KR101810846B1 - FAR-FIELD Plasmonic Lens AND FAR-FIELD Plasmonic Lens ASSEMBLY - Google Patents

Abstract

According to the present invention, a far-field plasmon lens comprises: a base substrate having a positive dielectric constant; and a nanostructure array having a negative dielectric constant, and formed by being extended in a longitudinal direction with a predetermined cross-sectional area in an upper part of the base substrate. The nanostructure array includes: a first nanostructure formed at a central position; and a plurality of second nanostructures separately arranged around the first nanostructure.

Description

FIELD PLASMONIC LENS AND FAR-FIELD PLASMONIC LENS ASSEMBLY BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The present invention relates to a lens for visible light that can be applied to an optical microscope, and more particularly, to a lens for visible light that can measure shape information below the diffraction limit of light using a surface plasmon resonance phenomenon induced by a metal nanostructure far-field plasmonic lens and a far-field plasmonic lens assembly.

Optical microscopes are widely used in basic science such as physics, chemistry, biology, and medical science as important tools for microstructure analysis. Here, a general optical lens applied to an optical microscope can not distinguish an object having a size smaller than a half wavelength of the applied wavelength due to the diffraction limit of light, and the resolution in the visible light range is 200 to 300 nm Level is recognized as a limit.

Research on surface plasmon resonance (SRP) phenomenon has emerged as a technique for overcoming the diffraction limit of light.

Surface plasmon resonance (SRP) is a phenomenon that resonates with the light incident on a surface plasmon existing at the interface between a metal and a dielectric. The resonance between the surface plasmon and the incident light causes the surface plasmon polariton (Surface Plasmon Polaritons, SPPs) are formed, and the electromagnetic field is reduced exponentially in the vertical direction from the interface.

However, research on surface plasmon resonance has been actively conducted in the biosensor field rather than optical microscope field, and a number of prior arts including Korean Patent No. 1,621,437 (a plasmonic sensor in which a multilayer thin film structure and a nanostructure are combined) Focuses on design techniques for plasmonic sensors that measure biomolecular properties (eg, refractive index or concentration change) using SPR phenomena.

At present, the design technique of a plasmonic lens applicable to an optical microscope does not show remarkable results. Some of the plasmonic lenses proposed so far have a complicated design structure, especially in the near-field mode in the visible light region Is limited. Accordingly, it is necessary to develop a novel plasmonic lens which can operate in a far-field mode in the visible light region by increasing the focal length while having a simple design structure.

Korean Patent No. 1,621,437

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a far-field plasmonic lens for visible light capable of measuring shape information below the diffraction limit of light using surface plasmon resonance .

In addition, the present invention provides a far-field light source for a visible ray capable of significantly improving a focal length and a space focusing rate through an optimal design structure of a periodically arranged nanostructure formed on a base substrate and a base substrate, field plasmonic lens.

The present invention also provides a far-field plasmonic lens in which a plurality of far-field plasmonic lenses having resonance wavelengths different from each other and focusing distances are arranged so that the plasmonic lenses can be easily changed as needed, Assembly.

Other objects of the present invention will become apparent from the following description of preferred embodiments.

According to an aspect of the present invention, a far-field plasmonic lens includes: a base substrate having a positive dielectric constant; And a nano-structure array having a negative dielectric constant and extending in a longitudinal direction with a predetermined cross-sectional area on the base substrate, wherein the nanostructure array includes a first nanostructure formed at a central position, And a plurality of second nanostructures spaced about one nanostructure.

In one embodiment, the plurality of second nanostructures may be spaced apart from each other by a predetermined period around the first nanostructure.

In one embodiment, the second nanostructure may be formed on an upper surface of the base substrate, and the first nanostructure may be formed by inserting at least a portion of the first nanostructure in a vertical downward direction with respect to an upper surface of the base substrate .

Here, the first nanostructure may be formed to have a vertical length that is higher than a vertical length of the second nanostructure with respect to an upper surface of the base substrate.

In one embodiment, the array of nanostructures may comprise at least two or more first nanostructures.

In one embodiment, the base substrate is formed of a dielectric, and the first and second nanostructures may be formed of a metal.

In one embodiment, the first and second nanostructures may be formed of any one of gold (Au), silver (Ag), and aluminum (Al).

In one embodiment, the base substrate may be formed of transparent materials.

In one embodiment, the upper portion of the base substrate is formed as a circular or elliptical plane, and may be formed to have a downwardly convex three-dimensional shape.

