CN108777368A - Surpass the reflective circular polarization plane super lens on surface based on graphene - Google Patents
Surpass the reflective circular polarization plane super lens on surface based on graphene Download PDFInfo
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- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims description 4
- 229910052737 gold Inorganic materials 0.000 claims description 4
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Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
- H01Q15/02—Refracting or diffracting devices, e.g. lens, prism
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
- H01Q15/0006—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices
- H01Q15/0013—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective
- H01Q15/002—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective said selective devices being reconfigurable or tunable, e.g. using switches or diodes
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Abstract
The present invention relates to a kind of reflective circular polarization plane super lens surpassing surface based on graphene, belong to Novel manual electromagnetic material and optical device field.The plane super lens include the metallic substrate layer of lower layer, the dielectric layer in middle level, the super superficial layer of the graphene for offering rectangle hole array on upper layer, polarization direction and propagation characteristic for controlling back wave, it is further provided with the control bias voltage device on connection graphene super surface and metallic substrates, Fermi's energy to adjust the super superficial layer of the graphene realizes the dynamic-tuning of graphene planes super lens focusing performance to change graphene layer conductivity.The plane super lens of the present invention may be implemented wide wavestrip and focus, and be easy to regulate and control, the efficiency of transmission too low compared to transmission-type super lens is more suitable for the application of actual scene, practicability higher.
Description
Technical field
The present invention relates to a kind of reflective circular polarization plane super lens surpassing surface based on graphene, belong to novel artificial electricity
Magnetic material and optical device field.
Background technology
Meta Materials (metamaterials) are the novel artificial electricity for having the extraordinary physical property not available for natural medium
The general designation of magnetic medium is usually formed by sub-wavelength metal or dielectric unit periodic arrangement that electroresponse and magnetic response can occur,
Its macroscopical Electromagnetism Characteristics is different from conventional material, with the new features not available for many nature materials.Super surface
(metasurface) it is the ultra-thin two-dimension array plane constructed by metamaterial structure unit, it both remains three-dimensional metamaterial
Strange properties, and overcome the difficulty that three-dimensional metamaterial is faced in preparation.By adjusting the geometry of super surface texture unit
Parameter (such as size, shape, direction etc.) can control the wave surface of back wave or transmitted wave, realize to electromagnetic wave phase, polarization side
The flexible Effective Regulation of the characteristics such as formula, communication mode.Due to the flexibility of design and the diversity of function, super surface can be used for
Modulator, phase shifter, sensor, detector, filter, wave absorbing device of function admirable etc., in compact, ultra-thin electromagnetic wave or photon
There is huge applications potential in terms of learning device.However, once Meta Materials or super surface structure based on metal or dielectric substance are solid
Fixed, electromagnetic performance can not just change, and be very limited in terms of flexible modulation electromagnetic wave.
Terahertz (THz) wave be often referred to frequency 0.1~10THz (wavelength be 0.03~3mm) range electromagnetic wave, between
It is the transition region between electronics and photonic propulsion between microwave and millimeter wave and infrared ray.THz wave has superior performance,
The basic research such as physics, chemistry, life subject and medical imaging, safety inspection, product testing, space communication, weapon guidance
Etc. application branches of learning all have important researching value and application prospect.Conventional material is difficult to realize that electromagnetism is rung in terahertz wave band
It answers, the appearance on Meta Materials and super surface compensates for this blank, and the superior THz devices of constructibility energy are realized to Terahertz
The detection of wave and effectively manipulation.
Currently, the super table for being operated in Terahertz and infrared band is constructed in this field using metal nano antenna structure mostly
Face regulates and controls the phase of electromagnetic wave using the surface plasmon resonance of metal Nano structure, realizes the control to wavefront.For side
Just it manufactures, carrying out alternative metals nano-antenna using metal nano pore structure constructs super surface again for this field.Whether metal
Still the super surface of metal nano-void with complementary structural features just has when it completes on nano-antenna super surface
To the changeless manipulation ability of electromagnetic wave, it is difficult to carry out the modulation of phase and amplitude again.Simultaneously in super lens field, due to
The operating mode efficiency of the loss of metal itself, the super surface of metal antenna is very low.When metal nano-void surpasses surface for transmission-type
When super lens, the transmissivity very low (10 of super lens-2Magnitude), only have certain researching value, practical value not high.
