KR20210056206A - Plasmonic angle-sensitive spectral filter with multiple resonances - Google Patents

Abstract

A plasmonic angle-sensitive spectral filter with multiple resonance modes according to the present disclosure includes a dielectric substrate, a first dielectric layer disposed on the dielectric substrate and having a plurality of nano holes, a first underlying metal structure layer located within the plurality of nano holes of the first dielectric layer, and a first upper metal structure layer disposed on the first dielectric layer and formed to form a layer different from the first lower metal structure layer. The plasmonic angle-sensitive spectral filter can express a multi-resonance mode by the first upper metal structure layer, and express an additional resonance mode by being added to the multi-resonance mode by the first upper metal structure layer and the first lower metal structure layer. The plasmonic angle-sensitive spectral filter can implement tunable multiple resonance modes over a wide band.

Description

PLASMONIC ANGLE-SENSITIVE SPECTRAL FILTER WITH MULTIPLE RESONANCES}

The present disclosure relates to a plasmonic angular spectral filter having multiple resonance modes.

Multispectral imaging is a next-generation multi-functional sensing technology that can provide augmented visual information beyond human's limited visual perception ability. 11 shows images of various fields using multispectral images.

Recently, as mobile platforms have become popular, research on miniaturization of multispectral image sensors has been actively conducted in order to integrate them on the platform. However, there is a limit to miniaturization only with existing technologies, so development of next-generation sensor technology is essential.

For a multispectral image, a tunable filter is required to obtain an image for each wavelength. Existing technologies (filter wheel, AOTF, LCTF, etc.) can implement a precise single peak, but have limitations in miniaturization due to an increase in the number and volume of optical components required to implement a high-performance peak.

According to an aspect of the present invention, it is intended to provide a plasmonic angular spectral filter capable of implementing tunable multi-resonant mode spectral scanning over a broadband with only a nano-scale ultra-thin film structure.

However, the problems to be solved by the embodiments of the present invention are not limited to the above-described problems and may be variously expanded within the scope of the technical idea included in the present invention.

A plasmonic angular spectral filter according to an embodiment of the present invention includes a dielectric substrate, a first dielectric layer positioned on the dielectric substrate and having a plurality of nano holes, and a plurality of nano holes of the first dielectric layer. And a first lower metal structure layer positioned therein, and a first upper metal structure layer positioned on the first dielectric layer and formed in a different layer from the first lower metal structure layer. The plasmonic angular-sensitive spectral filter expresses a multiple resonance mode by the first upper metal structure layer, and is added to the multiple resonance mode by the first upper metal structure layer and the first lower metal structure layer to provide additional resonance. Mode can be expressed.

The plurality of nano holes may be spaced apart from each other and may be independently formed.

The plurality of nano holes may be aligned horizontally and vertically on the dielectric substrate.

Each of the plurality of nano holes may have a circular cross section.

The first lower metal structure layer may be formed of a circular nanodisk.

The first upper metal structure layers may be connected to each other to be integrally formed.

The depth of each of the plurality of nano holes may be greater than the thickness of the first lower metal structure layer.

The first lower metal structure layer may be located on the dielectric substrate in the plurality of nano holes.

The first lower metal structure layers may be formed in each of the plurality of nano-holes, and the plurality of first lower metal structure layers may be formed as layers independent of each other.

The plasmonic angular spectral filter according to another embodiment of the present invention is positioned on the first dielectric layer so as to cover the first lower metal structure layer and the first upper metal structure layer, and has a plurality of nanoholes. A dielectric layer, a second lower metal structure layer positioned within a plurality of nanoholes of the second dielectric layer, and a second upper metal positioned on the second dielectric layer and forming a different layer from the second lower metal structure layer It may further include a structural layer.

The second dielectric layer may fill the nanoholes of the first dielectric layer and may be formed on the first lower metal structure layer.

Nanoholes of the first dielectric layer and nanoholes of the second dielectric layer may be disposed to overlap each other when viewed in a plan view.

The thickness measured perpendicular to the main surface of the dielectric substrate may be formed to fall within a range of 1 to 3 μm.

The height of the first dielectric layer, measured as a vertical distance between the dielectric substrate and the first upper metal structure layer, may be formed to fall within a range of 260 to 300 nm.

