Light field modulation method and photonic device

Abstract

This application provides an optical field modulation method and a photonic device, relating to the field of electromagnetic wave phase manipulation. The optical field modulation method includes: determining the target common rotation angle and target relative rotation angle of the superatoms based on the target modulation phase of the superatoms in a diatomic optical device building block; and determining the angular distribution of the superatoms based on the target common rotation angle and target relative rotation angle, thereby achieving target optical field modulation of the optical device constructed based on the diatomic optical device building block. The optical field modulation method provided in this application utilizes rotational degrees of freedom to achieve asymmetric photonic spin-orbit interactions, breaking the traditional understanding that rotation can only introduce spin-conjugated geometric phases. The optical field manipulation method provided in this application has significant application potential in fields such as polarization-switchable devices and dynamic control systems, enriching the mechanisms of optical field manipulation.

Description

Technical Field

[0001] This application relates to the field of electromagnetic wave phase modulation, and more specifically, to an optical field modulation method and a photonic device. Background Technology

[0002] Electromagnetic wave phase modulation is the precise adjustment of the phase distribution of electromagnetic waves through technical means, thereby altering their propagation characteristics or achieving specific functions. Building upon this, optical field phase modulation further focuses on the precise control of the phase distribution of optical fields to change the propagation behavior of light or achieve specific optical functions. As one of the core parameters of light waves, phase modulation can directly affect the interference, diffraction, and focusing properties of light, thereby optimizing key performance characteristics of light in imaging, communication, and sensing.

[0003] Metasurfaces can precisely control the phase of the optical field through subwavelength structures, enabling functions such as beam deflection, focusing, and holographic imaging. The subwavelength-scale phase control capability of metasurfaces makes them an efficient platform for optical field modulation.

[0004] Currently, although photonic spin-orbit interactions (SOIs) based on metasurfaces can cover the frequency range or even longer wavelength range of light, the geometric phase based on photonic spin-orbit interactions is limited by conjugate symmetry when modulating left-handed circularly polarized (LCP) and right-handed circularly polarized (RCP) light. This makes it impossible to achieve independent control of LCP and RCP light, thus limiting the flexibility of optical device design and the performance of optical devices. Summary of the Invention

[0005] The purpose of this application is to provide an optical field modulation method and a photonic device. This optical field modulation method relies only on rotational degrees of freedom to realize asymmetric SOIs, and makes reasonable use of the coupling phase, which is considered unfavorable in traditional viewpoints, and can control the coupling phase as needed.

[0006] In a first aspect, embodiments of this application provide an optical field modulation method, which includes: determining the target common rotation angle and the target relative rotation angle of the superatoms based on the target modulation phase of the superatoms in the dual-atom optical device building block; and determining the angular distribution of the superatoms according to the target common rotation angle and the target relative rotation angle, so as to realize the target optical field modulation of the optical device built based on the dual-atom optical device building block.

[0007] In the above implementation process, the optical field modulation method provided in this application determines the target common rotation angle and target relative rotation angle of the superatoms, thereby determining the angular distribution of the superatoms and ultimately achieving target modulation phase. By changing the relative rotation angle of the two superatoms, a spin-non-conjugated coupling phase is introduced; by changing the common rotation angle of the two superatoms, a spin-conjugated generalized higher-order geometric phase is introduced; asymmetric SOIs can be realized using only rotational degrees of freedom, breaking the traditional view that rotation can only introduce spin-conjugated geometric phases, enriching the mechanism of optical field manipulation, and providing a new theoretical basis for the design of optical devices.

[0008] Optionally, in this embodiment of the application, determining the target common rotation angle and target relative rotation angle of the superatoms based on the target modulation phase of the superatoms in the dual-atom optical device building block includes: determining the higher-order geometric phase component and the coupled phase component in the target modulation phase; and determining the target common rotation angle and target relative rotation angle in the relationship between the target modulation phase including the higher-order geometric phase component and the coupled phase component based on orthogonally circularly polarized light waves.

[0009] In the above implementation process, the optical field modulation method provided in this application uses an orthogonally circularly polarized light incident device to determine the higher-order geometric phase component and the coupled phase component in order to obtain the magnitude of the target common rotation angle and the target relative rotation angle. By simulating the phase distribution of LCP and RCP light and combining it with a mathematical model, each component of the target modulation phase can be efficiently extracted, thereby providing a precise phase control means for metasurface design.