Invention content
The reflective circular polarization plane super lens on surface are surpassed to solve based on graphene the object of the present invention is to provide a kind of
The super surface lens efficiency of metal is low at present, the problem that performance is untunable and practicability is not high.
In order to solve the above technical problems, the present invention proposes that a kind of reflective circular polarization plane surpassing surface based on graphene is super
Lens, which is characterized in that the plane super lens include the metallic substrate layer of lower layer, the dielectric layer in middle level, the graphene on upper layer
Super superficial layer is additionally provided with the super surface of the graphene between the super superficial layer of graphene and the metallic substrate layer
The bias voltage device of layer Fermi's energy；The identical rectangular opening battle array of size dimension of hollow out is offered on the super superficial layer of graphene
Row, to change the phase, intensity and polarization mode of back wave；The rectangle hole array is in the x-y plane where it with period c
Arranged distribution, the period refer to distance of the two neighboring rectangular opening geometric center on two-dimentional axis, row rectangle along the y-axis direction
The rotation angle of hole x-axis opposite with row rectangular opening along the x-axis direction with respect to the rotation angle of x-axis is equipped with, to realize super lens
To reflecting the focusing function of circularly polarised wave.
This programme gives a kind of plane super lens structure, using the graphene layer of distribution rectangle hole array as super surface
Apply the bias voltage regulation and control super surface electromagnetic performance of graphene convenient for passing through, it is final to realize the tunable of super lens focusing function.
Further, the rectangle number of perforations of any row rectangular opening is 2n or 2n+1, and often row is arranged to the left or to the right by center
The rectangular opening of row is successively increased with respect to the rotation angle of x-axis, to realize the variation of the relatively incident wave phase of back wave, every row center
The rectangular opening in left side and the rectangular opening of often row central right are distributed about the center of every row at point symmetry.
Further, rotation angle all same of each rectangular opening with respect to x-axis in either rank rectangular opening.
Further, rotation angle of the rectangular opening with respect to x-axisSpatial relationship be
Wherein, x indicates the position coordinates of the super superficial layer rectangular opening geometric center of graphene, when the rectangle of any row rectangular opening
When number of perforations is 2n+1, x=m1C, m1=0, ± 1, ± 2 ..., ± n, when the rectangle number of perforations of any row rectangular opening is 2n,m2=± 1, ± 2 ..., ± n, F are the focal length of plane super lens, λ0For incidence wave wavelength.
This programme gives a kind of arrangement of the super superficial layer rectangle hole array of specific super lens, which can be real
Now to the line focus of back wave.
Further, n is the integer more than or equal to 18.
Further, the dielectric layer material is SiO2。
Further, the metallic substrate material is gold, silver or copper.
This programme can provide excellent reflecting effect for super lens, and reflectivity can reach 0.7 or more, compared to transmission-type
The too low efficiency of transmission of super lens is more suitable for the application of actual scene, practicability higher.
Further, the width of the rectangular opening is 2.5 to 3.2 microns, and length is 4 to 7 microns, and the period c is 8 micro-
Rice.
Further, the adjustable range of the super superficial layer Fermi energy of graphene is 0.5eV to 1.1eV.
This programme allows to adjust Fermi's energy of the super superficial layer of graphene by applying different bias voltages, to change
Graphene layer conductivity realizes the dynamic-tuning of the reflection wave strength and phase of graphene super lens.
