Terahertz multi-order Bessel beam generator
By designing a terahertz multi-order Bessel beam generator with a composite metasurface unit structure, the problem of complex generation methods in existing technologies is solved, and multi-order Bessel beam generation with simple structure and easy integration is realized, which is suitable for fields such as 6G communication and bio-optical imaging.
Patent Information
- Application Number
- CN202511619068.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-06
- Publication Date
- 2026-02-03
AI Technical Summary
In existing technologies, terahertz Bessel beam generation methods are complex and difficult to integrate, which hinders their use in practical applications.
A terahertz multi-order Bessel beam generator is designed, which consists of a composite metasurface unit structure, including photosensitive silicon grating strips, an F4B dielectric layer, a metal notched ring, and a composite grating. The multi-order Bessel beam is formed by the periodic arrangement and combination of phases.
It realizes a terahertz multi-order Bessel beam generation with simple structure, easy operation and integration, which is suitable for future 6G communication, wireless power transmission and bio-optical imaging and other fields.
Smart Images
Figure CN121454793A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the fields of terahertz science, integrated photonics, and more particularly to a terahertz multi-order Bessel beam generator. Background Technology
[0002] Terahertz technology, as the last blank area in the electromagnetic spectrum (frequency 0.1THz~10THz, wavelength 3000μm~30μm), has attracted widespread attention and in-depth exploration internationally in recent years. Its unique technical characteristics—including ultra-wide bandwidth, low latency, high penetration, and strong directionality—make it a core candidate for next-generation communication technology, showing great potential, especially in fields such as 6G networks, high-speed communication, medical imaging, and security detection.
[0003] However, challenges remain in the application of terahertz technology. Terahertz waves are easily attenuated by water vapor and oxygen absorption when propagating in the atmosphere, limiting their transmission distance. Breakthroughs are still needed in the development of core components such as high-power sources, high-efficiency antennas, and terahertz wave generation and control modules, and these technologies are costly. Overall, a new generation of IT industries based on terahertz technology has begun to take shape, and terahertz communication technology is moving from the laboratory to practical applications. Its development depends not only on breakthroughs in basic research but also on interdisciplinary collaboration and industry chain integration. With the surge in global demand for 6G, intelligent sensing, and other fields, terahertz technology has the potential to reshape the information interaction model of human society.
[0004] Terahertz non-diffraction beams are a special type of electromagnetic beam that effectively suppresses the diffraction and diffusion characteristics of energy during propagation of ordinary electromagnetic waves. They maintain a certain electromagnetic power density even during long-distance transmission, making them ideal for future applications such as 6G communication, wireless power transmission, and bio-optical imaging. Common non-diffraction beams include Bessel beams and Airy beams. Bessel beams (especially high-order Bessel beams, which also possess OAM beam characteristics) have attracted much attention due to their non-diffraction and self-healing properties, and their propagation characteristics are superior to easily diverging OAM vortex beams. However, traditional methods for generating terahertz Bessel beams, such as circular slit and lens combinations, axial prisms, and spatial light modulators, typically require complex optical components, hindering the practical application of terahertz Bessel beam generation and control systems. Therefore, developing multi-order terahertz Bessel beam generators is of great significance for achieving miniaturization and integration of terahertz systems. Summary of the Invention
[0005] The purpose of this invention is to overcome the shortcomings of existing technologies, such as difficulty in integration and complex structure, and to provide a terahertz multi-order Bessel beam generator.
[0006] To achieve the above objectives, the technical solution of the present invention is as follows: This invention provides a terahertz multi-order Bessel beam generator, which is composed of several composite metasurface unit structures arranged and assembled according to a phase period. The composite metasurface unit structure includes a photosensitive silicon grating strip, a first F4B dielectric layer, a metal notched ring, a second F4B dielectric layer, and a composite grating, stacked sequentially. The photosensitive silicon grating strip is attached to the upper surface of the first F4B dielectric layer. The metal notched ring is sandwiched between the first and second F4B dielectric layers, forming a sandwich structure. The metal notched ring consists of an open metal ring and an inner connecting section. The ring is a metal ring with two openings, which are symmetrically distributed radially along the metal ring. Each opening has an inwardly folded protrusion at the two ends of the ring. The inner connecting section consists of an outer circular inner square metal ring and strip connecting sections on both sides along the radial direction. The outer circular inner square metal ring is connected to the inner wall of the opening metal ring through the strip connecting sections on both sides. The composite grating serves as the base layer of the entire composite metasurface unit structure and is composed of VO2 grating strips and metal grating strips alternately spliced along the plane. The length directions of both the VO2 grating strips and the metal grating strips are perpendicular to the length direction of the photosensitive silicon grating strips.