[0010] Optionally, in this embodiment, the relationship between the target modulation phase, including the higher-order geometric phase component and the coupled phase component, is: φ σ =φ PB +φ couplσng ; where φ σ For the target modulation phase, φ PB For higher-order geometric phase components, φ coupling The coupling phase component; a value of σ of 1 indicates that the incident light is a left-handed circularly polarized light wave, and a value of -1 indicates that the incident light is a right-handed circularly polarized light wave.

[0011] Optionally, in embodiments of this application, the higher-order geometric phase components are... k is related to the order of rotational symmetry of the superatom. The target common rotation angle.

[0012] In the above implementation process, the optical field modulation method provided in this application induces a higher-order geometric phase (e.g., C3, C5) by designing superatoms with high-order rotational symmetry (such as C3, C5) and embedding them into mismatched lattices (such as tetragonal lattices). or ).

[0013] Optionally, in embodiments of this application, the coupled phase components are... δ is the relative rotation angle of the target. For phase terms that include transmission phase and coupling phase, This refers to the transmission phase term.

[0014] In the above implementation process, the optical field modulation method provided in this application combines the coupling phase, which is traditionally considered an unfavorable factor, with the higher-order geometric phase, and realizes asymmetric SOIs that rely only on rotational degrees of freedom; it breaks through the traditional understanding that rotation can only introduce spin conjugated geometric phases, and provides new degrees of freedom for optical field manipulation.

[0015] Optionally, in this embodiment of the application, the range of the target common rotation angle is: The range of the target's relative rotation angle is Where m is the order of rotational symmetry of the superatom.

[0016] In the above implementation process, by associating the range of the target common rotation angle and the target relative rotation angle with the rotational symmetry order of the superatom, this embodiment can more accurately and reasonably control the higher-order geometric phase and coupling phase, thereby achieving flexible modulation of the light field.

[0017] In a second aspect, embodiments of this application provide a photonic device, which includes: a plurality of diatomic optical device building blocks; the photonic device is constructed from a plurality of diatomic optical device building blocks; wherein the angular distribution of superatoms in the diatomic optical device building blocks is determined according to the light field modulation method of the first aspect described above.

[0018] Optionally, in the embodiments of this application, the superatoms in the diatomic optical device building blocks have higher-order rotational symmetry.

[0019] Optionally, in the embodiments of this application, the lattice period of the superatomic building block in the x-direction is P. x The lattice period in the y-direction is P. y Among them, P x =2P y And P y <λ, where λ is the center wavelength.

[0020] Optionally, in the embodiments of this application, the material of the diatomic optical device building block includes metal or dielectric.

[0021] In the above implementation process, the optical device provided in this application introduces a spin-non-conjugated coupling phase by changing the relative rotation angle δ of the two superatoms; and changes the common rotation angle of the two superatoms. Introducing a higher-order geometric phase of spin conjugation. Asymmetric photon spin-orbit interaction can be achieved using only rotational degrees of freedom, breaking the traditional understanding that rotation can only introduce geometric phases of spin conjugation. This has wide applications in polarization-switchable devices, dynamic control systems, and other fields. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 The flowchart below shows the optical field modulation method provided in the embodiments of this application;

[0024] Figure 2 A flowchart for determining the rotation angle provided in this application embodiment;

[0025] Figure 3 A schematic diagram of a triple-symmetric superatomic structure provided in the embodiments of this application;

[0026] Figure 4 A three-dimensional schematic diagram of a triple-symmetric superatomic structure provided in the embodiments of this application;

[0027] Figure 5 A schematic diagram of a five-fold symmetry superatomic structure provided in the embodiments of this application;

[0028] Figure 6 The common rotation angle of the C3 structure provided in this application embodiment is Simulation results of amplitude at different relative rotation angles δ;

[0029] Figure 7 The simulation results of the coupling phase when two orthogonally circularly polarized lights are incident, provided in the embodiments of this application;

[0030] Figure 8 The high-order geometric phase simulation results provided in the embodiments of this application for the incidence of two orthogonally circularly polarized lights;

[0031] Figure 9 This is a top view structural diagram of the deflector provided in the embodiments of this application;

[0032] Figure 10 The phase distribution corresponding to the diatomic constituent units of the deflector provided in the embodiments of this application;

[0033] Figure 11Simulation and experimental test results of the beam deflector provided in the embodiments of this application;

