CN111009181B - Super-surface-based design method for realizing multiplexing of single-color random anti-counterfeiting pattern and double-color anti-counterfeiting pattern - Google Patents

Super-surface-based design method for realizing multiplexing of single-color random anti-counterfeiting pattern and double-color anti-counterfeiting pattern Download PDF

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CN111009181B
CN111009181B CN201911309879.7A CN201911309879A CN111009181B CN 111009181 B CN111009181 B CN 111009181B CN 201911309879 A CN201911309879 A CN 201911309879A CN 111009181 B CN111009181 B CN 111009181B
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counterfeiting pattern
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CN111009181A (en
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郑国兴
付娆
李子乐
单欣
李仲阳
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Wuhan University WHU
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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F3/00—Labels, tag tickets, or similar identification or indication means; Seals; Postage or like stamps
    • G09F3/02—Forms or constructions
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/002—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of materials engineered to provide properties not available in nature, e.g. metamaterials
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
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Abstract

The invention discloses a design method for realizing multiplexing of a single-color random anti-counterfeiting pattern and a double-color anti-counterfeiting pattern based on a super surface. Under the condition of dual-wavelength linearly polarized light incidence, a double-color anti-counterfeiting pattern can be generated through the rotary analyzer, and the multiplexing of the single-color random anti-counterfeiting pattern and the double-color anti-counterfeiting pattern is finally realized. The design method is ingenious, the random selection of the anti-counterfeiting pattern and the realization of the double-color anti-counterfeiting pattern by the double wavelengths improve the counterfeiting difficulty, so that the anti-counterfeiting pattern is difficult to copy and imitate, and the anti-counterfeiting safety is greatly improved. The super-surface structure is simple and compact, the volume is small, the weight is light, the integration to high-end chips, watches, diamond rings and other small valuable commodities is convenient, and the anti-counterfeiting label based on the design method of the invention is not easy to find, obtain and imitate.

Description

Super-surface-based design method for realizing multiplexing of single-color random anti-counterfeiting pattern and double-color anti-counterfeiting pattern
Technical Field
The invention relates to the technical field of micro-nano optics, in particular to a design method for realizing multiplexing of a single-color random anti-counterfeiting pattern and a double-color anti-counterfeiting pattern based on a super surface.
Background
The rapid development of modern scientific technology and the increasing rampant of various counterfeit and inferior activities promote the development of various anti-counterfeiting technologies, wherein the optical anti-counterfeiting technology is an important branch in the anti-counterfeiting technology, is widely applied to aspects of social life, and particularly widely adopts the optical anti-counterfeiting technology to prevent counterfeiting infringement in the fields of more counterfeiting and infringement of currencies, securities, certificates, seals, medicines, foods, cosmetics, clothing, agricultural products, automobile and agricultural machine accessories, audio and video products, software and computer chips and the like. However, the existing optical anti-counterfeiting label has a large area, is easy to find and obtain, and can be copied and imitated, so that the anti-counterfeiting safety is greatly reduced.
Disclosure of Invention
The super surface obtained by the design method can realize the multiplexing of the single-color random anti-counterfeiting pattern and the double-color anti-counterfeiting pattern, the counterfeiting difficulty is improved by the random selection of the anti-counterfeiting pattern and the realization of the double-color anti-counterfeiting pattern by double wavelengths, the copying and the imitation are difficult, and the anti-counterfeiting safety is greatly improved.
In order to achieve the purpose, the invention provides a super-surface-based design method for realizing multiplexing of a single-color random anti-counterfeiting pattern and a double-color anti-counterfeiting pattern, which is characterized by comprising the following steps: the method comprises the following steps:
1) the optimization design can realize the size parameter of the nano brick unit structure with the function of the polarizer under two different working wavelengths, so that linearly polarized light along the long axis of the nano brick in the direction of an electric field is normally incident to the nano brick unit structure at the wavelength lambda1Has the lowest transmittance and is at lambda2The transmittance is higher; and when linearly polarized light along the minor axis of the nano-brick in the direction of the electric field is normally incident to the nano-brick unit structure at the wavelength lambda2Has the lowest transmittance and is at lambda1The transmittance is higher, namely the size parameter of the optimized nano brick unit structure; the nano brick unit structure consists of a substrate and a nano brick etched on the substrate; the dimension parameters of the nano brick unit structure comprise the height H, the length L, the width W and the central interval C of the unit structure of the nano brick.
