CN117750749A - Method for realizing ultra-wideband light absorption enhancement by pyramid metamaterial multilayer film absorber - Google Patents
Method for realizing ultra-wideband light absorption enhancement by pyramid metamaterial multilayer film absorber Download PDFInfo
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- CN117750749A CN117750749A CN202311827662.1A CN202311827662A CN117750749A CN 117750749 A CN117750749 A CN 117750749A CN 202311827662 A CN202311827662 A CN 202311827662A CN 117750749 A CN117750749 A CN 117750749A
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- 230000031700 light absorption Effects 0.000 title claims abstract description 21
- 239000006096 absorbing agent Substances 0.000 title claims abstract description 15
- 238000000034 method Methods 0.000 title claims abstract description 15
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- 238000010521 absorption reaction Methods 0.000 claims abstract description 17
- 229910052751 metal Inorganic materials 0.000 claims description 36
- 239000002184 metal Substances 0.000 claims description 35
- 239000007769 metal material Substances 0.000 claims description 13
- 230000000737 periodic effect Effects 0.000 claims description 7
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 5
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- 238000002198 surface plasmon resonance spectroscopy Methods 0.000 claims description 4
- 238000002835 absorbance Methods 0.000 claims description 2
- 239000002131 composite material Substances 0.000 claims description 2
- 239000003989 dielectric material Substances 0.000 claims description 2
- 230000003247 decreasing effect Effects 0.000 claims 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 abstract description 8
- 235000012239 silicon dioxide Nutrition 0.000 abstract description 4
- 239000000377 silicon dioxide Substances 0.000 abstract description 4
- 239000010408 film Substances 0.000 description 71
- 239000010409 thin film Substances 0.000 description 14
- 239000000463 material Substances 0.000 description 12
- 238000009826 distribution Methods 0.000 description 6
- 230000005684 electric field Effects 0.000 description 5
- 229910052721 tungsten Inorganic materials 0.000 description 4
- 238000000862 absorption spectrum Methods 0.000 description 3
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- 238000010586 diagram Methods 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
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- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 2
- 239000010937 tungsten Substances 0.000 description 2
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Abstract
The invention discloses a method for realizing ultra-wideband light absorption enhancement by a pyramid metamaterial multilayer film absorber, wherein the structured multilayer film comprises SiO (silicon dioxide) 2 Substrate, siO 2 The film and the W film are laminated in turn from bottom to top; the structured multilayer film is integrally a pyramid-shaped structural array. The pyramid metamaterial multilayer film absorber provided by the invention has obvious wave absorbing characteristics on ultraviolet waves, visible light waves and infrared band light waves, can absorb electromagnetic wave energy, has high absorption efficiency and large absorption bandwidth, and has important value in the photovoltaic and stealth fields.
Description
Technical Field
The invention relates to the field of electromagnetic absorption, in particular to a pyramid metamaterial multilayer film absorber and a manufacturing method thereof.
Background
Metamaterials refer to some composite materials that have an artificially designed structure and exhibit unusual physical properties that natural materials do not possess. The material is based on the idea that the limitation of certain apparent natural laws is broken through by various physical structure designs, so that the material has an extraordinary material function. They possess special properties such as letting light, electromagnetic waves change their usual properties, which is not possible with conventional materials. There is nothing specific about the composition of metamaterials, their particular properties being due to their precise geometry and size. Wherein the microstructure, size scale is smaller than the wavelength it acts on, thus allowing the influence to be exerted on the wave. The six main types of metamaterials with representative significance are self-repairing materials, namely bionic plastics, thermoelectric materials, perovskite, aerogel and stanene, namely materials with 100% of electric conductivity and light manipulation materials.
In recent years, research on a metamaterial absorber in the visible light to near infrared band is paid attention to, and a great deal of work is sequentially carried out on the problem. However, the conventional structure for enhancing the light absorptivity in the visible light and near infrared bands mainly comprises a super-surface and super-material-based narrow-band absorber, and the absorption range is relatively narrow. In practical application, in order to improve the light absorption efficiency of the absorber, an ultra-wideband absorption effect is often required in a wider wave band, and meanwhile, a material required to be absorbed in the ultra-wideband needs to have a certain bearing capacity to high temperature to ensure the stability of the structure.
Disclosure of Invention
The invention provides a pyramid metamaterial multilayer film wave absorbing device and a pyramid metamaterial multilayer film wave absorbing method, which solve at least one of the following technical problems: the existing method has the problems of narrow light absorption bandwidth or low light absorption efficiency of the absorber. By adopting the device or the method, ultra-wideband light absorption with high light absorption efficiency can be realized in the near ultraviolet, visible light and the near infrared bands.
