A topological interface resonator based on synthetic translation dimension and a design method thereof and a photonic crystal nanobeam laser
Patent Information
- Application Number
- CN202610899326.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-22
- Publication Date
- 2026-10-13
AI Technical Summary
该类设计往往涉及多个耦合结构参数，设计过程复杂，对加工误差较为敏感；尤其在形成多波长级联阵列时，容易出现模态混杂、单模特性下降以及相邻波长间隔不稳定等问题
（1）本申请以空气孔的平移位移量作为核心合成维度参数，显著简化了纳米梁激光器的多参数耦合优化过程；
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Figure CN122907949A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of photonic crystal technology, specifically to a topological interface resonator based on synthetic translation dimension and its design method, and a photonic crystal nanobeam laser. Background Technology
[0002] Nanobeam photonic crystal lasers have become an important form of integrated coherent light source due to their small mode volume, high quality factor, and ease of on-chip integration. Traditional nanobeam lasers typically determine the resonant wavelength by introducing geometric defects to modulate the resonant mode, such as by jointly adjusting the defect aperture size, defect location, cavity length, and adjacent period parameters. This type of design often involves multiple coupling structure parameters, making the design process complex and sensitive to fabrication errors; especially when forming multi-wavelength cascaded arrays, problems such as mode mixing, degraded single-mode characteristics, and unstable spacing between adjacent wavelengths can easily occur.
[0003] Therefore, there is an urgent need for a photonic crystal nanobeam laser with few structural parameters, clear tuning relationships, easy fabrication and implementation, and suitable for multi-wavelength output. Summary of the Invention
[0004] Based on the shortcomings of existing technologies, the purpose of this application is to provide a topological interface resonator based on synthetic translation dimension and its design method, as well as a photonic crystal nanobeam laser.
[0005] To achieve the above objectives, the technical solution adopted in this application is as follows: In a first aspect of this application, a photonic crystal nanobeam laser based on a synthetic translation dimension is provided, comprising a photonic crystal nanobeam, wherein the photonic crystal nanobeam comprises a trivial topological photonic crystal region and at least one non-trivial topological photonic crystal region arranged sequentially along the light propagation direction; The trivial topological photonic crystal region includes a first unit cell arranged periodically along the light propagation direction. A first air hole is provided in the first unit cell. The translational displacement of the first air hole is 0. The translational displacement of the first air hole refers to the offset size of the center of the first air hole relative to the center of the first unit cell in the light propagation direction. The nontrivial topological photonic crystal region is provided with a second unit cell arranged periodically along the light propagation direction. The lattice constant of the first unit cell is the same as that of the second unit cell, which is a. A second air hole is provided in the second unit cell. The translational displacement of the second air hole is greater than 0 and less than a. The translational displacement of the second air hole refers to the offset of the center of the second air hole relative to the center of the second unit cell in the light propagation direction. A topological interface is formed at the boundary between the trivial topological photonic crystal region and the non-trivial topological photonic crystal region. A topologically protected local optical mode is generated at the topological interface to form the topological interface resonant cavity and to output laser light.
[0006] Preferably, 400nm≤a≤500nm.
[0007] Preferably, the translational displacement of the second air hole is 80~300nm.
[0008] Preferably, the thickness of the photonic crystal nanobeam is h. s ,200nm≤h s ≤320nm, the width of the photonic crystal nanobeam is w s 300nm≤w s ≤600nm.
[0009] Preferably, the first air hole is any one of a cuboid, a cube, and a cylinder.
[0010] More preferably, the first air hole has a cuboid structure, and the length of the first air hole is [dimension value missing]. l 1. The shorter side dimension is w1, 1.5 ≤ l 1 / w1≤3, 60nm≤w1≤90nm.
[0011] Preferably, the second air hole is any one of a cuboid, a cube, and a cylinder.
[0012] More preferably, the second air hole has a cuboid structure, and the length of the second air hole is [dimension value missing]. l 2. The shorter side dimension is w2, 1.5≤ l 2 / w2≤3, 60nm≤w2≤90nm.
[0013] Preferably, the number of non-trivial topological photonic crystal regions is not less than two.