2) A gray image1 with 256 (0-255) gray levels is formed by M multiplied by N pixels, and the gray values of all the pixels in the image form a gray matrix. Let Iin255, each gray value in the gray matrix is taken as Iout0In combination with formula Iout0＝(sin2Φ0)2IinCan calculate the direction angles of four nano bricks
Figure BDA0002324225840000021
Figure BDA0002324225840000022
And
Figure BDA0002324225840000023
the gray value of the pixel at the mth row and the nth column can be obtained.
3) And selecting a black-and-white binary image2 composed of M × N pixels and having gray values of only 0 and 255, wherein the pixel positions of the image2 and the image1 are in one-to-one correspondence. The pixel with 0 corresponds to a relatively small gray value IlowThe angle of orientation of the pixel's corresponding nano-brick is selected
Figure BDA0002324225840000024
And
Figure BDA0002324225840000025
any one of the above; the pixel with the gray value of 255 corresponds to a relatively large gray value Ihigh(Ihigh>Ilow) The angle of orientation of the pixel's corresponding nano-brick is selected
Figure BDA0002324225840000026
And
Figure BDA0002324225840000027
any one of them. And sequentially calculating the direction angles of all the nano brick unit structures to form a direction angle matrix phi.
4) The nanometer brick unit structures with consistent size and direction angles arranged according to the direction angle arrangement matrix phi are arranged at equal intervals in the length direction and the width direction to form a super surface capable of realizing multiplexing of a single-color random anti-counterfeiting pattern and a double-color anti-counterfeiting pattern.
5) Single-wavelength incidence to the super surface to generate a single-color random anti-counterfeiting pattern: when the incident light is in the direction of the electric field, the wavelength along the x-axis is lambda2When an analyzer with the transmission axis direction along the y axis is placed behind the super surface formed in the step 4), the transmitted light forms a gray scale image 1; when the super surface rotates clockwise by 22.5 degrees, the transmitted light forms a random anti-counterfeiting pattern image 3;
6) the dual wavelength is incident to the super surface to generate a bicolor anti-counterfeiting pattern: when the wavelength of the electric field along the x-axis is λ1And λ2The linearly polarized light is simultaneously and normally incident to the super surface formed in the step 4), and then an analyzer behind the super surface is transmittedWhen the optical axis direction is rotated by 90 degrees to be along the x-axis direction, the transmitted light forms a two-color anti-counterfeiting pattern image 4.
Preferably, the substrate material is silicon dioxide, and the nano brick material is silver. Wherein, the substrate is a silicon dioxide substrate, and the nano brick unit structure is a silver nano brick, but not limited thereto. The super-surface mode of operation is transmissive, but not limited thereto.
Further, in the step 1), the working wavelength is λ1625nm (red) and λ2500nm (green); the length L of the nano brick is 140nm, the width W of the nano brick is 85nm, the height H of the nano brick is 70nm, and the central interval C of the unit structure is 340 nm.
The invention has the following advantages and beneficial effects:
(1) the design method of the invention is ingenious and simple, can realize multiplexing of the single-color random anti-counterfeiting pattern and the double-color anti-counterfeiting pattern, improves the counterfeiting difficulty by the random selection of the anti-counterfeiting pattern and the double-color anti-counterfeiting pattern realized by double wavelengths, makes the anti-counterfeiting pattern difficult to copy and imitate, and greatly improves the anti-counterfeiting safety.
(2) The super-surface structure is simple and compact, the volume is small, the weight is light, the super-surface structure is convenient to integrate into valuable commodities with small volume such as high-end chips, watches, diamond rings and the like, and the optical anti-counterfeiting label based on the design method is difficult to find, obtain and imitate.
Drawings
FIG. 1 is a schematic diagram of the structure of a nano-brick unit according to the present invention;
FIG. 2 is a schematic diagram of the principle of implementing a single-color random anti-counterfeit pattern in the present invention;
FIG. 3 is a graph showing the variation of the intensity of the emergent light before and after the rotation of the unit structure of the nano-brick of the present invention;
FIG. 4 is a schematic diagram of a super-surface structure capable of realizing multiplexing of a single-color random anti-counterfeiting pattern and a double-color anti-counterfeiting pattern in the invention;
FIG. 5 is a graph of the transmittance and reflectance of the nano-brick unit cell structure designed in an example of the present invention;
FIG. 6 is a schematic diagram of an optical path and an effect diagram for implementing a monochrome gray scale image in an embodiment of the present invention;
FIG. 7 is a schematic diagram of an optical path and an effect diagram for implementing a monochromatic random anti-counterfeit pattern in an embodiment of the present invention;
FIG. 8 is a schematic view of the azimuthal distribution of a designed super surface in an embodiment of the present invention;
fig. 9 is a schematic diagram of a light path and an effect diagram for realizing a two-color anti-counterfeiting pattern in the embodiment of the invention.
