CN103176282A - Plane far-field super-resolution amplifying imaging device - Google Patents

Abstract

The invention belongs to the field of micro-imaging and relates to a plane far-field super-resolution amplifying imaging device adopting a flat-plate hyperbolic lens and a microobjective. The plane far-field super-resolution amplifying imaging device comprises a flat-plate hyperbolic lens for amplifying the details of an object to a degree so that the object details can be distinguished by a common microobjective, and a microobjective for further amplifying the middle image of the object. The plane far-field super-resolution amplifying imaging device is simple in structure, flexible in design, high in integrity and the like, and is expected to play an important role in the super-resolution real-time biomedical imaging field.

Description

A kind of plane far field super-resolution rate amplification imaging device

Technical field

The invention belongs to the micro-imaging field, relate to a kind of mixing arrangement of dull and stereotyped hyperbolic lens and microcobjective that utilizes and realize plane far field super-resolution rate amplification imaging device.

Background technology

At life science, microscope is being brought into play vital effect as a basic observation instrument on the cognitive level of the expansion mankind to outfield.Yet, being subjected to the restriction of the Rayleigh resolution limit, the traditional optical microtechnic almost has been developed to the end, can not satisfy the mankind far away to the exploration requirement of microworld.The Physical Mechanism that this problem occurs is, includes capable ripple and disappearance wave component in the light wave from object, and the row ripple represents the profile of object, can arrive image planes by imaging len smoothly; And the disappearance wave component that represents the detail section of object can only be delivered to the distance of wavelength magnitude and namely decays to zero in traditional imaging optical path, can't arrive image planes, causes the loss of object details in imaging process.The scanning tunnel microscope that once obtained the Nobel Prize promotes the resolving power of microtechnic with regard to being based on the principle that the disappearance ripple is converted into capable ripple.Yet scanning tunnel microscope is different from optical microscope, need to scan at body surface with probe, so efficient is lower, and variation that can not the real-time monitored object, and the dynamic process such as the cell division of urgently wishing to see such as scientist, wound healing.amplification and imaging (the Liu Z W of ripple although the super lens of the hyperbolic that grows up recent years can be realized disappearing, Lee H, Xiong Y, et al.Far-Field Optical Hyperlens Magnifying Sub-Diffraction-Limited Objects[J] .Science, 2007, 315:1686-1688.), but because object plane and image planes are all crooked, therefore can affect the location of object and the observation of image planes, although invented afterwards plane hyperbolic lens (Wang W, Xing H, Fang L, et al.Far-field imaging device:planar hyperlens with magnification using multi-layer metamaterial[J] .Opt.Express, 2008, 16 (25): 21142-21148.), but because the metal level of its design and dielectric layer thickness are uneven, with current microfabrication level, in fact be difficult to make successfully.

Summary of the invention

For the difficult point of prior art midplane to the plane super-resolution imaging, purpose of the present invention is exactly by a kind of simple in structure, flexible design, realizes the far-field optics imaging of super-resolution based on the imaging device of dull and stereotyped hyperbolic lens.

Technical scheme of the present invention is: a kind of plane far field super-resolution rate amplification imaging device, it is characterized in that, and comprising: dull and stereotyped hyperbolic lens is used for the object details is amplified to the discernmible degree of common microcobjective; Common microcobjective is used for the intermediary image of object is further amplified.

As preferably, described dull and stereotyped hyperbolic lens is comprised of super material, and in rectangular coordinate system, its dielectric tensors satisfy:

$\widehat{\mathrm{\ϵ}}(x,y)=\left[\begin{array}{cc}{\mathrm{\ϵ}}_r\frac{x^2}{x^2+y^2}+{\mathrm{\ϵ}}_{\mathrm{\θ}}\frac{y^2}{x^2{y}^2}& \frac{\mathrm{xy}({\mathrm{\ϵ}}_r-{\mathrm{\ϵ}}_{\mathrm{\θ}})}{x^2+y^2}\\ \frac{\mathrm{xy}({\mathrm{\ϵ}}_r-{\mathrm{\ϵ}}_{\mathrm{\θ}})}{x^2+y^2}& {\mathrm{\ϵ}}_{\mathrm{\θ}}\frac{x^2}{x^2+y^2}+{\mathrm{\ϵ}}_r\frac{y^2}{x^2+y^2}\end{array}\right],$

ε wherein _rBe the radially specific inductive capacity of super material, ε _θBe the angle specific inductive capacity of super material, and require ε _rReal part＜0, ε _θ Real part 0.