[0014] Preferably, the number of nontrivial topological photonic crystal regions is three, and the three nontrivial topological photonic crystal regions are arranged sequentially along the light propagation direction. Any two adjacent nontrivial topological photonic crystal regions are connected to form two second topological interfaces. Topologically protected local optical modes are generated at the first topological interface and the two second topological interfaces, respectively, to form three topological interface resonant cavities and output lasers respectively.
[0015] More preferably, along the light propagation direction, in the three nontrivial topological photonic crystal regions, the translational displacement of the second air hole in the nontrivial topological photonic crystal region at the first end is denoted as dx1, the translational displacement of the second air hole in the nontrivial topological photonic crystal region in the middle is denoted as dx2, and the translational displacement of the second air hole in the nontrivial topological photonic crystal region at the last end is denoted as dx3, where dx1 < dx2 < dx3.
[0016] Further preferred values are 0.2≤dx1 / a≤0.3, 0.35≤dx2 / a≤0.45, and 0.5≤dx3 / a≤0.6.
[0017] More preferably, in the direction of light propagation, the difference in resonant wavelength between any two adjacent topological interface resonant cavities is 10~50nm.
[0018] Preferably, the resonant wavelengths of the three topological interface resonators are each independently 1480nm~1620nm.
[0019] In a second aspect, this application provides a design method for a topological interface resonator based on a synthetic translation dimension, comprising the following steps: Establish an equivalent coupled model or equivalent Hamiltonian that includes translational displacement; Using the translational displacement as a synthesis dimension parameter, the mapping relationship between the translational displacement and the frequency or wavelength of the topological interface state within the bandgap is obtained. Select the translation displacement corresponding to the target frequency or target wavelength, and set a trivial topological photonic crystal region with a translation displacement of 0 and at least one non-trivial topological photonic crystal region with a translation displacement greater than 0 and less than a in the photonic crystal nanobeam. A topological interface is formed at the junction of any two adjacent photonic crystal regions to obtain a topological interface resonant cavity corresponding to the target frequency or target wavelength.
[0020] In a third aspect, this application provides a topological interface resonant cavity based on a synthetic translation dimension, which is designed by the above-described design method.
[0021] In this application, the topological interface resonator in the aforementioned photonic crystal nanobeam laser is designed using the aforementioned design method.
[0022] Compared with the prior art, the beneficial effects of this application are as follows: (1) This application uses the translational displacement of the air hole as the core synthesis dimension parameter, which significantly simplifies the multi-parameter coupling optimization process of the nanobeam laser; (2) This application can achieve deterministic mapping and continuous tuning of the wavelength of the topological interface state within the photonic bandgap by using a single air hole translation displacement parameter; (3) In this application, the topological interface states form a single local mode within the bandgap, which is beneficial to stable single-mode laser output; (4) This application uses multiple topological interface resonant cavities cascaded to form an array. Even if there is a certain structural deviation in the size of the air hole, the resonant wavelength spacing between adjacent topological interface resonant cavities remains highly stable. (5) The photonic crystal nanobeam laser based on the synthetic translation dimension in this application has a simple structure and a clear processing window, making it suitable for realization through standard micro-nano fabrication processes; (6) The design method provided in this application has few design parameters and a clear wavelength design relationship; (7) The photonic crystal nanobeam laser provided in this application has advantages such as single-mode stability, robust array wavelength spacing and easy micro-nano fabrication, and is suitable for on-chip multi-wavelength coherent light sources and high-density photonic integration. Attached Figure Description
[0023] The embodiments described in this application are not limited to the figures described below, which are only some of the embodiments described in this application. Those skilled in the art can obtain figures of other embodiments based on the content of this application.
[0024] Figure 1 A schematic diagram of the structure of a photonic crystal nanobeam provided in one embodiment of this application; Figure 2 A schematic diagram of the structure of the first unit cell provided in this application; Figure 3 This is a schematic diagram of the structure of the second unit cell provided in this application; Figures 4a to 4l Simulation results of the resonant wavelength of a photonic crystal nanobeam laser under different translational displacements; Figure 5 The quality factor of the photonic crystal nanobeam laser varies under different translational displacements. Figure 6 A schematic diagram of the structure of a photonic crystal nanobeam provided for another embodiment of this application; Figures 7a to 7c This is a schematic diagram showing the results of the wavelength spacing stability of adjacent modes in a photonic crystal nanobeam laser under different air hole size deviations. Detailed Implementation
[0025] To better illustrate the purpose, technical solution, and advantages of this application, the following description, in conjunction with specific embodiments and comparative examples, aims to provide a detailed understanding of the content of this application, rather than to limit its scope. All other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this application.
