Parallel all-optical logic device based on metasurface and operation method

Abstract

The application discloses a kind of parallel all-optical logic units based on super-structured surface and operation method, the logic unit is two different off-axis focusing phase encoding to the two independent degrees of freedom of super-structured surface Jones matrix, constructs polarization conversion double / single focusing lens, so that the output result after polarization conversion can support the parallel operation of two logic gates;Right-handed circularly polarized light and left-handed circularly polarized light are incident to the polarization conversion double / single focusing lens, and the output result of logic or gate, exclusive or gate and NOT gate is characterized in two off-axis focusing areas of focal plane, to form parallel all-optical logic unit. The operation method allows to realize the parallel operation of double-channel multiplexing logic gate in an efficient and compact manner, with the advantage of chip-level ultrafast optical computing.

Description

Technical Field

[0001] This invention belongs to the field of metasurface application technology, specifically designing a parallel all-optical logic device and operation method based on metasurface. Background Technology

[0002] Compared to electronic computers, all-optical computing demonstrates superior capabilities in ultrafast signal processing. Photonic circuits, by replacing electrons with photons, eliminate limitations imposed by operating speed and heat loss. Currently, mainstream optical logic gates primarily utilize multi-beam interference or nonlinear effects, both requiring precise optical configurations. Specifically, multi-beam interference necessitates precise control of the phase difference to effectively achieve high-intensity contrast in the output signal. The generation of nonlinear effects requires high-power incident light, which is challenging for practical optical system construction.

[0003] In recent years, the development of metasurfaces has provided an excellent solution for all-optical computing. Metasurfaces are two-dimensional versions of metamaterials, and subwavelength optical phase-shifting element arrays can be used to control parameters such as the phase, amplitude, and polarization of electromagnetic waves. By encoding multiple independent phases on metasurfaces and controlling the input polarization state, the required focused phase distribution can be flexibly extracted according to Boolean logic operation mechanisms to establish a monolithic parallel all-optical logic arithmetic unit. Furthermore, this logic arithmetic unit, combined with advanced micro-nano fabrication technology, is expected to achieve mass production. Summary of the Invention

[0004] In view of the above-mentioned technical problems in the prior art, the present invention provides a parallel all-optical logic device and operation method based on metasurface, which is reasonably designed, solves the shortcomings of the prior art, and has good effect.

[0005] To achieve the first objective of the invention, the following technical solution is adopted:

[0006] A parallel all-optical logic device based on a metasurface encodes two different off-axis focusing phases into two independent degrees of freedom of the Jones matrix of the metasurface, constructing a polarization conversion dual / single focusing lens. Right-handed and left-handed circularly polarized light are incident on the polarization conversion dual / single focusing lens, and the output results of the logic OR gate, XOR gate, and NOT gate are characterized in two off-axis focusing regions of the focal plane, thus forming a parallel all-optical logic device.

[0007] Furthermore, the metasurface includes a substrate and multiple elliptical nanopillar units arranged on the substrate. A phase database is established for the elliptical nanopillar units, which includes the relationship between different structural sizes and the phase and transmittance of the nanopillar units after 1550 nm light incident. Based on the designed Jones matrix, elliptical nanopillar units of different structural sizes are arranged on the substrate.

[0008] Furthermore, the structural parameters of the elliptical nanopillar unit include the major axis D. x short axis D y The size of the elliptical nanopillar unit structure can be changed by adjusting these three parameters: orientation angle θ.

[0009] Furthermore, the three independently adjustable degrees of freedom in the Jones matrix J of the metasurface are expressed as follows:

[0010]

[0011] Wherein, phase φ2 is a random distribution function, and phases φ1 and φ3 are used for different off-axis focusing, and their expressions are:

[0012]

[0013] in, It is the focal point on the focal plane; f, w, and c represent the focal length, angular frequency, and speed of light in a vacuum, respectively.

[0014] Furthermore, when right-handed or left-handed circularly polarized light (1±i) T At incidence, the output light field is represented as:

[0015]

[0016] When right-handed and left-handed circularly polarized light are added together, they combine to form a beam of linearly polarized light vibrating in the X direction (10). T At incidence, the output light field is represented as:

[0017]

[0018] Furthermore, the left off-axis spot I controlled by phase φ1 is designed as an OR gate, and the right off-axis spot II controlled by phase φ3 is designed as an XOR gate or NOR gate.

[0019] To achieve objective 2 of the invention, the following technical solution is adopted:

[0020] A computational method for a parallel all-optical logic device based on a metasurface is provided. The parallel all-optical logic device described above is used. When only right-hand circularly polarized light or left-hand circularly polarized light is incident, i.e. the input state is (1,0) or (0,1), focusing is achieved at both spot I and spot II. That is, the output of the OR gate is 1 and the output of the XOR gate is also 1.