[0034] Figure 12 Diffraction patterns of samples irradiated with circularly polarized lasers of different wavelengths, as provided in the embodiments of this application. Detailed Implementation

[0035] The technical solutions of the embodiments of this application will now be described with reference to the accompanying drawings. For example, the flowcharts and block diagrams in the drawings illustrate the architecture, functions, and operations of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagram may represent a module, program segment, or part of code, which contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, and combinations of blocks in the block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or can be implemented using a combination of dedicated hardware and computer instructions. In addition, the functional modules in the various embodiments of the present invention may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0036] Electromagnetic wave phase modulation refers to altering the propagation characteristics or achieving specific functions by adjusting the phase distribution of electromagnetic waves. Building upon this, optical field phase modulation further focuses on the precise control of the phase distribution of an optical field to change the propagation behavior of light or achieve specific optical functions. As one of the core parameters of light waves, phase modulation directly affects the interference, diffraction, and focusing properties of light, thereby optimizing key performance characteristics of light in imaging, communication, and sensing. For example, in optical imaging, phase modulation can achieve super-resolution imaging and wavefront correction; in optical communication, phase modulation can improve signal transmission efficiency and bandwidth; and in quantum optics, phase modulation provides an important means for manipulating quantum states.

[0037] Metasurfaces, as artificial materials composed of subwavelength structures, can achieve unique optical functions through precise manipulation of the phase of light fields. By designing the nanostructures of metasurfaces, the phase distribution of light waves can be manipulated at the subwavelength scale, thereby achieving complex light field modulation effects such as beam deflection, focusing, and holographic imaging. Metasurfaces provide a highly integrated and flexible platform for light field phase manipulation, breaking through the limitations of traditional optical devices and bringing new possibilities to fields such as compact optical systems, super-resolution imaging, and quantum optics.

[0038] Photon spin-orbit interactions (SOIs) on metasurfaces refer to the coupling effect between the spin (circularly polarized state) and orbit (spatial phase distribution) of photons, which can be controlled by the subwavelength structure of the metasurface. By designing nanostructures on metasurfaces, precise control of the phase of circularly polarized light can be achieved, thereby generating complex optical phenomena such as beam deflection, focusing, and vortex beam generation. This has significant application potential in fields such as super-resolution imaging, optical encryption, and quantum optics.

[0039] However, the geometric phase modulation is limited by conjugate symmetry (geometric phase, introduced when the superatom rotates around a certain axis, is conjugate for left-handed and right-handed circularly polarized light, meaning their phase changes are the same but opposite in sign), restricting the independent manipulation capability of LCP and RCP light. Due to conjugate symmetry, the phase responses of LCP and RCP light are interrelated and cannot be independently modulated, making it difficult to simultaneously achieve independent optical functions for LCP and RCP light on the same metasurface, thus limiting the flexibility and multifunctionality of optical field modulation.

[0040] The conventional view holds that breaking the symmetry of the geometric phase of SOIs requires the introduction of additional non-rotational degrees of freedom, such as the size or displacement of the modulation structure.

[0041] For example, the size of the modulation structure is achieved by changing the size of the metasurface unit structure (such as the diameter of the nanopillars) to break the symmetry of the geometric phase. For instance, designing an array of nanopillars with non-uniform sizes in a metasurface can independently control the phase response of left-handed circularly polarized (LCP) and right-handed circularly polarized (RCP) light, thereby realizing asymmetric optical functions.

[0042] For example, the displacement of the modulation structure can be achieved by adjusting the spatial position of the metasurface unit structure (such as the offset or aperiodic arrangement of nanopillars), which can break the conjugate symmetry of the geometric phase. For instance, introducing asymmetric displacement modes into the metasurface can achieve independent phase modulation of LCP and RCP light, thereby generating complex phase distributions or beam deflection effects.

[0043] When constructing a metasurface, the metasurface building block consists of two superatoms with high-order rotational symmetry. The rotation of the two superatoms will generate high-order geometric phase and coupling phase.

[0044] Higher-order geometric phase refers to the phase generated in a metasurface by designing a structure with higher-order rotational symmetry, which is equal to several times the rotation angle in the photon spin-orbit interaction (SOIs). The generation of higher-order geometric phase usually depends on lattice coupling effect or complex symmetry design.