[0026] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.
[0027] It is understood that spatial relation terms such as "below," "under," "below," "below," "above," "over," etc., can be used here to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as "below" or "under" or "below" of the other element or feature will be oriented "over" the other element or feature. Therefore, the exemplary terms "below" and "under" can include both upper and lower orientations. Furthermore, the device may also include other orientations (e.g., rotated 90° or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.
[0028] It should be noted that when one element is considered to be "connected" to another element, it can be directly connected to the other element or connected to the other element through an intermediary element. In the following embodiments, "connection" should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have the transmission of electrical signals or data between them.
[0029] It should be noted that the singular forms of “a,” “one,” and “the” can also include the plural forms, unless the context clearly indicates otherwise.
[0030] It should also be understood that the terms “including / comprise” or “have” specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof.
[0031] The technical features described in this application in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions.
[0032] It should be understood that, unless otherwise specified, the numerical ranges involved in this application are considered continuous, including the minimum and maximum values of the range, and every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the maximum and minimum values of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed in this application should be understood to include any or all of the subranges to which they are included.
[0033] In this application, the terms "first" and "second" are used only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features indicated, or implicitly indicating the order of the technical features indicated.
[0034] In this application, the terms "some embodiments," "examples," etc., refer to specific features, structures, materials, or characteristics described in connection with the embodiment or example that are included in at least one embodiment or example of this application. In this application, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0035] In this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.
[0036] Please see Figures 1-3 and Figure 6 In a first aspect of this application, this application provides a photonic crystal nanobeam laser based on a synthetic translation dimension, comprising a photonic crystal nanobeam 1, wherein the photonic crystal nanobeam 1 comprises a trivial topological photonic crystal region 11 and at least one non-trivial topological photonic crystal region 12 arranged sequentially along the light propagation direction. The trivial topological photonic crystal region 11 includes a first unit cell arranged periodically along the light propagation direction. A first air hole 111 is provided in the first unit cell. The translational displacement of the first air hole 111 is 0. The translational displacement of the first air hole 111 refers to the offset size of the center of the first air hole 111 relative to the center of the first unit cell in the light propagation direction. The nontrivial topological photonic crystal region 12 is provided with a second unit cell arranged periodically along the light propagation direction. The lattice constant of the first unit cell is the same as that of the second unit cell, which is a. A second air hole 121 is provided in the second unit cell. The translational displacement of the second air hole is greater than 0 and less than a. The translational displacement of the second air hole refers to the offset of the center of the second air hole relative to the center of the second unit cell in the light propagation direction. A topological interface 13 is formed at the junction of the trivial topological photonic crystal region 11 and the non-trivial topological photonic crystal region 12. A topologically protected local optical mode (i.e., topological interface state) is generated at the topological interface 13 to form the topological interface resonant cavity and to output laser light.
[0037] In this application, the light propagation direction refers to the propagation direction of the laser in the photonic crystal nanobeam 1, such as... Figure 1 and Figure 6 The direction X in the middle.
[0038] This application can simplify device design and improve the designability and structural robustness of multi-wavelength arrays by mapping the displacement of a single structural parameter to the target wavelength without increasing the actual structural dimensions.
[0039] The inventors discovered through research that by adjusting the translational displacement of the first air hole and the second air hole, the intrinsic frequency of the laser emitted from the topological interface can be continuously changed, and the resonant wavelength or lasing wavelength can be continuously tunable within the photonic bandgap, preferably covering the 1480nm~1620nm band.
[0040] In some implementations, 400nm ≤ a ≤ 500nm.
[0041] In some embodiments, the translational displacement of the second air hole is 80~300nm.
[0042] In some embodiments, the thickness of the photonic crystal nanobeam 1 is h. s ,200nm≤h s ≤320nm, the width of photonic crystal nanobeam 1 is w s 300nm≤w s ≤600nm.
[0043] In some embodiments, the first air hole is any of the following structures: cuboid, cube, and cylinder.
[0044] In some embodiments, the first air hole is a cuboid structure, and the length of the first air hole is [dimension value missing]. l 1. The shorter side dimension is w1, 1.5 ≤ l1 / w1≤3, 60nm≤w1≤90nm.