As preferably, described super material is the hyperbolic chromatic dispersion material.

As preferably, described hyperbolic chromatic dispersion material is alternately arranged by metal and dielectric substance and is formed, and the thickness of every layer material is identical and less than λ ₀/ 10, λ ₀Be operation wavelength, each layer medium consists of donut.

As preferably, on described operation wavelength, the absolute value of the specific inductive capacity of described dielectric and metal about equally.

As preferably, described metal is silver, and described dielectric is alundum (Al2O3).

The present invention has simple in structure, flexible design, the advantage such as highly integrated with respect to prior art, is expected to obtain important application in the real-time biomedical imaging of super-resolution field.

Description of drawings

Fig. 1: the structure principle chart that is plane of the present invention far field super-resolution rate amplification imaging device.

Fig. 2: the wave vector dispersion curve schematic diagram that is the hyperbolic chromatic dispersion material that the present invention relates to.

Fig. 3: the power flow point cloth that is the object plane that obtains of analog simulation that in the present invention, embodiment provides, intermediate image plane, final image planes xsect.

Wherein: 1 is dull and stereotyped hyperbolic lens, and 2 is common microcobjective, and k is wave vector, k _θBe the angle wave vector, kr is wave vector radially, and S is radiation direction.

Embodiment

Introduce in detail the present invention below in conjunction with the drawings and the specific embodiments.

The objective of the invention is planar object is realized the far field amplification imaging of super-resolution, the present invention includes dull and stereotyped hyperbolic lens 1 and common microcobjective 2, dull and stereotyped hyperbolic lens 1 is used for the object details is amplified to the discernmible degree of common microcobjective; Common microcobjective 2 is used for the intermediary image of object is further amplified, then coordinates eyepiece system, object finally can be amplified to the degree that the detectors such as human eye or CCD (charge-coupled image sensor) can be identified.Dull and stereotyped hyperbolic lens 1 is comprised of super material, and in rectangular coordinate system, its dielectric tensors satisfy:

$\widehat{\mathrm{\ϵ}}(x,y)=\left[\begin{array}{cc}{\mathrm{\ϵ}}_r\frac{x^2}{x^2+y^2}+{\mathrm{\ϵ}}_{\mathrm{\θ}}\frac{y^2}{x^2{y}^2}& \frac{\mathrm{xy}({\mathrm{\ϵ}}_r-{\mathrm{\ϵ}}_{\mathrm{\θ}})}{x^2+y^2}\\ \frac{\mathrm{xy}({\mathrm{\ϵ}}_r-{\mathrm{\ϵ}}_{\mathrm{\θ}})}{x^2+y^2}& {\mathrm{\ϵ}}_{\mathrm{\θ}}\frac{x^2}{x^2+y^2}+{\mathrm{\ϵ}}_r\frac{y^2}{x^2+y^2}\end{array}\right],$

ε wherein _rBe the radially specific inductive capacity of super material, ε _θBe the angle specific inductive capacity of super material, and require ε _rReal part＜0, ε _θReal part 0.Super material is the hyperbolic chromatic dispersion material.The hyperbolic chromatic dispersion material is alternately arranged by metal and dielectric substance and is formed, and the thickness of every layer material is identical and less than λ ₀/ 10, λ ₀Be operation wavelength, each layer medium consists of donut.Metal is silver, and dielectric is alundum (Al2O3).On operation wavelength, the absolute value of the specific inductive capacity of dielectric and metal about equally.

