Broadband spin splitting light field generation method and device based on magneto-optical superatom and dipole source, program and storage medium

Abstract

The invention discloses a broadband spin splitting light field generation method and device based on magneto-optical super atoms and a dipole source, a program and a storage medium, and belongs to the field of micro-nano photonics. The method comprises the following steps: establishing a space rectangular coordinate system; a dipole source is used for exciting magneto-optical super atoms in a wide frequency band to generate an electric dipole moment and a magnetic dipole moment; when the magnetic dipole moment meets the spin splitting condition, an equivalent circular polarization spin dipole source is formed, and a spin splitting light field with left-handed and right-handed circularly polarized light space reverse separation is generated in a far field through spin locking scattering; and the stability in the broadband is verified through normalized Stokes parameters. The limitation that spin splitting can only be achieved at a single frequency point in a traditional scheme is overcome, a stable and pure spin splitting light field in a wide frequency band is achieved through a simple structure, and the device has the advantages of being wide in frequency band and easy to integrate and can be applied to the fields of nanometer optical sensing, polarization precision measurement, spin-dependent photonic devices and the like.

Description

Technical Field

[0001] This invention relates to the field of micro-nano photonics technology, and in particular to a method, apparatus, program, and storage medium for generating a broadband spin-splitting optical field based on magneto-optical superatoms and dipole sources. Background Technology

[0002] The photonic spin Hall effect is a fundamental optical phenomenon originating from the spin-orbit coupling of light, characterized by the spatial separation of light with opposite chirality (left-handed and right-handed circular polarization). This effect can be used to achieve spin-splitting scattering, where oppositely chiral polarized light is distributed in opposite spatial directions within the scattered light field. Due to its significant application prospects in nanoscale optical sensing, precision polarization measurement, and spin-dependent photonic devices, the generation and control of spin-splitting light fields have received considerable attention in recent years. However, the photonic spin Hall effect in traditional systems is typically extremely weak, making it difficult to generate significant spin splitting. Superatoms, through electromagnetic design of subwavelength structures, can greatly enhance the interaction between light and matter, thereby achieving efficient and controllable spin-splitting light fields. Most existing techniques rely on polarized light for excitation and typically achieve spin splitting only near a single discrete frequency point, severely limiting their flexibility in multi-wavelength operation, dynamic tuning, and integrated applications. Summary of the Invention

[0003] The purpose of this invention is to provide a method, apparatus, program, and storage medium for generating a broadband spin-splitting optical field based on magneto-optical superatoms and dipole sources, and to achieve this effect over a wide frequency band.

[0004] This invention proposes a method, apparatus, program, and storage medium for generating a broadband spin-splitting optical field based on magneto-optical superatoms and dipole sources. The core technical solutions include the following:

[0005] A broadband spin-splitting optical field generation method based on magneto-optical superatoms and dipole sources includes the following steps:

[0006] Step 1: Using the perpendicular line from the centroid of the cross-section of the magneto-optical superatomic structure as... A spatial rectangular coordinate system is established using the axis; the type of dipole source is determined, and the dipole source is used to excite the magneto-optical superatoms in a wide frequency band, generating electric dipole moments and magnetic dipole moments inside them.

[0007] Step 2: Determine whether the electric dipole moment and magnetic dipole moment satisfy the spin splitting condition; if yes, proceed to the next step; otherwise, return to step 1.

[0008] Step 3: Based on the dipole moment that satisfies the spin splitting condition, form an equivalent circularly polarized spin dipole source.

[0009] Step 4: The equivalent circularly polarized spin dipole source induces spin-locked scattering, generating a scattering electric field in the far-field region, which in turn generates a spin-splitting light field in which left-handed and right-handed circularly polarized light are spatially separated in opposite directions.

[0010] Step 5: Calculate the Stokes polarization parameters based on the scattered electric field generated in the far-field region.

[0011] Step 6: Normalize the Stokes polarization parameters, and determine whether the spin-splitting optical field is stably generated in a wide bandwidth based on the changes of the normalized Stokes parameters with frequency and angle; if so, complete the generation of the wideband spin-splitting optical field; otherwise, return to step 1 and regenerate the dipole moment.