Detailed Description
The invention is further described in detail below with reference to the figures and specific examples.
1. The optimized design can realize the function of the polarizer under two different working wavelengths.
The following description will be given taking the nano-brick unit structure as a rectangular parallelepiped. The length, width and height of the nano brick unit structure are all sub-wavelength.
As shown in fig. 1, an xyz rectangular coordinate system is established, the long side direction of the nano-brick unit structure represents a long axis, the short side direction represents a short axis, and Φ is an included angle between the long axis and the x axis of the nano-brick unit structure, i.e., a direction angle (the value range of Φ is 0 ° to 180 °) of the nano-brick unit structure, as shown in fig. 1.
Optimizing the size parameters of the nano brick unit structure by electromagnetic simulation software, including the height H, the length L, the width W and the unit structure center interval C of the nano brick unit structure 1, as shown in figure 1, so that linearly polarized light with an electric field direction along the long axis of the nano brick is normally incident to the nano brick unit structure at the wavelength lambda1Has the lowest transmittance and is at lambda2The transmittance is higher; and when linearly polarized light along the minor axis of the nano-brick in the direction of the electric field is normally incident to the nano-brick unit structure at the wavelength lambda2Has the lowest transmittance and is at lambda1The transmittance is higher, namely the nano brick unit structure after the optimized design can realize the function of a polarizer under two different working wavelengths.
2. Single wavelength modulated light intensity principle.
As shown in FIG. 2, when the incident light is a single-wavelength linearly polarized light with the electric field direction along the x-axis and the transmission axis direction of the analyzer along the y-axis, the Malus law can be appliedKnowing the normalized emergent light intensity I after passing through the nano-brick unit structure and the analyzerout0Can be expressed as:
Iout0＝(sin2Φ0)2Iin。 (1)
wherein phi0Is an included angle between the long axis of the nano brick unit structure and the x axis, namely a direction angle; i isinIndicating the intensity of the incident light. When the nano brick unit structure rotates clockwise by 22.5 degrees, the included angle phi between the long axis of the nano brick unit structure and the x axis1＝Φ0-22.5 °, normalized emergent light intensity I after passing through the nano-brick unit structure and analyzerout1Can be expressed as:
Iout1＝(sin2Φ1)2Iin＝(sin(2Φ0-45°))2Iin。 (2)
as can be seen from the formulas (1) and (2), continuous light intensity adjustment can be realized by changing the direction angle of the nano-brick, and the light intensity change of emergent light before and after the rotation of the unit structure of the nano-brick is shown in figure 3.
3. Dual wavelength modulation two-color principle.
Respectively using Ts1And Tl2Denotes the wavelength λ1Along the minor axis and at a wavelength λ2Transmittance of linearly polarized light in the long axis direction of the electric field. When the wavelength of the electric field along the x-axis is λ1And λ2Is normally incident to a direction angle phi of 1:10When the transmission axis direction of an analyzer arranged behind the nano-brick unit structure is rotated by 90 degrees to the direction along the x axis, the two wavelengths of incident light are known by Malus law, and the light intensity of the transmitted light can be expressed as follows:
Iout＝(cosΦ0)4TlG+(sinΦ0)4TsR。 (3)
as shown in the formula (3), the transmitted light lambda can be changed by changing the direction angle of the unit structure of the nano-brick1And λ2To change the color of the transmitted light. Since the incident light consists of light of only two wavelengths, it is transmittedThe photo-formed image is referred to as a bi-color image.
