac surface plasma wave
In terms of fundamental property, had not been reported for generating terahertz emission.
In face of use above demand, the present invention proposes a kind of double frequency based on dirac semimetal surface plasma wave too
Hertzion radiation source, the SPPs of moving electron both of which from excitation is skimmed on dirac half metal film surface, both of which is all
It can be converted into the relevant Cherenkov's terahertz emission enhanced in substrate, the radiosity is by SPPs enhancing two to three
A order of magnitude can tune radiation frequency by adjusting dirac semimetal chemical potential and velocity of electrons in Terahertz frequency range.
The advantages that having gathered double frequency, power enhancing and tuning, the radiant power and frequency coverage in terahertz emission source can be promoted.
Summary of the invention
The present invention is in view of above-mentioned technical background, it is therefore intended that it is whole in the presence of that cannot cover to solve existing terahertz emission source technology
A terahertz wave band and the low problem of radiant power, provide it is a kind of have working and room temperature, double frequency, it is high-power, can cover it is whole
The coherent THz radiation source of a terahertz wave band.
For achieving the above object, the present invention adopts the following technical scheme that.The semimetallic conductivityσ of dirac can adopt
It is described with (Kubo) formula of library primary, then dielectric function is obtained by the relationship between conductivity and dielectric function.
εBDS(ω)=ε∞+σ/ωε0 (1)
Wherein: ε∞It is dielectric constant when frequency approach is infinite, ε0It is permittivity of vacuum, ω is circular frequency.
Simultaneous boundary condition solves different zones in the available structure of maxwell equation group under rectangular coordinate system
Electromagnetic field equation:
For upper half-space region (y > d):
Wherein:k0It is wave vector in vacuum, kzIt is the direction the z wave vector of SPPs, A1It is a coefficient.Di is drawn
Gram half metal film region (0 < x < d):
Wherein:A2And A3It is a coefficient.
For buffering layer region (- h < x < 0):
Wherein:ε3It is buffer layer dielectric constant, A4And A5It is a coefficient.
For medium substrate region (x <-h):
Wherein:εsIt is substrate dielectric constant, A6It is a coefficient.
After obtaining field equation, using field matching method by the coupling effect of charge in dirac half metal film upper and lower interface
It is included, the boundary condition is as follows:
The electromagnetic field equation in each region is brought into the boundary condition, field coefficient is eliminated and obtains comprising two SPPs moulds
The dispersion equation of formula, dispersion equation are as follows:
Solve the wave vector k of the available two SPPs modes corresponding to frequency of dispersion equationz。
Induction is generated an evanscent field by moving electron, this turns again as the SPPs in the excitation structure of in-field, SPPs
Turn to the radiation field in substrate.Solve the following nonhomogeneous available evanscent field of Helmholtz equation.
Wherein: μ0It is space permeability.
The current density of moving electron may be expressed as:
Jz=qv0δ(y-y0-d)δ(z-v0t) (9)
Wherein: v0For electronic movement velocity, y0It is moving electron at a distance from half metal film upper surface, q is moving electron
Linear charge density in the x-direction.
Simultaneous equations (8) and (9), and utilize the available evanscent field of Fourier transformation:
Wherein:kz=ω/v0It is the wave vector of evanscent field in the z-direction.
In the case where there is electron excitation, boundary condition becomes:
All field coefficients can be determined by bringing field equation into (11).Field coefficient can calculate transmitted spectrum, field after obtaining
The radiation problems such as distribution.
Detailed description of the invention
Fig. 1 is that moving electron excites dirac half metal film to cover with buffer layer underlying structure showing in YOZ plane
It is intended to.It is medium substrate, dielectric buffer layer, dirac half metal film and moving electron respectively from top to bottom in figure.
Fig. 2 is symmetric mode and asymmetric mould SPPs dispersion curve figure in structure.Gray shade part is Cherenkov's spoke
Area is penetrated, dispersion, which is located at SPPs in the region, can be converted into Cerenkov radiation, the intersection point of evanscent field electric wire and dispersion curve
For operating point.It can be seen that electric wire can intersect with symmetric mode and asymmetric mould SPPs dispersion curve in radiation area, because
This, the symmetric mode and asymmetric mould SPPs excited by moving electron can be converted into the Cherenkov being concerned in substrate too
Hertzion radiation.Illustration is transmitted spectrum figure, there are two frequency point is radiated, respectively corresponds symmetric mode and asymmetric mould SPPs.
A and b is respectively symmetric mode and asymmetric mould SPPs field pattern in Fig. 3, it can be seen that is excited by moving electron
Symmetric mode and asymmetric mould SPPs be converted into substrate be concerned with Cherenkov's terahertz emission.