[0012] Furthermore, the type of dipole source mentioned in step 1 specifically includes an electric dipole source or a magnetic dipole source.

[0013] If the dipole source type is an electric dipole source, then its along Axial polarization and excitation shaft and The electric dipole moment and magnetic dipole moment of the shaft.

[0014] If the dipole source type is a magnetic dipole source, then its along Axial polarization and excitation shaft and The electric dipole moment and magnetic dipole moment of the shaft.

[0015] Furthermore, the spin splitting conditions described in step 2 specifically include:

[0016] The amplitudes of the magnetic dipole moments are equal: .

[0017] The phase difference of the magnetic dipole moments is : .

[0018] The intensity of the electric dipole moment is much smaller than that of the magnetic dipole moment, and it has no effect on the generation of the light field.

[0019] in, For magnetic dipole moment along Components of the axis, For magnetic dipole moment along The components of the axis.

[0020] Furthermore, the far-field scattered electric field described in step 4 Specifically, it includes:

[0021]

[0022]

[0023]

[0024] in, For the pitch component of the far-field scattered electric field, For the azimuth component of the far-field scattered electric field, For free space wavenumber, Where is the dielectric constant. The distance from the observation point to the source point. The imaginary unit, is the base of the natural logarithm. For relative to The pitch angle of the axis, for shaft and Azimuth angle in the axial plane The magnetic dipole moments are respectively in axis, shaft and Components in the axial direction, The electric dipole moments are respectively in axis, shaft and The component along the axial direction.

[0025] Furthermore, the method for calculating the Stokes polarization parameter in step 5 specifically includes:

[0026]

[0027]

[0028] in, For the complex conjugate of the pitch component of the far-field scattered electric field, It is the complex conjugate of the azimuth component of the far-field scattered electric field.

[0029] A magneto-optical superatomic structure based on the above method includes a magnetic layer and a magneto-optical material layer; the magnetic layer and the magneto-optical material disk are stacked and connected vertically along the same axis to apply an external magnetic field to excite magnetic anisotropy in the magneto-optical superatomic structure.

[0030] A computer device includes a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the method described above.

[0031] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method.

[0032] A computer program product includes computer instructions that, when executed by a processor, implement the steps of the method described above.

[0033] The beneficial effects of this invention are as follows: Addressing the problem that existing adaptive multi-beamforming methods struggle to effectively beamform multiple signals with unknown directions and frequencies of arrival simultaneously in low signal-to-noise ratio (SNR) environments, thus hindering blind reception and blind source separation, this invention proposes a blind reception adaptive multi-beamforming method based on a combination of CNN and LSTM. This method can simultaneously perform multi-beamforming on multiple signals with unknown directions and frequencies of arrival in low SNR environments. Utilizing a CNN-LSTM model, it dynamically adjusts the attention weights of different levels on spatial features (inter-element correlation) and temporal features (signal timing), obtaining the differences in physical characteristics and temporal correlations of signals within different output channels, and using this to estimate the desired beamformed signal. This achieves efficient and accurate blind reception adaptive multi-beamforming. Finally, the beamformed signal is matched to channels with corresponding angular coverage ranges according to different incident angles. This design not only effectively addresses the inter-channel energy leakage problem present in traditional methods but also significantly improves the performance of beamforming technology when the direction and frequency of the incident signal are unknown. The network model takes as input the preprocessed signals received by each element in the array, and outputs the desired signal after network processing. This not only improves the accuracy of multibeamforming technology but also significantly increases its speed and real-time performance, providing a new method for the application of multibeamforming technology and blind source separation tasks. Attached Figure Description

[0034] Figure 1 This is a schematic diagram illustrating the spin-splitting optical field excited by different types of dipole sources according to the present invention.

[0035] Figure 2 This is a schematic diagram of the magneto-optical superatomic structure of the present invention.

[0036] Figure 3 This is a normalized Stokes parameter distribution diagram of the far field of magneto-optical superatomic radiation in an embodiment of the present invention.

