CN102289083B - Far-field super-resolution visual imaging device and imaging method - Google Patents

Abstract

The invention discloses a far-field super-resolution visual imaging device and an imaging method. The visual imaging device comprises a super-resolution amplifier and an optical microscope. Based on a short wavelength effect of a metal surface plasma wave, the surface plasma wave has stronger space differentiating capability than a free space electromagnetic wave with the same frequency; by using the characteristic, a super-resolution amplifier with an amplifying function is obtained; and the space information of an observed thing is initially amplified and is further amplified by using an optical microscope to obtain a super-resolution imaging result. The invention overcomes a restriction of a diffraction limit of a traditional optical microscope system, and realizes far-field visual imaging differentiation of an object of which the spacing is less than a traditional optical microscope resolution.

Description

A kind of Far-field super-resolution visual imaging device and formation method

Technical field

The present invention relates to a kind of imaging technique, specifically a kind of novel far field visual imaging device and the formation method with hyperresolution that can be combined with conventional optical microscope.

Background technology

Microscope is the human indispensable instrument of exploring microworld, has very widely in fields such as biology, chemistry, medical science and micro-nano structure preparations and uses.Yet conventional optical microscope is owing to be subject to the restriction of diffraction limit, can only differentiate size greater than half object of wavelength, and namely its resolution is about 200nm in the visible optical range, can't continue to extend to less yardstick.Along with developing rapidly of modern science, this restriction can not have been satisfied people's requirement far away, and therefore, development super-resolution imaging technology is extremely urgent task.The technology that has at present super resolution imaging function has following several: the one, and oil-immersion method, being about to micro objective and detecting object all immerses in the solution of high index of refraction, to reach the purpose that increases numerical aperture, thereby realize the super-resolution imaging to object, yet, the method is only applicable to not change the object observation of pattern and physiological characteristic in solution, conditional request is harsh; The 2nd, adopt short wavelength's electron beam to replace light, such as scanning electron microscope, yet scanning electron microscope is confined to the observation under the static condition.Therefore, the super-resolution imaging technology that can dynamically observe in real time that develops a kind of far field seems very necessary.Surface plasma wave can be applicable in the super-resolution imaging technology because its wavelength is short, and surface plasma wave can effectively change with the free space electromagnetic wave, based on these characteristics, can realize the super-resolution imaging technology that human eye is visual.The people such as Anatoly V.Zayats had carried out relevant exploration in 2005, obtained relevant super-resolution experimental result by the prism surface plasma structure with the mode of optical microscope combination, yet, this structure can only be carried out the detection of one dimension, the concept that does not also have the super-resolution camera lens can't form imaging device.In addition, based on short wavelength's characteristic of surface plasma wave, study at present the focal beam spot that more focusing structure can obtain to surpass diffraction limit, this proposition for Far-field super-resolution visual imaging device provides relevant foundation.

Summary of the invention

The technical problem to be solved in the present invention is: overcome the restriction of existing optical microscope resolution, a kind of Far-field super-resolution visual imaging device and formation method are provided, by being combined with optical microscope, realize the visual real-time resolution to sub-wavelength yardstick object.

Technical solution of the present invention: a kind of Far-field super-resolution visual imaging device comprises: the lighting source of irradiation imaging object, have super-resolution amplifier and the optical microscope of hyperresolution;

Described super-resolution amplifier is made of metal construction, substrate and dimpling lens, and the size of described dimpling lens is greater than the overall dimensions of metal construction; Described metal construction and dimpling lens lay respectively at two sides of same substrate, and wherein metal construction is positioned near imaging object one side, and the dimpling lens are positioned near optical microscope one side, and are confocal the connection with the object lens of optical microscope; Described metal construction is comprised of the metallic slit ring that the circular metal film that is positioned at core reaches near the circular metal film, and imaging object is positioned at the surface of described metal film.

Described lighting source is visible light, and the polarization direction is radial polarisation light, and human eye can directly be observed the super-resolution imaging result.