[0045] Coupled phase is a phase change caused by interactions between superatoms (such as near-field coupling or far-field interference). This phase is typically related to the arrangement, distance, and relative orientation of the superatoms. When two superatoms rotate relative to each other, a spin-dependent non-conjugate coupled phase is introduced. The coupled phase is non-conjugate symmetric and exhibits uncorrelated phase changes for left-handed and right-handed circularly polarized light.

[0046] In traditional thinking, the presence of coupling phase is generally considered detrimental. In weakly coupled systems, such as those with C2 (double symmetry), metasurface devices are designed with unit structures assumed to be independent. The structures are selected and arranged from a pre-constructed library of metaatoms based on the target phase distribution, and this library is typically built upon periodic boundary conditions. However, in practical applications, except for periodic devices like deflectors, these periodic boundary conditions are often broken, and the coupling between unit structures can affect device performance. To overcome the impact of coupling phase on device performance, various inverse optimization algorithms (such as topology optimization, boundary optimization, and machine learning) have been developed to improve performance. However, on-demand control of the coupling phase remains unrealized.

[0047] Based on this, this application proposes an optical field modulation method and a photonic device. The optical field modulation method is based on a diatomic structure with high-order rotational symmetry. It proposes a method to realize asymmetric SOIs by relying only on rotational degrees of freedom. It makes reasonable use of the coupling phase, which is considered unfavorable in the traditional view, and can control the coupling phase on demand.

[0048] Please refer to Figure 1 , Figure 1 A flowchart illustrating the optical field modulation method provided in this application embodiment; this application provides an optical field modulation method. The optical field modulation method includes the following steps:

[0049] Step S100: Based on the target modulation phase of the superatoms in the dual-atom optical device building block, determine the target common rotation angle and target relative rotation angle of the superatoms.

[0050] In step S100 above, the target common rotation angle and target relative rotation angle of the superatoms are determined based on the target modulation phase of the superatoms in the diatomic optical device building block. For example, during the construction of a metasurface, the target common rotation angle and target relative rotation angle of the superatoms are determined based on the target modulation phase of the superatoms in the metasurface building block that is to be controlled.

[0051] It should be noted that metasurface building blocks refer to the basic unit structures that make up a metasurface, which may be "supramatomic" or "multiatomic supramolecular". Metasurface building blocks are usually subwavelength-scale micro / nano structures, such as nanopillars, nanopores, and nanorings, and their shape, size, material, and arrangement can be adjusted according to design requirements. Each building block can independently control the amplitude, phase, polarization, and other characteristics of incident light. By arranging these building blocks according to specific rules, a metasurface with specific optical functions can be formed.

[0052] It should be noted that the two superatoms rotate around their respective central axes. If the two superatoms rotate by the same degree around their central axes... This is the common rotation angle. If two superatoms rotate around their central axes by angles θ1 and θ2 respectively, then the relative rotation angle is θ1 - θ2.

[0053] Step S200: Determine the angular distribution of the superatoms based on the target common rotation angle and the target relative rotation angle, so as to realize the target light field modulation of the optical device built based on the dual-atom optical device building block.

[0054] In step S200 above, based on the determined target common rotation angle and target relative angle, the angular distribution of the two superatoms is further determined, and the angular distribution of the two superatoms is controlled to modulate the phase of the metasurface building block to the target modulation phase, thereby realizing on-demand phase modulation.

[0055] pass Figure 1 As can be seen, the optical field modulation method provided in this application determines the target common rotation angle and target relative rotation angle of the superatoms, thereby determining the angular distribution of the superatoms and ultimately achieving target modulation phase. By changing the relative rotation angle of the two superatoms, a spin-non-conjugated coupling phase is introduced; by changing the common rotation angle of the two superatoms, a spin-conjugated generalized higher-order geometric phase is introduced; asymmetric SOIs can be realized using only rotational degrees of freedom, breaking the traditional view that rotation can only introduce spin-conjugated geometric phases, enriching the mechanism of optical field manipulation, and providing a new theoretical basis for the design of optical devices.

[0056] Please refer to Figure 2 , Figure 2A flowchart for determining the rotation angle provided in this application embodiment; in an optional embodiment of this application, the determination of the target common rotation angle and target relative rotation angle of the superatoms based on the target modulation phase of the superatoms in the dual-atom optical device building block in step S100 above can be achieved through the following steps:

[0057] Step S110: Determine the higher-order geometric phase component and the coupling phase component in the target modulation phase.