According to the plasmonic angular spectral filter of the embodiment of the present invention, since it is possible to implement multiple resonance wavelengths that can be tuned over a wide band with only a nano-scale ultra-thin film structure, it is very advantageous for miniaturization of sensors, and spectral information recovery using multiple peaks It is possible.

In addition, an infinite number of filter sets can be ideally implemented, and there is no need to divide and use the space of the optical sensor.

In addition, by assuming a two-dimensional structure period (nano hole array, nano disk array, etc.), it is possible to exclude errors in transmission characteristics due to polarization components of light compared to a one-dimensional structure. That is, since an additional polarizer is unnecessary, it has an advantage in miniaturization.

In addition, the present invention does not require an additional filter, for example, a near-infrared cut-off filter, etc., because all of the 400 to 1100 nm band, which is the operating range of the conventional commercially available optical sensor, is not required, and thus can have the advantage of miniaturization.

1 is a partial cut-away perspective view illustrating a plasmonic angular spectral filter based on a multi-nano structure layer having a multi-resonant mode according to an embodiment of the present invention.
FIG. 2 is a partially cut-away perspective view showing the unit structure of the plasmonic angular spectral filter shown in FIG. 1.
3 is a cross-sectional view illustrating a plasmonic angular spectral filter based on multiple nanostructured layers having multiple resonance modes according to another embodiment of the present invention.
4 is for explaining the variation of the resonance wavelength according to the grating orders and the dielectric constant, (a) is a partial cross-sectional view of the plasmonic angular spectral filter according to the embodiment shown in FIG. And (b) is a graph showing the resonant wavelength according to the diffraction order and dielectric constant.
FIG. 5 is a relationship between wavelength and transmittance of the occurrence of multiple resonance modes due to the diffraction order and dielectric constant shown in FIG. 4 and the occurrence of additional resonance modes due to the combination of two different nanostructures (the upper layer nanohole structure and the lower layer nanodisk structure). It is shown as a graph of.
FIG. 6 is a graph showing a result of calculation and numerical analysis of Finite-Difference Time-Domain (FDTD) for confirming a condition in which an additional resonance mode occurs due to the combination of two different nanostructures shown in FIG. 5.
7 is a cross-sectional view showing a Fabry-Perot etalon filter.
8 is a cross-sectional view illustrating a Fabry-Perot etalon effect functioning in a plasmonic angular spectral filter according to an embodiment of the present invention.
9 is a graph showing a Fabry-Farot effect according to a thickness change of a dielectric substrate in a plasmonic angular spectral filter according to an embodiment of the present invention.
FIG. 10A is a side cross-sectional view showing a plasmonic angular spectral filter based on a multiple nanostructure layer having multiple resonance modes according to an embodiment of the present invention and a transmittance graph according to wavelength, and (b) is (a) ) Is a graph showing the resonance mode division characteristics according to the change in the incident angle of the plasmonic angular spectral filter shown in ).
11 shows images of various fields using multispectral images.

Hereinafter, with reference to the accompanying drawings will be described in detail so that those of ordinary skill in the art can easily implement the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and the same reference numerals are assigned to the same or similar components throughout the specification. In addition, the accompanying drawings are for easy understanding of the embodiments disclosed in the present specification, and the technical idea disclosed in the present specification is not limited by the accompanying drawings, and all changes included in the spirit and scope of the present invention , It should be understood to include equivalents or substitutes.

Terms including ordinal numbers such as first and second may be used to describe various elements, but the elements are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another component.

When a component is referred to as being "connected" or "connected" to another component, it is understood that it may be directly connected or connected to the other component, but other components may exist in the middle. It should be. On the other hand, when a component is referred to as being "directly connected" or "directly connected" to another component, it should be understood that there is no other component in the middle.

Throughout the specification, terms such as "comprises" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof does not preclude in advance. Therefore, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components unless specifically stated to the contrary.

1 is a partially cut-away perspective view showing a plasmonic angular spectral filter based on a multi-nano structure layer having multiple resonance modes according to an embodiment of the present invention, and FIG. 2 is a plasmonic angular spectral filter shown in FIG. It is a partial cut-away perspective view showing the unit structure.

