A dynamic light field regulation method based on ferroelectric topological domain structure and application thereof

Abstract

The application discloses a dynamic light field regulation method based on a ferroelectric topological domain structure, which comprises the following steps: selecting a ferroelectric topological domain structure formed in a ferroelectric thin film material as a light field regulation medium, wherein the ferroelectric topological domain structure has a spatially distributed dipole arrangement; linearly or nonlinearly converting an incident fundamental wave light field by using the ferroelectric topological domain structure to generate a vortex light field or a vector light field; and adjusting the domain distribution and the dipole arrangement of the ferroelectric topological domain structure in real time through a thermal field, an electric field or a pulsed light field driving mode, dynamically changing the phase, the amplitude and the polarization state of the vortex light field or the vector light field, and realizing real-time correlation response of the light field parameters and the topological domain structure. The method disclosed by the application utilizes the topological domain structure in the ferroelectric material, realizes multi-dimensional regulation of the light field through the rich dipole arrangement, and can be applied to the fields of high-integration photonic circuits and reconfigurable large-capacity optical communication.

Description

Technical Field

[0001] This invention belongs to the field of micro-nano photonics and ferroelectric materials technology, and relates to a dynamic optical field modulation method based on ferroelectric topological domain structure and its application. Background Technology

[0002] In recent years, subwavelength structures have shown great potential in enhancing the spin-orbit interaction of light due to their unique optical field localization and manipulation capabilities. By breaking the traditional optical diffraction limit, these structures can achieve multidimensional manipulation of the phase, amplitude, and polarization state of the optical field at the nanoscale, providing key technological support for high-capacity optical communication, super-resolution microscopy, and quantum information processing. For example, optical metasurfaces, through artificially designed subwavelength unit structures, can efficiently control the spin-orbit angular momentum conversion of light, generating vortex beams carrying orbital angular momentum, significantly improving the channel capacity of optical communication. However, existing metasurfaces rely on fixed geometric designs, lack dynamic reconfigurability, and their complex and costly fabrication processes limit their large-scale application. Summary of the Invention

[0003] Purpose of the invention: The purpose of this invention is to provide a dynamic optical field control method based on ferroelectric topological domain structure. By utilizing the topological domain structure in ferroelectric materials, this method achieves efficient multidimensional control of the optical field, overcoming the shortcomings of traditional optical field control methods in terms of dynamism and integration.

[0004] Technical Solution: The present invention provides a dynamic optical field modulation method based on ferroelectric topological domain structures, comprising: selecting a ferroelectric topological domain structure formed in a ferroelectric thin film material as an optical field modulation medium, wherein the ferroelectric topological domain structure has a spatially distributed dipole arrangement; using the ferroelectric topological domain structure to linearly or nonlinearly transform the incident fundamental wave's optical field to generate a vortex optical field or a vector optical field, and adjusting the domain distribution and dipole arrangement of the ferroelectric topological domain structure in real time through an external field driving method, dynamically changing the phase, amplitude, and polarization state of the vortex optical field or vector optical field, thereby realizing a real-time correlation response between the optical field parameters and the topological domain structure; the external field driving method includes driving methods using a thermal field, an electric field, or a pulsed optical field.

[0005] Furthermore, the incident fundamental wave includes circularly polarized Gaussian mode light.

[0006] Further, in step S1, the ferroelectric topological domain structure includes vortex domains, bubble domains, skyrmions, half-ions, and closed domains; the geometric configuration of the topological domain structure includes circular symmetric distribution, periodic gradient distribution, spiral symmetric distribution, or fractal network distribution; the spatial scale of the ferroelectric topological domain structure is 1 nm to 10 mm.

[0007] Further, in step S1, the ferroelectric material includes one or more of barium titanate, lead titanate, bismuth ferrite, lithium niobate, lead zirconate titanate, potassium niobate, or ferroelectric materials doped with rare earth elements.

[0008] Furthermore, the thickness of the ferroelectric thin film material ranges from 1 nm to 100 μm.

[0009] Furthermore, in step S2, the linear conversion includes optical field polarization and optical field spatial mode conversion; the nonlinear conversion includes polarization and optical field spatial mode conversion during second harmonic generation, third harmonic generation, and fourth-wave mixing processes.