The spacing of two imaging object point A, B of imaging object is less than half of lighting source wavelength.

The material of described metal construction is gold, silver or aluminium.

The resolution of described Far-field super-resolution visual imaging device is 0.61 λ _Spp, λ wherein _SppThe surface plasma wave wavelength that excites in metal structure surface for imaging object point scattered light.

Described surface plasma wave satisfies:

$\frac{2\mathrm{\π}}{{\mathrm{\λ}}_{\mathrm{spp}}}=\frac{2\mathrm{\π}}{{\mathrm{\λ}}_0}\sqrt{\frac{{\mathrm{\ϵ}}_m{\mathrm{\ϵ}}_0}{{\mathrm{\ϵ}}_m+{\mathrm{\ϵ}}_0}}---\left(1\right)$

λ wherein ₀Be illumination light wavelength, ε _m, ε ₀Be respectively the specific inductive capacity of metal construction (121) and metal construction (121) surface dielectric.ε _mBe negative value.

The wavelength X of the surface plasma wave that excites (124) _SppLess than illumination light wavelength λ ₀

A kind of Far-field super-resolution visual formation method is characterized in that performing step is as follows:

(1) behind two imaging point A, the B of lighting source irradiation imaging object, produce the scattered light of all directions, scattered light keeps the radial polarisation characteristic, at the surface plasma wave of the circular metal film surface excitation that is positioned at core along all directions propagation;

(2) obtain by imaging point A according to formula (1), the wavelength of the light activated surface plasma wave of scattering of B is λ _Spp, λ _SppSatisfy;

$\frac{2\mathrm{\π}}{{\mathrm{\λ}}_{\mathrm{spp}}}=\frac{2\mathrm{\π}}{{\mathrm{\λ}}_0}\sqrt{\frac{{\mathrm{\ϵ}}_m{\mathrm{\ϵ}}_0}{{\mathrm{\ϵ}}_m+{\mathrm{\ϵ}}_0}}---\left(1\right)$

λ wherein ₀Be illumination light wavelength, ε _m, ε ₀Be respectively the specific inductive capacity of metal construction and metal structure surface medium, ε _mBe negative value, the wavelength X of the surface plasma wave that excites _SppLess than illumination light wavelength λ ₀

(3) surface plasma wave (124) is propagated to metallic slit along the surface of circular metal film, pass through again the coupling of metallic slit, the space of surface plasma wave from the coupling of imaging object one side to dimpling lens one side, and be converted to parallel beam, the exit direction angle θ that obtains the parallel beam direction between metal construction and the dimpling lens according to formula (2) satisfies:

$\sin \mathrm{\θ}=\frac{{\mathrm{\λ}}_0}{D}\·\frac{2d}{{\mathrm{\λ}}_{\mathrm{spp}}}---\left(2\right)$

The diameter of part circular metal film centered by the D wherein, d is that imaging object point A, B depart from the distance in the circular metal film center of circle.

(4) parallel beam is after the dimpling lens are collected focusing, form focal beam spot A ' B ' on the confocal plane of dimpling lens and optical microphotograph endoscope objective lens, obtained the spacing d ' of hot spot by formula (3), d ' is much larger than the resolution of optical microscope, namely obtained preliminary amplification result to imaging object point AB by the super-resolution amplifier;

Focal beam spot position d ' satisfies

d′＝f tan θ (3)

Wherein f is the focal length of dimpling lens;

(5) diffraction spot of the picture point A ' B ' behind the dimpling lens imaging is carried out further imaging by optical microscope and is amplified less than the spacing d ' of picture point, obtains the far field super-resolution imaging results visual to the human eye of imaging object point A, B.

