阅读说明：本技术 基于建立结构参数库的角度复用超表面及设计方法 (Angle multiplexing super surface based on building structure parameter library and design method ) 是由 李仲阳 万帅 郑国兴 万成伟 李哲 代尘杰 时阳阳 杨睿 王泽静 于 2021-06-30 设计创作，主要内容包括：本发明公开了基于建立结构参数库的角度复用超表面及设计方法。所述超表面由多个单元结构阵列于一平面构成；所述单元结构由底层金属反射层、电介质间隔层和顶部金属纳米天线层构成；通过单元结构参数优化,使得单元结构在不同入射角下激发不同的共振模式,以产生不同的振幅和相位响应；通过采集多个在不同角度下产生不同相位和振幅的单元结构的结构参数以构建结构参数库。复用设计方法：通过电磁仿真计算,建立结构参数库；确定角度复用的成像通道以及待显示图像；将不同的单元结构与图像信息对应,有序阵列以实现角度复用的功能。本发明可实现角度复用的全息图像以及纳米印刷图像可以广泛应用于纳米印刷、全息成像等光学领域。(The invention discloses an angle multiplexing super surface based on establishment of a structural parameter library and a design method. The super surface is formed by a plurality of unit structure arrays on a plane; the unit structure is composed of a bottom metal reflecting layer, a dielectric spacing layer and a top metal nano antenna layer; through optimization of unit structure parameters, the unit structure excites different resonance modes under different incidence angles to generate different amplitude and phase responses; the structural parameter library is constructed by collecting structural parameters of a plurality of unit structures which generate different phases and amplitudes under different angles. The multiplexing design method comprises the following steps: establishing a structural parameter library through electromagnetic simulation calculation; determining an imaging channel with multiplexed angles and an image to be displayed; and corresponding different unit structures to the image information, and orderly arraying to realize the function of angle multiplexing. The angle-multiplexing holographic image and the nano-printing image can be widely applied to the optical fields of nano-printing, holographic imaging and the like.)

1. Based on angle multiplexing super surface of establishing the structure parameter storehouse, its characterized in that:

the super surface is formed by a plurality of unit structure arrays on a plane;

the unit structure is composed of a bottom metal reflecting layer, a dielectric spacing layer and a top metal nano antenna layer; through optimization of unit structure parameters, the unit structure excites different resonance modes under different incidence angles to generate different amplitude and phase responses;

the method comprises the steps of establishing a structural parameter library by collecting a plurality of structural parameters of unit structures which generate different phases and amplitudes at different angles;

the structural parameter library comprises the following four types:

(1) the unit structure comprises three cuboid nano-antennas, wherein two blocks are arranged in parallel in the length direction, and the other block is vertically arranged on one side of the short sides of the front two blocks and forms a gap with the front two blocks;

(2) the unit structure comprises three cuboid nano-antennas to form an I-shaped structure;

(3) the unit structure comprises a cuboid nano antenna;

(4) the unit structure comprises three cuboid nano-antennas to form an n-type structure.

2. A super-surface according to claim 1, wherein: the bottom metal reflecting layer and the top metal nano antenna layer are made of gold and silver.

3. A super-surface according to claim 1, wherein: the material of the dielectric spacer layer is silicon dioxide.

4. A super-surface according to claim 1, wherein: the structural parameters include length, width and height of the underlying metal reflective layer and the dielectric spacer layer; length, width, and height of each nano-antenna.

5. A super-surface according to claim 1, wherein: the structural parameters of the bottom metal reflecting layer, the dielectric spacing layer and the top metal nano antenna layer are all in a sub-wavelength scale.

6. A super-surface according to claim 5, wherein: the thickness of the bottom metal reflecting layer is 100nm, the thickness of the dielectric spacing layer is 70nm, and the thickness of the top metal nano antenna layer is 30 nm.

7. The method for designing angle multiplexing imaging of super surface according to any one of claims 1 to 5, comprising the steps of:

(1) scanning various unit structures of a large number of structural parameters through electromagnetic simulation calculation, searching various unit structures generating different phases and amplitudes at different angles, and collecting related parameters of the unit structures to establish a structural parameter library;

(2) determining an imaging channel with multiplexed angles and an image to be displayed;

(3) calculating the amplitude and the phase of the wavefront required by the realization of the angle multiplexing imaging function according to a GS algorithm;

(4) selecting a corresponding unit structure from the structure parameter library, taking one unit structure as a pixel point, corresponding to each pixel of the image to be displayed one by one according to the calculated wavefront, and orderly arranging the unit structures into an array to form a super surface;

(5) the incident light rays with different angles irradiate the super-surface, and the corresponding reflected light rays display different holographic images so as to realize multi-channel holographic image display.

8. Use of a super surface according to any one of claims 1 to 5 for multiple channel holographic imaging and nano-printing.

Technical Field

The invention belongs to the technical field of micro-nano optics, and particularly relates to an angle multiplexing super surface based on establishment of a structural parameter library and a design method.