[0010] Furthermore, the linear or nonlinear transformation specifically refers to:

[0011] (1) Convert the plane wavefront of the fundamental mode light field into a spiral wavefront carrying orbital angular momentum;

[0012] (2) The topological charge of the vortex or vector optical field can be adjusted by the dipole arrangement symmetry of the ferroelectric topological domain structure.

[0013] (3) The polarization state conversion of the output light field is controlled by the linear or nonlinear effects of ferroelectric thin films.

[0014] Further, in step S3, the thermal field driving is achieved by a heating element, with a temperature range of 0°C to 300°C; the electric field driving is achieved by applying voltage to electrodes; and the optical field driving is achieved by pulsed light waves, with the intensity range of the pulsed light waves being 1kV / cm to 100kV / cm or the pulsed light wavelength being 400-3000nm.

[0015] Furthermore, the method also includes detecting the optical field parameters of the vortex optical field or vector optical field, and adjusting the domain distribution and dipole arrangement of the ferroelectric topological domain structure in real time according to the detection results, thereby dynamically changing the parameters of the vortex optical field or vector optical field. The detection includes light intensity detection, phase detection and polarization state detection.

[0016] Furthermore, the above methods are applied to photonic integrated circuits, reconfigurable high-capacity optical communication systems, and optical field manipulation devices in quantum information processing.

[0017] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: through the rich dipole arrangement of the ferroelectric topological domain structure, efficient multidimensional control of the phase, amplitude and polarization state of the optical field is achieved; it supports real-time adjustment of the ferroelectric topological domain structure by external field driving such as thermal field, electric field or optical field, realizing dynamic control of vortex optical field; it provides a brand-new solution for highly integrated photonic circuits and reconfigurable high-capacity optical communication, and has broad application prospects. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating the dynamic optical field modulation method based on ferroelectric topological domain structure of the present invention. In the figure, 1 is a schematic diagram of the topological domain structure in the ferroelectric thin film; 2 is the non-helical phase of the incident light; and 3 is the helical phase of the outgoing light.

[0019] Figure 2 The domain structure characterization results for ferroelectric thin films are as follows: A. Piezoelectric microscopy (PFM) test pattern; B. Second harmonic generation (SHG) test pattern.

[0020] Figure 3 This is a schematic diagram of the optical path for detecting a vortex light field, including polarization state detection and phase detection. A. Optical device for imaging a second harmonic (SH) vortex beam; B. Optical device for verifying the orbital angular momentum of a nonlinear vortex beam; where HWP: half-wave plate; QWP: quarter-wave plate; LP: linear polarizer; L1: spherical lens; L2: tube lens; VWP: vortex waveplate. HWP and QWP1 together form a circular polarizer, while QWP2 and LP form a circular analyzer. The color filter in front of the CCD is used to filter out the fundamental wave (FW) signal. QWP3 and VWP are used to verify the orbital angular momentum.

[0021] Figure 4 Experimental and optical simulation diagrams for generating vortex light from ferroelectric topological domains: A. Schematic diagram of experimental testing; B. Comparison of experimental and simulation results characterizing vortex light; C. Detection of topological charge of vortex light field using vortex waveplate.

[0022] Figure 5 This refers to the dynamic control of the vortex optical field by temperature-dependent ferroelectric topological domains (changes under the influence of the thermal field).

[0023] Figure 6 This diagram illustrates the electrode structure and the dynamic control of the vortex optical field by the electric field-dependent ferroelectric topological domains (changes under the influence of the electric field). A. Test image of vortex light under electric field control; B. Example diagram of the principle of electric field-controlled ferroelectric dipole distribution. Detailed Implementation

[0024] To more clearly illustrate this application, the following description, in conjunction with preferred embodiments and accompanying drawings, further clarifies the application. It should be noted that these embodiments are merely illustrative of the technical solutions of the present invention. Those skilled in the art can adjust material selection, process parameters, or structural design according to actual needs, and all such modifications should be considered to fall within the protection scope of the present invention.