Ask for an interview Fig. 1 and Fig. 2, key of the present invention is to adopt the hyperbolic chromatic dispersion material to advance by light radial direction along circular arc in planar structure.As shown in Figure 1, if realize the amplification of planar object, our desired plane object AB can be along AA' and BB'(namely: the path radial direction take coordinate axis initial point O as the circular arc in the center of circle) arrives intermediate image plane A'B'.Obviously for common isotropic material, because the parallel flat of its formation does not have focal power, chief ray can not advance along this path; But for anisotropic artificial structure's material, can realize.The characteristics of hyperbolic chromatic dispersion material as shown in Figure 2, Fig. 2 has described angle wave vector k _θWave vector k radially _rDispersion relation figure, the hyperbolic chromatic dispersion material is to be formed by positive specific inductive capacity (dielectric) and negative intensive alternately the arranging of specific inductive capacity (metal) material, the angle DIELECTRIC CONSTANT ε that it is equivalent _θ0, and the radially DIELECTRIC CONSTANT ε of equivalence _r＜0.According to linear wave:

(k0 is the wave number in vacuum), angle wave vector k _θWave vector k radially _rSatisfy hyperbolic relation, and the direction of light S is any normal direction on hyperbolic curve, as shown in Figure 2.If suitable designing material makes ε _r→ 0, hyperbolic curve will deteriorate to two straight lines that are parallel to the θ axle so, and corresponding radiation direction S is parallel to the r axle, namely along k _rDirection just means that also light will propagate along the radial direction of circular arc, realize the amplification of object.Here the physical meaning of " amplification " is not only for the capable ripple in object wave, also comprises simultaneously the disappearance ripple and amplifies.Disappearance ripple angle wave vector in amplification process constantly reduces, when it is decreased to less than k ₀The time, will be converted into capable ripple, mean that can break away from the hyperbolic chromatic dispersion material is delivered to the far field, thereby by the further amplification imaging of rear microcobjective, the present invention that Here it is realizes the principle of super-resolution far field, plane amplification imaging.

In the present invention, imaging len is a common microcobjective, is used for realization to the further amplification imaging of intermediary image A'B', coordinates eyepiece system object can be amplified to the discernmible degree of detector.

The distance of the true origin O of the front surface distance coordinate system shown in Figure 1 of dull and stereotyped hyperbolic lens is L ₁, thickness is L ₂, the enlargement ratio of dull and stereotyped hyperbolic lens imaging is M ₁=1+L ₂/ L ₁If the resolving power of the microcobjective at device rear is res, the resolving power of imaging device is res/M ₁

Concrete implementation is divided into following steps:

The first step: according to the characteristics of object to be seen, determine the basic input parameters of the amplification imaging device in the present invention, comprising: operation wavelength λ ₀, resolution β, article size (range of observation) S ₁, dull and stereotyped hyperbolic lens thickness L ₂

Second step: select microcobjective, determine its numerical aperture NA, thereby determine its resolution β ₂=λ ₀/ 2NA.

The 3rd step: the magnification M that determines dull and stereotyped hyperbolic lens ₁Height S with intermediary image ₂, wherein, magnification M ₁According to M ₁=β ₂/ β calculates, the height S of intermediary image ₂According to S ₂=S ₁M ₁Calculate.

The 4th step: the distance L of determining true origin and dull and stereotyped hyperbolic lens ₁, according to L ₁=L ₂/ (M ₁-1) calculate.

The 5th step: according to operation wavelength λ ₀Select the hyperbolic chromatic dispersion material, comprise metal and dielectric, require the absolute value of its specific inductive capacity about equally.

The present embodiment proposes a operation wavelength λ of meter ₀For 375nm, resolution β are 100nm, range of observation S ₁Be 10 μ m, dull and stereotyped hyperbolic lens thickness L ₂Plane super-resolution amplification imaging device for 800nm.

At first select a microcobjective, the numerical aperture NA that establishes microcobjective is 0.1, enlargement ratio M ₂Be 1.4 times, its resolution is β as calculated so ₂=λ ₀/ 2NA=1700nm.