Description of the drawings
Fig. 1 is a kind of structural representation of reflective circular polarization plane super lens surpassing surface based on graphene of the present invention
Figure；
Fig. 2-(a) is a kind of schematic diagram of the super superficial layer of graphene of the present invention；
Fig. 2-(b) is the structural unit schematic diagram of the super superficial layer of graphene shown in Fig. 2-(a)；
Fig. 3-(a) is a kind of reflective circular polarization plane super lens embodiment surpassing surface based on graphene of the present invention
Schematic diagram；
Fig. 3-(b) is the structural unit schematic diagram of the super superficial layer of graphene of super lens shown in Fig. 3-(a)；
Wherein, 1 is the super superficial layer of graphene, and 2 be dielectric layer, and 3 be metallic substrate layer, and c is the period of rectangle hole matrix,Rotation angle for rectangular opening with respect to x-axis；
Fig. 4 is in the embodiment of the present invention when all rectangular opening rotation angles areWhen reflectance spectrum, wherein incidence wave is
Right-hand circularly polarized wave, RRRAnd RRLRespectively represent the right-hand circular polarization wave component and Left-hand circular polarization wave component in back wave；
Fig. 5 is that the right-hand circularly polarized wave of frequency 5THz is incident to the left-handed circle reflected when super lens structure of the embodiment of the present invention
The reflectivity and reflected phase difference of polarized wave and graphene hole rotation angleRelationship；
Fig. 6 is working frequency 5THz, the graphene rectangular opening rotation angle of the plane super lens structure of focal length F=150umSpatial distribution curve along surface x-axis direction and corresponding back wave phase distribution curve；
Fig. 7-(a) is working frequency 5THz, and the plane super lens structure of focal length F=150um is in the dextrorotation that frequency is 5THz
When circularly polarized wave incidence, focusing effect figure of the Left-hand circular polarization back wave in x-z-plane；
Fig. 7-(b) is working frequency 5THz, and the plane super lens structure of focal length F=150um is in the dextrorotation that frequency is 5THz
When circularly polarized wave incidence, the electric field strength amplitude of Left-hand circular polarization back wave is in x=0 planes along the distribution of z-axis；
Fig. 7-(c) is working frequency 5THz, and the plane super lens structure of focal length F=150um is in the dextrorotation that frequency is 5THz
When circularly polarized wave incidence, the electric field strength amplitude of Left-hand circular polarization back wave is in z=140um planes along the distribution of x-axis；
Fig. 8-(a) is working frequency 5THz, and the plane super lens structure of focal length F=150um is inclined in different frequency dextrorotation circle
When vibration wave incidence, the electric field strength amplitude of Left-hand circular polarization back wave is in x=0 planes along the distribution of z-axis；
Fig. 8-(b) is working frequency 5THz, and the plane super lens structure of focal length F=150um is on the right side that frequency is 4.6THz
When handed polarized wave incidence, focusing effect figure of the Left-hand circular polarization back wave in x-z-plane；
Fig. 8-(c) is working frequency 5THz, and the plane super lens structure of focal length F=150um is in the dextrorotation that frequency is 6THz
When circularly polarized wave incidence, focusing effect figure of the Left-hand circular polarization back wave in x-z-plane；
Fig. 9-(a) is working frequency 5THz, and the plane super lens structure of focal length F=150um is in 5THz right-hand circularly polarized waves
Incidence, when graphene layer Fermi can be set as different value, the electric field strength amplitude of Left-hand circular polarization back wave is in x=0 planes
Along the distribution of z-axis；
Fig. 9-(b) is working frequency 5THz, and the plane super lens structure of focal length F=150um can be 1eV in graphene Fermi
When, focusing effect figure of the Left-hand circular polarization back wave in x-z-plane；
Fig. 9-(c) is working frequency 5THz, and the plane super lens structure of focal length F=150um can be in graphene Fermi
When 0.6eV, focusing effect figure of the Left-hand circular polarization back wave in x-z-plane.
Specific implementation mode
The specific implementation mode of the present invention is described further below in conjunction with the accompanying drawings.
It is as shown in Figure 1 the structural representation of the reflective circular polarization plane super lens for surpassing surface based on graphene of the present invention
Scheme, including metallic substrate layer 3, the dielectric layer 2 on basal layer, the super superficial layer 1 of graphene above dielectric layer, and connection
The control bias voltage device on the super surface of graphene and metallic substrates.