[0025] like Figure 1 As shown, the present invention provides a dynamic optical field modulation method based on ferroelectric topological domain structure, comprising: selecting a ferroelectric topological domain structure formed in a ferroelectric thin film material as an optical field modulation medium, wherein the ferroelectric topological domain structure has a spatially distributed dipole arrangement;

[0026] In specific embodiments, the ferroelectric material includes, but is not limited to, one or more of barium titanate (BaTiO3), lead titanate (PbTiO3), bismuth ferrite (BiFeO3), lithium niobate (LiNbO3), lead zirconate titanate (PZT), potassium niobate (KNbO3), or ferroelectric materials doped with rare earth elements, and the thickness of the ferroelectric thin film material ranges from 1 nm to 100 μm.

[0027] Ferroelectric topological domain structures are characterized by methods such as piezoelectric microscopy (PFM) and second harmonic generation (SHG). Ferroelectric topological domain structures include, but are not limited to, vortex domains, bubble domains, skyrmions, half-ions, and closed domains. The geometric configurations of the topological domain structures include circular symmetric distribution, periodic gradient distribution, spiral symmetric distribution, or fractal network distribution. The spatial scale of ferroelectric topological domain structures ranges from 1 nm to 10 mm.

[0028] Then, the circularly polarized Gaussian mode optical field is linearly or nonlinearly transformed using ferroelectric topological domain structures to generate vortex or vector optical fields with specific topological charges. The domain distribution and dipole arrangement of the ferroelectric topological domain structure are then adjusted in real time via external field driving, dynamically changing the phase, amplitude, and polarization state of the vortex or vector optical field, thus achieving a real-time correlation response between the optical field parameters and the topological domain structure. External field driving methods include, but are not limited to, driving methods using thermal fields, electric fields, or pulsed optical fields.

[0029] In specific embodiments, linear conversion includes optical field polarization and optical field spatial mode conversion; nonlinear conversion includes polarization and optical field spatial mode conversion during processes such as second harmonic generation (SHG), third harmonic generation (THG), and four-wave mixing (FWM). The linear or nonlinear conversion specifically refers to:

[0030] (1) Convert the plane wavefront of the fundamental mode light field into a spiral wavefront carrying orbital angular momentum;

[0031] (2) The topological charge of the vortex or vector optical field can be adjusted by the dipole arrangement symmetry of the ferroelectric topological domain structure.

[0032] (3) The polarization state conversion of the output light field is controlled by the linear or nonlinear effects of ferroelectric thin films.

[0033] The specific methods for adjusting the domain distribution and dipole arrangement of the ferroelectric topological domain structure in real time through external field driving methods such as thermal field, electric field, or pulsed light field can be as follows: Thermal field driving is achieved through heating elements with a temperature range of 0℃ to 300℃. By applying a thermal field, the domain configuration is dynamically switched, generating a ferroelectric-paraelectric phase transition and controlling the phase of the vortex light in real time; Electric field driving is achieved by applying voltage through electrodes. By applying an electric field, the domain configuration is dynamically switched, and the dipole is driven to flip through the inverse piezoelectric effect, controlling the phase of the vortex light in real time; Light field driving is achieved through pulsed light waves with an intensity range of 1kV / cm to 100kV / cm or a pulsed light wavelength of 400-3000nm. By applying a high-intensity pulsed light field to generate a thermal effect, the transient polarization and vortex light field control are achieved by adjusting the light intensity and pulse length.

[0034] In a specific embodiment, the parameters of the vortex or vector light field are detected, including light intensity detection, phase detection and polarization state detection. Based on the detection results, the domain distribution and dipole arrangement of the ferroelectric topological domain structure are adjusted in real time, thereby dynamically changing the parameters of the vortex or vector light field.

[0035] This embodiment selects ferroelectric topological domains in a self-supporting barium titanate (BTO) thin film for optical field modulation. It should be noted that the choice of ferroelectric thin film includes, but is not limited to, barium titanate. High-quality self-supporting barium titanate ferroelectric thin films are mainly grown using oxide molecular beam epitaxy (EBE). The epitaxial substrate material is strontium titanate, and the water-soluble sacrificial layer is Sr3Al2O6. The transfer method involves flipping this three-layer structure onto functional substrates such as sapphire, indium tin oxide (ITO), and Si wafers, as described in Chinese Invention Patent (Application No. CN202110830705.6), using external pressure to achieve the transfer of a flat self-supporting thin film. The characterization results of the topological domain structure in the barium titanate thin film are as follows: Figure 2 As shown, Figure 2 In section A, the ferroelectric topological domain structure was characterized using piezoelectric microscopy (PFM). Figure 2 In Figure B, the ferroelectric topological domain structure was characterized using the second harmonic generation (SHG) method. PFM and SHG together revealed the existence of central-type topological microdomain structures. Furthermore, the size of the topological domains reached the lateral micrometer scale, matching commonly used optical modes, laying the foundation for the subsequent application of ferroelectric topological domains in optical field manipulation.