[0045] In some embodiments, the second air hole is any of the following structures: cuboid, cube, and cylinder.
[0046] In some embodiments, the second air hole is a cuboid structure, and the length of the second air hole is [dimension value missing]. l 2. The shorter side dimension is w2, 1.5≤ l 2 / w2≤3, 60nm≤w2≤90nm.
[0047] In some embodiments, the number of first cells in the trivial topological photonic crystal region 11 is not less than 3, for example, it can be any or any combination of 3, 4, 5, 6, 7, 8, 9, 10, 11, 12.
[0048] In some embodiments, the number of second cells in the nontrivial topological photonic crystal region 12 is not less than three, for example, it can be any or any combination of three, four, five, six, seven, eight, nine, ten, eleven, and twelve.
[0049] In some implementations, the number of non-trivial topological photonic crystal regions 12 is not less than two.
[0050] In some embodiments, the number of nontrivial topological photonic crystal regions 12 is three. The three nontrivial topological photonic crystal regions 12 are arranged sequentially along the light propagation direction. Any two adjacent nontrivial topological photonic crystal regions 12 are connected to form two second topological interfaces 14. Topologically protected local optical modes are generated at the first topological interface 13 and the two second topological interfaces 14, respectively, to form three topological interface resonant cavities and to be used for laser output.
[0051] In some embodiments, along the light propagation direction, in the three nontrivial topological photonic crystal regions 12, the translational displacement of the second air hole 121 in the nontrivial topological photonic crystal region 12 located at the first end is denoted as dx1, the translational displacement of the second air hole 121 in the nontrivial topological photonic crystal region 12 located in the middle is denoted as dx2, and the translational displacement of the second air hole 121 in the nontrivial topological photonic crystal region 12 located at the last end is denoted as dx3, where dx1 < dx2 < dx3.
[0052] In some of these implementations, dx1 < dx2 < dx3.
[0053] In some implementations, 0.2 ≤ dx1 / a ≤ 0.3, 0.35 ≤ dx2 / a ≤ 0.45, and 0.5 ≤ dx3 / a ≤ 0.6.
[0054] In some embodiments, the difference in resonant wavelength between any two adjacent topological interface resonant cavities is 10~50nm.
[0055] In some of these implementations, the resonant wavelengths of the three topological interface resonators are each independently between 1480 nm and 1620 nm.
[0056] In some embodiments, when the long side dimension and / or the short side dimension of the first air hole deviates positively, and / or the long side dimension and / or the short side dimension of the second air hole deviates positively, the resonant wavelength of the topological interface resonant cavity formed at the first topological interface undergoes a blue shift.
[0057] When the long side dimension and / or the short side dimension of the second air hole deviate positively, the resonant wavelength of the topological interface resonant cavity formed at the second topological interface undergoes a blue shift.
[0058] When the long side dimension and / or the short side dimension of the first air hole deviate negatively, and / or the long side dimension and / or the short side dimension of the second air hole deviate negatively, the resonant wavelength of the topological interface resonant cavity formed at the first topological interface undergoes a redshift.
[0059] When the long side dimension and / or the short side dimension of the second air hole deviate negatively, the resonant wavelength of the topological interface resonant cavity formed at the second topological interface redshifts.
[0060] In a second aspect, this application provides a design method for the above-mentioned topological interface resonator based on the synthetic translation dimension, comprising the following steps: Establish an equivalent coupled model or equivalent Hamiltonian that includes translational displacement; Using the translational displacement as a synthesis dimension parameter, the mapping relationship between the translational displacement and the frequency or wavelength of the topological interface state within the bandgap is obtained. Select the translation displacement corresponding to the target frequency or target wavelength, and set a trivial topological photonic crystal region with a translation displacement of 0 and at least one non-trivial topological photonic crystal region with a translation displacement greater than 0 and less than a in the photonic crystal nanobeam. A topological interface is formed at the junction of any two adjacent photonic crystal regions to obtain a topological interface resonant cavity corresponding to the target frequency or target wavelength.
[0061] In this application, the topological interface resonator in the aforementioned photonic crystal nanobeam laser is designed using the aforementioned design method.
[0062] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments.