Referring to FIG. 1, the plasmonic angular spectral filter 100 according to the present embodiment includes a dielectric substrate 110 and a plurality of nano holes 121 positioned on the dielectric substrate 110. A first dielectric layer 120 may be included. The first lower metal structure layer 132 may be positioned in the plurality of nano holes 121 of the first dielectric layer 120, and the first upper metal structure layer 134 may be positioned on the first dielectric layer 120. have. Accordingly, the first lower metal structure layer 132 and the first upper metal structure layer 134 may form different layers and may be formed to be spaced apart from each other in the depth direction of the nano hole 121.

A plurality of nano holes 121 may be provided by forming a groove in the first dielectric layer 120 to a predetermined depth downward. For example, when the depth of the nano-hole 121 is formed by the thickness of the first dielectric layer 120, the nano-hole 121 penetrates the first dielectric layer 120, and the first dielectric layer 120 thus formed is By being combined on the dielectric substrate 110, the nano-holes 121 may maintain a closed lower side. In this case, the dielectric substrate 110 and the first dielectric layer 120 may be made of the same material or different materials.

The plurality of nano-holes 121 may be formed independently from each other, and may be aligned horizontally and vertically on the dielectric substrate 110. That is, the plurality of nano holes 121 may be disposed adjacent to each other along a direction perpendicular to each other when viewed from a plan view of the dielectric substrate 110. Each of the nano holes 121 may have a circular cross section, for example. The nano-hole 121 may form a cylindrical structure while a groove having a circular cross-section extends in the thickness direction of the first dielectric layer 120.

The first lower metal structure layer 132 formed in the nanoholes 121 having a circular cross section may be formed of a circular nanodisk. That is, the first lower metal structure layer 132 may be located on the inner bottom of the nano hole 121 of the first dielectric layer 120, for example, if the nano hole 121 is a through hole, the first lower metal structure layer The 132 may be located on the dielectric substrate 110 within the nano hole 121.

In addition, the depth of each of the plurality of nano holes 121 may be greater than the thickness of the first lower metal structure layer 132. That is, the first lower metal structure layer 132 is formed to have a thickness thinner than the depth of the nano-holes 121 and may be positioned adjacent to the bottom of the nano-holes 121. The first lower metal structure layer 132 may be positioned for each of the plurality of nano holes 121 to form a plurality of first lower metal structure layers 132. Since the plurality of nano holes 121 are arranged to be spaced apart from each other, the plurality of first lower metal structure layers 132 may be formed as layers independent of each other.

The first upper metal structure layers 134 positioned on the first dielectric layer 120 may be connected to each other to be integrally formed. The first upper metal structure layer 134 may have a corresponding opening 134a formed in a portion corresponding to the nanohole 121 of the first dielectric layer 120 when viewed in plan view. The corresponding opening 134a of the first upper metal structure layer 134 may be formed to have a circular cross-section, for example, and may have the same plan area as the plan area of the nano-holes 121 of the first dielectric layer 120. .

The first upper metal structure layer 134 may have the same thickness as the first lower metal structure layer 132. Accordingly, the first upper metal structure layer 134 may be formed to be thinner than the thickness of the first dielectric layer 120. Also, the first upper metal structure layer 134 may be made of the same metal material as the first lower metal structure layer 132.

According to the plasmonic angular spectral filter according to the present embodiment as described above, a nanocomposite structure composed of a dielectric substrate/metal nanohole/polymer pattern/metal nanodisc by a dielectric layer is composed of 400 to 1100 nanometers (nm ) It can have two or more resonance modes in the wavelength region. In addition, it is possible to form an ultra-thin composite structure having a thickness of several micrometers (µm), having a characteristic that the transmission wavelength is divided according to the change of the incident angle.

In the above, a nanocomposite structure in which a single layer of the first dielectric layer 120 and the first metal structure layer 130 are formed on the dielectric substrate 110 has been described. It includes both a nanocomposite structure of two or more multilayer dielectric layers and a metal structure layer formed by repeating the deposition of. In addition, according to the present invention, the nano-holes of the dielectric layer and the pattern of the metal structure layer include all of various sizes and shapes, periodic/aperiodic patterns, and various distributed arrangement types (for example, a square grid, a hexagonal grid, etc.).

3 is a cross-sectional view illustrating a plasmonic angular spectral filter based on multiple nanostructured layers having multiple resonance modes according to another embodiment of the present invention.

