Dynamic light field regulation and control method based on ferroelectric topological domain structure and application of dynamic light field regulation and control method

Abstract

The invention discloses a dynamic light field regulation and control method based on a ferroelectric topological domain structure, and the method comprises the steps: selecting the ferroelectric topological domain structure formed in a ferroelectric film material as a light field regulation and control medium, and the ferroelectric topological domain structure is provided with dipole arrangement in spatial distribution; the ferroelectric topological domain structure is used for carrying out linear or nonlinear conversion on a light field of incident fundamental waves to generate a vortex light field or a vector light field, and domain distribution and dipole arrangement of the ferroelectric topological domain structure are adjusted in real time through external field driving modes such as a thermal field, an electric field or a pulse light field. And dynamically changing the phase, the amplitude and the polarization state of the vortex light field or the vector light field to realize real-time correlation response of the light field parameters and the topological domain structure. According to the method, the topological domain structure in the ferroelectric material is utilized, multi-dimensional regulation and control of the light field are achieved through rich dipole arrangement, and the method can also be applied to the fields of high-integration photonic circuits and reconfigurable high-capacity optical communication.

Description

Technical Field

[0001] The present invention belongs to the technical fields of micro-nano photonics and ferroelectric materials, and relates to a method for dynamically regulating light fields based on ferroelectric topological domain structures and its applications. Background Art

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

[0003] Object of the Invention: The object of the present invention is to provide a method for dynamically regulating light fields based on ferroelectric topological domain structures, which realizes efficient multi-dimensional regulation of light fields by utilizing the topological domain structures in ferroelectric materials and solves the deficiencies of traditional light field regulation methods in terms of dynamics and integration.

[0004] Technical Solution: A method for dynamically regulating light fields based on ferroelectric topological domain structures according to the present invention includes: selecting the ferroelectric topological domain structure formed in a ferroelectric thin film material as the light field regulation medium, where the ferroelectric topological domain structure has a spatially distributed dipole arrangement; using the ferroelectric topological domain structure to perform linear or non-linear conversion on the light field of the incident fundamental wave to generate a vortex light field or a vector light field, and dynamically changing the phase, amplitude, and polarization state of the vortex light field or the vector light field by adjusting the domain distribution and dipole arrangement of the ferroelectric topological domain structure in real time through an external field driving method, thereby realizing the real-time correlation response between the light field parameters and the topological domain structure; the external field driving method includes driving methods such as a thermal field, an electric field, or a pulsed light field.

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

[0006] Further, in step S1, the ferroelectric topological domain structure includes vortex domains, bubble domains, skyrmions, merons, and closed domains; the geometric configuration of the topological domain structure includes circular symmetric distribution, periodic gradient distribution, helical symmetric distribution, or fractal network distribution; the spatial scale of the ferroelectric topological domain structure is from 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 a ferroelectric material doped with rare earth elements.

[0008] Further, the thickness range of the ferroelectric thin film material is from 1 nm to 100 μm.

[0009] Further, 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 in second harmonic generation, third harmonic generation, and four-wave mixing processes.

[0010] Further, the linear or nonlinear conversion is specifically:

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

[0012] (2) Realize adjustable topological charge numbers of vortex optical fields or vector optical fields through the dipole arrangement symmetry of the ferroelectric topological domain structure;

[0013] (3) Regulate the polarization state conversion of the output optical field based on the linear or nonlinear effects of the ferroelectric thin film.

[0014] Further, in step S3, the thermal field driving is realized through a heating element, and the temperature change range is from 0 °C to 300 °C; the electric field driving is realized by applying a voltage through an electrode; the optical field driving is realized by a pulsed light wave, and the intensity range of the pulsed light wave is from 1 kV / cm to 100 kV / cm or the pulsed light wavelength is 400 - 3000 nm.

[0015] Further, 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, so as to dynamically change the parameters of the vortex optical field or vector optical field. The detection includes light intensity detection, phase detection, and polarization state detection.

[0016] Further, apply the above method to optical field modulation devices in photonic integrated circuits, reconfigurable large-capacity optical communication systems, and quantum information processing.

[0017] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages: Through the rich dipole arrangements of the ferroelectric topological domain structure, efficient multi-dimensional modulation of the phase, amplitude, and polarization state of the optical field is achieved; it supports real-time adjustment of the ferroelectric topological domain structure through external field driving methods such as thermal field, electric field, or optical field, realizing dynamic modulation of the vortex optical field; it provides a brand-new solution for high-integration photonic circuits and reconfigurable large-capacity optical communication, and has broad application prospects. Description of the Drawings

[0018] Figure 1 This is a schematic flow chart of the dynamic optical field regulation method based on the 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; 3 is the helical phase of the outgoing light.

