Terahertz metasurface frequency multiplier based on continuous domain bound state
By setting a hollow cylinder within a silicon structure and introducing perturbation to break the symmetry and excite quasi-BIC resonance, the problem of low resonance quality factor in existing metasurface resonators is solved, achieving efficient harmonic generation, especially the enhancement of the third harmonic.
Patent Information
- Application Number
- CN202520100147.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-16
- Publication Date
- 2026-01-13
- Estimated Expiration
- 2035-01-16
AI Technical Summary
Existing metasurface resonators and terahertz frequency multipliers have low resonance quality factors and complex structures, making it difficult to achieve efficient resonance.
By setting a hollow cylinder within a silicon structure and introducing a disturbance, the symmetry of the unit structure is broken, symmetric protective quasi-BIC resonance is excited, and harmonic enhancement is achieved by utilizing the local field enhancement generated by the quasi-BIC resonance.
It achieves high-quality factor resonance, has a simple structure, and can effectively generate harmonics in the terahertz band, especially the third harmonic, thus improving resonance efficiency.
Smart Images
Figure CN223798203U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to millimeter wave communication equipment and its use accessory related technical field, especially based on the terahertz super surface frequency doubler of continuum bound state. BACKGROUND
[0002] Electromagnetic super material is by sub -wavelength metal or dielectric material is periodic or non -periodic arrangement composition, electromagnetic super material and the electric field and magnetic field of incident electromagnetic wave resonance coupling, can show some special electromagnetic response, create the nature material cannot realize the nature, such as negative refractive index material, zero refractive index material and super high refractive index material etc.Electromagnetic super surface, simply called as'super surface', is the concept derived from electromagnetic super material, it can be regarded as the two-dimensional plane form of three-dimensional super material, the basic unit structure of super material is arranged on the plane according to certain sequence or rule and constitutes two-dimensional super surface.Compared with three-dimensional super material, super surface has smaller mass and volume, and has important significance for further reducing the size of optical device.Secondly, the processing difficulty and processing cost of super surface are greatly reduced.In the past few years, super surface is often used in the design and manufacture of optical devices and optical systems, and its performance far exceeds that of traditional diffractive optical elements, and at present, super surface has become an important branch of super material research, and has great application potential in engineering.
[0003] Terahertz (Terahertz, referred to as THz) wave is usually defined as the electromagnetic wave with frequency of 0.1THz-10THz (wavelength of 3mm-30μm), and its frequency spectrum is located between the infrared electromagnetic wave and the microwave spectrum in the electromagnetic spectrum. Because of its special frequency location, terahertz wave is the transition zone from electronics to photonics, and is also the transition zone from macroscopic classical theory to microscopic quantum theory. The photon energy of terahertz radiation is lower than the energy between most chemical bonds, and it has good penetration characteristics for most dielectrics. The frequency band of terahertz wave is wide, and the vibration and rotation energy levels of many biological macromolecules are in the terahertz wave band. This wave band contains rich spectral information, which is conducive to the study of the spectral characteristics of other substances in this wave band, and the substances can be detected and distinguished through characteristic resonance. Terahertz wave also has the advantages of low radiation energy, high spatial resolution and wideband spectral analysis. Therefore, terahertz wave has excellent performance and great development potential in the fields of communication, national security, biological medicine, etc.
[0004] Bound states in the continuum (BIC) is a localized mode of open systems, which coexists with the continuous radiation wave that can take away energy. BIC provides a new way to achieve high quality factor (Q factor) resonance, which can theoretically achieve resonance with infinite Q factor. The concept of BIC was first proposed in quantum mechanics, and then was generalized as a universal wave phenomenon, which has been experimentally verified in many fields. In 2008, Marinica et al. first introduced the concept of BIC into optics by taking two parallel dielectric gratings and two parallel dielectric cylinders as examples. Ideal BIC shows zero bandwidth resonance in the frequency spectrum, which can only be obtained in lossless and infinite structures. In practice, it is difficult to achieve ideal BIC using metasurfaces due to material loss, device size constraints, and processing defects. Generally, ideal BIC is converted into quasi-BIC (quasi-BIC) mode with limited high Q value to meet application requirements. The high Q value of the quasi-BIC based metasurface resonator shows excellent performance in biochemical sensing, harmonic enhancement, and laser.
[0005] In view of the above defects, the present design person actively researches and innovates to create a terahertz metasurface frequency doubler based on bound states in the continuum, so that it has more industrial utilization value. Content of the utility model
[0006] To solve the above technical problems, the purpose of the present application is to provide a terahertz metasurface frequency doubler based on bound states in the continuum.
[0007] To achieve the above purpose, the present application adopts the following technical solutions:
[0008] A terahertz metasurface frequency doubler based on bound states in the continuum includes a plurality of periodically arranged structural units, and each structural unit is composed of the same structure.