[0037] Figure 4 The normalized Stokes parameter at the corresponding cross section (shown by the purple dashed line) in this embodiment of the invention varies with... The relationship between the angle and the frequency of the dipole.

[0038] Figure 5 The figures show the amplitude and phase diagrams of dipoles inside the magneto-optical superatom at different frequencies and when excited by different types of dipole sources in the embodiments of the present invention. Detailed Implementation

[0039] The following is combined Figure 1 and Figure 2 The present invention will be further described below.

[0040] refer to Figure 2 A magneto-optical superatomic structure includes a magnetic layer and a magneto-optical material layer; the magnetic layer and the magneto-optical material disk are stacked and connected vertically along the same axis to apply an external magnetic field to excite magnetic anisotropy in the magneto-optical superatomic structure.

[0041] A broadband spin-splitting optical field generation method based on magneto-optical superatoms and dipole sources includes the following steps:

[0042] Step 1: Using the perpendicular line from the centroid of the cross-section of the magneto-optical superatomic structure as... A spatial rectangular coordinate system is established; the type of dipole source is determined, and the dipole source is used to excite the magneto-optical superatoms in a wide frequency band, generating electric dipole moments and magnetic dipole moments inside them.

[0043] refer to Figure 1 The dipole source specifically includes an electric dipole source or a magnetic dipole source;

[0044] If the dipole source type is an electric dipole source, then its along Axial polarization and excitation shaft and The electric dipole moment and magnetic dipole moment of the shaft;

[0045] If the dipole source type is a magnetic dipole source, then its along Axial polarization and excitation shaft and The electric dipole moment and magnetic dipole moment of the shaft.

[0046] Step 2: Determine whether the electric dipole moment and magnetic dipole moment satisfy the spin splitting condition; if yes, proceed to the next step; otherwise, return to step 1.

[0047] The spin splitting conditions specifically include:

[0048] The amplitudes of the magnetic dipole moments are equal: ;

[0049] The phase difference of the magnetic dipole moments is : ;

[0050] The intensity of the electric dipole moment is much smaller than that of the magnetic dipole moment, and it has no effect on the generation of the optical field;

[0051] in, For magnetic dipole moment along Components of the axis, For magnetic dipole moment along The components of the axis.

[0052] Step 3: Based on the dipole moment that satisfies the spin splitting condition, form an equivalent circularly polarized spin dipole source.

[0053] Step 4: The equivalent circularly polarized spin dipole source induces spin-locked scattering, generating a scattering electric field in the far-field region, which in turn generates a spin-splitting light field in which left-handed and right-handed circularly polarized light are spatially separated in opposite directions.

[0054] The far-field scattered electric field Specifically, it includes:

[0055]

[0056]

[0057]

[0058] in, For the pitch component of the far-field scattered electric field, For the azimuth component of the far-field scattered electric field, For free space wavenumber, Where is the dielectric constant. The distance from the observation point to the source point. The imaginary unit, is the base of the natural logarithm. For relative to The pitch angle of the axis, for shaft and Azimuth angle in the axial plane The magnetic dipole moments are respectively in axis, shaft and Components in the axial direction, The electric dipole moments are respectively in axis, shaft and The component along the axial direction.

[0059] Step 5: Calculate the Stokes polarization parameters based on the scattered electric field generated in the far-field region.

[0060] The method for calculating the Stokes polarization parameter specifically includes:

[0061]

[0062]

[0063] in, For the complex conjugate of the pitch component of the far-field scattered electric field, It is the complex conjugate of the azimuth component of the far-field scattered electric field.

[0064] Step 6: Normalize the Stokes polarization parameters, and determine whether the spin-splitting optical field is stably generated in a wide bandwidth based on the changes of the normalized Stokes parameters with frequency and angle; if so, complete the generation of the wideband spin-splitting optical field; otherwise, return to step 1 and regenerate the dipole moment.

