Dual-polarization multiplexed electromagnetic metasurface logic operator

Abstract

The application discloses a kind of bipolarization multiplexing electromagnetic super surface logic operator, belong to artificial electromagnetic super material field, overall include: mask plate and the independent phase control of super surface to double polarized incident electromagnetic wave, by changing the polarization mode of electromagnetic wave and the shape of mask plate causes different focal points formed by electromagnetic wave in observation surface, to represent the result of different logic operation;The shape of the same mask plate carries out different logic operation under different polarization mode.Compared with the conventional single polarization phase control super surface, the bipolarization super surface used in the application can independently transmit phase control for x polarization and y polarization incident wave.In the logic operation function of the application, the bipolarization super surface expands the channel capacity of the system, so that the precise logic operation that needs double diffraction layer in traditional work can be realized using single layer super surface now effectively.Meanwhile the application structure is simple, high accuracy, and has broad application prospect.

Description

Technical Field

[0001] This invention belongs to the field of artificial electromagnetic metamaterials, specifically relating to a dual-polarization multiplexed electromagnetic metasurface logic arithmetic unit. Background Technology

[0002] Compared to traditional electronic computing devices, numerical computation using electromagnetic wave-based light-speed devices offers advantages such as parallel processing, ultra-high speed, and low power consumption, attracting significant interest in recent years. Logical operations utilizing electromagnetic waves, as fundamental computational operations, play a crucial role in ultra-high-speed information transmission and communication.

[0003] However, conventional electromagnetic logic gates rely heavily on precise control of input electromagnetic signals, including their phase difference, polarization, and the intensity and size of the incident beam. Due to the complexity and difficulty of this precise control, the logic states of the two output beams exhibit high instability, and the output results are not readily comparable. Furthermore, miniaturizing electromagnetic logic gates becomes challenging when considering the additional bulky equipment required for control. Therefore, realizing a device with a simple structure that can accurately perform electromagnetic operations from an application perspective has become a pressing problem.

[0004] Electromagnetic metasurfaces, as a novel type of artificial electromagnetic material, possess a simple structure and subwavelength thickness, avoiding the inherent large size problem of traditional lens-based computing devices and making it possible to realize miniaturized electromagnetic computing devices. Because they can precisely control the amplitude and phase of the incident wave, metasurfaces overcome the alignment and aberration problems caused by lens characteristics. This opens up possibilities for the miniaturization and integration of electromagnetic computing.

[0005] Therefore, applying metasurfaces to the manipulation of electromagnetic waves in various directions has become one of the current hot topics, providing a wider range of possibilities for the application of electromagnetic waves. Summary of the Invention

[0006] Purpose of the invention: The present invention aims to provide a dual-polarized multiplexed electromagnetic metasurface logic operator, which obtains different focusing points by changing the incident wave entering the dual-polarized metasurface, and uses these to represent different calculation results, thereby realizing the function of logic operation and enabling its application in scenarios such as electromagnetic wave diffraction calculation.

[0007] Technical solution: To achieve the above objectives, the technical solution adopted by this invention is as follows:

[0008] A dual-polarization multiplexed electromagnetic metasurface logic operator includes a mask and a metasurface that independently modulates the phase of a dual-polarized incident electromagnetic wave. By changing the polarization of the electromagnetic wave and the shape of the mask, different focal points are formed on the observation surface to represent the results of different logic operations. The same mask shape performs different logic operations under different polarization modes.

[0009] Preferably, the mask template is provided with an operator area for logical AND and OR operations. The operator area performs logical AND / OR operations for incident x-polarized electromagnetic waves and logical OR / AND operations for incident y-polarized electromagnetic waves.

[0010] Preferably, the mask is the same size as the metasurface and is divided into six parts, which respectively represent the operator, the left-hand "0" and "1" of the operator, the right-hand "0" and "1" of the operator, and the logical operation "NOT".

[0011] Preferably, the logic unit consists of a mask layer and a metasurface layer that allows for independent phase modulation of the dual-polarized incident electromagnetic wave.