[0009] The structural unit includes a substrate and a silicon structure on the substrate.
[0010] A hollow cylinder is arranged in the silicon structure, and after introducing disturbance, the hollow cylinder in the silicon structure is offset to the horizontal direction to break the symmetry of the unit structure.
[0011] As a further improvement of the present application, the substrate is a quartz structure.
[0012] As a further improvement of the present application, the cross section of the substrate is a square.
[0013] As a further improvement of the present application, the period of the substrate is 280-320 μm, and the thickness of the substrate is 600 μm.
[0014] As a further improvement of the utility model, the cross section of the silicon structure is circular.
[0015] As a further improvement of the utility model, the height of the silicon structure is 130-170 μm, and the diameter of the silicon structure is 160-200 μm.
[0016] As a further improvement of the utility model, the diameter of the hollow cylinder is 65-75 μm.
[0017] By the above scheme, the utility model has at least the following advantages:
[0018] The utility model introduces the disturbance on the symmetry of the unit structure, excites the symmetric protection type quasi-BIC resonance, and realizes the harmonic enhancement by the nonlinear effect caused by the local field enhancement generated by the quasi-BIC resonance.
[0019] The utility model solves the problems of low resonance quality factor and complex structure in the existing metasurface resonator and terahertz frequency doubler.
[0020] The above description is only a summary of the technical scheme of the utility model, in order to more clearly understand the technical means of the utility model, and the content of the specification can be implemented, the following is the preferred embodiment of the utility model and the detailed description of the drawings. DRAWINGS
[0021] In order to more clearly illustrate the technical scheme of the embodiment of the utility model, the following will briefly introduce the drawings needed to be used in the embodiment, it should be understood that the following drawings only show some embodiments of the utility model, therefore should not be regarded as the limitation to the scope, for the ordinary skilled person in the art, under the premise of not paying the creative labor, other related drawings can also be obtained according to these drawings.
[0022] Figure 1 It is the structure schematic diagram of the terahertz metasurface frequency doubler based on continuous domain bound state of the utility model;
[0023] Figure 2 It is the array diagram of Figure 1 ;
[0024] Figure 3 It is the schematic diagram after introducing disturbance Figure 1 ;
[0025] Figure 4 It is the schematic diagram of the transmission spectrum corresponding to the metasurface of the utility model when the terahertz wave is vertically incident;
[0026] Figure 5 It is the schematic diagram of the transmission spectrum corresponding to the metasurface of the utility model when the terahertz wave is vertically incident.
[0027] Figure 6 The utility model is under the condition of terahertz wave vertical incidence, and the relationship between the third harmonic power corresponding to the resonance frequency point and the pump light power is shown in the schematic diagram.
[0028] In the figure, the meanings of the various reference signs are as follows.
[0029] Substrate 1, silicon structure 2, hollow cylinder 3. DETAILED DESCRIPTION
[0030] The specific embodiments of the utility model will be further described in detail below in combination with the drawings and examples. The following examples are used to illustrate the utility model, but are not used to limit the scope of the utility model.
[0031] In order to enable personnel in the technical field to better understand the utility model scheme, the technical scheme in the utility model embodiments will be clearly and completely described below in combination with the drawings in the utility model embodiments. Obviously, the described embodiments are only a part of the embodiments of the utility model, rather than all the embodiments. The components of the utility model embodiments described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the utility model provided in the drawings is not intended to limit the scope of the claimed utility model, but only represents selected embodiments of the utility model. Based on the embodiments of the utility model, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the utility model.
[0032] EMBODIMENT
[0033] The utility model provides a kind of terahertz super surface frequency doubler based on continuous domain bound state, by introducing the disturbance on the symmetry of unit structure, excitation symmetry protection quasi-BIC resonance, the nonlinear effect caused by local field enhancement generated by quasi-BIC resonance is used to realize harmonic enhancement, the present application solves the problems, such as low resonant quality factor and complex structure in existing super surface resonator and terahertz frequency doubler.
[0034] As Figures 1-3 Shown, a kind of terahertz super surface frequency doubler based on continuous domain bound state, including multiple periodically arranged structure units, the composition of each structure unit is same. Structure unit includes substrate 1 and silicon structure 2 on substrate 1.
[0035] Hollow cylinder 3 is arranged in the inside of silicon structure 2, after introducing disturbance, so that the hollow cylinder 3 in silicon structure 2 is offset to horizontal direction and thereby breaks unit structure symmetry. That is Figure 2 In it, the inside center offset of hollow cylinder 3 is d.
[0036] Substrate 1 is a quartz structure with a square cross-section and a period of 280-320 μm (i.e., Figure 1 In section a), the thickness of substrate 1 is 600 μm (i.e. Figure 1 (l in the middle).