[0065] Example

[0066] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0067] This embodiment specifically employs a combination of magneto-optical superatoms and dipole sources (including electric dipole sources and magnetic dipole sources) in a wide bandwidth ( The innovative aspect of generating a spin-splitting light field lies in its use of a simple double-layer magnet to excite the light field, unlike previous methods that achieved spin splitting at a single frequency point. The magnetic anisotropy of the material can be combined with a dipole source with a wide excitation frequency to generate a spin-splitting optical field.

[0068] refer to Figure 1 When the electric dipole When placed at the high center of the magneto-optical superatomic cylinder, a perfect spin splitting phenomenon appears in the far field of scattering.

[0069] refer to Figure 2 The magneto-optical superatomic structure consists of three cylindrical layers: the top and bottom layers are both made of magnetic material, with a thickness of [missing information]. ,diameter The middle layer is a magneto-optical material. Thickness is The diameter is the same as the upper and lower layers. ).

[0070] It is a cubic crystal with intrinsic isotropic properties. However, when an external magnetic field is applied, due to its magneto-optical properties, It will exhibit magnetic anisotropy.

[0071] In order to stimulate The magnetic anisotropy of the material is addressed by employing a double-layer magnet on the upper and lower layers to support the middle layer. Symmetrical clamping is employed. It should be noted that a single-layer magnet structure can also be used, placing it solely within... Asymmetric excitation is performed on the upper or lower side of the layer, at which point the magneto-optical superatom adjusts to a bilayer composite configuration accordingly. The magnet is in Microwave frequencies have electromagnetic response characteristics equivalent to those of an ideal electrical conductor. The materials used can be selected from magnetic metals including iron, cobalt, nickel and their alloys, or other magnetic materials that can achieve similar electromagnetic responses in this frequency band.

[0072] Electric field scattered in the far field region It can be decomposed into three mutually orthogonal components: , and Here Relative to The pitch angle of the axis, Then it means Azimuth angle in a plane. Electric field components in spherical coordinates. and The expression is as follows:

[0073]

[0074]

[0075] Stokes polarization parameters The intensity of the scattered electric field is characterized by the following expression:

[0076]

[0077] Stokes polarization parameters The intensity difference characterizing right-handed and left-handed circularly polarized light is defined as:

[0078]

[0079] Normalized Stokes polarization parameter Values These correspond to right-handed and left-handed circular polarization states, respectively, while a value of 0 corresponds to a linear polarization state. Combining this with the formula, we can derive:

[0080]

[0081] Therefore, when When, corresponding plane (i.e.) , The linear polarization state within ) and. Values When, they correspond to the following expressions respectively:

[0082]

[0083]

[0084] This indicates that when and Equal amplitude and phase difference At that time, in normalization In the spherical representation of the parameter distribution, the corresponding centers of the upper and lower hemispheres can realize completely right-handed and completely left-handed circularly polarized electric fields, respectively. In the scattered field, polarized light of opposite chirality separates, with right-handed and left-handed circularly polarized light distributed in opposite directions.

[0085] Reference state 3 is the normalized far-field of the scattered data. The parameter distribution diagram shows that the structure design, combined with the dipole source, can effectively generate perfect spin splitting scattering.

[0086] refer to Figure 4 Normalization at the corresponding cross section (shown by the dashed line) Parameter age The relationship between the angle and the dipole frequency shows that a perfect spin-splitting light field can be effectively generated.

[0087] refer to Figure 5 By analyzing the relationship between the electric and magnetic dipole moments of the magneto-optical superatom at different excitation frequencies, it was theoretically verified that this structure, whether combined with an electric dipole source or a magnetic dipole source, can excite spin-splitting behavior over a wide bandwidth. The conditional dipole mode generates a highly pure spin-splitting light field.

[0088] refer to Figure 5 Amplitude diagrams of intrapoles within the magneto-optical superatom when excited by electric and magnetic dipole sources respectively; it can be seen that the main excited component is the magnetic dipole, and in The frequency range always has and The amplitudes are equal.

[0089] refer to Figure 5 Phase relationship diagrams of dipoles within a magneto-optical superatom when excited by electric and magnetic dipoles respectively; it can be seen that the magnetic dipoles are the main excited ones, and in The frequency range always has and Phase difference is .