[0012] Preferably, the unit structure of the metasurface for independent phase modulation of dual-polarized incident electromagnetic waves consists of, from top to bottom, a first metal layer, a first dielectric layer, a second metal layer, a second dielectric layer, a third metal layer, a third dielectric layer, and a fourth metal layer; by controlling the size of the metal patches on the metal layers, transmission phase modulation can be fully covered within a 360° range under incident x-polarized and y-polarized waves.

[0013] Preferably, the four metal layers are formed by overlapping orthogonal ellipses and located at the center of the unit. Pure phase modulation covering a 360° range of incident waves can be achieved by changing the length of the major axis of the two orthogonal ellipses.

[0014] As a preferred method, the output result is determined by different focusing states on the observation surface, and only one focus appears for a fixed input method.

[0015] This invention also provides a design method for a dual-polarization multiplexed electromagnetic metasurface logic arithmetic unit, comprising the following steps:

[0016] Step 1: At a given operating frequency, ensure complete coverage of 360° range of dual-polarization transmission phase modulation by changing the size of the metasurface unit, the thickness and dielectric constant of the dielectric substrate, and the size of the metal patch, as a backup unit;

[0017] Step 2: Determine the size of the metasurface array, select a mask of the same size as the metasurface, and divide the mask into different regions to represent different operational inputs, ensuring that it can represent all input modes of AND, OR, and NOT logic gates;

[0018] Step 3: At a given operating frequency and focal length, use the Rayleigh-Somerfi formula to simulate the intensity distribution of the incident wave on the observation surface after passing through the mask and metasurface;

[0019] Step 4: Analogous to a neural network, each metasurface unit is considered as a neuron, phase adjustment as a linear transformation of the input, and the propagation of electromagnetic waves in space as an activation function; the phase of each unit is optimized using the backpropagation algorithm to obtain the phase distribution of the entire array; the phase of each unit is optimized for the logic operations corresponding to different polarization modes.

[0020] Step 5: Design the array based on the relationship between the metal patch size and phase response obtained in Step 1 and the phase of each cell in the array obtained in Step 4.

[0021] The present invention also provides a computer system, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program, when loaded onto the processor, implements the steps of the design method for a dual-polarization multiplexed electromagnetic metasurface logic arithmetic unit.

[0022] The present invention also provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the steps of the design method for a dual-polarization multiplexed electromagnetic metasurface logic arithmetic unit.

[0023] Beneficial Effects: This invention proposes a dual-polarization multiplexed electromagnetic metasurface logic arithmetic unit. By using masks of different shapes and controlling the transmission phase of the metasurface, it can simultaneously achieve transmission-type focusing functions in two polarization channels when electromagnetic waves are incident on the metasurface. Compared with existing technologies, this invention has the following advantages:

[0024] 1. Compared to single-polarized phase-tunable metasurfaces, the dual-polarized electromagnetic metasurface used in this invention offers greater freedom and flexibility, allowing for independent design of diffraction characteristics for incident waves of different polarizations. In logic operations, the use of the dual-polarized metasurface expands the system's channel capacity, enabling precise logic operations that traditionally require two diffraction layers to be effectively achieved using a single metasurface. Simultaneously, its transmission efficiency reaches over 0.8, demonstrating high energy utilization.

[0025] 2. This invention effectively reduces the requirements for incident electromagnetic waves by providing a photomask and a corresponding metasurface. Traditionally, when using electromagnetic wave diffraction for logic operations, the amplitude and phase of the incident electromagnetic wave require high precision, which places high demands on the instruments controlling the incident wave. In this invention, however, by controlling different polarization modes of the input electromagnetic wave, complete logic operation functions can be achieved under the action of the photomask and metasurface. Furthermore, this invention eliminates the need for instruments controlling the incident wave, making the miniaturization of electromagnetic wave logic gates possible.