4. A design method for arranging direction angles of a nano brick unit structure.
(1) A gray image1 with 256 (0-255) gray levels is selected, which is composed of M × N pixels and has only gray levels and no color change. The gray values of all pixels in the image constitute a gray matrix. Let Iin255, each gray value in the gray matrix is taken as Iout0Combining with FIG. 3, the direction angles of four nano-bricks can be obtained according to the formula (1)
Figure BDA0002324225840000051
And
Figure BDA0002324225840000052
the gray value of the pixel at the mth row and the nth column can be obtained. When the nano brick unit structure rotates by 22.5 degrees clockwise, the four direction angles correspond to two different rotated gray values Iout1. Wherein the direction angle
Figure BDA0002324225840000053
And
Figure BDA0002324225840000054
corresponding to a comparatively large gray value Ihigh，
Figure BDA0002324225840000055
And
Figure BDA0002324225840000056
corresponding to a comparatively small gray value Ilow(Ihigh>Ilow)。
(2) And selecting a black-and-white binary image2 composed of M × N pixels and having gray values of only 0 and 255, wherein the pixel positions of the image2 and the image1 are in one-to-one correspondence. The pixel with 0 corresponds to a relatively small gray value IlowThe angle of orientation of the pixel's corresponding nano-brick is selected
Figure BDA0002324225840000057
And
Figure BDA0002324225840000058
any one of the above; the pixel with the gray value of 255 corresponds to a relatively large gray value IhighThe angle of orientation of the pixel's corresponding nano-brick is selected
Figure BDA0002324225840000059
And
Figure BDA0002324225840000061
any one of them. And sequentially calculating the direction angles of all the nano brick unit structures to form a direction angle matrix phi.
(3) The super surface is formed by arranging the nanometer brick unit structures with the same size of M multiplied by N and different direction angles at equal intervals in the length direction and the width direction, the direction angles of the nanometer brick unit structures are arranged according to a direction angle matrix phi, and the structural schematic diagram of the super surface is shown in figure 4.
(4) The single wavelength is incident to the super surface to generate a monochromatic random anti-counterfeiting pattern.
When the incident light is in the direction of the electric field, the wavelength along the x-axis is lambda2When an analyzer is placed behind the super-surface, with the transmission axis oriented along the y-axis, the transmitted light forms a gray scale image 1. When the super surface rotates clockwise by 22.5 degrees, the transmitted light forms a random anti-counterfeiting pattern image 3.
(5) The dual wavelength is incident to the super surface to generate a two-color anti-counterfeiting pattern.
When the wavelength of the electric field along the x-axis is λ1And λ2The linearly polarized light is normally incident to the super surface at the same time, and then when the transmission axis direction of an analyzer behind the super surface is rotated by 90 degrees to the direction along the x axis, the transmission light forms a two-color anti-counterfeiting pattern image 4.
Wherein, the substrate is a silicon dioxide substrate, and the nano brick unit structure is a silver nano brick, but not limited thereto. The super-surface mode of operation is transmissive, but not limited thereto.
The invention will be further explained with reference to the drawings.
In the design method for realizing multiplexing of the single-color random anti-counterfeiting pattern and the two-color anti-counterfeiting pattern based on the super surface, the expected realization function is that when the incident light is the electric field direction, the wavelength along the x axis is lambda2When an analyzer with a transmission axis oriented along the y-axis is placed behind the super-surface, the transmitted light forms a gray scale image 1. When the super surface rotates clockwise by 22.5 degrees, the transmitted light forms a random anti-counterfeiting pattern image 3. When the wavelength of the electric field along the x-axis is λ1625nm (red) and λ2Linearly polarized light of 500nm (green) is simultaneously incident to the super surface normally, and then when the transmission axis direction of an analyzer behind the super surface is rotated by 90 degrees to be along the x-axis direction, the transmitted light forms a two-color anti-counterfeiting pattern image 4.
In this embodiment, the nano-unit structure is composed of a silicon dioxide substrate and silver nano-bricks etched on the substrate, as shown in fig. 1. Two design wavelengths selected as lambda1625nm (red) and λ2And (2) performing optimization simulation on the unit structure of the nano brick through electromagnetic simulation software CST (green), wherein the size parameters of the optimized silver nano brick are as follows: the length is 140nm, the width is 85nm, the height is 70nm, and the center interval of the unit structure is 340 nm. The transmittance and reflectance of the nano-brick unit structure under the structural parameters are shown in FIG. 5, wherein Rll、Tll、RssAnd TssThe reflectance and transmittance of linearly polarized light vibrating in the major axis and minor axis directions are shown, respectively. As can be seen from fig. 5, when linearly polarized light along the long axis of the nano-brick in the electric field direction is normally incident on the nano-brick unit structure, the transmittance at the wavelength of 625nm (red) is lower than 1%, and the transmittance at the wavelength of 500nm (green) is 83%; and when linearly polarized light along the minor axis of the nano-brick in the electric field direction is normally incident to the nano-brick unit structure, the transmittance at the wavelength of 500nm (green) is lower than 3%, and the transmittance at the wavelength of 625nm (red) is as high as 97%, namely the optimally designed nano-brick unit structure can realize the function of a polarizer under two different working wavelengths.