Background

While metasurfaces show great potential for manipulating light, most controllable optical parameters have been widely explored and implemented with new independent degrees of freedom in light manipulation and optical multiplexing, such as wavelength, polarization, etc. However, as one of the key parameters in optics, the study of the incident wave vector (k) on optical multiplexing has not been sufficiently studied and studied. Most super-surface lighting operation effects are performed under a certain lighting angle. When illuminated at different angles of incidence, the metasurfaces often do not maintain the same optical performance nor exhibit independent new functions.

There is a lack of a super-surface that can achieve independent display of images under multiple incident angles of light.

Disclosure of Invention

Aiming at the angle multiplexing super surface function which is lacked in the prior art, the invention provides an angle multiplexing super surface based on a structure parameter library and a design method.

The present invention proposes a general, systematic method to guide the design of angle multiplexing meta-curved surfaces, enabling them to display completely independent nano-printed images and meta-holograms. The method is to scan and search the units which can generate angle-dependent response, and fill the simulation data into the corresponding positions of the parameter space. When the parameter space filling rate is greater than 75%, it can be considered that the two corresponding parameters can be arbitrarily combined to realize completely independent adjustment. In this way, any different optical function can be embedded into a single layer super-surface at different angles of incidence. The invention establishes a new platform for realizing complex functions under different illumination angles, which is the capability which can not be realized before the current equipment, and obviously expands the light wave operation capability of the super surface.

The technical scheme provided by the invention is as follows:

the invention provides an angle multiplexing super surface based on building a structure parameter library, which is formed by a plurality of unit structure arrays on a plane; the unit structure is composed of a bottom metal reflecting layer, a dielectric spacing layer and a top metal nano antenna layer; through optimization of unit structure parameters, the unit structure excites different resonance modes under different incidence angles to generate different amplitude and phase responses;

the method comprises the steps of establishing a structural parameter library by collecting a plurality of structural parameters of unit structures which generate different phases and amplitudes at different angles;

the structural parameter library comprises the following four types:

(1) the unit structure comprises three cuboid nano-antennas, wherein two blocks are arranged in parallel in the length direction, and the other block is vertically arranged on one side of the short sides of the front two blocks and forms a gap with the front two blocks;

(2) the unit structure comprises three cuboid nano-antennas to form an I-shaped structure;

(3) the unit structure comprises a cuboid nano antenna;

(4) the unit structure comprises three cuboid nano-antennas to form an n-type structure.

Further, the materials of the bottom metal reflection layer and the top metal nano-antenna layer comprise gold and silver.

Further, the material of the dielectric spacer layer is silicon dioxide.

Further, the structural parameters include length, width and height of the underlying metal reflective layer and dielectric spacer layer; length, width, and height of each nano-antenna.

Further, the structural parameters of the bottom metal reflecting layer, the dielectric spacing layer and the top metal nano antenna layer are all in a sub-wavelength scale.

Furthermore, the thickness of the bottom metal reflecting layer is 100nm, the thickness of the dielectric spacing layer is 70nm, and the thickness of the top metal nano antenna layer is 30 nm.

The second aspect of the present invention provides the above method for designing super-surface angle multiplexing imaging, comprising the following steps:

(1) through electromagnetic simulation calculation, a large number of different unit structures are scanned, various unit structures generating different phases and amplitudes under different angles are searched, and then data are filled into a parameter space (such as a parameter space) shown in FIG. 4) To establish a structural parameter library (containing information such as dimensional parameters and optical responses of various structures), and when the filling rate of the parameter space (the ratio of the area enclosed by the dots to the whole parameter space area) is greater than 75%, two corresponding parameters (such asAnd) Can be independently adjusted;

(2) determining an imaging channel with multiplexed angles and an image to be displayed;

(3) calculating the amplitude and the phase of the wavefront required by the realization of the angle multiplexing imaging function according to a GS algorithm;

(4) selecting a corresponding unit structure from the structure parameter library, taking one unit structure as a pixel point, corresponding to each pixel of the image to be displayed one by one according to the calculated wavefront, and orderly arranging the unit structures into an array to form a super surface;

(5) the incident light rays with different angles irradiate the super-surface, and the corresponding reflected light rays display different holographic images so as to realize multi-channel holographic image display.

A third aspect of the invention provides the use of the above-described metasurface for multiple channel holographic imaging and nano-printing.

Compared with the traditional multiplexing holographic imaging and nano printing imaging devices, the angle multiplexing super surface based on the establishment of the structural parameter library and the design method have the following beneficial effects:

(1) the holographic imaging and the nano printing imaging of incident angle multiplexing are realized, which cannot be realized by the traditional device.

(2) By basing on the established structural parameter library, completely independent multi-channel imaging can be realized.

(3) Meanwhile, the imaging functions of a plurality of channels are integrated on a single-layer super-surface device, and the device has the important advantages of simple structure, ultramicro size and easiness in integration.

(4) The angle multiplexing super surface designed by the invention can realize the functions of holographic imaging, nano printing and the like of a plurality of channels under the illumination of a plurality of angles.