[0026] 3. This invention uses a two-dimensional metasurface for phase adjustment. Compared with the traditional method of using propagation phase for phase adjustment which requires controlling different heights of the medium, the metasurface of this invention has a fixed thickness, which is beneficial for the integration of the structure.

[0027] 4. The dual-polarization multiplexed electromagnetic metasurface logic arithmetic unit proposed in this invention has the advantages of high accuracy, thinness, simple structure and easy processing while realizing electromagnetic logic gates. It may be further developed in integrated chips and is expected to be applied in many fields such as medical instruments and biological lenses.

[0028] 5. The design scheme proposed in this invention has good scalability. In addition to the microwave band application shown in this invention, it can also be used to achieve the design of millimeter wave, terahertz band and optical frequency band by adjusting structural parameters and other means. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of a dual-polarization multiplexed electromagnetic metasurface logic arithmetic unit according to an embodiment of the present invention.

[0030] Figure 2 This is a schematic diagram of the metasurface unit structure in an embodiment of the present invention.

[0031] Figure 3(a) shows the relationship between the amplitude response of the metasurface unit and the length of the major axis of the metal elliptical sheet in an embodiment of the present invention.

[0032] Figure 3(b) shows the relationship between the phase response of the metasurface unit and the length of the major axis of the metal elliptical plate in an embodiment of the present invention.

[0033] Figure 4(a) is a diagram of the phase parameters of the metasurface when the input wave is an x-polarized wave.

[0034] Figure 4(b) is a diagram of the phase parameters of the metasurface when the input wave is a y-polarized wave.

[0035] Figure 5 This is a schematic diagram of the overall metasurface structure in an embodiment of the present invention.

[0036] Figure 6 This is a schematic diagram of the mask shape in an embodiment of the present invention.

[0037] Figure 7 This is a schematic diagram of the input wave polarization mode and mask template during different logical operations in embodiments of the present invention.

[0038] Figure 8(a) is a schematic diagram of the observation surface output corresponding to each input in an embodiment of the present invention.

[0039] Figure 8(b) is a schematic diagram of the normalized energy distribution of the results corresponding to each input at the center height of the observation surface in an embodiment of the present invention. Detailed Implementation

[0040] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, it should be understood that the present invention can be implemented in various forms. Some exemplary and non-limiting embodiments shown in the drawings and described below are not intended to limit the present invention to the specific embodiments described.

[0041] like Figure 1 As shown in the illustration, this invention discloses a dual-polarization multiplexed electromagnetic metasurface logic operator, comprising a mask and a metasurface capable of independently controlling the phase of a dual-polarized incident electromagnetic wave. By changing the polarization of the electromagnetic wave and the shape of the mask, different focal points are formed on the observation surface, representing the results of different logic operations. The input electromagnetic wave passes through a pre-designed mask, which is patterned to form multiple regions. Without sacrificing versatility, each region in the mask is set to two different transmittance states, with the high (low) transmittance state indicating that the region is selected (not selected) for logic operations. The shape of the same mask allows for different logic operations under different polarization modes.

[0042] In this embodiment of the invention, the mask template is provided with an operator area shared by logical AND and OR operations. The operator area performs logical AND / OR operations for incident x-polarized electromagnetic waves and logical OR / AND operations for incident y-polarized electromagnetic waves. The polarization type of the input plane wave is determined according to the required operation. For example, when the required operation is "1 or 1", "1 or 0", "0 or 1", "0 or 0", or "not 0", the input wave is an x-polarized wave of the same size as the metasurface; when the required operation is "1 and 1", "1 and 0", "0 and 1", "0 and 0", or "not 1", the input wave is a y-polarized wave of the same size as the metasurface.

