Topological posture single photon source device and quantum light source

Abstract

The invention provides a topological posture single photon source device and a quantum light source, and relates to the technical field of topological quantum light sources. The topological state single photon source device comprises a GaAs layer; the SiO2 / Au structure comprises a SiO2 layer and an Au layer, and is positioned below the GaAs layer to serve as a reflecting mirror for inhibiting backward photon leakage; the topological state microcavity is processed and formed on the GaAs layer; and the quantum dots grow in the GaAs layer and are coupled with the topological posture of the topological posture microcavity to generate a topological posture single photon source. According to the invention, the coupling efficiency of the quantum dots and the microcavity is effectively improved by using the mode volume with a relatively large topological posture, the bottleneck that the coupling probability is low due to the limited volume of a traditional mode is broken through, and a better scheme is provided for realizing the interaction of high-efficiency light and substances.

Description

Technical Field

[0001] The present application relates to the technical field of topological quantum light sources, and in particular to a topological single-photon source device and a quantum light source. Background Art

[0002] In many quantum information application scenarios such as quantum communication, optical quantum simulation, sensing, and computing, single-photon quantum bits are of great significance as important information carriers. Self-assembled semiconductor quantum dots have become key candidates for building scalable solid-state quantum information platforms due to their ultra-high brightness and seamless interconnection with material quantum bits. Based on the principle of cavity quantum electrodynamics (CQED), high-quality single photons can be generated by coupling a single quantum dot with a carefully designed optical structure. At present, various optical micro-nanostructures such as micro-pillar cavities, open micro-cavities, circular Bragg gratings, two-dimensional photonic crystal (PC) defect cavities, and one-dimensional PC waveguides have become important research targets for realizing high-performance single-photon sources.

[0003] However, at the micrometer or nanometer scale, these optical micro-nanostructures have obvious defects: on the one hand, the interaction between light and matter is extremely sensitive to defects and disorder introduced by the processing process or environmental disturbances, and small changes can lead to a significant decline in device performance; on the other hand, the randomly grown individual quantum dots and the optical modes in the micro-nanostructure are prone to spatial and spectral mismatches, making high-precision cavity-dot coupling difficult to achieve and the probability of realization is low. To address these problems, researchers have developed complex quantum dot positioning technologies such as wide-field photoluminescence (PL) imaging and super-resolution snapshot hyperspectral imaging, but these methods also increase the complexity and cost of the technology.

[0004] Topological quantum optical interfaces combine quantum radiation sources with topologically protected cavity modes, bringing new possibilities for constructing topologically robust quantum light sources that are insensitive to structural defects. Currently, quantum light sources based on 0-dimensional and 1-dimensional topological boundary states and 0-dimensional topological corner states have been experimentally verified, revealing novel physical phenomena such as chiral quantum interfaces and Purcell enhancement in topological non-trivial regions. However, in the field of quantum optics, the bulk properties of topological structures have not been deeply explored, and the extraction efficiency of single-photon sources under topological protection has not received sufficient attention and research. Currently, bulk topological effects have been applied in laser physics to achieve high-performance single-mode lasers with vertical emission and high directionality. This unique topological bulk state also has important application potential in related fields such as quantum photonics.

[0005] The existing technologies mainly focus on the coupling of topological boundary states or topological corner states with quantum dots. These technical solutions use micro-nanostructures such as photonic crystals or microring coupling arrays to establish 0-dimensional or 1-dimensional topological interfaces, and couple single quantum dots to the topological boundary states or topological corner states at the topological interfaces to realize quantum light sources with topological properties. However, the existing technologies focus on the coupling of topological boundary states or topological corner states with quantum dots. These modes are at the topological interfaces, and the mode volume is limited, resulting in a low probability of achieving efficient cavity-dot coupling. It is necessary to find new coupling methods to improve the coupling probability. In addition, the existing technologies only focus on the topological interface effects and ignore the bulk properties in the topological structure. In addition, the extraction efficiency of the topological quantum light source in the existing technologies is low, and no effective optimization scheme has been proposed. Summary of the Invention

[0006] In order to solve at least one of the above problems, the present application proposes a topological single-photon source device and a quantum light source.