[0007] Preferably, the photosensitive silicon grating strip has a thickness of 12.5 μm to 14 μm, a width of 34 μm to 36 μm, and a conductivity of 10. 6 S / m.
[0008] Preferably, the F4B material used in the first F4B dielectric layer has a dielectric constant of 2.7, a loss tangent of 0.0023, and a thickness of 20μm~40μm.
[0009] Preferably, the second F4B dielectric layer uses F4B material with a dielectric constant of 2.7, a loss tangent of 0.0023, and a thickness of 20μm~40μm.
[0010] Preferably, the thickness of the metal notched ring is 10μm~20μm, the outer radius of the open metal ring is 40μm~50μm, the inner radius is 20μm~30μm, the opening width is 4μm~8μm, and the length of the inward folded protrusion is 0μm~20μm.
[0011] Preferably, in the metal notched ring, the outer radius of the inner square metal ring of the inner connecting section is 14μm~16μm, the side length of the inner square opening is 9μm~11μm, and the width of the strip connecting sections on both sides is 9μm~11μm.
[0012] Preferably, in the composite grating, the width of a single VO2 grating strip is 14μm to 16μm, the width of a single metal grating strip is 9μm to 11μm, and the thickness is 0.9 to 1.1μm.
[0013] Preferably, the VO2 grating strip has an electrical conductivity of 10 S / m, and the metal grating strip is made of copper.
[0014] Preferably, the period of the composite metasurface unit structure is 100μm~120μm.
[0015] As a preferred option, all composite metasurface unit structures are arranged and combined according to the phase period of the Bessel beam to form a terahertz multi-order Bessel beam generator.
[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention designs a terahertz multi-order Bessel beam generator, which utilizes the characteristic of multi-layer composite metasurface units to facilitate periodic arrangement and combination according to the phase distribution of Bessel beams. By changing the arrangement of the composite metasurface units, multi-order Bessel beam generation is achieved, exhibiting characteristics such as simple structure, easy operation, and easy integration. It is suitable for future fields such as 6G communication, wireless power transmission, and bio-optical imaging. Attached Figure Description
[0017] Figure 1 These are schematic diagrams of the three-dimensional unit structure of the terahertz multi-order Bessel beam generator (a), internal schematic diagram of the unit structure (b), and schematic diagram of the metal notch ring structure (c). Figure 2 It is the metasurface phase distribution of a terahertz zero-order Bessel beam; Figure 3 The electric field distribution of a terahertz zero-order Bessel beam with or without rectangular PEC obstacles in the xoz plane; Figure 4 The phase distribution of the metasurface of the first-order Bessel beam in terahertz waveguides is shown when α=6° (a) and α=12° (b). Figure 5 The electric field intensity distribution of the first-order Bessel beam in the xoz plane when α=6° is (a), and the electric field intensity distribution of the first-order Bessel beam at different distances in the xoy plane when α=6° is (b). Figure 6 The electric field intensity distribution of the first-order Bessel beam in the xoz plane when α=12° is (a), and the electric field intensity distribution of the first-order Bessel beam at different distances in the xoy plane when α=12° is (b). Figure 7It is the phase distribution of the second-order Bessel beam metasurface in terahertz waves; Figure 8 The electric field intensity distribution of the second-order Bessel beam in the xoz plane is shown in (a), and the electric field intensity distribution of the second-order Bessel beam at different distances in the xoy plane is shown in (b). Detailed Implementation
[0018] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. Technical features in the various embodiments of the present invention can be combined accordingly without mutual conflict.
[0019] For ease of description, the present invention defines... Figure 1 middle x and y The direction is the periodic extension direction of the composite metasurface unit structure. z The direction is the thickness direction.
[0020] like Figure 1 As shown in (a), in one embodiment of the present invention, a three-dimensional unit structure for a terahertz multi-order Bessel beam generator is provided. This terahertz multi-order Bessel beam generator is composed of several composite metasurface unit structures arranged and assembled on a plane according to a preset phase period. The period of the composite metasurface unit structures needs to be arranged according to the actual functional requirements of the device, while the number of unit structures needs to be set according to the actual device size and is not a limitation. The terahertz multi-order Bessel beam generator uses the contact surface between the photosensitive silicon grating strip 3 and air as the first port 1, and the contact surface between the composite grating and air as the second port 2.