[0021] When right-handed circularly polarized light and left-handed circularly polarized light are incident simultaneously, i.e., the input state is (1,1), focusing is achieved at spot I, and focusing does not occur at spot II. That is, the OR gate output is 1 and the XOR gate output is 0.

[0022] When there is no incident light, i.e. the input state is (0,0), no focusing occurs at spot I and spot II, i.e. the OR gate output is 0 and the XOR gate output is also 0;

[0023] When right-hand circularly polarized light is used as the control beam and left-hand circularly polarized light is incident, i.e. the input state is 1, no focusing occurs at spot II, i.e. the NOT gate output is 0;

[0024] When right-hand circularly polarized light is used as the control beam and left-hand circularly polarized light is not incident (i.e., the input state is 0), focusing occurs at spot II, i.e., the NOT gate output is 1.

[0025] The beneficial technical effects of this invention are as follows:

[0026] This invention provides a parallel all-optical logic device and operation method based on metasurface polarization optics. It employs a pair of orthogonally circularly polarized lights as the two input channels of the logic unit, with four possible input combinations perfectly matching various binary input states. Correspondingly, different phases are encoded into the metasurface, enabling the polarization-converted output to support parallel operation of two logic gates. This method allows for the efficient and compact implementation of parallel operation of dual-channel multiplexed logic gates, offering the advantages of chip-level ultrafast optical computing. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the parallel logic arithmetic unit in this invention;

[0028] Figure 2 This is a schematic diagram of the structure of an elliptical nanopillar unit and a substrate in this invention;

[0029] Figure 3 for Figure 2 Top view;

[0030] Figure 4 This is a diagram showing the results of the parallel logic arithmetic unit operations in this invention;

[0031] Figure 5 This is a simulation diagram of the parallel logic unit operation in this invention;

[0032] Among them, 1-polarization conversion dual / single focusing lens; 2-elliptical nanopillar unit; 3-substrate; Detailed Implementation

[0033] The specific embodiments of the present invention will be further described below with reference to specific examples:

[0034] This invention provides a parallel all-optical logic device based on a metasurface. Two different off-axis focusing phases are encoded into two independent degrees of freedom of the Jones matrix of the metasurface to construct a polarization conversion dual / single focusing lens 1. Right-hand circularly polarized light and left-hand circularly polarized light are incident on the polarization conversion dual / single focusing lens 1. The output results of the logic OR gate, XOR gate, and NOT gate are characterized in two off-axis focusing regions of the focal plane, thereby forming a parallel all-optical logic device.

[0035] The three independently controllable degrees of freedom in the Jones matrix J of the metasurface are represented as follows:

[0036]

[0037] Wherein, phase φ2 is a random distribution function, and phases φ1 and φ3 are used for different off-axis focusing, and their expressions are:

[0038]

[0039] in, It is the focal point on the focal plane; f, w, and c represent the focal length, angular frequency, and speed of light in a vacuum, respectively.

[0040] When right-handed circularly polarized light (RCP) or left-handed circularly polarized light (LCP) (1 ±i) T At incidence, the output light field is represented as:

[0041]

[0042] The output field consists of three different polarization components: x-linearly polarized light with phase φ1, y-linearly polarized light with phase φ3, and circularly polarized light with phase φ2.

[0043] When right-handed and left-handed circularly polarized light are added together, they combine to form a linearly polarized light beam (XLP) that vibrates along the X-direction (1 0). T At incidence, the output light field is represented as:

[0044]

[0045] The output field consists of two distinct polarization components: x-linearly polarized light with phase φ1 and y-linearly polarized light with phase φ2. For example... Figure 1As shown, right-handed and left-handed circularly polarized light are used as two input channels, where the high or low level ("1" or "0") is determined by the light intensity in the corresponding port. After wavefront phase modulation, off-axis focusing is performed on the focal plane according to different input conditions, and the binary logic output ("1" or "0") directly depends on whether there is a spot in the designed area on the focal plane. In parallel logic operations, the left off-axis spot I controlled by phase φ1 is designed as an AND gate, and the right off-axis spot II controlled by phase φ3 is designed as an XOR gate or NOR gate.

[0046] like Figure 2 and 3 As shown, the metasurface comprises a silicon dioxide (SiO2) substrate 2 and multiple silicon (Si) elliptical nanopillar units 2 arranged on the substrate. Each silicon elliptical nanopillar unit 2 has a fixed square lattice constant p = 600 nm and a height H = 1200 nm, and is periodically arranged on the silicon dioxide substrate 3. The elliptical nanopillar unit 2 has three independent adjustable parameters: the major axis (D... x ), short axis (D) y By adjusting these three parameters (θ) and orientation angle, the size of the elliptical nanopillar unit structure can be changed, thus constructing a superatomic library.

[0047] A phase database was established for elliptical nanopillar units, which included the relationship between the phase and transmittance of nanopillar units with different structural sizes after 1550 nm light incident. Based on the designed Jones matrix, the elliptical nanopillar units with the most appropriate phase and transmittance at each position on the silicon dioxide substrate were found using the constructed superatomic library, and elliptical nanopillar units with different structural sizes were arranged on the substrate.