[0007] According to the first aspect of the present application, at least one embodiment of the present application provides a topological single-photon source device, comprising: a GaAs layer; a SiO2 / Au structure, comprising a SiO2 layer and an Au layer, located below the GaAs layer to act as a reflector to suppress back-photon leakage; a topological microcavity, processed and formed on the GaAs layer; and quantum dots, grown in the GaAs layer, coupled with the topological state of the topological microcavity to generate a topological single-photon source.

[0008] For example, in some embodiments of the present application, the topological bulk microcavity includes: a hexagonal optical microcavity including a topologically trivial photonic crystal; and a topologically non-trivial photonic crystal surrounding the outside of the hexagonal optical microcavity.

[0009] For example, in some embodiments of the present application, the topologically trivial photonic crystal is obtained by shrinking the triangular air hole lattice points in each unit cell of the hexagonal lattice.

[0010] For example, in some embodiments of the present application, the topologically non-trivial photonic crystal is obtained by expanding the triangular air hole lattice points in each unit cell of the hexagonal lattice.

[0011] For example, in some embodiments of the present application, near the Γ point, the components of the p and d modes in the energy bands of the topologically trivial photonic crystal and the topologically non-trivial photonic crystal can be reversed, so that the light waves can be reflected by the topological interface and confined within the hexagonal optical microcavity to form the topological state.

[0012] For example, in some embodiments of the present application, the topological microcavity is formed in the GaAs layer by an etching process.

[0013] For example, in some embodiments of the present application, the quantum dots include In(Ga)As quantum dots.

[0014] For example, in some embodiments of the present application, the quantum dots are grown in the GaAs layer by molecular beam epitaxy.

[0015] For example, in some embodiments of the present application, the thickness of the GaAs layer is 150nm-200nm; the thickness of the SiO2 layer is 250nm-350nm; and the thickness of the Au layer is 150nm-250nm.

[0016] According to the second aspect of the present application, at least one embodiment of the present application provides a quantum light source, comprising: a topological single-photon source device as described in any one of the first aspects, for generating single photons.

[0017] Through the above exemplary embodiments, the present application provides a topological bulk single-photon source device that deeply explores the bulk properties of topological structures and applies them to quantum light source design, achieving at least one of the following beneficial effects:

[0018] Improving cavity-dot coupling performance: Breaking through the limitation of existing technologies that rely solely on topological boundary states or corner states to couple with quantum dots, the larger mode volume of topological states is utilized to effectively improve the coupling efficiency between quantum dots and microcavities. This breaks through the bottleneck of low coupling probability caused by the limited mode volume of traditional topological boundary states or corner states, providing a better solution for achieving efficient light-matter interaction.

[0019] Significantly improve the single-photon source extraction efficiency: The designed topological single-photon source device has greatly improved the extraction efficiency. Simulation calculations show that the far-field divergence angle of the radiation field of this light source is only 6.2°, and the extraction efficiency can reach 92%; when the numerical aperture of the collection objective lens is only 0.15, the extraction efficiency can still reach 77%.

[0020] Enhanced adaptability to quantum dot radiation wavelength: The single-photon source has a large tolerance for the quantum dot radiation wavelength. When the excitation wavelength varies from 928nm to 936nm, the extraction efficiency can be maintained above 80%, which enhances the stability and applicability of the single-photon source, reduces the stringent requirements for precise matching of quantum dots and cavity mode wavelengths, and broadens the application range of single-photon sources in different scenarios.

[0021] Achieving charge-adjustable function: This single-photon source is compatible with electrical injection and can achieve charge adjustment without the need for additional integrated electrical contact bridges. This provides a new approach for the development of new quantum light sources, simplifies the device structure and preparation process, and offers more possibilities for the further development and application of quantum light sources.

[0022] It should be understood that the foregoing general description and the following detailed description are merely illustrative and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] By describing in detail exemplary embodiments thereof with reference to the accompanying drawings, the above and other objects, features and advantages of the present application will become more apparent. The drawings described below are only some embodiments of the present application, and are not intended to limit the present application.

[0024] Figure 1 A schematic diagram of a topological single-photon source device is shown according to an exemplary embodiment;

[0025] Figure 2 Schematic diagrams showing topologically trivial photonic crystals and topologically non-trivial photonic crystals;

[0026] Figure 3 The energy band calculation results of topologically trivial photonic crystals and topologically non-trivial photonic crystals are shown;

[0027] Figures 4a-4c The near-field and far-field distributions of the topological state at a frequency of 321 THz obtained through three-dimensional simulation are shown;

[0028] Figure 5a and Figure 5b The high extraction efficiency of the topological single-photon source obtained by three-dimensional simulation is shown. DETAILED DESCRIPTION

[0029] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be embodied in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concepts of the example embodiments to those skilled in the art. Like reference numerals in the drawings represent like or similar parts, and thus repetitive description thereof will be omitted.