According to another aspect of the invention, a far-field plasmonic lens assembly includes a plurality of far-field plasmonic lenses spaced apart; And a mounting part for fixing and supporting the spaced-apart plurality of far-field plasmonic lenses, wherein each of the plurality of far-field plasmonic lenses has a positive dielectric constant; And a nano-structure array having a negative dielectric constant and extending in the longitudinal direction with a predetermined cross-sectional area on the base substrate, wherein the nanostructure array includes a first nanostructure formed at a center position, And a plurality of second nanostructures spaced apart from each other by a predetermined periodic unit around one nanostructure.

Here, each of the plurality of long-distance plasmonic lenses may be designed so that at least one of the shape of the base substrate, the refractive index of the base substrate, and the arrangement period of the second nanostructure is different from each other.

The present invention can be applied to an optical microscope for visible light so that shape information below the diffraction limit of light can be measured.

Further, the present invention can significantly improve the focal length and the spatial focusing rate through the optimal design structure of the periodically arranged nanostructures formed on the base substrate and the base substrate.

In addition, the present invention arranges a plurality of long-distance plasmonic lenses having resonance wavelengths and focusing distances different from each other, so that the plasmonic lens can be easily changed as needed.

1 is a cross-sectional view of a far-field plasmonic lens according to the present invention.
2 is a perspective view of a far-field plasmonic lens according to the present invention.
3 is a cross-sectional view of a far-field plasmonic lens according to the present invention.
4 is a cross-sectional view of a far-field plasmonic lens according to an embodiment of the present invention.
5 is a perspective view of a far-field plasmonic lens according to an embodiment of the present invention.
6 is a cross-sectional view of a far-field plasmonic lens according to another embodiment of the present invention.
7 is a cross-sectional view of a far-field plasmonic lens according to another embodiment of the present invention.
8 is a perspective view of a far-field plasmonic lens assembly in accordance with the present invention.
9 is a cross-sectional view of a far-field plasmonic lens assembly in accordance with the present invention.
10 to 16 are reference views for explaining the operation and effects of the far-field plasmonic lens according to the present invention and the embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

The present invention relates to a lens for visible light that can be applied to an optical microscope, and more particularly, to a lens for visible light that can measure shape information below the diffraction limit of light using a surface plasmon resonance phenomenon induced by a metal nanostructure far-field plasmonic lens and a far-field plasmonic lens assembly. As described above, at present, a plasmonic lens applicable to an optical microscope has a complicated design structure, and is limited to a near-field mode, in particular, a focal length is short in the visible light region.

As a result of intensive efforts to solve the above-described problems, the present inventors have found that when a nanostructure array having a negative dielectric constant is formed on a base substrate having a positive dielectric constant, if the design structure of the nanostructure array and the shape of the base substrate are optimized, The distance can be increased and the space focusing rate can be improved. Thus, the far-field plasmonic lens according to the present invention is completed.

Hereinafter, a far-field plasmonic lens according to the present invention will be described in detail with reference to the accompanying drawings.

1 and 3 are cross-sectional views of a far-field plasmonic lens according to the present invention. Fig. 2 is a cross-sectional view of a far- Fig. 3 is a perspective view of a far-field plasmonic lens according to the embodiment of the present invention.

1 to 3, a far-field plasmonic lens 100 according to the present invention includes a base substrate 110 having a positive dielectric constant and nanostructure arrays 120 and 130 having a negative dielectric constant. Here, the nanostructure arrays 120 and 130 include a plurality of nanostructures 120 and 130 formed on an upper portion of a base substrate 110 and extending in a longitudinal direction with a certain cross-sectional area.

In one embodiment, the nanostructure arrays 120 and 130 may be formed of a metal material and may be formed of any one of gold (Au), silver (Ag), and aluminum (Al) Gold (Au).

In one embodiment, the base substrate 110 may be formed of a dielectric. Here, the base substrate 110 may be formed of transparent materials, for example, one of quartz (SiOx) and glass.

The nanostructure arrays 120 and 130 include a first nanostructure 120 formed at a central position and a plurality of second nanostructures 130 spaced about the first nanostructure 120.

1 and 2, the far-field plasmonic lens 100 includes a base substrate 110 having a flat plate shape, a plurality of nano-structure arrays formed on the base substrate 110, The first nanostructure 120 may be arranged at a central position and the second nanostructures 131 to 136 may be arranged apart from the first nanostructure 120 in both directions .