The first object of the invention is to provide a pyramid metamaterial multilayer film wave absorbing device, which comprises a metal-dielectric multilayer film structure, a metal film and a dielectric substrate. The metal-dielectric multilayer film structure is formed by alternating metal and dielectric stacks, and the width is sequentially increased from top to bottom; the metal thin film is positioned below the metal-dielectric multilayer film structure; the dielectric substrate is positioned below the metal film. Due to the cavity resonance effect of the multilayer film, the cavities of different layers correspond to different light absorption wavelengths, and the ultra-wideband absorption of the structure in near ultraviolet light, visible light and near infrared light bands can be realized by combining a plurality of different heights and widths.
The basic unit of the periodic microstructure comprises a metal-medium multilayer film, a metal film and a medium substrate below.
In one embodiment of the present invention, the metal-dielectric multilayer film structure of the wave absorbing device includes 7 metal films and 8 dielectric films.
In one embodiment of the present invention, the thickness of the metal film in the metal-dielectric multilayer film of the wave absorbing device is h 1 The thickness of the dielectric film is h 2 。
In one embodiment of the present invention, the metal film width of the metal-dielectric multilayer film of the wave absorbing device is L 1 、L 2 、L 3 … …, etc., the width of the dielectric film is W 1 、W 2 、W 3 … …, etc.
In one embodiment of the present invention, the thickness of the metal film of the wave absorbing device is h 3 The width is d.
In one embodiment of the present invention, the wave absorbing device further includes a substrate; the base type optical substrate with a smooth surface is used as a supporting microstructure and can support a periodic microstructure.
In one embodiment of the present invention, the substrate is silicon dioxide (SiO 2 ) A substrate.
In one embodiment of the present invention, the metal-dielectric multilayer film and the metal material of the metal film are tungsten (W).
In one embodiment of the invention, the periodic microstructure should be a sub-wavelength structure, in particular the period λ of the elementary units is less than 400nm.
In one embodiment of the present invention, when the thickness of the metal film in the metal-dielectric multilayer film is in the range of 8-30nm and the thickness of the dielectric film is in the range of 40-120nm, the light absorption wavelength of the wave absorbing structure may cover near ultraviolet, visible light and near infrared bands.
In one embodiment of the invention, the period lambda of the basic unit is 240nm, and the thickness h of the metal film in the metal-medium multilayer film 1 The width of the metal film from top to bottom is 8nm and is L respectively 1 Is 30nm, L 2 Is 60nm, L 3 Is 90nm, L 4 Is 120nm, L 5 Is 150nm, L 6 Is 180nm, L 7 210nm, dielectric thickness h 2 80nm, the widths of the dielectric films from top to bottom are W respectively 1 Is 30nm, W 2 Is 60nm, W 3 Is 90nm, W 4 Is 120nm, W 5 Is 150nm, W 6 Is 180nm, W 7 Is 210nm, W 8 Thickness h of the metal film at 240nm 3 The super-wideband absorption of the pyramid metamaterial multilayer film wave-absorbing structure can be realized by 385nm and 240nm of width d.
In one embodiment of the invention, the light absorption efficiency of the pyramid metamaterial multilayer film wave-absorbing structure of the wave-absorbing device in the wave band of 215-2519nm is higher than 90%.
The second object of the invention is to provide an ultra-wideband absorption method for realizing the pyramid metamaterial multilayer film wave-absorbing structure by adopting the device.
In one embodiment of the invention, ultra-wideband light absorption is achieved due to graded width metal-dielectric microstructure excited plasmon near field coupling, localized plasmon resonance, and fabry-perot resonant cavities of the metal-dielectric multilayer thin film structure.
In one embodiment of the present invention, the absorption efficiency of the wave-absorbing structure is expressed as:
wherein I is AM1.5(w) The energy corresponding to the standard solar spectrum data is R (w) is reflectivity, and T (w) is transmissivity.
In one embodiment of the present invention, the pyramid-shaped metamaterial multilayer film wave-absorbing structure has a relative absorption bandwidth bw=2 (λ L -λ M )/(λ L +λ M )＝168.54％,λ L And lambda (lambda) M Is the upper and lower limit of the wavelength range where the absorbance is higher than 90%.