Then calculate the parameter of dull and stereotyped hyperbolic lens, its enlargement ratio is: M ₁=β ₂/ β=17 times, the height S of intermediary image ₂=S ₁M ₁=170 μ m, the distance L of true origin and dull and stereotyped hyperbolic lens ₁=L ₂/ (M ₁-1)=50nm.

Select at last the material of dull and stereotyped hyperbolic lens.At the 375nm wave band, more satisfactory material is silver (Ag) and alundum (Al2O3) (Al2O3), and its specific inductive capacity is respectively-3.12+0.21i and 3.21, and its absolute value is very approaching, satisfies the requirement of hyperbolic dispersion.

The imaging situation of plane of the present invention far field super-resolution rate amplification imaging device that adopted Electromagnetic Simulation software Comsol4.2 sunykatuib analysis.Fig. 3 has provided TM mould (p ripple) that simulation obtains through the power flow point cloth of the xsect of the object plane of amplification imaging device, intermediate image plane, final image planes.Calculating according to the front, the desired resolution of microcobjective is only 1700nm, after adding dull and stereotyped hyperbolic lens, two some things that are spaced apart 100nm are differentiated in intermediate image plane, and further be delivered to the far field, the object interval also extends to approximately 2400nm by 100nm, has realized the super-resolution amplification imaging, reaches purpose of design.

Above content is the further description of the present invention being done in conjunction with optimum implementation, can not assert that concrete enforcement of the present invention is only limited to these explanations.It should be appreciated by those skilled in the art, limit in the situation that do not break away from by appended claims, can carry out in detail various modifications, all should be considered as belonging to protection scope of the present invention.

Claims (6)

1. a plane far field super-resolution rate amplification imaging device, is characterized in that, comprising:

Dull and stereotyped hyperbolic lens (1) is used for the object details is amplified to the discernmible degree of common microcobjective;

Common microcobjective (2) is used for the intermediary image of object is further amplified.

2. plane according to claim 1 far field super-resolution rate amplification imaging device, it is characterized in that: described dull and stereotyped hyperbolic lens (1) is comprised of super material, and in rectangular coordinate system, its dielectric tensors satisfy:

$\widehat{\mathrm{\ϵ}}(x,y)=\left[\begin{array}{cc}{\mathrm{\ϵ}}_r\frac{x^2}{x^2+y^2}+{\mathrm{\ϵ}}_{\mathrm{\θ}}\frac{y^2}{x^2{y}^2}& \frac{\mathrm{xy}({\mathrm{\ϵ}}_r-{\mathrm{\ϵ}}_{\mathrm{\θ}})}{x^2+y^2}\\ \frac{\mathrm{xy}({\mathrm{\ϵ}}_r-{\mathrm{\ϵ}}_{\mathrm{\θ}})}{x^2+y^2}& {\mathrm{\ϵ}}_{\mathrm{\θ}}\frac{x^2}{x^2+y^2}+{\mathrm{\ϵ}}_r\frac{y^2}{x^2+y^2}\end{array}\right],$

ε wherein _rBe the radially specific inductive capacity of super material, ε _θBe the angle specific inductive capacity of super material, and require ε _rReal part＜0, ε _θReal part 0.

3. plane according to claim 2 far field super-resolution rate amplification imaging device, it is characterized in that: described super material is the hyperbolic chromatic dispersion material.

4. plane according to claim 3 far field super-resolution rate amplification imaging device, it is characterized in that: described hyperbolic chromatic dispersion material is alternately arranged by metal and dielectric substance and is formed, and the thickness of every layer material is identical and less than λ ₀/ 10, λ ₀Be operation wavelength, each layer medium consists of donut.

5. plane according to claim 4 far field super-resolution rate amplification imaging device, it is characterized in that: on described operation wavelength, the absolute value of the specific inductive capacity of described dielectric and metal about equally.

6. plane according to claim 4 far field super-resolution rate amplification imaging device, it is characterized in that: described metal is silver, and described dielectric is alundum (Al2O3).

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