[0021] like Figure 1 As shown in (b), each composite metasurface unit structure includes a photosensitive silicon grating strip 3, a first F4B dielectric layer 4, a metal-notched ring 5, a second F4B dielectric layer 6, and a composite grating, which are stacked sequentially. The photosensitive silicon grating strip 3 is attached to the upper surface of the first F4B dielectric layer 4. The metal-notched ring 5 is sandwiched between the first F4B dielectric layer 4 and the second F4B dielectric layer 6, forming a sandwich structure. Figure 1As shown in (c), the metal notched ring 5 consists of an open metal ring and an inner connecting section. The open metal ring is a metal ring with two openings, which are symmetrically distributed radially along the metal ring. At the two ends of the ring on both sides of each opening, there are strip-shaped inwardly folded protrusions of uniform width, thus forming four curved parts on the inner side of the ring. The inner connecting section of the metal notched ring 5 consists of an outer circular inner square metal ring and strip-shaped connecting sections on both sides along the radial direction. The outer circular inner square metal ring is connected to the inner wall of the open metal ring through the strip-shaped connecting sections on both sides. In addition, the composite grating, as the base layer of the entire composite metasurface unit structure, is composed of VO2 grating strips 7 and metal grating strips 8 alternately spliced along the plane. The length directions of both VO2 grating strips 7 and metal grating strips 8 are perpendicular to the length direction of the photosensitive silicon grating strip 3.
[0022] Furthermore, the specific selection and dimensional parameters of each structure of the aforementioned devices can be optimized according to actual performance requirements, with the final device performance meeting the usage needs as the standard. In the embodiments of the present invention, the specific materials and parameters of each structure of the terahertz multi-order Bessel beam generator are optimized as follows: The photosensitive silicon grating strip 3 has a thickness of 12.5 μm to 14 μm, a width of 34 μm to 36 μm, and an electrical conductivity of 10. 6 S / m. The first F4B dielectric layer 4 uses F4B material with a dielectric constant of 2.7, a loss tangent of 0.0023, and a thickness of 20μm~40μm. The second F4B dielectric layer 6 uses F4B material with a dielectric constant of 2.7, a loss tangent of 0.0023, and a thickness of 20μm~40μm. The metal notched ring 5 has a thickness of 10μm~20μm, see [reference needed]. Figure 1 As shown in (c), the outer radius R of the open metal ring is 40μm~50μm, the inner radius r is 20μm~30μm, the width of the opening g is 4μm~8μm, and the length d of the inwardly folded protrusion is 0μm~20μm. Additionally, the outer radius of the inner square metal ring of the inner connecting section is 14μm~16μm, the side length of the inner square opening is 9μm~11μm, and the width of the strip connecting sections on both sides is 9μm~11μm. In the composite grating, the width of a single VO2 grating strip 7 is 14μm~16μm, the width of a single metal grating strip 8 is 9μm~11μm, and the thickness of both is 0.9μm~1.1μm. The VO2 material of the VO2 grating strip 7 has an electrical conductivity of 10 S / m, while the metal material of the metal grating strip 8 is copper. The period of the composite metasurface unit structure is 100μm~120μm.
[0023] It should be noted that the aforementioned composite metasurface unit structures are arranged and combined according to the phase period of the Bessel beam to form a terahertz multi-order Bessel beam generator. The phase of each composite metasurface unit structure can be controlled by adjusting the size parameters of the metal notch ring 5.
[0024] This invention proposes a terahertz multi-order Bessel beam generator based on a multi-layer composite metasurface. It is constructed by arranging and splicing composite metasurface units according to a preset Bessel beam phase period, thereby realizing the generation and transmission control functions of terahertz multi-order Bessel beams. It exhibits the characteristics of simple structure, easy operation, and easy integration, and is suitable for future applications in fields such as 6G communication, wireless power transmission, and bio-optical imaging.
[0025] The above-mentioned terahertz multi-order Bessel beam generator will be applied to a specific example to demonstrate its technical effect.