[0043] Electromagnetic waves enter the metasurface through a photomask. In this embodiment of the invention, the metasurface unit is composed of four metal layers and three dielectric layers stacked alternately, from top to bottom: a first metal layer, a first dielectric layer, a second metal layer, a second dielectric layer, a third metal layer, a third dielectric layer, and a fourth metal layer. By controlling the size of the metal patches on the metal layers, transmission phase modulation covering a complete 360° range is achieved under incident x-polarized and y-polarized waves. The three dielectric layers have the same shape and dielectric constant, being square; the four metal layers have the same shape, formed by overlapping orthogonal ellipses located at the center of each dielectric layer, with the major axes of the two ellipses parallel to the edges of the dielectric substrate. By changing the length of the major axes of the two orthogonal ellipses, pure phase modulation covering 360° of the incident wave is achieved. In addition to the dual-polarized metasurface unit structure in this embodiment, other units capable of dual-polarization modulation can also be used.

[0044] Electromagnetic waves modulated by a metasurface can be focused at a preset focal length. Different focal points will appear depending on the polarization of the input wave and the shape of the mask, thus representing the output of "0" or "1". For a fixed input method, only one focal point will appear.

[0045] In this embodiment of the invention, the metasurface unit cell utilizes a resonant structure to achieve an independent phase response to an incident cross-polarized wave. This allows for the representation of ten operations corresponding to the three logic gates (AND, OR, and NOT) by controlling the polarization of the input wave and the different shapes of the mask. Based on the Rayleigh-Somerfi diffraction formula, the phase parameters of the array are trained using a backpropagation algorithm via deep learning. When an incident wave illuminates a specific operating region of the metasurface, the corresponding unit cell is activated and can scatter the incident wave into two designated regions containing logical information in the output layer, thereby representing an output result of 0 or 1.

[0046] This invention discloses a design method for a dual-polarization multiplexed electromagnetic metasurface logic arithmetic unit, comprising the following steps:

[0047] Step 1: At a given operating frequency, ensure complete coverage of 360° range of dual-polarization transmission phase modulation by changing the size of the metasurface unit, the thickness and dielectric constant of the dielectric substrate, and the size of the metal patch, as a backup unit;

[0048] Step 2: Select an appropriate metasurface array size, select a mask of the same size as the metasurface, and divide the mask into different regions to represent different operational inputs, ensuring that it can represent all input modes of AND, OR, and NOT logic gates;

[0049] Step 3: At a given operating frequency and focal length, use the Rayleigh-Somerfi formula to simulate the intensity distribution of the incident wave on the observation surface after passing through the mask and metasurface;

[0050] Step 4: Analogous to a neural network, each metasurface unit is considered as a neuron, phase adjustment as a linear transformation of the input, and the propagation of electromagnetic waves in space as an activation function; the phase of each unit is optimized using the backpropagation algorithm to obtain the phase distribution of the entire array; the phase of each unit is optimized for the logic operations corresponding to different polarization modes.

[0051] Step 5: Design the array based on the relationship between the metal patch size and phase response obtained in Step 1 and the phase of each cell in the array obtained in Step 4.

[0052] The following example uses a dual-polarized multiplexed electromagnetic metasurface logic arithmetic unit with an operating frequency of 17 GHz to illustrate the design and implementation effects of this invention. This invention discloses a dual-polarized multiplexed electromagnetic metasurface logic arithmetic unit that supports AND, OR, and NOT logic gate operations under dual-polarized wave incident light. Its overall structure includes photomasks of different shapes and a two-dimensional metasurface. In this embodiment, the incident wave frequency f = 17 GHz and the wavelength is 17.6 mm. Figure 2 As shown, the metasurface array is 42cm x 42cm in size. Each metasurface unit consists of three substrates with four printed metal patterns. The thickness of the metal patch in the metasurface unit is h1 = 0.018mm, the thickness of the dielectric substrate is h2 = 1mm, and the side length is p = 10mm. The metal patch is made of copper, and the dielectric substrate has a relative permittivity of 3.5 and a loss tangent of 0.001. The minor axis length of the two orthogonal ellipses of the metal patch is fixed at 2.5mm. The major axis length of the two orthogonal ellipses is determined by the phase adjustment required by the unit. The major axis length of the ellipse with its major axis on the x-axis controls the phase modulation of the x-polarized wave, and the major axis length of the ellipse with its major axis on the y-axis controls the phase modulation of the y-polarized wave. The major axis lengths of the two ellipses are l... x With l y The range is 2.5–5.6 mm, achieving 360° full coverage of the incident electromagnetic wave phase. Simulation verification shows the relationship between the amplitude and phase response of the metasurface unit and the length of the major axis of the metal patch ellipse, as shown in Figures 3(a) and 3(b).