In one embodiment, the plurality of second nanostructures 130 may be spaced apart from the first nanostructure 120 by a predetermined period (L). 3, the second nanostructures 131 and 132 are disposed at equal distances from the first nanostructure 120 on both sides of the first nanostructure 120, and then the second nanostructures 133 and 132, 136 may be arranged with the same period L in the direction away from the first nanostructure 120, respectively.

In one embodiment, each of the plurality of second nanostructures 131 to 136 may be formed to have the same width W and height H, and the first nanostructure 120 may be formed of the second nanostructure 131 - 136). ≪ / RTI >

1 to 3 are illustrative examples of the far-field plasmonic lens 100 according to the present invention, and are not intended to limit the scope of the present invention, and the number, width, and size of the first and second nanostructures, It will be appreciated that the height, length, shape, and spacing may be designed differently from the attached drawings depending on the needs (requirements).

An operation state when the far-field plasmonic lens 100 according to the present invention is applied to an optical microscope will be described.

The far-field plasmonic lens 100 may be positioned between the objective lens of the optical microscope and the sample, and the light source may transmit the light in the visible ray region from the upper portion of the far-field plasmonic lens 100 through the objective lens in a downward direction You can investigate. At this time, surface plasmon (SPP) due to coupling between surface plasmon and photon at the interface between the nanostructure array 120, 130 of the far-field plasmonic lens 100 and the base substrate 110 polariton may be generated. Here, as the SPP appears in the form of an electromagnetic field, the SPP can converge to a region smaller than the limit (diffraction limit) of the spatial aggregation property of the light. As a result, the light source primarily focused through the objective lens is secondarily focused by the plasmonic lens described in the present invention, is incident on the surface of the sample, and the light reflected from the sample is measured by a detector. ≪ / RTI >

The SPP may be focused at a certain focal length in the process of moving downward of the base substrate 110. The focusing distance may vary depending on the shape or refractive index of the base substrate 110, The resonance wavelength may be changed according to the spacing L of the second nanostructure 130 and the refractive index of the base substrate (or nanostructure).

The focusing wavelength according to the design of the nanostructures 120 and 130 in the far-field plasmonic lens 100 according to the present invention will be described in detail. Here, the convergent wavelength is a resonance wavelength that can exhibit surface plasmon resonance, and a high field intensity at a convergent wavelength may be exhibited.

10 is a reference diagram for confirming the surface plasmon resonance wavelength. 10 is a graph showing the relationship between the width W and height H of the nanostructures 120 and 130 at 164 nm and 50 nm and the spacing L of the second nanostructure 130 at 535 nm, (Ff) of the nanostructure (ideally, a metal material) in the entire plasmonic lens is designed to be 0.3, which is a result of computer simulation of transmission per wavelength.

10, when the first nanostructure (PS tooth) is not formed in the plasmonic lens and only the second nanostructure 130 is periodically arranged, a decrease in transmittance occurs at wavelengths of about 540 nm and 790 nm . Here, the reduction of the transmittance at the wavelength of 540 nm is indicated by the conversion of the incident photons to the surface plasmons (AM mode) according to the occurrence of SPP at the air-nano structure (air-metal) interface and the decrease of the transmittance at the wavelength of 790 nm It can be interpreted that the incident photons are converted into surface plasmons according to the generation of SPP at the interface of the nanostructure-base substrate (MS-mode) (MS mode).

On the other hand, according to the present invention, a first nano structure (PS tooth) is constituted, and the second nanostructures 130 are arranged to be periodically spaced apart from the first nanostructure 120 (ideally, the first nanostructure 120 may have a separation distance of about half a cycle from the period of the second nanostructure 130), transmittance decreases at about 540 nm (AM mode) and 750 nm (MS mode) It can be confirmed that the transmittance is further reduced even at a wavelength of 650 nm. In other words, when the first nanostructure 120 is formed, the resonance wavelength position in the MS mode is blue-shifted and the additional nanostructure 120 exhibiting surface plasmon resonance can be obtained, as compared with the case where the first nanostructure 120 is not constituted. The resonance wavelength (about 650 nm) can be observed.