If Fig. 2-(a) show a kind of schematic diagram of the super superficial layer of graphene of the present invention, the super superficial layer of the graphene is logical
It crosses and opens up rectangle hollow hole arranged in arrays in single-layer graphene on piece and be made, all rectangular opening size dimensions are identical.Such as
Fig. 2-(b) show the structural unit schematic diagram of the super superficial layer of graphene shown in Fig. 2-(a), wherein the period of rectangle hole array
Period for c, rectangle hole array refers in the x-y plane of rectangular graphene hole place that two neighboring rectangular opening geometric center exists
Distance on two-dimentional axis.Rectangular opening is with respect to the rotation angle of x-axisIn a line rectangular opening along the x-axis direction, rectangle number of perforations is
2n or 2n+1, it is preferred that n takes the integer more than or equal to 18, the rotation of the n rectangular opening arranged from the center of every row to from left to right
Angle gradually increases, to realize phase change of the back wave with respect to incidence wave from 0 degree to 360 degree；Often n rectangular opening of row center left
With every n rectangular opening of row central right about every row center at point symmetry, i.e., the rectangular opening rotation angle of the left and right sides is in x-axis
It is distributed at point symmetry on direction.Row rectangular opening along the y-axis direction, rotation angle can flexible configuration according to actual needs, coordinate x-axis
The row rectangular opening in direction is to realize that the space phase needed for planar lens function is distributed.Wherein, it is 2n's for row rectangle hole count
Situation, often the capable from left to right midpoint of n-th of rectangular opening and (n+1)th rectangular opening geometric center line is the center of the row
The case where point is 2n+1 for row rectangle hole count, often the geometric center of capable from left to right (n+1)th rectangular opening is in the row
Heart point.
Preferably, width a=2.5~3.2um of rectangular opening, length b=4~7um.
Preferred dielectric layer is SiO2, thickness t=8.5um.
Preferred metallic substrate layer optional material is gold, silver, copper.
The period of the rectangle hole array is regular quadrangle array, preferred planar-periodic c=8um.
Preferably, graphene Fermi can 0.5eV≤Ef≤1.1eV。
In Terahertz to middle infrared band, graphene has the feature of metalloid, support surface plasmon resonance, stone
The surface plasmon resonance performance of black alkene micro-nano structure can also pass through external voltage and change in addition to relying on its geometrical structure parameter
Fermi's energy of doping regulation and control graphene is learned, and then changes graphene conductivity to control.Compared to metal and dielectric substance, graphite
The flexible controllable dielectric properties of alkene make it have significant advantage at the super surface of construction electromagnetic performance dynamic-tuning.Based on graphite
The wave plate or lens on the super surface of alkene can overcome that conventional lenses resolution ratio is low, volume is big and the super surface of metal, dielectric is not active
The unfavorable factors such as state regulation and control, in electromagnet wave device and electromagnetic wave technology field, such as THz communications, high-resolution THz displays
And the advanced imaging sides THz face has huge potential using value and foreground.
Specific explanations are come with an embodiment below and illustrate technical scheme of the present invention：
A kind of reflective circular polarization plane super lens surpassing surface based on graphene as Fig. 3-(a) show the present invention are real
The schematic diagram of example is applied, including the super superficial layer 1 of graphene of rectangle hole array, (the specifically used SiO here of dielectric layer 2 is distributed with2
Dielectric layer), metallic substrate layer 3 applies the Fermi that graphene is adjusted in bias voltage V between metallic substrate layer and graphene layer
Energy.SiO2The thickness of dielectric layer is 8.5um.The rectangle hole matrix for surpassing superficial layer to graphene is set as follows, will along the y-axis direction
The rotation angle of any one row rectangular opening be set as same size.As Fig. 3-(b) show the list on the super surface of embodiment graphene
Meta structure schematic diagram, the width for forming the rectangular graphene hole of array are a, length b, setting rectangular opening wide a=2.8um, long b
=5.6um, arrangement period c=8um.A line hole arranged along the x-axis direction includes 50 units, and x=0 is symmetry axis, right side
25 holes have different rotation angles25 holes in left side are obtained by translating the hole in the symmetric position of right side.Along the y-axis direction
One row hole of arrangement includes 25 units, and rectangular opening geometric parameter is identical.