[0053] In a metasurface array, each cell behaves like an independent neuron in a neural network, propagating through space via electromagnetic wave diffraction, based on the Rayleigh-Somerzy formula, located at... The unit at that location serves as a secondary wave source, and the Huygens beam excited by this secondary wave source can be transmitted through... To describe, in which:

[0054]

[0055] In the above formula, Any point in space and distance, It is the wave number of the electromagnetic wave at the operating frequency in free space, a complex factor. Input wave entering the unit and the transmission coefficient of the unit The product determines that, i.e. Therefore, the total propagation field It is formed by the superposition of fields excited by each unit, and is expressed by the following formula:

[0056]

[0057] Because the distribution of electromagnetic waves in space follows the forward propagation law given by equation (2), by learning the phase parameters of the metasurface unit, the electromagnetic waves after being encoded by the mask and metasurface can be focused to any position in space.

[0058] To train the array phase parameters, this embodiment sets the loss function Loss to the ratio of energy in the region outside the focal point to the total energy on the observation surface. Since the Poynting vector representing energy flux density is S = E × H, and in vacuum there is |H| = |E| / η0 (E is the electric field strength, H is the magnetic field strength, and η0 is the impedance in vacuum), the energy ratio can be converted into the ratio of the squares of the electric field strengths. Therefore, the specific expression of the loss function is as follows:

[0059]

[0060] Based on this, this embodiment uses the backpropagation algorithm to optimize the loss function. After a certain number of training rounds, the phase parameters in this embodiment can be obtained. The specific data of the phase parameters corresponding to the input wave being x-polarized and y-polarized are as follows: Figure 4(a) , 4(b) As shown.

[0061] refer to Figure 5 The mask thickness is a = 5mm, the distance between the mask and the metasurface is z0 = 5mm, and the focal length selected in this embodiment is 200mm. The mask area is divided by... Figure 6 As shown, the diagram is divided into six equally sized sections to represent different regions that represent the inputs for logical operations. After determining the polarization of the input wave according to the required logical operation, the corresponding mask is selected accordingly. Finally, each logical operation, its corresponding input wave polarization, and the mask shape are as follows: Figure 7 As shown, the gray areas contain a mask and have a transmittance of 0; the white areas do not contain a mask and have a transmittance of 1. (Reference) Figure 1The electromagnetic waves are focused on the observation surface through the metasurface. The focal center of the output result "0" or "1" is at y = 210 mm, the focal center of the result "1" is at x = 105 mm, and the focal center of the result "0" is at x = 315 mm (x,y∈[0,420]).

[0062] Figure 8(a) , 8(b) The focusing results of ten logical operations implementing AND, OR, and NOT logic gates on the observation surface and the normalized energy distribution at the center height of the observation surface are given in turn.

[0063] This invention realizes a dual-polarization multiplexed electromagnetic metasurface logic arithmetic unit, which has advantages such as high accuracy, thinness, simple structure, and ease of fabrication compared with previous related achievements. It helps to realize the high speed, miniaturization and integration of logic gates and has broad application prospects.

[0064] This invention also discloses a computer system, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is loaded onto the processor, it implements the steps of the design method for a dual-polarization multiplexed electromagnetic metasurface logic arithmetic unit.

[0065] This invention also discloses a computer program product, including a computer program / instruction, which, when executed by a processor, implements the steps of the design method for a dual-polarization multiplexed electromagnetic metasurface logic arithmetic unit.