[0048] An operational method for a parallel all-optical logic device based on a metasurface, employing the parallel all-optical logic device described above, such as... Figure 4 As shown:

[0049] When only right-handed or left-handed circularly polarized light is incident, i.e., the input state is (1,0) or (0,1), focusing is achieved at both spot I and spot II, i.e., the OR gate output is 1 and the XOR gate output is also 1.

[0050] When right-handed circularly polarized light and left-handed circularly polarized light are incident simultaneously, i.e., the input state is (1,1), focusing is achieved at spot I, and focusing does not occur at spot II. That is, the OR gate output is 1 and the XOR gate output is 0.

[0051] When there is no incident light, i.e. the input state is (0,0), no focusing occurs at spot I and spot II, i.e. the OR gate output is 0 and the XOR gate output is also 0;

[0052] When right-hand circularly polarized light is used as the control beam and left-hand circularly polarized light is incident, i.e. the input state is 1, no focusing occurs at spot II, i.e. the NOT gate output is 0;

[0053] When right-hand circularly polarized light is used as the control beam and left-hand circularly polarized light is not incident (i.e., the input state is 0), focusing occurs at spot II, i.e., the NOT gate output is 1.

[0054] like Figure 5 As shown, the corresponding intensity distribution on the focal plane displays the results of parallel logic operations. The dashed box on the left represents the OR gate, and the one on the right represents the XOR / NOT gate. Whether the focus is on or off directly reflects the output logic state "1" or "0". The normalized intensity distribution after the focal spot is cut along the horizontal centerline shows that the light intensity can be well confined within the designed logic operation area.

[0055] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A parallel all-optical logic device based on a metasurface, characterized in that, Two distinct off-axis focusing phases are encoded into two independent degrees of freedom of the Jones matrix on the metasurface to construct a polarization-conversion dual / single focusing lens. Right-handed and left-handed circularly polarized light are incident on this polarization-conversion dual / single focusing lens, and the outputs of OR, XOR, and NOT gates are characterized by two off-axis focusing regions on the focal plane, thus forming a parallel all-optical logic device. The metasurface includes a substrate and multiple elliptical nanopillar units arranged on the substrate. A phase database is established for the elliptical nanopillar units, which includes the relationship between different structural sizes and the phase and transmittance of the nanopillar units after 1550 nm light incident. Elliptical nanopillar units of different structural sizes are arranged on the substrate according to the designed Jones matrix. The metasurface Jones matrix The three independently adjustable degrees of freedom are represented as follows: ； Among them, phase Given a random distribution function, phase and phase For different off-axis focusing methods, the expression is: ， ； in, It is the focal point on the focal plane; , , These represent focal length, angular frequency, and the speed of light in a vacuum, respectively.

2. The parallel all-optical logic device based on a metasurface according to claim 1, characterized in that, The structural parameters of the elliptical nanopillar unit include the major axis D. x short axis D y The size of the elliptical nanopillar unit structure can be changed by adjusting these three parameters: the orientation angle φ.

3. A parallel all-optical logic device based on a metasurface according to claim 1, characterized in that, When right-handed or left-handed circularly polarized light At incidence, the output light field is represented as: ； When right-handed and left-handed circularly polarized light are added together, they combine into a beam of linearly polarized light vibrating along the X-direction. At incidence, the output light field is represented as: 。 4. A parallel all-optical logic device based on a metasurface according to claim 3, characterized in that, By phase The controlled left-side off-axis spot I is designed as an OR gate, controlled by phase. The right-side off-axis light spot II is designed as an XOR gate or NOR gate.

5. A computational method for a parallel all-optical logic device based on a metasurface, characterized in that, Using the parallel all-optical logic device as described in any one of claims 1-4, when only right-hand circularly polarized light or left-hand circularly polarized light is incident, i.e. the input state is (1,0) or (0,1), focusing is achieved at both spot I and spot II, i.e. the OR gate output is 1 and the XOR gate output is also 1; When right-handed circularly polarized light and left-handed circularly polarized light are incident simultaneously, i.e., the input state is (1,1), focusing is achieved at spot I, and focusing does not occur at spot II. That is, the OR gate output is 1 and the XOR gate output is 0. When there is no incident light, i.e. the input state is (0,0), no focusing occurs at spot I and spot II, i.e. the OR gate output is 0 and the XOR gate output is also 0; When right-hand circularly polarized light is used as the control beam and left-hand circularly polarized light is incident, i.e. the input state is 1, no focusing occurs at spot II, i.e. the NOT gate output is 0; When right-hand circularly polarized light is used as the control beam and left-hand circularly polarized light is not incident (i.e., the input state is 0), focusing occurs at spot II, i.e., the NOT gate output is 1.

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