Utilize the wave optics mould of finite element electromagnetic field simulation software Comsol Multiphysics (Comsol Inc.)
Block carries out simulation calculating.In the terahertz wave band studied, dielectric layer SiO2Relative dielectric coefficient be set as εr=3.75, damage
Consumption is just being cut to δ=0.0184 tan.Metallic substrate layer is replaced with perfect electric conductor boundary.Actual (real) thickness is the single layer stone of 0.35nm
Black alkene can use surface current layer to substitute in calculating simulation, and current density isWherein σ represents the conductance of graphene
Rate can be described by following formula
In formula, H (ω)=sinh (ω/ωT)/[cosh(ωF/ωT)+cosh(ω/ωT)],σ (ω) indicates conductivity, EfIndicate Fermi's energy, ω is the frequency of incident light, and e is the electricity of electronics
Lotus, T are temperature, kBIt is Boltzmann constant,It is reduced Planck constant,Represent relaxation rate, vF≈c/
300 and μ=10000cm2/ Vs respectively represents Fermi velocity and mobility.Formula (1) includes two, and first item is indicated with interior jump
It moves, Section 2 indicates band-to-band transition.Transition process accounts for leading in terahertz wave band, electronic band, and interband jump can be ignored in conductivity
Move the contribution of item.According to formula (1), graphene Fermi can EfVariation can directly result in graphene conductivity variations.
By " the super surface/dielectric layer/metallic substrates of graphene " the plane super lens that structure is constituted, back wave phase can be made
SPA sudden phase anomalies are occurred to incidence wave.By arranging different super surface cells, spy can be generated in lens surface tangential direction
Fixed phase gradient distribution, changes reflection direction of wave travel, makes its convergence.In order to realize lens function, in super surface x-axis side
To, phase distribution should meet following formula,
Wherein, when the rectangle number of perforations of any row rectangular opening is 2n+1, x=m1C, m1=0, ± 1, ± 2 ..., ± n, when
When the rectangle number of perforations of any row rectangular opening is 2n,M2=± 1, ± 2 ..., ± n, F represent focal length, and x is indicated
The position coordinates of the super surface texture unit of graphene of lens are formed, c is the structural unit period, it is preferred that the value of n is not less than
18, | x | reflection graphene hole unit center to the distance of lens centre, λ0For incidence wave wavelength.According to Pancharatnam
Berry phase potential theorys, when the rotation angle of rectangular slot isWhen, the SPA sudden phase anomalies of back wave areTherefore, in super surface x-axis
Direction needs the rotation angle of rectangular opening to meet shown in following formula to realize the required particular phases distribution of electromagnetic wave convergence
Distribution relation
Fig. 4 show back wave Left-hand circular polarization wave component and right-hand circular polarization wave component and incidence in the embodiment of the present invention
Relational graph between wave frequency rate, it is shown that right-hand circularly polarized wave is incident to " the super surface/dielectric layer/metallic substrates of graphene " knot
Reflectance spectrum when structure, RRRFor the right-hand circular polarization wave component in back wave, RRLFor the Left-hand circular polarization wave component in back wave,
Here graphene hole has identical geometric parameter, i.e. a=2.8um, b=5.6um, c=8um,In 4.7THz~6THz frequencies
Within the scope of rate, left-handed circular polarized wave reflectivity reaches 0.7 in back wave, and right-hand circularly polarized wave reflectivity is less than 0.05, realizes
The polarization conversion of incident right-hand circular polarization wave direction reflection left-handed circular polarized wave, and there is very high polarization conversion efficiency.Equally,
If it is left-handed circular polarized wave incidence, then left-handed circular polarized wave can be achieved to the identical polarization conversion of right-hand circularly polarized wave
Rate.