[0058] In step S110 above, changing the relative rotation angle of the two superatoms can introduce a spin-non-conjugated coupling phase; changing the common rotation angle of the two superatoms can introduce a spin-conjugated higher-order geometric phase. Therefore, it is necessary to determine the higher-order geometric phase component and the coupling phase component in the target modulation phase.

[0059] In other words, during phase modulation, the goal is to modulate the phase to the target modulation phase φ. σ Two components need to be determined, one of which is the coupling phase φ introduced by the relative rotation angle. coupling Another component is the higher-order geometric phase φ introduced by the common rotation angle. PB That is, φ σ =φ coupling +φ PB .

[0060] Step S120: Based on orthogonally circularly polarized light waves, determine the target common rotation angle and the target relative rotation angle in the relationship between the target modulation phase, including the higher-order geometric phase component and the coupled phase component.

[0061] In step S120 above, orthogonally circularly polarized light (left-handed circularly polarized light LCP and right-handed circularly polarized light RCP) is incident on the device, and the equation (i.e., φ) is solved. σ =φ coupling +φ PB The geometric phase component and the coupled phase component are solved separately, and the target common rotation angle and the target relative rotation angle are further determined.

[0062] The relationship between the target modulation phase, including the higher-order geometric phase component and the coupled phase component, is as follows: φ σ =φ PB +φ coupling Among them, φ σ For the target modulation phase, φ PB For higher-order geometric phase components, φ coupling The coupling phase component; a value of σ of 1 indicates that the incident light is a left-handed circularly polarized light wave, and a value of -1 indicates that the incident light is a right-handed circularly polarized light wave.

[0063] In the above implementation process, orthogonally circularly polarized light (LCP and RCP) is used to solve for the higher-order geometric phase components and coupled phase components because the phase response characteristics of LCP and RCP light can clearly separate the geometric phase and coupled phase. By simulating the phase distribution of LCP and RCP light and combining it with a mathematical model, the geometric phase and coupled phase of the target modulation phase can be extracted efficiently.

[0064] pass Figure 2 As can be seen, the optical field modulation method provided in this application uses an orthogonally circularly polarized light incident device to determine the higher-order geometric phase component and the coupled phase component in order to obtain the magnitude of the target common rotation angle and the target relative rotation angle. By simulating the phase distribution of LCP and RCP light and combining it with a mathematical model, each component of the target modulation phase can be efficiently extracted, thereby providing a precise phase control means for metasurface design.

[0065] In an alternative embodiment, please refer to... Figures 3 to 5 , Figure 3 A schematic diagram of a triple-symmetric superatomic structure provided in the embodiments of this application; Figure 4 A three-dimensional schematic diagram of a triple-symmetric superatomic structure provided in the embodiments of this application; Figure 5 A schematic diagram of a five-fold symmetry superatomic structure provided in an embodiment of this application; exemplarily, Figure 3 and Figure 4 The rotation angles of the two superatoms are respectively and Among them, the higher-order geometric phase components k is related to the order of rotational symmetry of the superatom. Let be the target common rotation angle. For rotation angle dependent The higher-order geometric phase of spin-conjugate symmetry can be altered by changing the common rotation angle of the two superatoms. For C3 or C5 superatoms, k = 6 or -10.

[0066] Since the geometric phase depends not only on the symmetry of the superatom but also on the symmetry of the crystal lattice, for superatoms with rotational symmetry ≥ 3, a higher-order geometric phase as described above can be induced when the symmetries of the superatom and the crystal lattice are mismatched. For example, for a C3 (triple symmetry) superatom in a tetragonal lattice, the higher-order geometric phase of its induced band is... For a C5 (five-fold symmetry) superatom in a tetragonal lattice, its induced higher-order geometric phase is:

[0067] Similarly, in the case of a dual-lattice structure, for a C3 (triple symmetry) superatom in a tetragonal lattice, the higher-order geometric phase of its induced band is: For a C5 (five-fold symmetry) superatom in a tetragonal lattice, its induced higher-order geometric phase is:

[0068] It should be noted that the optical field modulation method provided in this application embodiment can be used not only for the triplet and quintet symmetry superatomic structures in the above examples, but also for other higher-order symmetry superatomic structures, whose higher-order geometric phase is related to the order of its symmetry.

[0069] Therefore, the optical field modulation method provided in this application, by designing superatoms with high-order rotational symmetry (such as C3, C5) and embedding them into mismatched lattices (such as tetragonal lattices), can induce high-order geometric phases (such as... or The generation of higher-order geometric phases significantly enhances the degree of freedom in optical field modulation, providing a foundation for realizing more complex phase distributions and optical functions.