[0063] Example 1 like Figures 1-3 As shown, this embodiment provides a photonic crystal nanobeam laser based on a synthetic translation dimension, including a photonic crystal nanobeam 1. The photonic crystal nanobeam 1 includes a trivial topological photonic crystal region 11 and at least one non-trivial topological photonic crystal region 12 arranged sequentially along the light propagation direction. The trivial topological photonic crystal region 11 includes four first unit cells arranged periodically along the light propagation direction. A first air hole 111 is provided in the first unit cell. The translation displacement of the first air hole 111 is 0. The translation displacement of the first air hole 111 refers to the offset size of the center of the first air hole 111 relative to the center of the first unit cell in the light propagation direction. The nontrivial topological photonic crystal region 12 is provided with four second unit cells arranged periodically along the light propagation direction. A second air hole 121 is provided in the second unit cell. The lattice constant of the first unit cell is the same as that of the second unit cell, which is a, where a is 445 nm. The translational displacement of the second air hole 121 is 174 nm. The translational displacement of the second air hole refers to the offset size of the center of the second air hole relative to the center of the second unit cell in the light propagation direction. A first topological interface 13 is formed at the junction of the trivial topological photonic crystal region 11 and the non-trivial topological photonic crystal region 12. A topologically protected local optical mode (i.e., topological interface state) is generated at the first topological interface 13. The optical field local region corresponding to the topological interface state constitutes the topological interface resonant cavity. Stimulated emission output can be realized when an active gain material is introduced and pumped.
[0064] The thickness of the photonic crystal nanobeam 1 is h. s The width of photonic crystal nanobeam 1 is w s h s For 260nm, w s It is 445nm.
[0065] The first air hole has a cuboid structure, and the length of the first air hole is [dimension value missing]. l 1. The shorter side dimension is w1. l 1 is 155nm, and w1 is 75nm.
[0066] The second air hole has a cuboid structure, and the length of the second air hole is [dimension value missing]. l 2. The shorter side dimension is w2. l 2 is 155nm, and w2 is 75nm.
[0067] The photonic crystal nanobeam 1 is made of InP material, and the refractive index of InP is 3.2.
[0068] Example 2 The difference between this embodiment and embodiment 1 is that, based on embodiment 1, this embodiment maintains h s w s a, l 1, w1, l 2. Keep w2 unchanged, only change the translational displacement of the second air hole in the nontrivial topological photonic crystal region (e.g.) Figures 4a to 4l (dx in the image), to obtain photonic crystal nanobeam lasers with different dx.
[0069] A three-dimensional electromagnetic numerical simulation method was used to simulate and test various photonic crystal nanobeam lasers. During the simulation, the nanobeam material parameters (i.e., the refractive index of InP is 3.2), the lattice constant a, the size of each air hole, and the cross-sectional size of the nanobeam were input. The upper and lower cladding of the photonic crystal nanobeam lasers were both air. During the simulation, the position of the resonance peak corresponding to the topological interface state was extracted by scanning the translational displacement of different air holes.
[0070] Simulation results are as follows Figures 4a to 4l As shown, when the translational displacement of the second air hole in the nontrivial topological photonic crystal region varies between 0 and a, the resonant wavelength of the topological interface resonant cavity continuously varies within the photonic bandgap, achieving lasing output of approximately 1480 nm to 1620 nm. The tunable lasing modes corresponding to the translational displacement of the second air hole in all different nontrivial topological photonic crystal regions maintain single-mode output within the above tuning range, with no significant side-mode radiation. This feature indicates that the present invention does not achieve wavelength variation through conventional defect mode drift, but rather achieves deterministic spectral tuning by synthesizing translation-driven topological interface states.
[0071] Example 3 The difference between this embodiment and embodiment 1 is that, based on embodiment 1, this embodiment maintains h s w s a, l 1, w1, l 2. Keeping w2 unchanged, only changing the translational displacement dx of the second air hole in the non-trivial topological photonic crystal region, photonic crystal nanobeam lasers with different dx can be obtained.
[0072] The quality factor Q of the topological interface states was calculated under different dx conditions, and the results are as follows: Figure 5 As shown.
[0073] like Figure 5As shown, as the translational displacement dx of the second air hole in the nontrivial topological photonic crystal region changes, the ratio of dx to a (dx / a) changes accordingly, the localization degree of the interface state and the radiation leakage channel change, resulting in a change in the quality factor Q. It can be seen that the quality factor Q of the topological interface state can be continuously controlled.