[0090] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for generating a broadband spin-splitting optical field based on magneto-optical superatoms and dipole sources, characterized in that, Includes the following steps: Step 1: Using the perpendicular line from the centroid of the cross-section of the magneto-optical superatomic structure as... Establish a spatial rectangular coordinate system; determine the type of dipole source, and use the dipole source to excite the magneto-optical superatoms in a wide bandwidth to generate electric dipole moments and magnetic dipole moments inside them; Step 2: Determine whether the electric dipole moment and magnetic dipole moment satisfy the spin splitting condition; if yes, proceed to the next step; otherwise, return to step 1. Step 3: Based on the dipole moment that satisfies the spin splitting condition, form an equivalent circularly polarized spin dipole source; Step 4: The equivalent circularly polarized spin dipole source induces spin-locked scattering, generating a scattering electric field in the far-field region, which in turn generates a spin-splitting light field in which left-handed and right-handed circularly polarized light are spatially separated in opposite directions. Step 5: Calculate the Stokes polarization parameters based on the scattered electric field generated in the far-field region; Step 6: Normalize the Stokes polarization parameters, and determine whether the spin-splitting optical field appears stably in a wide bandwidth based on the changes of the normalized Stokes parameters with frequency and angle; if so, complete the generation of the wideband spin-splitting optical field; otherwise, return to step 1 and regenerate the dipole moment.

2. The broadband spin-splitting optical field generation method based on magneto-optical superatoms and dipole sources according to claim 1, characterized in that: The dipole source mentioned in step 1 specifically includes an electric dipole source or a magnetic dipole source; If the dipole source type is an electric dipole source, then its along Axial polarization and excitation shaft and The electric dipole moment and magnetic dipole moment of the shaft; If the dipole source type is a magnetic dipole source, then its along Axial polarization and excitation shaft and The electric dipole moment and magnetic dipole moment of the shaft.

3. The broadband spin-splitting optical field generation method based on magneto-optical superatoms and dipole sources according to claim 2, characterized in that, The spin splitting conditions described in step 2 specifically include: The amplitudes of the magnetic dipole moments are equal: ; The phase difference of the magnetic dipole moments is : ; The intensity of the electric dipole moment is much smaller than that of the magnetic dipole moment, and it has no effect on the generation of the optical field; in, For magnetic dipole moment along Components of the axis, For magnetic dipole moment along The components of the axis.

4. The broadband spin-splitting optical field generation method based on magneto-optical superatoms and dipole sources according to claim 1, characterized in that, The far-field scattered electric field described in step 4 Specifically, it includes: in, For the pitch component of the far-field scattered electric field, For the azimuth component of the far-field scattered electric field, For free space wavenumber, Where is the dielectric constant. The distance from the observation point to the source point. The imaginary unit, is the base of the natural logarithm. For relative to The pitch angle of the axis, for shaft and Azimuth angle in the axial plane The magnetic dipole moments are respectively in axis, shaft and Components in the axial direction, The electric dipole moments are respectively in axis, shaft and The component along the axial direction.

5. The broadband spin-splitting optical field generation method based on magneto-optical superatoms and dipole sources according to claim 4, characterized in that, The method for calculating the Stokes polarization parameter in step 5 specifically includes: in, For the complex conjugate of the pitch component of the far-field scattered electric field, It is the complex conjugate of the azimuth component of the far-field scattered electric field.

6. A magneto-optical superatomic structure based on the method of any one of claims 1 to 5, characterized in that: It includes a magnetic layer and a magneto-optical material layer; the magnetic layer and the magneto-optical material disk are stacked and connected vertically along the same axis, and are used to apply an external magnetic field to excite magnetic anisotropy in the magneto-optical superatomic structure.

7. A computer device comprising a memory, a processor, and a computer program stored in the memory, characterized in that: The processor executes the computer program to implement the steps of the method according to any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When executed by a processor, the computer program implements the steps of the method according to any one of claims 1 to 5.

9. A computer program product comprising computer instructions, characterized in that: When executed by a processor, the computer instructions implement the steps of the method according to any one of claims 1 to 5.

Images