The beneficial effects of the invention are as follows:
the invention provides a pyramid metamaterial multilayer film wave absorbing device and method. The periodic nano array with the microstructure cascade is sequentially arranged from top to bottom to be a metal-medium multilayer film structure, a metal film and a medium substrate with sequentially increasing widths. By changing the thickness of the metal thin film and the dielectric thin film in the metal-dielectric multilayer thin film structure, the electric field at the short wave is mainly concentrated at the upper part of the metal-dielectric multilayer thin film structure and the metal surface in the structure, the light field energy is mainly concentrated at the bottom of the metal-dielectric multilayer thin film structure and in the cavity of the structure at the long wave, the light field energy of the middle wavelength is mainly concentrated at the middle part of the metal-dielectric multilayer thin film, in the cavity of the structure and on the surface of the metal thin film, the surface plasmon resonance excited by the metal thin film of the metal-dielectric multilayer thin film structure absorbs the light wave with the short wavelength, the plasma resonance generated by the cavity of the metal-dielectric multilayer thin film structure absorbs the light wave with the middle wavelength in the hybridization mode of the surface plasmon resonance and the Fabry-Perot resonance, and ultra-wideband absorption enhancement can be realized in the near ultraviolet and visible light to near infrared bands. The light absorption in the wavelength range 215-2519nm, i.e. near ultraviolet, visible to near infrared, is higher than 90%. Therefore, the invention has application value in the fields of stealth materials, solar cells, light modulators and photoelectric detection.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic view of a pyramid-shaped metamaterial multilayer film wave-absorbing structure according to an embodiment of the present invention, where the structural units include a metal-dielectric multilayer film structure, a metal film, and a dielectric substrate: the left image is an integral structure diagram, the right image is a partial enlarged image, wherein d is the width of the metal film and the medium substrate, and h 3 For the thickness of the metal film, L 1 、L 2 、L 3 Dielectric film widths, W, of first through third layers, respectively, of metal-dielectric multilayer film 1 、W 2 、W 3 The widths of the metal films from the first layer to the third layer in the metal-dielectric multilayer film are respectively h 1 Is the thickness of the medium film in the metal-medium multilayer film, h 2 The thickness of the metal film in the metal-dielectric multilayer film;
FIG. 2 is a graph of the absorption and reflection spectra of the optimal parameters according to the present invention;
FIG. 3 shows the electric field distribution and magnetic field distribution corresponding to five peaks in FIG. 2, (a-e) X-Z electric field distribution, (f-j) Y-Z electric field distribution, (k-o) X-Z magnetic field distribution, and (p-t) Y-Z magnetic field distribution according to the present invention; the wavelengths corresponding to each row of images are 228nm, 276nm, 397nm, 600nm and 1739nm respectively;
FIG. 4 is a graph showing absorption spectra of different metal materials according to an embodiment of the present invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the embodiments of the present invention will be described in further detail with reference to the accompanying drawings.
Embodiment one: the pyramid metamaterial multilayer film wave absorbing structure is adopted to design the near ultraviolet, visible light and near infrared band ultra-wideband wave absorber, and the structural schematic diagram is shown in figure 1. The metal and dielectric materials are tungsten (W) and silicon dioxide (SiO) 2 ) Since this structure makes the periodic structure, for one unit structure, a metal-dielectric multilayer film structure, a metal thin film, and a dielectric substrate are included. The metal-dielectric multilayer film structure comprises 7 layers of metal films and 8 layers of dielectric films, wherein the thickness of the metal films in the metal-dielectric multilayer film is h 1 The thickness of the dielectric film is h 2 The width of the metal film in the metal-dielectric multilayer film is L 1 、L 2 、L 3 … …, etc., the width of the dielectric film is W 1 、W 2 、W 3 … …, etc., the thickness of the metal film is h 3 The wave absorbing device further comprises a substrate, wherein the width of the wave absorbing device is d; the base type optical substrate with a smooth surface is used as a supporting microstructure and can support a periodic microstructure.
The metal-dielectric multilayer film structure is formed by alternating metal and dielectric stacks, and the width is sequentially increased from top to bottom; the metal thin film is positioned below the metal-dielectric multilayer film structure; the dielectric substrate is positioned below the metal film. Due to the cavity resonance effect of the multilayer film, the cavities of different layers correspond to different light absorption wavelengths, and the ultra-wideband absorption enhancement of the structure in near ultraviolet light, visible light and near infrared light bands can be realized by combining a plurality of different heights and widths.
The selected design wave band is near ultraviolet, visible light and near infrared wave band (200-3500 nm), and the structural parameter is lambda=240 nm, h 1 ＝8nm、L 1 ＝30nm、L 2 ＝60nm、L 3 ＝90nm、L 4 ＝120nm、L 5 ＝150nm、L 6 ＝180nm、L 7 ＝210nm、h 2 ＝80nm、W 1 Is 30nm, W 2 ＝60nm、W 3 ＝90nm、W 4 ＝120nm、W 5 ＝150nm、W 6 ＝180nm、W 7 ＝210nm、W 8 ＝240nm、h 3 ＝385nm、d＝240nm，SiO 2 The refractive index of w varies with wavelength, with both the real and imaginary parts of the refractive index from the Palik database, having a refractive index of 1.47. Under the above parameter conditions, the absorption spectrum under the condition that TM (electric field along x direction) polarized light is perpendicularly incident is calculated by using a finite time domain difference method, and fig. 2 is obtained. As can be seen from fig. 2, forThe whole structure has the absorption efficiency higher than 90% in the wavelength range of 215-2519nm, the relative absorption bandwidth BW= 168.54%, the average absorption rate 99.03%, and the ultra-wideband light absorption performance of the absorber is excellent.