The specific design steps are as follows:
(1) selecting one frameA grayscale image1 having 256(0 to 255) grayscale levels is composed of 500 × 500 pixels, as shown in fig. 6. The image has only grey levels and no color changes. The gray values of all pixels in the image constitute a gray matrix. Let Iin255, each gray value in the gray matrix is taken as Iout0Combining with FIG. 3, the direction angles of four nano-bricks can be obtained according to the formula (1)
Figure BDA0002324225840000071
And
Figure BDA0002324225840000072
the gray value of the pixel at the mth row and the nth column can be obtained. When the nano brick unit structure rotates by 22.5 degrees clockwise, the four direction angles correspond to two different rotated gray values Iout1. Wherein the direction angle
Figure BDA0002324225840000073
And
Figure BDA0002324225840000074
corresponding to a comparatively large gray value Ihigh，
Figure BDA0002324225840000075
And
Figure BDA0002324225840000076
corresponding to a comparatively small gray value Ilow(Ihigh>Ilow)。
(2) Then, a black-and-white binary image2 with the gray scale value of only 0 and 255, which is composed of 500 × 500 pixels, is selected, and as shown in fig. 7, the positions of the pixels of the image2 and the image1 are in one-to-one correspondence. The pixel with 0 corresponds to a relatively small gray value IlowThe angle of orientation of the pixel's corresponding nano-brick is selected
Figure BDA0002324225840000077
And
Figure BDA0002324225840000078
any one of the above; the pixel with the gray value of 255 corresponds to a relatively large gray value IhighThe angle of orientation of the pixel's corresponding nano-brick is selected
Figure BDA0002324225840000079
And
Figure BDA00023242258400000710
any one of them. And sequentially calculating the direction angles of all the nano brick unit structures to form a direction angle matrix phi, as shown in fig. 8.
(3) The super surface is formed by arranging 500 multiplied by 500 nano brick unit structures with the same size and different direction angles at equal intervals in the length direction and the width direction, the direction angles of the nano brick unit structures are arranged according to a direction angle matrix phi, and the structural schematic diagram of the super surface is shown in fig. 4.
(4) The single wavelength is incident to the super surface to generate a monochromatic random anti-counterfeiting pattern.
When the incident light is linearly polarized along the x-axis with the wavelength of 500nm (green) in the direction of the electric field and an analyzer along the y-axis in the direction of the light transmission axis is placed behind the super surface, the transmitted light forms a gray scale image 1. When the super surface rotates clockwise by 22.5 degrees, the transmitted light forms a random anti-counterfeiting pattern image3, and the schematic diagram and the effect diagram are shown in fig. 7.
(5) The dual wavelength is incident to the super surface to generate a two-color anti-counterfeiting pattern.
When linearly polarized light with the wavelength of 500nm (green) and 625nm (red) along the x-axis in the direction of an electric field is simultaneously and normally incident to the super surface, and then the transmission axis direction of an analyzer behind the super surface is rotated by 90 degrees to the direction along the x-axis, the transmission light forms a two-color anti-counterfeiting pattern image4, and the schematic diagram and the effect diagram are shown in fig. 9.
The design method for realizing multiplexing of the single-color random anti-counterfeiting pattern and the double-color anti-counterfeiting pattern based on the super surface in the embodiment of the invention at least comprises the following technical effects:
under the condition of single-wavelength linearly polarized light incidence, random anti-counterfeiting patterns can be added into the original gray anti-counterfeiting patterns by rotating the super surface. Under the condition of dual-wavelength linearly polarized light incidence, a double-color anti-counterfeiting pattern can be realized through the rotary analyzer, and the multiplexing of a single-color random anti-counterfeiting pattern and the double-color anti-counterfeiting pattern is finally realized. The design method for realizing multiplexing of the single-color random anti-counterfeiting pattern and the double-color anti-counterfeiting pattern based on the super surface is ingenious, the counterfeiting difficulty is improved by the random selection of the anti-counterfeiting pattern and the realization of the double-color anti-counterfeiting pattern by the double wavelengths, the anti-counterfeiting is difficult to copy and imitate, and the anti-counterfeiting safety is greatly improved. The super-surface structure is simple and compact, the volume is small, the weight is light, the super-surface structure is convenient to integrate into valuable commodities with small volume such as high-end chips, watches, diamond rings and the like, and the optical anti-counterfeiting label based on the design method is difficult to find, obtain and imitate.