Each resonance mode (photon-surface plasmon coupling) can be confirmed by computer simulation. 11 is a reference diagram showing an H-field according to a change in wavelength applied to a far-field plasmonic lens. 11 (a) to (d), strong H-fields can be observed at the air-nanostructure interface at a wavelength of about 540 nm (AM mode) and about 650 nm coupling mode and about 750 nm In the MS mode, it can be seen that a strong H-field progressing in a downward direction appears. On the other hand, the convergence rate of the H-field is relatively weak at the wavelength of 1,000 nm instead of the resonance wavelength.

That is, according to the far-field plasmonic lens 100 according to the present invention, it is possible to obtain two ranges of focusable wavelengths by constructing the first nanostructure 120.

In the present invention, the focusable wavelength of the far-field plasmonic lens 100 can be changed according to the separation period L of the second nanostructure 130. 12 is a reference view showing a transmission per wavelength according to a separation period L of the second nanostructure 130. Referring to FIG. 12, the separation period L of the second nanostructure 130 is As the gradual increase from 435 nm to 635 nm

The MS mode (or AM mode) wavelength gradually becomes red. That is, the far-field plasmonic lens 100 according to the present invention can change the focusable wavelength by varying the spacing L of the second nanostructure 130 as needed.

Hereinafter, a preferred embodiment of the far-field plasmonic lens according to the present invention will be described in detail with reference to FIG. 4 to FIG. FIGS. 4, 6 and 7 are cross-sectional views of a far-field plasmonic lens according to an embodiment of the present invention, and FIG. 5 is a perspective view of a far-field plasmonic lens according to an embodiment of the present invention.

According to a preferred embodiment of the present invention described below, the focusing rate can be increased to about 7 times or more and the focusing distance to about 15 m or more in comparison with the far-field plasmonic lens 100 described above.

In one embodiment, the upper portion of the base substrate 110 is formed as a circular or elliptical plane, and may be formed to have a downwardly convex three-dimensional shape. For example, as shown in FIGS. 4 and 5, the base substrate 210 of the far-field plasmonic lens 200 may be formed in a hemisphere shape having an upper circular shape.

FIG. 13 is a reference view showing the wavelength applied to the far-field plasmonic lens 200 and the H-field according to the shape of the base substrate 210, and FIG. 14 is a graph showing the field intensity according to the traveling distance of the SPP FIG. Referring to FIGS. 13 and 14, when the base substrate 210 is formed as a semi-spherical body, the electric field focusing rate is increased by about 7 times or more as compared with the planar base substrate 210.

Hereinafter, a design structure capable of further improving the focusing rate of the far-field plasmonic lens 200 according to a preferred embodiment of the present invention described above with reference to FIGS. 6 and 7 (approximately 70% or more) will be described .

In one embodiment, the second nanostructure 130 is formed on the upper surface of the base substrate 210, and the first nanostructure 320 is formed at least in the vertical downward direction with respect to the upper surface of the base substrate 210 A part of which can be inserted and formed. For example, as shown in FIG. 6, the first nanostructure 320 may be partially inserted with respect to the upper surface of the base substrate 210, unlike the second nanostructure 130.

In one embodiment, the first nanostructure 320 may be formed to have a vertical length greater than the vertical length of the second nanostructure 130 with respect to the upper surface of the base substrate 210. 7, the first nanostructure 320 is partially inserted with respect to the upper surface of the base substrate 210, and is formed to have a vertical length higher than that of the second nanostructure 130. As shown in FIG. 7, .

15 is a reference diagram showing the field intensity according to the traveling distance of the SPP. 15, when the Au PS tooth is inserted in the downward direction by 0.5 μm with respect to the upper surface of the base substrate 210 and is formed to be 0.1 μm higher than the second nanostructure 130 And the first nanostructure (Au PS tooth) are formed at the same height as the second nanostructure 130, the electric field focusing rate is improved by 11.3% (wavelength 811 nm-MS mode).

Furthermore, when the Au PS tooth is inserted 0.5 μm downward with respect to the upper surface of the base substrate 210 and 0.5 μm higher than the second nano structure 130, It can be confirmed that the electric field focusing rate is improved by 71.5% (wavelength 811 nm-MS mode) as compared with the case where the Au tooth is formed at the same height as the second nanostructure 130.

That is, in the design of the far-field plasmonic lens 300, the base substrate 210 is designed in a downwardly convex three-dimensional shape, and the first nanostructure 320 is arranged on the upper surface of the base substrate 210 When a part is inserted in the lower direction and designed to have a vertical length higher than that of the second nanostructure 130, the maximum focusing distance and the focusing rate can be shown.