[0074] As the translational displacement of the second air hole in the nontrivial topological photonic crystal region gradually increases, the Q value first rises and reaches a peak near an optimal value, then decreases as dx continues to increase. This variation indicates that the synthetic translational dimension parameter dx not only determines the spectral position of the topological interface states in the bandgap, but also has a significant impact on the mode's radiation loss and energy confinement capability. Therefore, it can be used as an important control parameter for realizing the engineering design of the quality factor.
[0075] Example 4 The difference between this embodiment and Embodiment 1 is that in this embodiment, the number of non-trivial topological photonic crystal regions 12 is three, such as... Figure 6 As shown, three nontrivial topological photonic crystal regions 12 are arranged sequentially along the light propagation direction. Any two adjacent nontrivial topological photonic crystal regions 12 are connected to form two second topological interfaces 14. Topologically protected local optical modes are generated at the first topological interface 13 and the two second topological interfaces 14, respectively, to form three topological interface resonators and output lasers respectively.
[0076] Along the light propagation direction, in the three nontrivial topological photonic crystal regions 12, the translational displacement of the nontrivial topological photonic crystal region 12 located at the first end is denoted as dx1, the translational displacement of the nontrivial topological photonic crystal region 12 located in the middle is denoted as dx2, and the translational displacement of the nontrivial topological photonic crystal region 12 located at the last end is denoted as dx3, where dx1 = 0.265a, dx2 = 0.405a, and dx3 = 0.560a. In the three topological interface resonant cavities, the difference in resonant wavelength between any two adjacent topological interface resonant cavities is approximately 30nm.
[0077] The resonant wavelength of the topological interface resonant cavity refers to the wavelength of the laser emitted by the topological interface resonant cavity.
[0078] Example 5 Based on Example 4, the dimensional deviation of the first air hole and the second air hole is further considered.
[0079] By introducing a predetermined positive or negative deviation into the dimensions of the first and second air holes, and comparing the resonant wavelengths between adjacent topological interface resonant cavities, the results are as follows: Figures 7a to 7cAs shown, TP1 is the topological interface resonant cavity formed at the first topological interface, and TP2 and TP3 represent the topological interface resonant cavities formed at the two second topological interfaces, respectively. Figure 7a middle l 1 and l Both 1 and w1 are 165nm, and both w1 and w2 are 85nm, which is a positive deviation compared to Example 4; Figure 7b The dimensions of the first and second air holes are the same as those in Example 4, with no deviation. Figure 7c middle l 1 and l Both 1 and w1 are 145nm, while w1 and w2 are both 65nm, showing a negative deviation.
[0080] The results show that when the long side dimension and the short side dimension of the first air hole deviate positively, and the long side dimension and the short side dimension of the second air hole deviate positively, the resonant wavelength of the topological interface resonant cavity formed at the first topological interface undergoes a blue shift. When the long side dimension and / or the short side dimension of the second air hole deviate positively, the resonant wavelength of the topological interface resonant cavity formed at the second topological interface undergoes a blue shift. When the long side dimension and the short side dimension of the first air hole deviate negatively, and the long side dimension and the short side dimension of the second air hole deviate negatively, the resonant wavelength of the topological interface resonant cavity formed at the first topological interface undergoes a redshift. When the long side dimension and the short side dimension of the second air hole deviate negatively, the resonant wavelength of the topological interface resonant cavity formed at the second topological interface redshifts.
[0081] Since the resonant mode originates from the topological interface state, its wavelength mapping relationship is constrained by the topological properties. Therefore, the geometric size deviation of the air hole has little impact on the resonant wavelength difference between adjacent topological interface resonant cavities, thus maintaining the stability of the multi-wavelength output interval better.
[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit the scope of protection of this application. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the substance and scope of the technical solutions of this application.