Relational graph of the Fig. 4 between radiation frequency and dirac semimetal chemical potential and velocity of electrons.It can be seen that passing through
Radiation frequency can be tuned in Terahertz frequency range by adjusting dirac semimetal chemical potential and velocity of electrons.
Specific embodiment
Embodiment is that dirac half metal film is covered in the medium substrate with buffer layer.Fig. 1 gives structure and exists
Schematic diagram in YOZ plane is medium substrate, dielectric buffer layer, dirac half metal film and movement electricity respectively from top to bottom
The production of son, the structure is processed also in compliance with principle from top to bottom.It is chosen at the common medium substrate material of terahertz wave band first
Material, the common organic buffer layer that then spin coating can be bought on the market on base material, and with photoresist spinner spin coating glue got rid of it is even,
Use chemical vapor deposition growth dirac half metal film on the buffer layer again.The revolving speed that buffer layer thickness passes through change photoresist spinner
Control.The thickness of dirac half metal film is controlled by growth time.
Coupling strongly occurs for dirac half metal film upper and lower surface charge, so that SPPs dispersion generates division and formed symmetrically
Mould and asymmetric mould, asymmetric mould SPPs energy enhance because of coupling, cause its wave vector that can match with transmission wave wave vector in substrate,
Asymmetric mould SPPs and symmetric mode SPPs, asymmetric mould SPPs will have been excited by skimming over film surface by the moving electron of emission of cathode
It can be converted into coherent THz radiation, as shown in b in Fig. 2 and Fig. 3.The energy of symmetric mode SPPs is reduced because of coupling,
When not having buffer layer, SPPs wave vector is the transmission wave wave vector being always larger than in medium substrate.There are when buffer layer, symmetric mode
SPPs energy can be enhanced by reducing buffer layer dielectric constant, right when buffer layer dielectric constant is smaller than substrate dielectric constant
Claim mould surface plasma wave wave vector that can match with transmission wave wave vector in substrate, thus the symmetrical surface excited by moving electron
Plasma wave can also be converted into coherent THz radiation, as shown in a in Fig. 2 and Fig. 3.
Radiant power improves two to three orders of magnitude by dirac semimetal SPPs.Radiosity can reach 6.7
×104W/cm2, suitable with the power density that graphene SPPs is converted into terahertz emission.Structure size is in square centimeter magnitude feelings
Under condition, the radiant power which generates has been able to satisfy requirement of the practical application to THz source radiant power.Change Di to draw
Gram semimetal chemical potential and velocity of electrons can tune radiation frequency in Terahertz frequency range, and Fig. 4 demonstrates this point.
A specific embodiment of the invention already described above, it should be appreciated that this is only mentioned with a kind of exemplary forms
Out, property that there is no restriction.Therefore, it can make without departing from the spirit and scope of the present invention in diversified forms and in details
Change, this is it will be apparent that without creative work for those familiar with the art.Above-mentioned these are all answered
It is considered as coverage of the invention.
Claims (5)
1. a kind of double frequency terahertz emission source based on dirac semimetal surface plasma wave, it includes by half gold of dirac
Belong to film and covers the medium substrate with buffer layer, the surface plasma of moving electron both of which from film surface skims over excitation
Bulk wave, one is symmetric modes, and one is asymmetric mould, both of which can be converted into the relevant Qie Lunke enhanced in substrate
Husband's terahertz emission.
2. a kind of double frequency terahertz emission source based on dirac semimetal surface plasma wave as described in claim 1,
It is further characterized in that strong coupling occurs for dirac half metal film upper and lower surface charge, so that surface plasma wave dispersion produces
Estranged to split to form symmetric mode and asymmetric mould, asymmetric mould surface plasma wave energy leads to its wave because coupling greatly enhancing
Arrow can be matched with transmission wave wave vector in substrate, can directly be turned by the asymmetric mould surface plasma wave that moving electron has excited
Turn to coherent THz radiation.
3. a kind of double frequency terahertz emission source based on dirac semimetal surface plasma wave as described in claim 1,
It is further characterized in that symmetric mode surface plasma wave energy can greatly enhance by reducing buffer layer dielectric constant, work as buffering
When layer dielectric constant is lower than substrate dielectric constant, symmetric mode surface plasma wave wave vector can be with transmission wave wave vector in substrate
Match, so that the symmetric mode surface plasma wave excited by moving electron can be converted into coherent THz radiation.