[0019] Figure 2 This is the characterization result of the domain structure of the ferroelectric thin film. A. Piezoresponse force microscopy (PFM) test diagram; B. Second harmonic generation (SHG) test diagram.

[0020] Figure 3 This is a schematic diagram of the detection optical path of the vortex optical field, including polarization state detection and phase detection. A. Optical device for imaging the second harmonic (SH) vortex beam; B. Optical device for verifying the orbital angular momentum of the nonlinear vortex beam; where, HWP: half-wave plate; QWP: quarter-wave plate; LP: linear polarizer; L1: spherical lens; L2: tube lens; VWP: vortex wave plate. 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 This is the experimental and optical simulation diagram of the generation of vortex light by ferroelectric topological domains. A. Schematic diagram of the experimental test; B. Comparison of the experimental and simulation results diagrams for characterizing vortex light; C. Detection of the topological charge of the vortex optical field using a vortex wave plate.

[0022] Figure 5 This is the temperature-dependent dynamic regulation of the ferroelectric topological domain on the vortex optical field (changes under the action of the thermal field).

[0023] Figure 6 This is a schematic diagram of the electrode structure and the dynamic regulation of the ferroelectric topological domain on the vortex optical field depending on the electric field (changes under the action of the electric field). A. Test diagram of the vortex light under electric field regulation; B. Schematic example diagram of the principle of regulating the ferroelectric dipole distribution by the electric field. Detailed implementation manners

[0024] To more clearly illustrate the present application, the following further describes the present application in combination with preferred embodiments and the accompanying drawings. It should be noted that this embodiment is only used to exemplarily show the technical solution of the present invention, and those skilled in the art can adjust the material selection, process parameters or structural design according to actual needs, and these variations should all be regarded as falling within the protection scope of the present invention.

[0025] As Figure 1 shown, a dynamic optical field regulation method based on the ferroelectric topological domain structure of the present invention includes: selecting the ferroelectric topological domain structure formed in the ferroelectric thin film material as the optical field regulation medium, and the ferroelectric topological domain structure has a spatially distributed dipole arrangement;

[0026] In a specific embodiment, the ferroelectric material includes, but is not limited to, barium titanate (BaTiO 3 ), lead titanate (PbTiO 3 ), bismuth ferrite (BiFeO 3 ), lithium niobate (LiNbO 3 ), lead zirconate titanate (PZT), potassium niobate (KNbO 3 ), or one or more of ferroelectric materials doped with rare earth elements. The thickness range of the ferroelectric thin film material is from 1 nm to 100 μm.

[0027] The ferroelectric topological domain structure is characterized by methods such as piezoresponse force microscopy (PFM) and second harmonic generation (SHG). The ferroelectric topological domain structure includes, but is not limited to, vortex domains, bubble domains, skyrmions, merons, closed domains, etc. The geometric configurations of the topological domain structure include circular symmetric distribution, periodic gradient distribution, helical symmetric distribution, or fractal network distribution. The spatial scale of the ferroelectric topological domain structure is from 1 nm to 10 mm.

[0028] Then, the ferroelectric topological domain structure is used to perform linear or nonlinear conversion on the circularly polarized Gaussian fundamental mode optical field to generate a vortex optical field or a vector optical field with a specific topological charge number. The domain distribution and dipole arrangement of the ferroelectric topological domain structure are adjusted in real time by an external field driving method, and the phase, amplitude, and polarization state of the vortex optical field or the vector optical field are dynamically changed to achieve real-time correlation response between the optical field parameters and the topological domain structure. The external field driving methods include, but are not limited to, thermal field, electric field, or pulsed optical field driving methods.

[0029] In a specific embodiment, the linear conversion includes optical field polarization and optical field spatial mode conversion; the nonlinear conversion includes polarization and optical field spatial mode conversion in processes such as second harmonic generation (SHG), third harmonic generation (THG), and four-wave mixing (FWM). The linear or nonlinear conversion is specifically as follows:

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

[0031] (2) Achieve adjustable topological charge number of the vortex optical field or the vector optical field through the dipole arrangement symmetry of the ferroelectric topological domain structure;

[0032] (3) Regulate the polarization state conversion of the output optical field based on the linear or nonlinear effects of the ferroelectric thin film.