Claims
1. A photonic crystal nanobeam laser based on synthetic translation dimension, characterized in that, The invention includes photonic crystal nanobeams, wherein the photonic crystal nanobeams comprise a trivial topological photonic crystal region and at least one non-trivial topological photonic crystal region arranged sequentially along the light propagation direction; The trivial topological photonic crystal region includes a first unit cell arranged periodically along the light propagation direction. A first air hole is provided in the first unit cell. The translational displacement of the first air hole is 0. The translational displacement of the first air hole refers to the offset size of the center of the first air hole relative to the center of the first unit cell in the light propagation direction. The nontrivial topological photonic crystal region is provided with a second unit cell arranged periodically along the light propagation direction. The lattice constant of the first unit cell is the same as that of the second unit cell, which is a. A second air hole is provided in the second unit cell. The translational displacement of the second air hole is greater than 0 and less than a. The translational displacement of the second air hole refers to the offset of the center of the second air hole relative to the center of the second unit cell in the light propagation direction. A first topological interface is formed at the boundary between the trivial topological photonic crystal region and the non-trivial topological photonic crystal region. A topologically protected local optical mode is generated at the first topological interface to form the topological interface resonant cavity and to output laser light.
2. The photonic crystal nanobeam laser based on synthetic translation dimension as described in claim 1, characterized in that, 400nm≤a≤500nm.
3. The photonic crystal nanobeam laser based on synthetic translation dimension as described in claim 1, characterized in that, The translational displacement of the second air hole is 80~300nm.
4. The photonic crystal nanobeam laser based on synthetic translation dimension as described in claim 1, characterized in that, The thickness of the photonic crystal nanobeam is h. s ,200nm≤h s ≤320nm, the width of the photonic crystal nanobeam is w s 300nm≤w s ≤600nm.
5. The photonic crystal nanobeam laser based on synthetic translation dimension as described in claim 1, characterized in that, The first air hole is any one of a cuboid, a cube, and a cylinder, and / or the second air hole is any one of a cuboid, a cube, and a cylinder.
6. The photonic crystal nanobeam laser based on synthetic translation dimension as described in claim 5, characterized in that, The first air hole has a cuboid structure, and the length of the first air hole is [dimension value missing]. l 1. The shorter side dimension is w1, 1.5 ≤ l 1 / w1≤3, 60nm≤w1≤90nm; And / or, the second air hole has a cuboid structure, and the long side dimension of the second air hole is... l 2. The shorter side dimension is w2, 1.5≤ l 2 / w2≤3, 60nm≤w2≤90nm.
7. The photonic crystal nanobeam laser based on synthetic translation dimension as described in claim 1, characterized in that, The number of nontrivial topological photonic crystal regions is three, and the three nontrivial topological photonic crystal regions are arranged sequentially along the light propagation direction. Any two adjacent nontrivial topological photonic crystal regions are connected to form two second topological interfaces. Topologically protected local optical modes are generated at the first topological interface and the two second topological interfaces, respectively, to form three topological interface resonant cavities and to be used for laser output.
8. The photonic crystal nanobeam laser based on synthetic translation dimension as described in claim 7, characterized in that, Along the light propagation direction, in the three nontrivial topological photonic crystal regions, the translational displacement of the second air hole in the nontrivial topological photonic crystal region at the first end is denoted as dx1, the translational displacement of the second air hole in the nontrivial topological photonic crystal region in the middle is denoted as dx2, and the translational displacement of the second air hole in the nontrivial topological photonic crystal region at the last end is denoted as dx3, where dx1 < dx2 < dx3; And / or, in the direction of light propagation, the difference in resonant wavelength between any two adjacent topological interface resonant cavities is 10~50nm; And / or, the resonant wavelengths of the three topological interface resonators are each independently 1480nm~1620nm.
9. A design method for a topological interface resonant cavity based on synthetic translation dimension, characterized in that, Includes the following steps: Establish an equivalent coupled model or equivalent Hamiltonian that includes translational displacement; Using the translational displacement as a synthesis dimension parameter, the mapping relationship between the translational displacement and the frequency or wavelength of the topological interface state within the bandgap is obtained. Select the translation displacement corresponding to the target frequency or target wavelength, and set a trivial topological photonic crystal region with a translation displacement of 0 and at least one non-trivial topological photonic crystal region with a translation displacement greater than 0 and less than a in the photonic crystal nanobeam. A topological interface is formed at the junction of any two adjacent photonic crystal regions to obtain a topological interface resonant cavity corresponding to the target frequency or target wavelength.
10. A topological interface resonant cavity based on synthetic translation dimension, characterized in that, It is designed by the design method as described in claim 9.