Embodiment two: ultra-wideband light absorption phenomenon applicable to various metal materials based on pyramid metamaterial multilayer film wave-absorbing structure
The pyramid metamaterial multilayer film wave-absorbing structure based on the first embodiment has the same structural parameters as the first embodiment, and changes metal materials under the condition that incident polarized light is unchanged, and adopts a plurality of metal materials common in wave absorbers, such as W, ti, au, cr, ni, wherein the refractive indexes of the metal materials change along with the wavelength, and the real part and the imaginary part of the refractive indexes of the metal materials are from a Palik database. The absorption spectrum of the wave-absorbing structure when the metal material is changed is calculated by adopting a finite time domain difference method, and the graph 4 is obtained.
As can be seen from fig. 4, except Au, when the metal material is W, ti, cr, ni, the light absorption efficiency in the corresponding ultra-wide band is higher than 80%, which shows that the metal material has a relatively good structure, and the metal material can be adjusted according to different preparation requirements and conditions, so as to reduce the preparation difficulty and control the cost.
It should be noted that the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made thereto without departing from the spirit and scope of the technical solution of the present invention, which is intended to be covered by the scope of the claims of the present invention.
Claims (8)
1. The pyramid metamaterial multilayer film wave absorbing structure is characterized by comprising a cascaded periodic pyramid film array, wherein the pyramid film structure is formed by cascading metal-medium multilayer films.
2. The pyramid metamaterial multilayer film wave absorbing structure as defined in claim 1, wherein a dielectric substrate is arranged at the bottom of the cascaded pyramid multilayer film array, and the composite structure is a metal-dielectric multilayer film structure, a metal film and a dielectric substrate in sequence from top to bottom.
3. The pyramidal metamaterial multilayer film wave-absorbing structure of claim 2, wherein the metal-dielectric multilayer film structure is formed from alternating stacks of metal and dielectric, and the widths are sequentially increasing from top to bottom.
4. The pyramid-type metamaterial multi-layer film wave-absorbing structure as in claim 3, wherein the metal material in said metal-dielectric multi-layer film and metal film is W, and the dielectric material in said metal-dielectric multi-layer film structure and dielectric substrate is SiO 2 The SiO is 2 The substrate has a size of 10 μm, the pyramid array structure has an overall height of 1.01 μm, and each of the structural units has a W film thickness of 8nm and SiO 2 The film thickness is 80nm, and the total of 8 layers of SiO 2 Film and 8W film, each two films decreasing by 30nm in width. The size of the W film at the lowest layer is 385nm, and the SiO at the uppermost layer 2 The film width was 30nm. SiO (SiO) 2 And the real and imaginary parts of the refractive index of W are from the Palik database.
5. The method for realizing ultra-wideband light absorption enhancement by adopting the pyramid-type metamaterial multilayer film absorber is characterized in that any one of the structures 1-4 is a pyramid-type metamaterial multilayer film structure, and the method comprises the following steps: the pyramid-type metamaterial multilayer film wave absorbing structure is used for ultra-wideband light absorption, TM or TE polarized light is incident, when a light source is incident, surface plasmon resonance excited by the metal-medium multilayer film structure sequentially absorbs light waves with short wavelengths from top to bottom, fabry-Perot cavity resonance of the metal-medium multilayer film structure absorbs light waves with long wavelengths, hybrid modes of the surface plasmon resonance and the Fabry-Perot cavity resonance absorb light waves with intermediate wavelengths, and ultra-wideband light absorption enhancement is achieved in the ultraviolet-visible light-near infrared band.
6. The method of claim 5, wherein the pyramidal metamaterial multilayer film absorber structure has a light absorption efficiency greater than 90% in the wavelength range of 215-2519 nm.
7. The method of claim 6, wherein the pyramidal metamaterial multilayer film wave-absorbing structure is insensitive to TM or TE polarized light incidence.
8. The method of claim 7, wherein the pyramidal metamaterial multilayer film absorber structure has a relative absorption bandwidth bw=2 (λ L -λ M )/(λ L +λ M )＝168.54％,λ L And lambda (lambda) M Is the upper and lower limit of the wavelength range where the absorbance is higher than 90%.
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