[0033] The specific method for real-time adjusting the domain distribution and dipole arrangement of the ferroelectric topological domain structure through an external field driving method such as a thermal field, an electric field, or a pulsed light field can be as follows: The thermal field driving is achieved through a heating element, with the temperature change range being from 0°C to 300°C. By applying a thermal field, the domain configuration is dynamically switched to generate a ferroelectric-paraelectric phase transition, and the phase of the vortex light is real-time regulated. The electric field driving is achieved by applying a voltage through an electrode. By applying an electric field, the domain configuration is dynamically switched, and the dipole is driven to flip through the inverse piezoelectric effect to real-time regulate the phase of the vortex light. The light field driving is achieved through a pulsed light wave. The intensity range of the pulsed light wave is from 1 kV / cm to 100 kV / cm, or the pulsed light wavelength is 400 - 3000 nm. By applying a high-intensity pulsed light field to generate a thermal effect and adjusting means such as its light intensity and pulse length, transient polarization and vortex light field regulation are achieved.

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

[0035] In this embodiment, the ferroelectric topological domains in the self-supporting barium titanate (BTO) thin film are selected for light field regulation. It should be noted that the selection of the ferroelectric thin film includes but is not limited to barium titanate. The high-quality self-supporting barium titanate ferroelectric thin film is mainly grown by the oxide molecular beam epitaxy technique. The epitaxial substrate material is strontium titanate, and the water-soluble sacrificial layer is Sr 3 Al 2 O 6 . The transfer method is to invert this three-layer structure onto functional substrates such as sapphire, indium tin oxide, and Si wafers. For example, as described in the Chinese invention patent (application number: CN202110830705.6), the transfer of the flat self-supporting thin film is achieved through an external pressure. The characterization results of the topological domain structure in the barium titanate thin film are as Figure 2 shown, Figure 2 where A in Figure 2 is the characterization of the ferroelectric topological domain structure by the piezoresponse force microscopy (PFM) method, and B in

[0036] is the characterization of the ferroelectric topological domain structure by the second harmonic generation (SHG) method. PFM and SHG together reveal the existence of the central-type topological microdomain structure. In addition, the size of the topological domain reaches the transverse micron scale, matching the common optical modes, laying a foundation for the subsequent use of ferroelectric topological domains for light field regulation. Figure 3 and Figure 4As shown. To reveal the internal mechanism of the interaction between nonlinear light and matter, the second harmonic (SH) vortex beam was decoupled and analyzed. The experimental (first row) and simulated (second row) intensity distributions of polarization discrimination are compared as Figure 4 shown in B, and the optical path used is as Figure 3 shown in A. The experimental results are in good agreement with the optical simulations, indicating the important role of the rotating dipole structure in the ferroelectric topological domain in the modulation of spatial vortex light. Based on the single-rotation symmetry (C1) of the in-plane dipoles in the tetragonal phase BTO, 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. By inserting a vortex phase plate ( Figure 3 in B) into the optical path, an additional topological charge (m = ±1) can be loaded onto the initial SH vortex beam. By observing the disappearance of the dark core of the central spot (i.e., l 2 ω + m = 0), the l 2 ω value can be accurately determined. The experimental results show that the central-converging topological structure generated by the BTO thin film can simultaneously generate two vortex light states independent of the polarization of the incident light, realizing the regulation of orbital angular momentum from 0 to ±1.

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

[0038] In the present invention, the realization of dynamic light field regulation is mainly achieved by dynamically switching the topological microdomain structure through a thermal field or an electric field, changing the dipole arrangement configuration, and thus realizing the dynamic regulation of the light field phase, amplitude, and polarization state. The thermal field regulation is as Figure 5 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 sheet, and the temperature of the thin film is regulated by controlling the voltage applied across the heating sheet. When the temperature exceeds the Curie point (~140 °C), the ferroelectric phase transforms into the paraelectric phase and the topological domains disappear; after cooling to room temperature, the domain structure resumes to the original topological configuration to adapt to the internal strain state. The dynamic modulation of the vortex light field driven by an electric field is as Figure 6 shown. The BTO thin film is sandwiched between two layers of amorphous Al 2 O 3 (25 nm) / ITO (180 nm) glass ([[]] Figure 6 in B). The ITO layer serves as a transparent electrode, and the amorphous Al 2 O 3The layer is used to prevent the generation of leakage current. When a vertical electric field is applied, the in-plane dipoles are gradually pulled to the out-of-plane direction due to the action of the electric field, resulting in the transformation of the non-trivial polar topology into a trivial out-of-plane single domain. Due to the existence of the depolarization field effect, this out-of-plane polarization state is unstable and returns to the initial topological configuration after the electric field is removed, thus forming a reversible electric field dynamic regulation.