[0026] Example The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. The various features described in the embodiments can be combined to form multiple alternative solutions. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present invention are shown in the accompanying drawings, not the entire structure. In this embodiment, the shapes of the components of the terahertz multi-order Bessel beam generator are as described above; see details below. Figure 1 Further details will not be elaborated here. The specific parameters of each component in this example are as follows: The photosensitive silicon grating strip 3 has a thickness of 14 μm, a width of 35 μm, and an electrical conductivity of 10. 6 S / m. The first F4B dielectric layer 4 uses F4B material with a dielectric constant of 2.7, a loss tangent of 0.0023, and a thickness of 20 μm. The second F4B dielectric layer 6 uses F4B material with a dielectric constant of 2.7, a loss tangent of 0.0023, and a thickness of 20 μm. The metal notched ring 5 has a thickness of 10 μm, the outer radius R of the open metal ring is 40 μm, the inner radius r is 30 μm, the opening g is 8 μm wide, and the length d of the inner folded protrusion is set in four different sizes: 0 μm / 5 μm / 10 μm / 20 μm. In addition, the outer radius of the inner square metal ring of the inner connecting section is 15 μm, the side length of the inner square opening is 10 μm, and the width of the strip connecting sections on both sides is 10 μm. In the composite grating, the width of a single VO2 grating strip 7 is 15 μm, the width of a single metal grating strip 8 is 10 μm, and the thickness of both is 1 μm. The VO2 material of the VO2 grating strip 7 has an electrical conductivity of 10 S / m, while the metal material of the metal grating strip 8 is copper. The period of the composite metasurface unit structure is 100 μm.
[0027] This embodiment simulates the aforementioned terahertz multi-order Bessel beam generator to demonstrate its technical effects. In the simulation calculation, CST Microwave Studio simulation software is used to create a 2D model to simulate the actual structure. The phase of each composite metasurface unit structure can be controlled by adjusting the size parameters of the metal notched ring 5. In this embodiment, a total of eight units with different phases were designed using different size parameters. Table 1 shows the relationship between the phase of the metal notched ring and the size parameters of the metal notched ring 5 under incident linearly polarized terahertz waves at a frequency of 1.1 THz.
[0028] Table 1. Phase and size relationship of the notched metal ring The phase required for generating a terahertz zero-order Bessel beam using a composite metasurface needs to satisfy... The operating wavelength is λ0 = 273 μm, and α is the base angle of the conical lens. When a linearly polarized terahertz wave with a radiation frequency of 1.1 THz is incident, α = 20°, the phase distribution required to generate a zero-order Bessel beam is as follows. Figure 2 As shown, the metasurface is divided into annular bands, each with the same phase distribution, and the composite metasurface units are arranged and combined according to a preset phase period. To verify the self-healing property of the Bessel beam, a PEC (Perfect Electric Conductor) obstacle was placed above the main lobe region. The electric field distribution of the terahertz zero-order Bessel beam with and without the rectangular PEC obstacle in the xoz plane is shown in the figure. Figure 3 As shown, the main lobe region of the Bessel beam that is blocked can self-repair, restoring the main lobe to the same intensity distribution shape as when it was not blocked.
[0029] Phase required for generating terahertz first-order Bessel beams using composite metasurfaces When a linearly polarized terahertz wave with a radiation frequency of 1.1 THz is incident, a first-order Bessel beam is generated. l =1, α=6° and α=12°, Figure 4 The phase required to generate a first-order Bessel beam in terahertz waves is shown in (a) and (b). The composite metasurface units are arranged and combined according to a preset phase period. 。 Figure 5 (a) and Figure 6 (a) The normalized electric field intensity distribution of the first-order Bessel beam on the xoz plane when α=6° and α=12° respectively. It can be seen from the figure that the smaller the bottom angle α of the conical lens, the longer the propagation distance of the terahertz first-order Bessel beam. Figure 5 (b) and Figure 6(b) First-order Bessel beam at three observation points (Z=10λ0, Z=15λ0, Z=20λ0) when α=6° and α=12° respectively. xoy The normalized electric field intensity distribution on the plane, as shown in the figure, reveals the vortex electromagnetic wave distribution in the central void region of the terahertz wave electric field.