[0036] When the incident fundamental wave is circularly polarized Gaussian mode light, the ferroelectric topological domain structure in the BTO thin film converts it into vortex light through nonlinear effects, such as SHG. The test optical path and test results are as follows: Figure 3 and Figure 4 As shown. To reveal the internal mechanism of nonlinear light-matter interaction, a second harmonic (SH) vortex beam was decoupled and analyzed. A comparison of the polarization-distinguished experimental (first row) and simulated (second row) intensity distributions is shown below.Figure 4 As shown in B, the optical path used is as follows: Figure 3 As shown in Figure A. The experimental results are in high agreement with the optical simulation, demonstrating the important role of the rotating dipole structure in the ferroelectric topological domain in spatial vortex light modulation. Based on the single rotational symmetry (C1) of the tetragonal phase BTO in-plane dipole, according to the symmetry selection rule, the second harmonic (SH) components of circularly polarized light (left-handed LCP and right-handed RCP) are both allowed to be generated. A vortex phase plate is inserted into the optical path ( Figure 3 B) An additional topological charge (m = ±1) can be applied to the initial SH vortex beam. By observing the disappearance of the dark nucleus in the central spot (i.e., l2ω + m = 0), the value of l2ω can be accurately determined. Experimental results show that the centrally converging topological structure generated by the BTO thin film can simultaneously produce two vortex light states independent of the incident light polarization, achieving control of the orbital angular momentum from 0 to ±1.

[0037] The intrinsic mechanism of controlling the phase of the optical field using ferroelectric topological domain structure originates from the nonlinear geometric phase effect: the nonlinear polarizability of the polar topology (which determines the interference characteristics of the SH wave) is constructed by the geometrication of its spatial dipole moment configuration; after the interaction between light and matter, the nonlinear geometric phase is introduced into the nonlinear polarization of the generated SH wave, driving the spin-orbit angular momentum conversion of light, forming a spiral wavefront and generating vortex light.

[0038] In this invention, dynamic optical field manipulation is achieved primarily by dynamically switching the topological microdomain structure using thermal or electric fields, thereby altering the dipole arrangement and ultimately realizing dynamic control over the phase, amplitude, and polarization state of the optical field. Thermal field manipulation is as follows: Figure 5 As shown, the polar microdomains in the BTO thin film can be reversibly switched through thermal cycling. The BTO thin film is fixed on a heating plate, and the temperature of the film is controlled by adjusting the voltage applied across the heating plate. When the temperature exceeds the Curie point (~140℃), the ferroelectric phase transforms into the paraelectric phase, and the topological domains disappear; after cooling to room temperature, the domain structure recovers to its original topological configuration to adapt to the internal strain state. The dynamic modulation of the vortex optical field driven by the electric field is as follows... Figure 6 As shown. A BTO thin film is sandwiched between two layers of amorphous Al2O3 (25nm) / ITO (180nm) glass. Figure 6 B). The ITO layer serves as the transparent electrode, while the amorphous Al2O3 layer prevents leakage current. When a perpendicular electric field is applied, the in-plane dipoles are gradually pulled outward due to the electric field, causing the non-trivial polar topology to transform into a trivial out-of-plane single domain. Due to the depolarization field effect, this out-of-plane polarization state is unstable. After the electric field is removed, the initial topological configuration is restored, thus forming a reversible dynamic control of the electric field.