[0039] A dynamic optical field regulation method based on ferroelectric topological domain structure proposed by the present invention innovatively proposes a mechanism for dynamically regulating the optical field using ferroelectric topological domains, realizing multi-dimensional real-time manipulation of the optical field phase, amplitude and polarization state, and having the characteristics of high integration, low loss and ultra-fast response. Its core innovation lies in: using the rich dipole structure parameters in the ferroelectric thin film to provide a new material system for optical field regulation; constructing the optical field spiral wavefront through linear or nonlinear geometric phase effects; the dynamic reconfigurability provides a new material research platform and innovative solutions for high-capacity optical communication and intelligent photonic devices (such as programmable metasurfaces), and helps to promote the technological innovation in the fields of optical communication, quantum technology and biophotonics.

[0040] As described above, it is only a specific implementation manner for exemplary display of the present invention; however, the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its improved concept, makes equivalent substitution or change, and should be covered by the protection scope of the present invention.

Claims

1. A dynamic light field control method based on ferroelectric topological domain structure, characterized in that: include: A ferroelectric topological domain structure formed in a ferroelectric thin film material is selected as a light field control medium, wherein the ferroelectric topological domain structure has a spatially distributed dipole arrangement; The ferroelectric topological domain structure is used to perform linear or nonlinear conversion on the incident fundamental wave light field to generate a vortex light field or a vector light field, and the domain distribution and dipole arrangement of the ferroelectric topological domain structure are adjusted in real time by external field driving, and the phase, amplitude and polarization state of the vortex light field or the vector light field are dynamically changed to achieve real-time correlation response between the light field parameters and the topological domain structure; the external field driving method includes the driving method of thermal field, electric field or pulsed light field.

2. The dynamic light field control method based on ferroelectric topological domain structure according to claim 1 is characterized in that: The incident fundamental wave includes circularly polarized Gaussian fundamental mode light.

3. The dynamic light field control method based on ferroelectric topological domain structure according to claim 1 is characterized in that: In step S1, the ferroelectric topological domain structure includes vortex domains, bubble domains, skyrmions, skyrmions, and closed domains; the geometric configuration of the topological domain structure includes circularly symmetric distribution, periodic gradient distribution, spirally symmetric distribution, or fractal network distribution; the spatial scale of the ferroelectric topological domain structure is 1 nm to 10 mm.

4. The dynamic light field control method based on ferroelectric topological domain structure according to claim 1 is 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 a ferroelectric material doped with a rare earth element.

5. The dynamic light field control 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.

6. The dynamic light field control method based on ferroelectric topological domain structure according to claim 1, characterized in that: In step S2, the linear conversion includes light field polarization and light field spatial mode conversion; the nonlinear conversion includes polarization and light field spatial mode conversion in the second harmonic generation, third harmonic generation and four wave mixing process.

7. The dynamic light field control method based on ferroelectric topological domain structure according to claim 1, characterized in that: The linear or nonlinear conversion is specifically: (1) Convert the plane wavefront of the fundamental mode light field into a helical wavefront carrying orbital angular momentum; (2) The topological charge of the vortex light field or vector light field can be adjusted through the dipole arrangement symmetry of the ferroelectric topological domain structure; (3) Regulate the polarization state conversion of the output light field based on the linear or nonlinear effects of ferroelectric thin films.

8. The dynamic light field control 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, and the temperature variation range is 0°C to 300°C; the electric field driving is achieved by applying voltage to electrodes; the optical field driving is achieved by pulsed light waves, and the intensity range of the pulsed light waves is 1kV / cm to 100kV / cm or, the wavelength of the pulsed light is 400-3000nm.

9. The dynamic light field control method based on ferroelectric topological domain structure according to claim 1, characterized in that: The method also includes detecting light field parameters of the vortex light field or the vector light 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 light field or the vector light field, wherein the detection includes light intensity detection, phase detection and polarization state detection.

10. The dynamic light field control method based on ferroelectric topological domain structure according to any one of claims 1 to 9, characterized in that: The method is applied to photonic integrated circuits, reconfigurable large-capacity optical communication systems and optical field control devices in quantum information processing.

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