Described focal spot position d ' is greater than the diffraction spot size of described dimpling lens The resolution that obtains described Far-field super-resolution visual imaging device is 0.61 λ _Spp

The present invention's advantage compared with prior art is:

(1) the present invention has realized the visual imaging observation in far field to the object point that surpasses the conventional optical microscope diffraction limit that is spaced apart the sub-wavelength magnitude, because the wavelength in the wavelength ratio free space of surface plasma wave is short, therefore the surface plasma wave phase differential that excites of object diverse location is greater than the scattering wave of its free space, and surface plasma wave can be changed mutually with free space beam, utilize surface plasma wave as the intermediate conversion medium, the spatial information of object will be exaggerated;

(2) has extraordinary compatibility with conventional optical microscope, only need to add the super-resolution amplifier as the front end camera lens at the microscope front end that simultaneously lighting source is changed into the radial polarisation light source, microscopic system has just obtained the far field super-resolution function, therefore use simply, cost is low;

(3) the present invention compares with other super-resolution imaging technology, structure and the media environment of detecting object are not consisted of destruction (such as biological solution), the super-resolution image position that becomes is in the far field, can directly observe by human eye or detector array, be with a wide range of applications, for the development of optical microphotograph imaging technique has advanced a huge step.

Description of drawings

Fig. 1 is structural representation of the present invention; Wherein: 11 is lighting source, 12 is the super-resolution amplifier, 121 is metal construction, 122 is basalis, and 123 is the dimpling lens, and 15 is imaging object, 124 for the light activated surface plasma wave of scattering of imaging object point, 125 is the light beam in the substrate of super-resolution amplifier, and 13 is dimpling lens and the common focal plane of optical microphotograph endoscope objective lens, and 14 is the optical microscope objective lens;

Fig. 2 is the planimetric map of metal construction; Wherein: 1211 is the circular metal film of center section, and 1212 is the metallic slit structure near the circular metal film, is positioned at the surface of circular metal film.

Embodiment

Introduce in detail the present invention below in conjunction with the drawings and the specific embodiments.But following embodiment only limits to explain the present invention, and protection scope of the present invention should comprise the full content of claim, and namely can realize the full content of claim of the present invention by following examples those skilled in the art.

As shown in Figure 1, 2, a kind of Far-field super-resolution visual imaging device of the present invention comprises: lighting source 11, the super-resolution amplifier 12 with hyperresolution and optical microscope 14.Super-resolution amplifier 12 is made of metal construction 121, substrate 122 and dimpling lens 123, and the size of dimpling lens 123 is greater than the overall dimensions of metal construction 121.Metal construction 121 and dimpling lens 123 lay respectively at a side of same substrate 122, and metal construction 121 is positioned near imaging object 15 1 sides, and dimpling lens 123 are positioned near optical microscope 14 1 sides, and are confocal the connection with the object lens of optical microscope 14.Metal construction 121 is comprised of the metallic slit ring 1212 that the circular metal film 1211 that is positioned at core reaches near circular metal film 1211, and imaging object 15 is positioned at the surface of described circular metal film 1211.Lighting source 11 is visible light, and the polarization direction is radial polarisation light, and human eye can directly be observed the super-resolution imaging result.

As shown in Figure 1, 2, Far-field super-resolution visual formation method implementation procedure of the present invention is as follows:

(1) lighting source 11 wavelength are defined as the visible light of 632.8nm, and the polarization direction is radial polarisation light;

(2) the imaging object point AB spacing d=300nm of imaging object 15 less than lighting source 11 wavelength half, has namely surpassed the resolution of conventional optical microscope;

(3) behind the imaging point AB of lighting source 11 irradiation imaging objects 15, produce the scattered light of all directions, scattered light keeps the radial polarisation characteristic, at the surface plasma wave 124 of circular metal film 1211 surface excitations that are positioned at core along all directions propagation;

(4) material of metal construction 121 is selected gold, and according to the A of formula (1) acquisition by imaging object point 15, the wavelength of the light activated surface plasma wave 124 of the scattering of B is λ _Spp=473nm;

Surface plasma wave 124 satisfies:

$\frac{2\mathrm{\π}}{{\mathrm{\λ}}_{\mathrm{spp}}}=\frac{2\mathrm{\π}}{{\mathrm{\λ}}_0}\sqrt{\frac{{\mathrm{\ϵ}}_m{\mathrm{\ϵ}}_0}{{\mathrm{\ϵ}}_m+{\mathrm{\ϵ}}_0}}---\left(1\right)$

λ wherein ₀Be illumination light wavelength, ε _m, ε ₀Be respectively the specific inductive capacity of metal construction 121 and metal construction 121 surface dielectrics, wherein ε _m=-9.3418 is negative value, and gets ε ₀=1.5, the wavelength X of the surface plasma wave 124 that excites _SppLess than illumination light wavelength λ 0;

(5) central circular metal film 1211 diameters in the present embodiment are 6um, the width of metallic slit 1212 is 300nm, substrate and microlens material are selected K9 glass, surface plasma wave 124 is propagated to metallic slit 1212 along the surface of circular metal film 1211, pass through again the coupling of metallic slit 1212, the space of surface plasma wave 124 from the coupling of imaging object 15 1 sides to dimpling lens 123 1 sides, and being converted to parallel beam 125, the parallel beam exit direction angle θ that obtains between metal construction 121 and the dimpling lens 123 according to formula (2) satisfies

$\sin \mathrm{\θ}=\frac{{\mathrm{\λ}}_0}{D}\·\frac{2d}{{\mathrm{\λ}}_{\mathrm{spp}}}---\left(2\right)$

θ＝7.69；

(6) focal distance f=50um of dimpling lens, parallel beam is after the dimpling lens shown among Fig. 1 123 are collected focusing, at the confocal plane 13 formation focal beam spot A ' Bs ' of dimpling lens 123 with optical microphotograph endoscope objective lens 14, obtain the spacing d ' of hot spot=22.2974d=6.689um by formula (3), much larger than the resolution of optical microscope, namely obtained preliminary amplification result to imaging object point AB by super-resolution amplifier 12;

Focal beam spot position d ' satisfies

d′＝f tan θ (3)

Wherein f is the focal length of dimpling lens 123;

(7) diffraction spot of the picture point A ' B ' after 123 imagings of dimpling lens size is 6.43um, diffraction spot is less than the spacing d ' of picture point, obtain the distinguishable minimum spacing d=288.53nm of object point, the resolution that is Far-field super-resolution visual imaging device is 288.53nm, and the resolution that this resolution has surpassed conventional optical microscope (is 0.5 λ ₀=316.4nm).Carry out further imaging by 14 couples of A ' B ' of optical microscope and amplify, obtain the visual far field super-resolution imaging results of human eye of the object point AB that can't differentiate conventional optical microscope.

The part that the present invention does not elaborate belongs to the known technology of this area.

Claims (4)

1. a Far-field super-resolution visual imaging device is characterized in that comprising: lighting source (11), the super-resolution amplifier (12) with hyperresolution and the optical microscope (14) of irradiation imaging object (15);

Described super-resolution amplifier (12) is made of metal construction (121), substrate (122) and dimpling lens (123), and the size of described dimpling lens (123) is greater than the overall dimensions of metal construction (121); Described metal construction (121) and dimpling lens (123) lay respectively at two sides of same substrate (122), wherein metal construction (121) is positioned near imaging object (15) one sides, dimpling lens (123) are positioned near optical microscope (14) one sides, and are confocal the connection with the object lens of optical microscope (14); Described metal construction (121) is comprised of the metallic slit ring (1212) that the circular metal film (1211) that is positioned at core reaches near circular metal film (1211), and imaging object (15) is positioned at the surface of described circular metal film (1211);

Described lighting source (11) is visible light, and the polarization direction is radial polarisation light, and human eye can directly be observed the super-resolution imaging result;

The material of described metal construction (121) is gold, silver or aluminium;

The resolution of described Far-field super-resolution visual imaging device is 0.61 λ _Spp, λ wherein _SppBe the wavelength of imaging object point scattered light at the surface plasma wave (124) of metal construction (121) surface excitation;