In one embodiment, the far-field plasmonic lens 300 may include at least two first nanostructures 320. Referring to FIG. 16, three first nanostructures (Au PS tooth) inserted 0.5 μm downward and 0.5 μm higher than the second nanostructure 130 are formed on the upper surface of the base substrate 210 The intensity of the system and the focusing distance are not significantly changed as compared with the case where the first nanostructure (Au PS tooth) is constituted by one.

Hereinafter, a far-field plasmonic lens assembly according to the present invention will be described with reference to Figs. 8 and 9. Fig. FIG. 8 is a perspective view of a far-field plasmonic lens assembly in accordance with the present invention, and FIG. 9 is a cross-sectional view of a far-field plasmonic lens assembly in accordance with the present invention.

8 and 9, the far-field plasmonic lens assembly 400 includes a plurality of far-field plasmonic lenses 300-1 to 300-3 spaced from each other, a plurality of far- (Not shown). Here, the far-field plasmonic lens of the above-described various embodiments may be applied to the far-field plasmonic lens.

In one embodiment, each of the plurality of far-field plasmonic lenses 300-1 to 300-3 may be designed such that at least one of the shape of the base substrate, the refractive index of the base substrate, and the arrangement period of the second nanostructure are different from each other have. That is, each of the plurality of long-distance plasmonic lenses 300-1 to 300-3 is designed to have a convergent wavelength or a focusing distance different from each other, and can be fixedly arranged on one mounting portion 410.

The far-field plasmonic lens assembly 400 according to the present invention may be configured to be mounted on an optical microscope and to be applied with a suitable long-distance plasmonic lens as necessary through a moving device and a control device configured in an optical microscope.

It will be apparent to those skilled in the relevant art that various modifications, additions and substitutions are possible, without departing from the spirit and scope of the invention as defined by the appended claims. The appended claims are to be considered as falling within the scope of the following claims.

100, 200, 300: far-field plasmonic lens
110, 210: Base substrate
120, 320: a first nanostructure
130: second nanostructure
410:

Claims (11)

A base substrate having a positive dielectric constant; And
And a nano-structure array having a negative dielectric constant and extending in the longitudinal direction with a predetermined cross-sectional area on the base substrate,
The array of nanostructures
A first nanostructure formed at a central position and a plurality of second nanostructures spaced about the first nanostructure,
The second nanostructure comprises
And a second electrode formed on the upper surface of the base substrate,
The first nanostructure comprises
And at least a part of which is inserted in a vertical downward direction with respect to an upper surface of the base substrate.
The method of claim 1, wherein the plurality of second nanostructures comprise
Wherein the first nanostructure is spaced apart from the first nanostructure at regular intervals.
delete The method of claim 1, wherein the first nanostructure comprises
And a vertical length greater than a vertical length of the second nanostructure with respect to an upper surface of the base substrate.
5. The nanostructure array of claim 4,
Wherein the at least two first nanostructures comprise at least two first nanostructures.
The method according to claim 1,
Wherein the base substrate is formed of a dielectric and the first and second nanostructures are formed of a metal.
7. The method of claim 6, wherein the first and second nanostructures are
Is formed of any one of gold (Au), silver (Ag), and aluminum (Al).
7. The method of claim 6, wherein the base substrate
Wherein the distance is formed of transparent materials.
The semiconductor device according to claim 1, wherein the base substrate
Wherein the upper portion is formed in a circular or elliptical plane and is formed to have a downward convex three-dimensional shape.
In a far-field plasmonic lens assembly,
A plurality of spaced apart far-field plasmonic lenses; And
And a mounting portion for fixedly supporting the plurality of spaced apart far-field plasmonic lenses,
Wherein each of the plurality of far-field plasmonic lenses
A base substrate having a positive dielectric constant; And
And a nano-structure array having a negative dielectric constant and extending in the longitudinal direction with a predetermined cross-sectional area on the base substrate,
Wherein the nanostructure array includes a first nanostructure formed at a central position and a plurality of second nanostructures spaced apart from each other by a predetermined period around the first nanostructure,
Wherein the second nanostructure is formed on an upper surface of the base substrate and the first nanostructure is formed at least partially inserted in a vertical downward direction with respect to an upper surface of the base substrate.
11. The apparatus of claim 10, wherein each of the plurality of far-field plasmonic lenses
Wherein at least one of the shape of the base substrate, the refractive index of the base substrate, and the arrangement period of the second nanostructure is designed to be different from each other.

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