[0037] The cross-section of silicon structure 2 is circular, and the height of silicon structure 2 is 130-170 μm (i.e., Figure 1 In the h), the diameter of silicon structure 2 is 160-200 μm (i.e., h). Figure 1 The diameter of the hollow cylinder 3 is 65-75 μm (i.e., w). Figure 1 (b)
[0038] like Figure 4 As shown, Figure 4 The transmission spectrum corresponding to the metasurface when terahertz waves are incident perpendicularly is given. After breaking the symmetry of the unit cell structure, the resonance is transformed from the ideal BIC mode to the quasi-BIC mode, which is manifested in the transmission spectrum as a resonance peak with an extremely high quality factor.
[0039] like Figure 5 As shown, Figure 5 A terahertz metasurface frequency multiplier based on continuous domain bound states is presented, showing the transmission spectrum and frequency doubling efficiency under perpendicular terahertz wave incidence. Harmonic enhancement occurs at the quasi-BIC resonance, and the harmonic conversion efficiency decreases after deviating from the resonance frequency. At the resonance frequency (0.47075THz), the third harmonic (1.41225THz) frequency doubling efficiency can reach 0.14%.
[0040] like Figure 6 As shown, Figure 6 This invention presents the relationship between the third harmonic power and the pump light power at the resonant frequency point of a terahertz metasurface frequency multiplier based on a continuous domain bound state under the condition of perpendicular terahertz wave incidence. The excitation third harmonic power is linearly related to the incident pump light power, proving that a terahertz metasurface frequency multiplier based on a continuous domain bound state can be used as a third frequency multiplier.
[0041] This invention introduces a periodic perturbation, causing a change in the minimum period of the unit structure. This allows a quasi-continuous bound-state mode to be achieved in a terahertz metasurface frequency multiplier based on continuous-domain bound states. It achieves high-quality factor resonance in the terahertz band, and the nonlinear response is significantly enhanced when the pump light is adjusted to the resonant frequency, enabling the generation of the third harmonic. This invention can be applied to the design of nonlinear devices in the millimeter-wave and terahertz bands.
[0042] In the description of the utility model, need understanding is, the term "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "internal", "external" and so on indicate the orientation or positional relation based on the orientation or positional relation shown in the drawing, just for the convenience of describing the utility model and simplifying the description, and not indicate or imply that the indicated device or element must have a particular orientation, construct and operate in a particular orientation, therefore can not be understood as the limitation of the utility model. In addition, the term "first", "second" and so on are only for the purpose of description, and can not be understood as indicating or implying relative importance or implying the number of the indicated technical features. Therefore, the features limited by "first", "second" and so on can be explicitly or implicitly included one or more features. In the description of the utility model, unless otherwise specified, the meaning of "a plurality of" is two or more.
[0043] In the description of the utility model, it should be pointed out that, unless otherwise specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, can be fixedly connected, can be detachably connected, or integrally connected, can be mechanically connected, can be electrically connected, can be directly connected, can be indirectly connected through an intermediate medium, can be the communication inside two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood through specific circumstances.
[0044] The above is only the preferred embodiment of the utility model, and is not used to limit the utility model, it should be pointed out that, for ordinary skilled in the art, on the premise of not departing from the technical principles of the utility model, can make several improvements and variations, these improvements and variations also should be regarded as the protection scope of the utility model.
Claims
1. A continuous domain bound state based terahertz metasurface frequency doubler, characterized in that, The structure comprises a plurality of structural units arranged periodically, each of the structural units having the same composition; The structural unit comprises a substrate (1) and a silicon structure (2) on the substrate (1); A hollow cylinder (3) is arranged in the silicon structure (2), and after a disturbance is introduced, the hollow cylinder (3) in the silicon structure (2) is offset to the horizontal direction to break the symmetry of the unit structure.
2. A continuous domain bound state based terahertz metasurface frequency doubler as claimed in claim 1, wherein, The substrate (1) is a quartz structure.
3. A continuous domain bound state based terahertz metasurface frequency doubler as claimed in claim 1, wherein, The cross section of the substrate (1) is square.
4. A continuous domain bound state based terahertz metasurface frequency doubler as claimed in claim 1, wherein, The period of the substrate (1) is 280-320 μm, and the thickness of the substrate (1) is 600 μm.
5. A continuous domain bound state based terahertz metasurface frequency doubler as claimed in claim 1, wherein, The cross section of the silicon structure (2) is circular.
6. A continuous domain bound state based terahertz metasurface frequency doubler as claimed in claim 1, wherein, The height of the silicon structure (2) is 130-170 μm, and the diameter of the silicon structure (2) is 160-200 μm.
7. A continuous domain bound state based terahertz metasurface frequency doubler as claimed in claim 1, wherein, The diameter of the hollow cylinder (3) is 65-75 μm.