[0070] In an alternative embodiment, the coupled phase components are... δ is the relative rotation angle of the target. For phase terms that include transmission phase and coupling phase, This refers to the transmission phase term.

[0071] Changing the rotation angle introduces not only the higher-order geometric phase mentioned above, but also other phases. For spin-non-conjugated phase terms... Define the phase induced by rotation as the coupling phase, i.e. Therefore, the coupling phase can be controlled by changing the relative rotation angle δ between the two superatoms.

[0072] In the above implementation process, δ is the target relative rotation angle, representing the difference in rotation angle between adjacent superatoms; It is the total phase term that includes the transport phase and the coupling phase, where the transport phase is related to the geometry and material of the superatom, while the coupling phase is the phase induced by rotation; This is a term containing only the transport phase, representing the phase response when there is no relative rotation angle (i.e., δ = 0). Thus, the coupled phase component can be separated from other phase contributions caused by interactions between superatoms.

[0073] In traditional weakly coupled systems, such as C2, it is usually assumed that nanostructures are independent of each other and the coupling between structures is ignored. In this case, the metasurface building block is described as an ideal linear birefringent waveplate, and the transmission coefficient in its Jones matrix is ​​considered constant. Therefore, the rotation of the structure only introduces a spin-conjugated geometric phase.

[0074] However, in strongly coupled systems with structures possessing high-order rotational symmetry, the optical field modulation method provided in this application re-examines the effect of structure-lattice coupling on the transmission coefficient. The influence of this study was investigated, and its dependence on the structural rotation angle was revealed.

[0075] For the C3 superatomic dual-lattice structure, its Jones matrix Where R(θ) represents the rotation matrix, To and The effective principal spindle rotation angle related to δ, and the transmission coefficient Also depends on With δ.

[0076] Therefore, in circularly polarized light Under illumination, the expression for its output orthogonally polarized light should be:

[0077]

[0078] in, σ = ±1 represents the circular polarization state of the incident light. A value of 1 indicates that the incident light is a left-handed circularly polarized light wave, and a value of -1 indicates that the incident light is a right-handed circularly polarized light wave.

[0079] Furthermore, by adjusting the rotation angles of the two superatoms, the phase modulation of the orthogonally circularly polarized light generated under left- and right-hand circularly polarized light illumination is as follows:

[0080]

[0081] In photonic device design, the target modulation phase distribution φ can be calculated using the above equation (2). σ Required rotation angle And coupling phase, thereby determining the angular distribution of superatoms.

[0082] Therefore, the optical field modulation method provided in this application combines the coupling phase, which is traditionally considered a disadvantage, with the higher-order geometric phase, and realizes asymmetric SOIs that rely solely on rotational degrees of freedom; it breaks through the traditional understanding that rotation can only introduce spin conjugated geometric phases, and provides new degrees of freedom for optical field manipulation.

[0083] In an optional embodiment, the range of the target common rotation angle is: The range of the target's relative rotation angle is Where m is the order of rotational symmetry of the superatom.

[0084] In the above implementation process, for superatomic structures with rotational symmetry of different orders, the range of their target common rotation angle and the range of their target relative rotation angle are related to the order of their symmetry. For example, for the C3 superatomic structure, the range of its target relative rotation angle is... The range of its target common rotation angle is For example, for the C5 superatomic structure, the range of its target relative rotation angle is: The range of its target common rotation angle is

[0085] Therefore, by associating the range of the target common rotation angle and the target relative rotation angle with the rotational symmetry order of the superatom, this embodiment can more accurately and reasonably control the higher-order geometric phase and coupling phase, thereby achieving flexible modulation of the light field.

[0086] Please refer to Figure 6 , Figure 6 The common rotation angle of the C3 structure provided in this application embodiment is Simulation results of amplitude at different relative rotation angles δ; Figure 6 (a) shows the amplitude simulation results obtained based on CST software. Figure 6 (b) shows the amplitude calculation results obtained using Matlab software based on the traditional diatomic interference theory. It can be seen that, thanks to the significant structure-lattice coupling effect in the high-order rotationally symmetric structure, the optical field modulation method proposed in this application can achieve enhanced efficiency anomalous interference.