Referring to FIG. 3, the plasmonic angular spectral filter 200 according to the present embodiment includes two or more layers formed by repeating the dielectric layer and the metal structure layer patterned with nano holes on the dielectric substrate 210. It may include a nanocomposite structure of a dielectric layer and a metal structure layer. For example, as shown in FIG. 4, a first metal structure layer 230 is formed on the first dielectric layer 220, and a second dielectric layer 240 and a second metal structure layer ( 250) may be sequentially formed, and a third dielectric layer 260 may be formed on the top and covering the second metal structure layer 250. In this case, the first to third dielectric layers 220, 240, and 260 may be formed of different types of dielectric materials or all of the same types of dielectric materials.

Each of the first and second dielectric layers 220 and 240 is patterned with a plurality of nano holes 221 and 241, and the nano holes 221 and 241 contain a first metal structure layer 230 and a second metal structure. Layer 250 may be partially deposited and positioned. That is, the first metal structure layer 230 is disposed on the first lower metal structure layer 232 and the first dielectric layer 220 positioned on the inner bottom of the nanoholes 221 of the first dielectric layer 220. A first upper metal structure layer 234 may be included. In addition, the second metal structure layer 250 is a second lower metal structure layer 252 positioned on the inner bottom of the nanohole 241 of the second dielectric layer 240 and the second dielectric layer 240. 2 upper metal structure layer 254 may be included. Accordingly, the upper metal structure layers 234 and 254, which are upper metal patterns and the lower metal structure layers 232 and 252, which are lower metal patterns, may be formed by combining each of the dielectric layers 220 and 240 in a complementary arrangement. .

In this case, the second dielectric layer 240 may fill the nanoholes 221 of the first dielectric layer 220 and may be formed on the first metal structure layer 230, and the third dielectric layer 260 is a second dielectric layer. The nano-holes 241 of the dielectric layer 240 may be filled and formed on the second metal structure layer 250. In addition, the nano-holes 221 of the first dielectric layer 220 and the nano-holes 241 of the second dielectric layer 240 may be disposed to overlap each other when viewed in a plan view.

The metal structure layers 230 and 250 constituting the nanocomposite structure of the plasmonic angular spectral filter 200 according to the present embodiment are subjected to excitation of free electrons, propagation, oscillation, and Resonance may be achieved, and for example, conventional metal materials such as gold, silver, copper, and aluminum may be applied. In addition, a solid/liquid/gas dielectric layer may be positioned to surround the metal structure layers 230 and 250. These solid/liquid/gas dielectrics are not only solid substrates (glass, silicon nitride film, etc.), generally used in semiconductor processes, but also dielectrics made of polymers (ultraviolet-curable polymer compounds, etc.), and solids including the aforementioned metals. Includes a liquid/gaseous dielectric (vacuum, water, ethanol, etc.) surrounding the structure. In addition, the dielectric substrate 210 may include solid substrate materials generally used in semiconductor processes, such as glass, silicon, indium tin oxide (ITO), and silicon nitride.

4 is for explaining the variation of the resonance wavelength according to the grating orders and the dielectric constant, (a) is a partial cross-sectional view of the plasmonic angular spectral filter according to the embodiment shown in FIG. And (b) is a graph showing the resonant wavelength according to the diffraction order and dielectric constant.

Equation 1 below shows the relationship between the grating orders and the resonant wavelength (λ _max ) according to the dielectric constant (see HF Ghaemi et al., Phys. Rev. B (1998)).

[Equation 1]

Here, λ _max is the center wavelength of plasmonic resonance, ε _d is the dielectric constant of the dielectric, ε _m is the dielectric constant of the metal, and (i,j) is the pair of diffraction orders. a is the period of pattern. For example, the dielectric constant (ε _d1 ) of air is 1, the dielectric constant (ε _m ) of a silver thin film is -23.7+0.534i when the thickness is 700 nm, and the dielectric constant (ε _{d2) of glass} ) Can be 1.4.

_{Λ max, which} is the result of Equation 1, refers to the position of the resonance mode. Based on this, the peak positions are roughly disclosed in (b) of FIG. 4. A method of determining the location of each resonance mode on the graph of FIG. 4B is as follows. A mode located near 700nm indicated by a thick line was arbitrarily set, calculated and displayed by a proportional formula according to (i, j) based on Equation 1, and the mode near 700nm, which is a reference, is the most common dielectric, air (ε _d Assuming =1), it is based on the calculated value.

Referring to FIG. 4, the principle of generating multiple resonance modes, which is one of the characteristics of the present invention, is as follows.