4. a kind of double frequency terahertz emission source based on dirac semimetal surface plasma wave as described in claim 1,
It is further characterized in that radiation frequency can be carried out in Terahertz frequency range by adjusting dirac semimetal chemical potential and velocity of electrons
Tuning.
5. a kind of double frequency terahertz emission source based on dirac semimetal surface plasma wave as described in claim 1,
It is further characterized in that radiant power enhances two to three orders of magnitude by surface plasma wave.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910281219.6A CN109950777A (en) | 2019-04-09 | 2019-04-09 | Double frequency terahertz emission source based on dirac semimetal surface plasma wave |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910281219.6A CN109950777A (en) | 2019-04-09 | 2019-04-09 | Double frequency terahertz emission source based on dirac semimetal surface plasma wave |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN109950777A true CN109950777A (en) | 2019-06-28 |
Family
ID=67012792
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910281219.6A Pending CN109950777A (en) | 2019-04-09 | 2019-04-09 | Double frequency terahertz emission source based on dirac semimetal surface plasma wave |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109950777A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110512282A (en) * | 2019-09-29 | 2019-11-29 | 中国人民解放军军事科学院国防科技创新研究院 | A kind of implementation method in novel terahertz emission source |
| CN113422196A (en) * | 2021-05-27 | 2021-09-21 | 山东师范大学 | Terahertz heat radiation source capable of generating ultra-narrow bandwidth and working method thereof |
-
2019
- 2019-04-09 CN CN201910281219.6A patent/CN109950777A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110512282A (en) * | 2019-09-29 | 2019-11-29 | 中国人民解放军军事科学院国防科技创新研究院 | A kind of implementation method in novel terahertz emission source |
| CN113422196A (en) * | 2021-05-27 | 2021-09-21 | 山东师范大学 | Terahertz heat radiation source capable of generating ultra-narrow bandwidth and working method thereof |
| CN113422196B (en) * | 2021-05-27 | 2022-06-24 | 山东师范大学 | Terahertz heat radiation source capable of generating ultra-narrow bandwidth and working method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Kandwal et al. | Low-profile spoof surface plasmon polaritons traveling-wave antenna for near-endfire radiation | |
| Khan et al. | Graphene patch antennas with different substrate shapes and materials | |
| Varshney et al. | A proximity coupled wideband graphene antenna with the generation of higher order TM modes for THz applications | |
| George et al. | Analysis of single band and dual band graphene based patch antenna for terahertz region | |
| Wu et al. | Graphene-based Yagi-Uda antenna with reconfigurable radiation patterns | |
| US20070075263A1 (en) | Ultra-small resonating charged particle beam modulator | |
| CN110011166A (en) | Multifrequency terahertz emission source based on dirac semimetal transmission grating | |
| CN112510469B (en) | Polarization tunable terahertz radiation source based on spin emission and linearly polarized light current | |
| Rodrigues et al. | Smart terahertz graphene antenna: operation as an omnidirectional dipole and as a reconfigurable directive antenna | |
| CN109950777A (en) | Double frequency terahertz emission source based on dirac semimetal surface plasma wave | |
| Tian et al. | Compact high-efficiency resonator antennas based on dispersion engineering of even-mode spoof surface plasmon polaritons | |
| CN109830875A (en) | Cherenkov's terahertz emission source based on multi-layer graphene surface plasma wave | |
| Saraereh et al. | Design and analysis of a novel antenna for THz wireless communication | |
| Bratman et al. | Design and numerical analysis of W-band oscillators with hollow electron beam | |
| Youssef et al. | A novel slotted antenna design for future Terahertz applications. | |
| Kumar et al. | Nano spherical dielectric resonator antenna for rectenna application | |
| Rao et al. | Optimization assisted antipodal vivaldi antenna for UWB communication: optimal parameter tuning by improved grey wolf algorithm | |
| Odarenko et al. | Novel THz sources with profiled focusing field and photonic crystal electrodynamic systems | |
| Pierantoni et al. | Analysis of a microwave graphene-based patch antenna | |
| CN109873287A (en) | Cherenkov's terahertz emission source based on cylinder graphene surface plasma wave | |
| Wang et al. | Energy absorption effects of the electromagnetic waves in collisional dusty plasmas | |
| Shi et al. | A frequency tunable relativistic magnetron with a wide operation regime | |
| Makhalov et al. | Design and modeling of a slow-wave 260 GHz tripler | |
| Fanrong et al. | Experimental and numerical studies on the receiving gain enhancement modulated by a sub-wavelength plasma layer | |
| Saravanan et al. | A compact graphene based nano-antenna for communication in nano-network |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20190628 |
|
| WD01 | Invention patent application deemed withdrawn after publication |