Described surface plasma wave (124) satisfies:

$\frac{2\mathrm{\π}}{{\mathrm{\λ}}_{\mathrm{spp}}}=\frac{2\mathrm{\π}}{{\mathrm{\λ}}_0}\sqrt{\frac{{\mathrm{\ϵ}}_m{\mathrm{\ϵ}}_0}{{\mathrm{\ϵ}}_m+{\mathrm{\ϵ}}_0}}---\left(1\right)$

λ wherein ₀Be illumination light wavelength, ε _m, ε ₀Be respectively the specific inductive capacity of metal construction (121) and metal construction (121) surface dielectric, ε _mBe negative value;

The wavelength X of the surface plasma wave that excites (124) _SppLess than illumination light wavelength λ ₀

2. a kind of Far-field super-resolution visual imaging device according to claim 1 is characterized in that: the spacing of two imaging object point A, B of described imaging object (15) is less than half of lighting source (11) wavelength.

3. Far-field super-resolution visual formation method is characterized in that performing step is as follows:

(1) behind two imaging point A, the B of lighting source (11) irradiation imaging object (15), produce the scattered light of all directions, scattered light keeps the radial polarisation characteristic, at the surface plasma wave (124) of circular metal film (1211) surface excitation that is positioned at core along all directions propagation;

(2) according to the imaging object point A of formula (1) acquisition by imaging object (15), the wavelength of the light activated surface plasma wave of the scattering of B (124) is λ _Spp, λ _SppSatisfy;

$\frac{2\mathrm{\π}}{{\mathrm{\λ}}_{\mathrm{spp}}}=\frac{2\mathrm{\π}}{{\mathrm{\λ}}_0}\sqrt{\frac{{\mathrm{\ϵ}}_m{\mathrm{\ϵ}}_0}{{\mathrm{\ϵ}}_m+{\mathrm{\ϵ}}_0}}---\left(1\right)$

λ wherein ₀Be illumination light wavelength, ε _m, ε ₀Be respectively the specific inductive capacity of metal construction (121) and metal construction (121) surface dielectric, ε _mBe negative value, the wavelength X of the surface plasma wave that excites (124) _SppLess than illumination light wavelength λ ₀

(3) surface plasma wave (124) is propagated to metallic slit (1212) along the surface of circular metal film (1211), pass through again the coupling of metallic slit (1212), the space of surface plasma wave (124) from the coupling of imaging object (15) one sides to dimpling lens (123) one sides, and be converted to parallel beam (125), obtain the exit direction angle θ of the parallel beam direction between metal construction (121) and the dimpling lens (123) according to formula (2):

$\sin \mathrm{\θ}=\frac{{\mathrm{\λ}}_0}{D}\·\frac{2d}{{\mathrm{\λ}}_{\mathrm{spp}}}---\left(2\right)$

The diameter of part circular metal film (1211) centered by the D wherein, d is the distance that imaging object point A, B depart from circular metal film (1211) center of circle;

(4) parallel beam is after dimpling lens (123) are collected focusing, at confocal plane (13) the formation focal beam spot A ' B ' of dimpling lens (123) with optical microscope (14) object lens, obtain focal beam spot position d ' by formula (3), d ' is much larger than the resolution of optical microscope (14), namely obtained preliminary amplification result to imaging object point A, B by super-resolution amplifier (12);

Focal beam spot position d ' satisfies

d′＝f tanθ （3）

Wherein f is the focal length of dimpling lens (123);

(5) the diffraction spot size of the picture point A ' B ' after dimpling lens (123) imaging is less than focal beam spot position d ', carry out further imaging by optical microscope (14) and amplify, obtain the far field super-resolution imaging results visual to the human eye of imaging object point A, B.

4. a kind of Far-field super-resolution visual formation method according to claim 3 is characterized in that: described focal beam spot position d ' is greater than the diffraction spot size of described dimpling lens (123)

The resolution that obtains described Far-field super-resolution visual imaging device is 0.61 λ _Spp

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