Metal nanopatterns generally have a resonant mode for incident light. If the nanopatterns are arranged at regular intervals, they have a grating order, and accordingly, various resonance modes occur in a broadband. In this case, when two or more types of dielectrics having different dielectric constants surrounding the metal nanopatterns are more than one, the number of resonance modes is further increased by the number of different dielectric constants.

Therefore, in the nanocomposite structure of the spectral filter described with reference to FIGS. 1 to 4, the number of various resonance modes determined by these elements by variously changing the shape, type, size, and thickness of the dielectric substrate, dielectric layer, and metal structure layer And a wavelength.

FIG. 5 is a relationship between wavelength and transmittance of the occurrence of multiple resonance modes due to the diffraction order and dielectric constant shown in FIG. 4 and the occurrence of additional resonance modes due to the combination of two different nanostructures (the upper layer nanohole structure and the lower layer nanodisk structure). It is shown as a graph of.

Referring to FIG. 5, it was confirmed that dielectrics having different dielectric constants and multiple resonances due to grating order may occur around nanoholes of the dielectric layer of the plasmonic angular spectral filter according to the present embodiment. Yes (refer to part ① of the graph). In addition, it can be seen that additional resonances that occur as the nano-disks of the metal structure layer (lower metal structure layer) are adjacent to the nano holes are also present (refer to part ② of the graph). In addition, an additional resonance mode may occur due to an interference phenomenon between two different nanostructures combined in a complementary arrangement.

FIG. 6 is a graph showing a result of calculation and numerical analysis of Finite-Difference Time-Domain (FDTD) for confirming a condition in which an additional resonance mode occurs due to the combination of two different nanostructures shown in FIG. 5.

In FIG. 6, for each of the nanodisk (ND), the nanohole (NH), the complementary bonding structure of the nanodisk and the nanohole (NH+ND), a change in the transmission spectrum according to the height H of the first dielectric layer is shown. It can be seen that whether an additional resonance wavelength is generated and the location of the resonance wavelength may vary depending on the height H of the dielectric layer. Here, the height H of the first dielectric layer may be a vertical distance measured between the dielectric substrate and the first upper metal structure layer (see FIG. 6C ).

In the case of the nanodisk (ND) and the nanohole (NH), even if the first dielectric layer height (H) is different, the additional resonance wavelength does not occur, as well as the change in the transmission spectrum itself is insignificant (Fig. 6(a)). And (b)). On the other hand, in the complementary bonding structure (NH+ND) of the nanodisk and the nanohole, it can be seen that when the first dielectric layer height H is in the range of 260 to 300 nm and in the range of 340 to 380 nm, an additional resonance wavelength occurs ( See (c) of FIG. 6).

On the other hand, since the length of the additional resonance wavelength generated when the height of the first dielectric layer is in the range of 340 to 380 nm is 950 nm or more, it is suitable when considering the general photosensitive range (400 to 900 nm) of the image sensor, which is the main application field of the present invention. I don't. Accordingly, the optimal height H of the first dielectric layer for inducing the additional resonance wavelength may be a value in the range of 260 to 300 nm. That is, if the height (H) of the first dielectric layer is less than 260 nm, there is a problem that an additional resonance wavelength does not occur, and when the height (H) of the first dielectric layer is more than 300 nm, the length of the additional resonance wavelength is 950 nm or more, thereby reducing the general photosensitive range (400 to 900 nm) of the image sensor. There is a problem that is not suitable for consideration. Therefore, the plasmonic angular spectral filter according to the present embodiment can be finely and precisely designed to have an additional resonance mode in the near-infrared (NIR) region, unlike other similar structures, by the results of FIG. 5 and the calculation process of FIG. 6. I can.

7 is a cross-sectional view showing a Fabry-Perot etalon filter, and FIG. 8 is a Fabry-Perot functioning in the plasmonic angular spectral filter according to an embodiment of the present invention. It is a cross-sectional view shown to explain the Talon effect.

The Fabry-Perot etalon filter 30 shown in FIG. 7 has a structure in which two mirrors 32 and 36 having a high reflectivity face each other at a certain distance, and a cavity 34 is formed therebetween. Can be done. The light waves generated in the cavity 34 and the reflected light waves cause complementary and destructive interference, of which only light waves of a specific wavelength remain and all others are canceled, so that only light waves of a specific wavelength can selectively pass through and appear as output. have.