[0039] This invention proposes a dynamic optical field manipulation method based on ferroelectric topological domains. It innovatively proposes a mechanism for dynamic optical field manipulation using ferroelectric topological domains to control thermal / electrical / optical fields, achieving multi-dimensional real-time control of optical field phase, amplitude, and polarization state, while exhibiting high integration, low loss, and ultrafast response characteristics. Its core innovations lie in: utilizing the abundant dipole structure parameters in ferroelectric thin films to provide a new material system for optical field manipulation; achieving spiral wavefront construction of the optical field through linear or nonlinear geometric phase effects; and providing a novel material research platform and innovative solutions for high-capacity optical communication and intelligent photonic devices (such as programmable metasurfaces) through dynamic reconfigurability, thus contributing to technological innovation in optical communication, quantum technology, and biophotonics.

[0040] The above description is merely a specific embodiment of the present invention for illustrative purposes; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solutions and improved concepts of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for dynamic optical field manipulation based on ferroelectric topological domain structures, characterized in that, include: Ferroelectric topological domain structures formed in ferroelectric thin film materials are selected as optical field modulation media, wherein the ferroelectric topological domain structures have spatially distributed dipole arrangements; The ferroelectric topological domain structure is used to linearly or nonlinearly transform the incident fundamental wave's optical field to generate a vortex optical field or a vector optical field. The domain distribution and dipole arrangement of the ferroelectric topological domain structure are adjusted in real time via external field driving, dynamically changing the phase, amplitude, and polarization state of the vortex or vector optical field, thus achieving a real-time correlation response between the optical field parameters and the topological domain structure. The external field driving method includes thermal field, electric field, or pulsed optical field driving methods. The incident fundamental wave includes circularly polarized Gaussian mode light. The linear or nonlinear transformation specifically involves: (1) Convert the plane wavefront of the fundamental mode light field into a spiral wavefront carrying orbital angular momentum; (2) The topological charge of the vortex or vector optical field can be adjusted by utilizing the dipole arrangement symmetry of the ferroelectric topological domain structure; (3) The polarization state conversion of the output light field is controlled by the linear or nonlinear effects of ferroelectric thin films.

2. The dynamic optical field manipulation method based on ferroelectric topological domain structure according to claim 1, characterized in that, In step S1, the ferroelectric topological domain structure includes vortex domains, bubble domains, skyrmions, half-ions, and closed domains; the geometric configuration of the topological domain structure includes circular symmetric distribution, periodic gradient distribution, spiral symmetric distribution, or fractal network distribution; the spatial scale of the ferroelectric topological domain structure is 1 nm to 10 mm.

3. The dynamic optical field manipulation method based on ferroelectric topological domain structure according to claim 1, characterized in that, In step S1, the ferroelectric material includes one or more of barium titanate, lead titanate, bismuth ferrite, lithium niobate, lead zirconate titanate, potassium niobate, or ferroelectric materials doped with rare earth elements.

4. The dynamic optical field manipulation method based on ferroelectric topological domain structure according to claim 1, characterized in that, The thickness of the ferroelectric thin film material ranges from 1 nm to 100 μm.

5. The dynamic optical field manipulation method based on ferroelectric topological domain structure according to claim 1, characterized in that, In step S2, the linear conversion includes optical field polarization and optical field spatial mode conversion; the nonlinear conversion includes polarization and optical field spatial mode conversion during second harmonic generation, third harmonic generation, and fourth-wave mixing processes.

6. The dynamic optical field manipulation method based on ferroelectric topological domain structure according to claim 1, characterized in that, In step S3, the thermal field driving is achieved by a heating element, with a temperature range of 0°C to 300°C; the electric field driving is achieved by applying voltage to electrodes; and the optical field driving is achieved by pulsed light waves, with the intensity range of the pulsed light waves being 1 kV / cm to 100 kV / cm or the pulsed light wavelength being 400-3000 nm.

7. The dynamic optical field manipulation method based on ferroelectric topological domain structure according to claim 1, characterized in that, The method further includes detecting the optical field parameters of the vortex optical field or vector optical field, and adjusting the domain distribution and dipole arrangement of the ferroelectric topological domain structure in real time according to the detection results, thereby dynamically changing the parameters of the vortex optical field or vector optical field. The detection includes light intensity detection, phase detection and polarization state detection.

8. The dynamic optical field manipulation method based on ferroelectric topological domain structure according to any one of claims 1-7, characterized in that, The method is applied to photonic integrated circuits, reconfigurable high-capacity optical communication systems, and optical field manipulation devices in quantum information processing.

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