[0087] Without loss of generality, this embodiment uses a Y-shaped nanopillar with C3 symmetry in the long-wave infrared band as an example for illustration, with gold as the structural material. Electromagnetic simulation software was used to simulate and optimize the structure in the 9-12 μm band. The optimized unit structure parameters are: Px = 16 μm, Py = 8 μm, W = 1.4 μm, L = 3.6 μm, and H = 8.2 μm.

[0088] Please refer to the following: Figure 7 and Figure 8 , Figure 7 The simulation results of the coupling phase when two orthogonally circularly polarized lights are incident, provided in the embodiments of this application; Figure 8 The high-order geometric phase simulation results provided in the embodiments of this application for the incidence of two orthogonally circularly polarized lights; Figure 7 (a) shows the simulation results of the coupling phase when LCP light is incident. Figure 7 (b) shows the simulation results of the coupling phase when RCP light is incident; Figure 8 (a) shows the simulation results of the higher-order geometric phase when LCP light is incident. Figure 8 (b) shows the simulation results of the higher-order geometric phase when RCP light is incident. Figure 7 and Figure 8 It can be seen that the coupled phase exhibits spin non-conjugation characteristics, and the common rotation angle between the higher-order geometric phase and the structure... It exhibits a linear relationship and satisfies

[0089] Please refer to Figure 9 , Figure 9 This is a top view schematic diagram of the deflector provided in the embodiments of this application; to verify the feasibility of the proposed asymmetric SOIs design method, a spin-decoupled beam deflector was designed and fabricated, whose diatomic constituent units are as follows: Figure 9 As shown, each cycle consists of 12 supramolecular molecules. Figure 8 (Medium gray dashed box).

[0090] The phases applied to LCP or RCP light by two adjacent columns of supramolecular light are respectively and The angular distribution of the required constituent units is shown in Table 1. Please refer to Table 1 for details. Figure 10 , Figure 10 The phase distribution corresponding to the two-atom constituent units of the deflector provided in the embodiments of this application; the corresponding phase distribution is shown in Figure 10 It can be seen that when a certain phase is applied to LCP or RCP light at different rotation angles, the phase distribution is asymmetric.

[0091] Table 1

[0092]

[0093] Please refer to Figure 11 , Figure 11 Simulation and experimental test results of the beam deflector provided in the embodiments of this application; Figure 11 In the middle (a), the simulation results of the far-field intensity distribution of the orthogonally polarized components in the reflected light are obtained when light with different circular polarizations is incident at a wavelength of 10.6 μm. Figure 11 (b) shows the simulation and experimentally measured diffraction efficiencies for different target diffraction orders.

[0094] According to the generalized Snell's law, the theoretical deflection angle of the corresponding orthogonally polarized light is: and Figure 11 Figure (a) shows the normalized far-field intensity distribution of the deflector at a wavelength of 10.6 μm when LCP and RCP light are incident. It can be observed that the energy is mainly concentrated at the -1st and +2nd orders of the target diffraction, with far-field deflection angles of 3.2° and 6.3°, respectively, which is consistent with the theoretical calculation results.

[0095] It is worth noting that within the wavelength range of 9.7–10.4 μm, the average diffraction efficiency of the deflector exceeds 60%, such as… Figure 11 As shown in (b). Figure 11 The dots in (b) indicate the experimentally measured diffraction efficiencies of the target orders, with an average diffraction efficiency of approximately 58% at 9.6 μm. Here, diffraction efficiency is defined as the ratio of the optical power of the -1st or +2nd order to the reflected optical power.

[0096] Please refer to Figure 12 , Figure 12 The diffraction patterns of samples irradiated with circularly polarized lasers of different wavelengths provided in the embodiments of this application; such as Figure 12 The diagram shows diffraction images recorded by a CCD when a sample is irradiated with circularly polarized lasers of different wavelengths. The -1st, 0th, and +2nd orders represent the orders of the diffracted light, with the 0th order being the directly reflected light, and the -1st and +2nd orders being different orders of the diffracted light. In this embodiment, the orthogonally polarized RCP and LCP light from the sample is diffracted to the -1st and +2nd orders, respectively. The simulation and experimental results verified the existence of the coupled phase and demonstrated the feasibility of realizing asymmetric SOIs using only rotational degrees of freedom, as proposed in this embodiment.