Referring to FIG. 8, when the dielectric substrate 110 positioned at the lowermost portion of the plasmonic angular spectral filter 100 according to the present embodiment is maintained as a thin film, a Fabry-Parot phenomenon can be induced. You can effectively increase the number.

9 is a graph showing a Fabry-Farot effect according to a thickness change of a dielectric substrate in a plasmonic angular spectral filter according to an embodiment of the present invention. Here, the thickness of the dielectric substrate may be a thickness measured in a direction perpendicular to the main surface of the dielectric substrate.

FIG. 9A is a graph showing a change in a transmission spectrum according to a thickness L of a dielectric substrate for an etalon structure composed of a metal thin film, a dielectric layer, and a dielectric substrate without a nano pattern (nano hole or nano disk). It can be seen that as the thickness L of the dielectric substrate increases, the number of Fabry-Farot interference resonance modes increases.

9B is a graph showing a change in the number of resonance modes according to an increase in the thickness L of a dielectric substrate for the structure disclosed in (a), the structure of the embodiment of the present invention, and the above two structures. In the structure of the exemplary embodiment of the present invention, it can be seen that the number of resonance modes increases as the thickness L of the dielectric substrate increases.

According to the above results, there are infinitely many resonance modes for an infinitely thick substrate, but the intensity of the mode is very weak due to the absorption of light from the substrate material, and as the interval between the mode and the mode is very narrow, the resonance mode or The meaning as a peak may fade.

만큼 기울이게 되면, 빛의 굴절(deflection) 현상에 의해 원래 진행하던 방향으로부터 d 만큼 편차(deviation; d)를 가지고 기판을 벗어나게 된다. 최대 기울임 각도(

)를 35°라고 가정할 때, 기판의 두께가 3㎛ 이상이 되면 광 편차(d)가 1㎛ 이상 발생한다. 일반적인 이미지 센서의 픽셀 크기가 1㎛ 임을 감안할 때, 픽셀 크기보다 큰 광 편차가 발생하면 이미지 시프트(shift)가 발생하므로 적절하지 않다.9C is a graph showing a change in light deviation (d) according to a change in the inclination angle (θ) of the dielectric substrate and the thickness (L) of the dielectric substrate. Referring to this, in order to tune the resonance mode according to the angle of incidence, the substrate is

If it is tilted by as much, it leaves the substrate with a deviation (d) as much as d from the direction it was originally traveling due to the deflection of light. Maximum tilt angle (

Assuming that) is 35°, when the thickness of the substrate is 3 μm or more, light deviation (d) is 1 μm or more. Considering that the pixel size of a typical image sensor is 1 μm, it is not appropriate because an image shift occurs when a light deviation larger than the pixel size occurs.

On the other hand, for a very thin substrate thickness, due to problems such as a decrease in mechanical stability due to a residual stress that increases in inverse proportion to the thickness and an increase in uniformity errors in a process process (for example, an etching process), In general, it is difficult to fabricate less than 1㎛.

Accordingly, in the embodiment of the present invention, the thickness of the dielectric substrate may be set to fall within the range of 1 μm to 3 μm. When the thickness of the dielectric substrate is more than 3㎛, there is a problem that the light deviation is larger than the pixel size of a general image sensor, resulting in image shift. If the thickness of the dielectric substrate is less than 1㎛, mechanical stability decreases and uniformity error increases in the manufacturing process. there is a problem.

That is, by designing the dielectric substrate to be very thin, it is possible to induce a Fabry-Parot effect and increase the applicability as an ultra-thin spectral filter. In addition, as the thickness of the dielectric substrate becomes very thin, there is an effect that a deviation by deflection that occurs when incident light is incident at a specific angle does not occur in this embodiment.

FIG. 10A is a side cross-sectional view showing a plasmonic angular spectral filter based on a multiple nanostructure layer having multiple resonance modes according to an embodiment of the present invention, and a transmittance graph according to wavelength, and (b) is (a) ) Is a graph showing the resonance mode division characteristics according to the change in the incident angle of the plasmonic angular spectral filter shown in ).