When Fig. 5 is that the right-hand circularly polarized wave of frequency 5THz is incident to the graphene super lens structure, the left-handed circle of reflection is inclined
The reflectivity and reflected phase difference of vibration wave and graphene hole rotation angleRelationship.When graphene hole rotation angle is changed to from 0 °
At 180 °, reflected phase difference realizes the change of 0~2 π, and phase difference changes the rotation angle linear approximate relationship with graphene hole,
Meet Berry phase potential theorys.It, can be to the row of graphene hole unit based on the relationship of phase difference variation and graphene hole rotation angle
Cloth is designed, by graphene hole of the arrangement with different rotary angle, to control the reflected phase distribution on super lens surface, from
And realize the super lens with particular focal length.
Fig. 6 is to be designed according to theoretical formula (2), the plane super lens structure of working frequency 5THz, focal length F=150um
The reflected phase distribution curve of surface along the x-axis direction gives in Fig. 6 according to Berry phase potential theorys, i.e. formula (3) obtains
Graphene rectangular opening rotation angleAlong the spatial distribution curve of surface x-axis direction.
It is detected analysis below by the super lens designed by Fig. 6, to illustrate this super lens of the embodiment of the present application
Characteristic.
To the working frequency 5THz designed by embodiment, the plane super lens structure of focal length F=150um carries out back wave and gathers
Burnt analog simulation detection, the results are shown in Figure 7.When Fig. 7-(a) is the right-hand circularly polarized wave incidence of frequency 5THz, a left side for reflection
Focusing effect figure of the handed polarized wave in x-z-plane；Fig. 7-(b) is the electric field strength amplitude of Left-hand circular polarization back wave in x
Along the distribution of z-axis in=0 plane；Fig. 7-(c) is the electric field strength amplitude of Left-hand circular polarization back wave in z=140um planes
Along the distribution of x-axis.Due to structural unit limited amount, the Fresnel number (Fresnel Number) of super lens is smaller, reflection
Cross polarization circularly polarized wave converges near the super surface z=140um of distance, is slightly less than designed focal length (F=150um).If
Incidence wave is left-hand polarized wave, then the right-handed polarized wave convergence result reflected is same as above, similar below.
To the working frequency 5THz designed by embodiment, focal length F=150um plane super lens structures are focused into line width wavestrip
The analog simulation of performance detects, and the results are shown in Figure 8.When Fig. 8-(a) is different frequency right-hand circularly polarized wave incidence, left-handed circle is inclined
Shake back wave electric field strength amplitude in x=0 planes along the distribution of z-axis.Fig. 8-(b) and 8- (c) respectively illustrates frequency and is
When the right-hand circularly polarized wave incidence of 4.6THz and 6THz, focusing effect figure of the Left-hand circular polarization back wave in x-z-plane.By scheming
8 it is found that when changing incident wave frequency rate, which still may be implemented back wave convergence, but focal length can change.When entering
When penetrating the frequency of circularly polarized wave and increasing to 6.2THz from 4.4THz, corresponding back wave focal length increases to 190um from 110um, real
Show wide wavestrip to focus.
Focusing can be regulated and controled by being biased voltage change graphene Fermi to the plane super lens structure designed by embodiment
The analog simulation detection of energy, the results are shown in Figure 9.Fig. 9-(a) is that 5THz right-hand circularly polarized waves are incident, and graphene Fermi can be not
When with value, the electric field strength amplitude of Left-hand circular polarization back wave is in x=0 planes along the distribution of z-axis；Fig. 9-(b) and 9- (c) points
When not showing that graphene Fermi can be 1eV and 0.6eV, focusing effect figure of the Left-hand circular polarization back wave in x-z-plane.When
When so that graphene layer Fermi is tapered into using bias voltage, the focal length of super lens does not change, but focal position light intensity subtracts
Weak, focusing performance reduces.
The making on the super surface of graphene can be prepared as follows in the present invention：
(1) using chemical vapour deposition technique graphene single layer is prepared in copper foil surface.
(2) graphene single layer is transferred to preprepared SiO using wet method transfer techniques2In/metallic substrates.
(3) electron beam lithography and oxygen plasma etch technology is used to etch rectangle hole array in graphene monolayer surface
Pattern.