Drawings

FIG. 1 is a schematic diagram of an angular multiplexed super surface array and cell structure in accordance with the present invention;

FIG. 2 is a side view and schematic of an angularly multiplexed super-surface array in accordance with the present invention;

FIG. 3 is a schematic diagram of some cell structures in the present invention and an electromagnetic simulated electric field diagram, thus illustrating that the cell structures can excite different modes at different incident angles;

FIG. 4 is a schematic diagram of six structural parameter libraries established in an embodiment of the present invention;

FIG. 5 is a reflectance spectrum in some of the cell structure experiments and simulations of the present invention;

FIG. 6 is a partial Scanning Electron Microscope (SEM) image of a sample designed and fabricated in an example of the present invention;

FIG. 7 is a schematic illustration of angle multiplexed multi-pass holographic imaging and nanoimprint imaging as implemented in embodiments of the present invention, in which completely different holographic and nanoimprint images can be produced at different angles.

Detailed Description

In order to more clearly explain the structure and function of the present invention, the present invention will be further described with reference to the following embodiments in conjunction with the accompanying drawings. The content of the invention is not limited to this at all.

Examples

The embodiment is a specific design process of an angle multiplexing super surface and a specific implementation method for realizing multi-channel holographic imaging by using the angle multiplexing super surface.

As an example, it is first determined that the unit structure of the super surface is a metal-dielectric-metal type structure, and as shown in fig. 1, a fabry-perot cavity is formed by a bottom silver reflective layer, a silicon dioxide spacer layer, and a top silver nano-celestial layer.

FIG. 2 is a schematic side view of a designed super-surface and a schematic diagram of the structure producing different amplitude and phase responses under different incident lights. Under the irradiation of incident light with different angles, the excited surface plasmon resonance and the optical cavity length of the fabry-perot cavity formed by the three-layer structure are changed, so that the structure can generate different amplitude and phase responses under different incident angles, as shown in fig. 3.

Electromagnetic simulation is carried out on the nano-antenna with different size parameters by using electromagnetic simulation software FDTD Solutions, as shown in FIG. 3.

The structure parameter library of the unit structure of the present embodiment includes the following four types:

(1) the unit structure comprises three cuboid nano-antennas, wherein two blocks are arranged in parallel in the length direction, and the other block is vertically arranged on one side of the short sides of the front two blocks and forms a gap with the front two blocks;

(2) the unit structure comprises three cuboid nano-antennas to form an I-shaped structure;

(3) the unit structure comprises a cuboid nano antenna;

(4) the unit structure comprises three cuboid nano-antennas to form an n-type structure.

From the electric field diagrams of several cell structures, it can be seen that under different angles (0 ° and 30 °) of illumination, these structural cells can excite different resonance modes, thereby generating different amplitude and phase responses; establishing a size parameter library for retrieval by simulating a large number of nano antenna structures with different size parameters, as shown in fig. 4; as shown in fig. 5, the simulated and experimental actual reflectance spectra of the two fabricated cell structures fit well, and the data in the dimensional parameter library can be proved to be relatively reliable.

In the embodiment, in the design of angle multiplexing multichannel holographic imaging and nano printing imaging, an image to be displayed is selected as a target image of the holographic imaging and the nano printing imaging; calculating amplitude and phase responses required to be realized under different incidence angles through MATLAB software; and selecting a corresponding unit structure from the structure parameter library, taking one unit structure as a pixel point, corresponding to each pixel of the image to be displayed one by one according to the calculated wavefront, and orderly arranging the unit structures into an array to form the super surface. A designed super-surface sample was fabricated by a nano-fabrication process, and a local Scanning Electron Microscope (SEM) image of the sample is shown in fig. 6. In this example, the top layer metal thickness is 30nm, the spacer layer thickness is 70nm, and the bottom layer metal thickness is 100 nm.

The dimensional parameters of the four typical cell structures shown in fig. 3 are specified below:

establishing a xoy rectangular coordinate system by taking the center of the unit structure as an origin,

structure (1):

the coordinates of the center points of the three rectangles are left (-120nm, -55nm), right (120nm, -55nm) and upper (0nm, 180 nm).

The dimensions of the three rectangles are left (100nm, 220nm), right (100nm, 220nm) and top (300nm, 60nm), respectively.

Structure (2):

the central coordinates of the three rectangles are respectively lower (0nm, -90nm), upper (0nm, 90nm) and middle (0nm ).

The dimensions of the three rectangles are lower (120nm, 60nm), upper (120nm, 60nm) and middle (60nm, 120nm), respectively.

Structure (3):

the coordinates of the center of the rectangle are (0nm ). The length and width of the rectangle are 280nm and 340 nm.

Structure (4):

the lower extension line of the beam with the n-shaped structure is taken as a parting line and is divided into three rectangles;

the central coordinates of the three rectangles are respectively left (-170nm, 40nm), right (170nm, 40nm) and middle (0nm, 180 nm).

The length and width of the three rectangles are respectively left (60nm, 220nm), right (60nm, 220nm) and middle (400nm, 60 nm).

The sample manufactured in this example has a working wavelength of 633nm, corresponds to different imaging channels, and can reflect light under incident light of different angles to display different holographic imaging and nano-printing imaging functions, as shown in fig. 7.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any modification, equivalent replacement, and improvement made by those skilled in the art within the technical scope of the present invention should be included in the scope of the present invention.