When the plasmonic angular spectral filter 100 according to the present embodiment is inclined (rotated by Δθ with respect to the vertical direction) and irradiated with light on the upper surface, the incident angle of light incident on the nanocomposite structure is out of the vertical. At this time, the surface plasmon resonance (SPR) or surface plasmon propagation (SPP) propagating in parallel with the incident plane along the metal surface, that is, the surface of the first upper metal structure layer 134, has an acute angle. It is divided into a component that propagates at an acute angle and a component that propagates at an obtuse angle. For this reason, the multiple resonance modes that are expressed when normal incidence (θ=0°) are divided into two resonance modes in an inclined state (rotated by Δθ with respect to the vertical direction), and as a result, the transmission band is divided, resulting in a much more diverse transmission. You can have a band.

That is, as in the plasmonic angular spectral filter 100 according to the present embodiment, when the incident angle of light is changed for the nanocomposite structure composed of nanoholes and nanodisks, the existing resonance wavelength is separated over a broadband and It can be seen that there are multiple resonance modes that occur while moving.

Therefore, the plasmonic angular spectral filter 100 according to the present embodiment can further increase spectral information obtained by utilizing the resonance mode division characteristic according to the change of the angle of incidence, and broadband spectral scanning is performed by the continuous change of the angle of incidence. It can be provided with a possible spectroscopic filter.

Since the plasmonic angular spectral filter according to the present embodiment features multiple transmission bands and broadband spectral scanning by the possibility of active tuning of the transmission bands, a spectrometer or spectral camera requiring spectral scanning ) Can be used as a core part. In addition, since the spectral filter of the present embodiment is composed of an ultra-thin structure layer having a size of less than a wavelength, it can be applied/applied exclusively to a field requiring an ultra-compact optical system.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the claims, the detailed description of the invention, and the accompanying drawings, and this is also the present invention. It is natural to fall within the scope of the invention.

Claims (14)

A dielectric substrate;
A first dielectric layer positioned on the dielectric substrate and having a plurality of nano holes;
A first lower metal structure layer positioned within the plurality of nanoholes of the first dielectric layer; And
A first upper metal structure layer formed on the first dielectric layer and forming a different layer from the first lower metal structure layer
Including,
A plasmonic angle in which a multiple resonance mode is expressed by the first upper metal structure layer, and an additional resonance mode can be expressed by being added to the multiple resonance mode by the first upper metal structure layer and the first lower metal structure layer. Sensitive spectral filter. The method of claim 1,
The plurality of nano-holes are spaced apart from each other and each independently formed, a plasmonic angular spectral filter. The method of claim 2,
The plurality of nano-holes are arranged in a horizontal and vertical direction on the dielectric substrate, a plasmonic angular spectral filter. The method of claim 1,
Each of the plurality of nano-holes has a circular cross-section, a plasmonic angular spectral filter. The method of claim 4,
The first lower metal structure layer is made of a circular nano-disc, plasmonic angular spectral filter. The method of claim 1,
The first upper metal structure layers are connected to each other to be integrally formed, a plasmonic angular spectral filter. The method of claim 1,
The depth of each of the plurality of nano-holes is formed to be greater than the thickness of the first lower metal structure layer, plasmonic angular spectral filter. The method of claim 1,
The first lower metal structure layer is located on the dielectric substrate in the plurality of nano-holes, plasmonic angular spectral filter. The method of claim 1,
The first lower metal structure layer is formed in each of the plurality of nano-holes, the plurality of first lower metal structure layers are formed as independent layers of each other, plasmonic angular spectral filter. The method of claim 1,
A second dielectric layer positioned on the first dielectric layer to cover the first lower metal structure layer and the first upper metal structure layer and having a plurality of nano holes;
A second lower metal structure layer positioned within the plurality of nanoholes of the second dielectric layer; And
A second upper metal structure layer formed on the second dielectric layer and forming a different layer from the second lower metal structure layer
Plasmonic angular spectral filter comprising a. The method of claim 10,
The second dielectric layer fills the nanoholes of the first dielectric layer and is formed on the first lower metal structure layer. The method of claim 10,
The nano-holes of the first dielectric layer and the nano-holes of the second dielectric layer are disposed to overlap each other when viewed in a plan view. The method of claim 1,
A plasmonic angular spectral filter having a thickness measured perpendicular to the main surface of the dielectric substrate in a range of 1 to 3 μm. The method of claim 1,
A plasmonic angular spectral filter, wherein a height of the first dielectric layer, measured as a vertical distance between the dielectric substrate and the first upper metal structure layer, falls within a range of 260 to 300 nm.

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