[0030] Phase required for generating terahertz second-order Bessel beams using composite metasurfaces When the terahertz wave radiation frequency is 1.1 THz, a first-order Bessel beam is generated. l When =2, α=8°, Figure 7 The phase required to generate a second-order Bessel beam in terahertz waves is shown, and the composite metasurface units are arranged and combined according to a preset phase period. 。 Figure 8 (a) shows the normalized electric field intensity distribution of the second-order Bessel beam on the xoz plane when α=8°. It can be seen from the figure that the OAM beam has obvious diffraction and diffusion phenomena during propagation. Figure 8 (b) shows the second-order Bessel beam at three observation points (Z=6λ0, Z=12λ0, Z=18λ0, Z=24λ0) when α=8°. xoy The normalized electric field intensity distribution on the plane, as shown in the figure, reveals a vortex electromagnetic wave distribution in the central void region of the terahertz wave electric field. The spot radius varies little at different observation points Z, indicating a relatively concentrated energy distribution, thus verifying the non-diffraction nature of the Bessel beam. The results demonstrate that the designed terahertz multi-order Bessel beam generator can achieve control over the generation and transmission of terahertz waves via Bessel beams.
[0031] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, all technical solutions obtained through equivalent substitution or transformation fall within the protection scope of the present invention.
Claims
1. A terahertz multi-order Bessel beam generator, characterized in that, It is composed of several composite metasurface unit structures arranged and assembled according to the phase period; the composite metasurface unit structure includes a photosensitive silicon grating strip (3), a first F4B dielectric layer (4), a metal notch ring (5), a second F4B dielectric layer (6), and a composite grating stacked sequentially; the photosensitive silicon grating strip (3) is attached to the upper surface of the first F4B dielectric layer (4); the metal notch ring (5) is sandwiched between the first F4B dielectric layer (4) and the second F4B dielectric layer (6), forming a sandwich structure; the metal notch ring (5) is composed of an open metal ring and an inner connecting section, the open metal ring having two The metal ring has an opening, and the two openings are symmetrically distributed along the radial direction of the metal ring. The two ring ends on both sides of each opening are provided with an inward folded protrusion. The inner connecting section of the ring consists of an outer circle and an inner square metal ring and strip connecting sections on both sides along the radial direction. The outer circle and inner square metal ring is connected to the inner wall of the opening metal ring through the strip connecting sections on both sides. The composite grating serves as the base layer of the entire composite metasurface unit structure and is composed of VO2 grating strips (7) and metal grating strips (8) alternately spliced along the plane. The length directions of the VO2 grating strips (7) and metal grating strips (8) are perpendicular to the length direction of the photosensitive silicon grating strip (3).
2. A terahertz multi-order Bessel beam generator according to claim 1, characterized in that, The photosensitive silicon grating strip (3) has a thickness of 12.5 μm to 14 μm, a width of 34 μm to 36 μm, and an electrical conductivity of 10. 6 S / m.
3. A terahertz multi-order Bessel beam generator according to claim 1, characterized in that, The first F4B dielectric layer (4) uses F4B material with a dielectric constant of 2.7, a loss tangent of 0.0023, and a thickness of 20μm~40μm.
4. A terahertz multi-order Bessel beam generator according to claim 1, characterized in that, The second F4B dielectric layer (6) uses F4B material with a dielectric constant of 2.7, a loss tangent of 0.0023, and a thickness of 20μm~40μm.
5. A terahertz multi-order Bessel beam generator according to claim 1, characterized in that, The thickness of the metal notched ring (5) is 10μm~20μm, wherein the outer radius of the open metal ring is 40μm~50μm, the inner radius is 20μm~30μm, the opening width is 4μm~8μm, and the length of the inward folded protrusion is 0μm~20μm.
6. A terahertz multi-order Bessel beam generator according to claim 5, characterized in that, In the metal notched ring (5), the outer radius of the inner square metal ring of the inner connecting section is 14μm~16μm, the side length of the inner square opening is 9μm~11μm, and the width of the strip connecting sections on both sides is 9μm~11μm.
7. A terahertz multi-order Bessel beam generator according to claim 1, characterized in that, In the composite grating, the width of a single VO2 grating strip (7) is 14~16μm, the width of a single metal grating strip (8) is 9~11μm, and the thickness is 0.9~1.1μm.
8. A terahertz multi-order Bessel beam generator according to claim 1, characterized in that, The conductivity of the VO2 grating strip (7) is 10 S / m, and the metal material of the metal grating strip (8) is copper.
9. A terahertz multi-order Bessel beam generator according to claim 1, characterized in that, The period of the composite metasurface unit structure is 100μm~120μm.
10. A terahertz multi-order Bessel beam generator according to claim 1, characterized in that, All composite metasurface unit structures are arranged and combined according to the phase period of the Bessel beam to form a terahertz multi-order Bessel beam generator.