[0066] The above description is only a preferred embodiment of the present invention. The same structure can be flexibly designed by scaling down or enlarging the structural size to realize the working frequency band of the metasurface for dual-polarization logic operation, and extended to the millimeter-wave band, terahertz band and optical band, etc.

[0067] Obviously, those skilled in the art, after understanding the content and principles of this invention, may make various modifications and changes in form and detail without departing from the principles and structure of this invention. Any simple equivalent changes and modifications made in accordance with the claims and the description of this invention should still fall within the scope of this patent.

Claims

1. A dual-polarization multiplexed electromagnetic metasurface logic arithmetic unit, characterized in that, The system includes a mask and a metasurface for independent phase modulation of dual-polarized incident electromagnetic waves. By changing the polarization of the electromagnetic wave and the shape of the mask, different focal points are formed on the observation surface to represent the results of different logical operations. The same mask shape performs different logical operations under different polarizations. The mask has an operator region shared by logical AND and OR operations, and the operator region is configured for the incident electromagnetic waves. x Polarized electromagnetic waves are subjected to logical AND / OR operations, for incident waves... y The polarized electromagnetic wave is a logical OR / AND operation; the mask is the same size as the metasurface and is divided into six parts, which respectively represent the operator, the left target of the operator "0" and "1", the right target of the operator "0" and "1", and the logical operation "NOT"; The metasurface unit structure for independently phase-tunable dual-polarized incident electromagnetic waves comprises, from top to bottom, a first metal layer, a first dielectric layer, a second metal layer, a second dielectric layer, a third metal layer, a third dielectric layer, and a fourth metal layer; this is achieved by controlling the size of the metal patches on the metal layers. x Polarized waves and y Under polarized wave incidence, transmission phase modulation is fully covered within a 360° range; the four metal layers are formed by overlapping orthogonal ellipses and located at the center of the unit. Pure phase modulation covering a 360° range for the incident wave is achieved by changing the length of the major axis of the two orthogonal ellipses.

2. The dual-polarization multiplexed electromagnetic metasurface logic arithmetic unit according to claim 1, characterized in that, The logic unit consists of a mask layer and a metasurface layer that allows for independent phase modulation of the bipolar incident electromagnetic wave.

3. The dual-polarization multiplexed electromagnetic metasurface logic arithmetic unit according to claim 1, characterized in that, The output result is determined by different focusing states on the observation surface. For a fixed input method, only one focus will appear.

4. The design method of a dual-polarization multiplexed electromagnetic metasurface logic arithmetic unit according to any one of claims 1-3, characterized in that, Includes the following steps: Step 1: At a given operating frequency, ensure complete coverage of 360° range of dual-polarization transmission phase modulation by changing the size of the metasurface unit, the thickness and dielectric constant of the dielectric substrate, and the size of the metal patch, as a backup unit; Step 2: Determine the size of the metasurface array, select a mask of the same size as the metasurface, and divide the mask into different regions to represent different operational inputs, ensuring that it can represent all input modes of AND, OR, and NOT logic gates; Step 3: At a given operating frequency and focal length, use the Rayleigh-Somerfi formula to simulate the intensity distribution of the incident wave on the observation surface after passing through the mask and metasurface; Step 4: Analogous to a neural network, each metasurface unit is considered as a neuron, phase adjustment as a linear transformation of the input, and the propagation of electromagnetic waves in space as an activation function; the phase of each unit is optimized using the backpropagation algorithm to obtain the phase distribution of the entire array; the phase of each unit is optimized for the logic operations corresponding to different polarization modes. Step 5: Design the array based on the relationship between the metal patch size and phase response obtained in Step 1 and the phase of each cell in the array obtained in Step 4.

5. A computer system comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the computer program is loaded into the processor, it implements the steps of the design method for a dual-polarization multiplexed electromagnetic metasurface logic arithmetic unit according to claim 4.

6. A computer program product comprising a computer program / instructions, characterized in that, When the computer program / instructions are executed by the processor, they implement the steps of the design method for a dual-polarization multiplexed electromagnetic metasurface logic arithmetic unit according to claim 4.

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