(4) it uses electron beam lithography and electron beam evaporation process to prepare metal electrode on graphene surface layer, is used for graphene
The bias voltage regulation and control of Fermi's energy.
In the embodiment of the present invention, graphene layer rectangle hole array along the row rectangular opening of y-axis rotation angle it is identical be in order to most
Realize that the congruence of super lens is poly- eventually, it, can also be according to reality of course for the point convergence or other aggregation types for realizing super lens
It needs to carry out respective flexible design, is a kind of arrangement mode of point convergence shown in Fig. 2-(a), in this kind of arrangement mode, square
The equidistant rectangular opening of shape pore geometry center to rectangular opening array center its rotation angle, size are identical, and rotation angle
Size accordingly increases with the increase of the distance, said program should also fall into the present invention protect in the range of.
Specific embodiment is presented above, but the present invention is not limited to described embodiment.The base of the present invention
This thinking is above-mentioned basic scheme, the change carried out without departing from the principles and spirit of the present invention to embodiment
Change, change, replacing and modification is still fallen in protection scope of the present invention.
Claims (9)
1. surpassing the reflective circular polarization plane super lens on surface based on graphene, which is characterized in that under the plane super lens include
The metallic substrate layer of layer, the dielectric layer in middle level, the super superficial layer of graphene on upper layer, the super superficial layer of graphene and the gold
It is additionally provided with the bias voltage device of the super superficial layer Fermi energy of the graphene between category basal layer；The graphene is super
The identical rectangle hole array of size dimension that hollow out is offered on superficial layer, to change the phase, intensity and polarization side of back wave
Formula；For the rectangle hole array with period c arranged distribution in the x-y plane where it, the period refers to two neighboring rectangle
Distance of the pore geometry center on two-dimentional axis, the rotation angle and row along the x-axis direction of row rectangular opening along the y-axis direction with respect to x-axis
Rectangular opening is equipped with respect to the rotation angle of x-axis, to realize focusing function of the super lens to reflection circularly polarised wave.
2. the reflective circular polarization plane super lens according to claim 1 for surpassing surface based on graphene, which is characterized in that
The rectangle number of perforations of any row rectangular opening is 2n or 2n+1, often goes the rectangular opening arranged to the left or to the right by center with respect to x-axis
Rotation angle successively increase, to realize the variation of the relatively incident wave phase of back wave, often the rectangular opening of row center left with it is every
The rectangular opening of row central right is distributed about the center of every row at point symmetry.
3. the reflective circular polarization plane super lens according to claim 2 for surpassing surface based on graphene, which is characterized in that
Rotation angle all same of each rectangular opening with respect to x-axis in either rank rectangular opening.
4. the reflective circular polarization plane super lens according to claim 3 for surpassing surface based on graphene, which is characterized in that
Rotation angle of the rectangular opening with respect to x-axisDistribution relation be
Wherein, x indicates the position coordinates of the super superficial layer rectangular opening geometric center of graphene, when the rectangle hole count of any row rectangular opening
When mesh is 2n+1, x=m1C, m1=0, ± 1, ± 2 ..., ± n, when the rectangle number of perforations of any row rectangular opening is 2n,F is the focal length of plane super lens, λ0For incidence wave wavelength.
5. special according to any reflective circular polarization plane super lens for surpassing surface based on graphene of claim 2-4
Sign is that n is the integer more than or equal to 18.
6. the reflective circular polarization plane super lens according to claim 5 for surpassing surface based on graphene, which is characterized in that
The dielectric layer material is SiO2。
7. the reflective circular polarization plane super lens according to claim 6 for surpassing surface based on graphene, which is characterized in that
The metallic substrate material is gold, silver or copper.
8. the reflective circular polarization plane super lens for being surpassed surface based on graphene described according to claim 6 or 7, feature are existed
In the width of the rectangular opening is 2.5 to 3.2 microns, and length is 4 to 7 microns, and the period c is 8 microns.
9. the reflective circular polarization plane super lens according to claim 1 for surpassing surface based on graphene, which is characterized in that
The adjustable range of the super superficial layer Fermi energy of graphene is 0.5eV to 1.1eV.
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