[0097] Please continue reading. Figures 3 to 5 This application provides a photonic device comprising multiple diatomic optical device building blocks. The photonic device is constructed from these multiple diatomic optical device building blocks; wherein the angular distribution of the superatoms within the diatomic optical device building blocks is determined according to the aforementioned light field modulation method.

[0098] In an alternative embodiment, the superatoms in the diatomic optical device building blocks possess higher-order rotational symmetry. Please refer to [link to previous document]. Figure 3 , Figure 4 and Figure 5 , Figure 3 and Figure 4 The image shows a superatomic structure with triple symmetry; Figure 5 The diagram shows a superatomic structure with fivefold symmetry.

[0099] In an optional embodiment, the superatomic building blocks have a lattice period of P in the x-direction. x The lattice period in the y-direction is P. y Among them, P x =2P y And P y <λ, where λ is the center wavelength.

[0100] Please refer to the following: Figure 3 and Figure 4 Taking a triple-symmetric superatomic structure as an example, such as Figure 4As shown, the superatomic building block comprises two identical superatoms 1 with controllable rotation angles and a substrate 2. This triple-symmetric superatomic structure has a height of H, a linewidth of W, an arm length of L, a lattice period of Px in the x-direction, and a lattice period of Py in the y-direction. The lattice periods in the x and y directions are related to the central wavelength.

[0101] It should be noted that the light field modulation method provided in this application embodiment is universal and applicable to the mid-infrared band, visible light band, etc.

[0102] In an alternative embodiment, the material of the diatomic optical device building block includes metals or dielectrics, such as gold, silver, silicon, etc.

[0103] Therefore, the optical device provided in this application introduces a spin-non-conjugated coupling phase by changing the relative rotation angle δ of the two superatoms; and changes the common rotation angle of the two superatoms. Introducing a higher-order geometric phase of spin conjugation. Asymmetric photon spin-orbit interaction can be achieved using only rotational degrees of freedom, breaking the traditional understanding that rotation can only introduce geometric phases of spin conjugation. This has wide applications in polarization-switchable devices, dynamic control systems, and other fields.

[0104] In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, without necessarily requiring or implying any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0105] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for optical field modulation, characterized in that, The optical field modulation method includes: Based on the target modulation phase of the superatoms in the dual-atom optical device building block, the target common rotation angle and target relative rotation angle of the superatoms are determined. Based on the target common rotation angle and the target relative rotation angle, the angular distribution of the superatoms is determined to achieve target light field modulation of the optical device constructed based on the dual-atom optical device building blocks; The method for determining the target common rotation angle and target relative rotation angle of the superatoms in the superatoms based on the target modulation phase of the dual-atom optical device building block includes: determining the higher-order geometric phase component and the coupled phase component in the target modulation phase; and determining the target common rotation angle and target relative rotation angle in the relationship between the target modulation phase including the higher-order geometric phase component and the coupled phase component based on orthogonally circularly polarized light waves. The relationship between the target modulation phase, including the higher-order geometric phase component and the coupled phase component, is as follows: ;in, The target is modulated phase. The higher-order geometric phase component, The coupled phase component; a value of σ of 1 indicates that the incident light is a left-handed circularly polarized light wave, and a value of -1 indicates that the incident light is a right-handed circularly polarized light wave; Among them, the higher-order geometric phase components = k is related to the order of rotational symmetry of the superatom. Let be the target common rotation angle.

2. The method according to claim 1, characterized in that, in, The coupling phase component = , The relative rotation angle of the target. For phase terms that include transmission phase and coupling phase, This refers to the transmission phase term.

3. The method according to any one of claims 1-2, characterized in that, The range of the target common rotation angle is [ , The range of the target's relative rotation angle is []. , ]; where m is the order of rotational symmetry of the superatom.

4. A photonic device, characterized in that, The photonic device includes: multiple diatomic optical device building blocks; The photonic device is constructed from the plurality of diatomic optical building blocks; wherein the angular distribution of the superatoms in the diatomic optical building blocks is determined according to the light field modulation method as described in any one of claims 1-3.

5. The photonic device according to claim 4, characterized in that, The superatoms in the building blocks of the diatomic optical device have high-order rotational symmetry.

6. The photonic device according to claim 4, characterized in that, The superatom building blocks have a lattice period P in the x direction x , and a lattice period P in the y direction y ; where P x = 2P y , and P y < λ, λ being the central wavelength.

7. The photonic device according to claim 4, characterized in that, The building blocks of the diatomic optical devices are made of materials including metals or dielectrics.

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