Claims (3)

1. A design method for realizing multiplexing of a single-color random anti-counterfeiting pattern and a double-color anti-counterfeiting pattern based on a super surface is characterized by comprising the following steps of: the method comprises the following steps:
1) the optimization design can realize the nano brick unit structure of the function of the polarizer under two different working wavelengths, and the size parameters of the nano brick unit structure comprise: the height H, the length L, the width W and the central interval C of the unit structure of the nano brick are optimized, so that linearly polarized light along the long axis of the nano brick in the electric field direction is normally incident to the unit structure of the nano brick at the wavelength lambda1Has the lowest transmittance and is at lambda2The transmittance is higher; and when linearly polarized light along the minor axis of the nano-brick in the direction of the electric field is normally incident to the nano-brick unit structure at the wavelength lambda2Has the lowest transmittance and is at lambda1The transmittance is higher, and the size parameter of the optimized nano brick unit structure is obtained at the moment; the nano brick unit structure consists of a substrate and a nano brick etched on the substrate;
2) selecting a gray image1 with 256 gray levels formed by M multiplied by N pixels, wherein the gray values of all the pixels in the image form a gray matrix; let Iin255, each gray value in the gray matrix is taken as Iout0From formula Iout0＝(sin2Φ0)2IinIt can be known that each pixel corresponds to four different orientation angles of the nano-brick
Figure FDA0002776200180000011
And
Figure FDA0002776200180000012
the same gray value can be obtained, wherein the lower corner marks m and n represent the pixels of the mth row and the nth column of the image;
3) selecting a black-and-white binary image2 composed of M multiplied by N pixels and having gray values of only 0 and 255, wherein the pixel positions of the image2 and the image1 are in one-to-one correspondence; the pixel with 0 corresponds to a relatively small gray value IlowThe angle of orientation of the pixel's corresponding nano-brick is selected
Figure FDA0002776200180000013
And
Figure FDA0002776200180000014
any one of the above; the pixel with the gray value of 255 corresponds to a relatively large gray value IhighIn which Ihigh>IlowThe angle of orientation of the pixel's corresponding nano-brick is selected
Figure FDA0002776200180000015
And
Figure FDA0002776200180000016
any one of the above; sequentially solving the direction angles of all the nano brick unit structures to form a direction angle matrix phi;
4) the nanometer brick unit structures with consistent size and direction angles arranged according to a direction angle arrangement matrix phi are arranged at equal intervals in the length direction and the width direction to form a super surface capable of realizing multiplexing of a single-color random anti-counterfeiting pattern and a double-color anti-counterfeiting pattern;
5) single-wavelength incidence to the super surface to generate a single-color random anti-counterfeiting pattern: when the incident light is in the direction of the electric field, the wavelength along the x-axis is lambda2When a polarization analyzer with the transmission axis direction along the y axis is arranged behind the super surface formed in the step 4), the transmitted light forms a gray scale imageimage 1; when the super surface rotates clockwise by 22.5 degrees, the transmitted light forms a random anti-counterfeiting pattern image 3;
6) the dual wavelength is incident to the super surface to generate a bicolor anti-counterfeiting pattern: when the wavelength of the electric field along the x-axis is λ1And λ2The linearly polarized light is simultaneously and normally incident to the super surface formed in the step 4), and then when the transmission axis direction of an analyzer behind the super surface is rotated by 90 degrees to be along the x-axis direction, the transmission light forms a two-color anti-counterfeiting pattern image 4.
2. The super-surface-based design method for realizing multiplexing of the single-color random anti-counterfeiting pattern and the double-color anti-counterfeiting pattern according to claim 1, characterized in that: the substrate material is silicon dioxide, and the nano brick material is silver.
3. The super-surface-based design method for realizing multiplexing of single-color random anti-counterfeiting patterns and double-color anti-counterfeiting patterns according to claim 1 or 2, wherein in the step 1), the working wavelength is λ1625nm and λ2500 nm; the length L of the nano brick is 140nm, the width W of the nano brick is 85nm, the height H of the nano brick is 70nm, and the center-to-center interval C of the unit structure is 340 nm.
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