[0030] The described features, structures or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced without one or more of these specific details, or other methods, components, materials, devices, etc. may be employed. In these cases, well-known structures, methods, devices, implementations, materials or operations will not be shown or described in detail.

[0031] The flowcharts shown in the drawings are only illustrative, and do not necessarily include all the contents and operations / steps, nor are they necessarily executed in the order described. For example, some operations / steps can be further decomposed, and some operations / steps can be combined or partially combined, so the actual execution order can be changed according to actual conditions.

[0032] The terms "first", "second", and the like in the specification and claims of the present application and the above drawings are used to distinguish different objects, and are not used to describe a specific order. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but can optionally include steps or units not listed, or can optionally include other steps or units inherent to the process, method, product, or device.

[0033] Those skilled in the art can understand that the drawings are only schematic diagrams of example embodiments, and the modules or flows in the drawings are not necessarily essential for implementing the present application, and therefore cannot be used to limit the protection scope of the present application.

[0034] Figure 1 A schematic diagram of a topological state single photon source device is shown.

[0035] As shown in Figure 1 , the topological state single photon source device includes a GaAs layer, a SiO2 / Au structure, a topological state microcavity, and a quantum dot.

[0036] The longitudinal structure of the topological state single photon source device is GaAs / SiO2 / Au. The SiO2 / Au structure is located below the GaAs layer to serve as a high-efficiency mirror to suppress back photon leakage. The topological state microcavity is processed and shaped on the GaAs layer. The quantum dot is grown in the GaAs layer and coupled to the topological state of the topological state microcavity to generate a topological state single photon source. The single photon emission of this cavity-dot coupling system exhibits out-of-plane vertical directionality.

[0037] According to some embodiments, the topological state microcavity is processed and shaped on the GaAs layer through an etching process.

[0038] According to some embodiments, the quantum dot includes an In(Ga)As quantum dot. The quantum dot is grown and shaped in the GaAs layer through molecular beam epitaxy.

[0039] The thickness of the GaAs layer can be 150-200 nm; the thickness of the SiO2 layer can be 250-350 nm; and the thickness of the Au layer can be 150-250 nm.

[0040] Preferably, the thickness of the GaAs layer is 170 nm, the thickness of the SiO2 layer is 300 nm, and the thickness of the Au layer is 200 nm, so as to match the In(Ga)As quantum dots. This application only takes this as an example, but is not limited thereto.

[0041] According to an exemplary embodiment, a topological bulk microcavity includes a hexagonal optical microcavity and a topologically nontrivial photonic crystal, wherein the hexagonal optical microcavity includes the topologically trivial photonic crystal, and the topologically nontrivial photonic crystal surrounds the outside of the hexagonal optical microcavity.

[0042] like Figure 2 As shown in FIG, a topologically trivial photonic crystal (PC) is obtained by shrinking the triangular air hole lattice points in each unit cell of the hexagonal lattice. A topologically non-trivial photonic crystal is obtained by expanding the triangular air hole lattice points in each unit cell of the hexagonal lattice. Figure 2 The lattice constants in the topologically trivial photonic crystal and the topologically non-trivial photonic crystal are also shown. This application is only taken as an example, but is not limited thereto.

[0043] The energy bands of topologically trivial and non-trivial photonic crystals obtained by simulation are as follows Figure 3 As shown. Near the Γ point, the components of the p and d modes in the energy bands of the topologically trivial photonic crystal and the topologically non-trivial photonic crystal can be reversed, so that the light wave can be reflected by the topological interface and confined in the topological microcavity to form a topological state. Figure 3 The energy band calculation results of topologically trivial photonic crystals and topologically non-trivial photonic crystals are shown. The color of the energy band indicates the proportion of dipole (p) and quadrupole (d) modes. The inset is the z component of the magnetic field of the p and d modes at the Γ point of the lower energy band (H z ) field distribution.

[0044] Figures 4a-4c The near-field and far-field distributions of the topological state at a frequency of 321 THz obtained through three-dimensional simulation are shown. Figure 4a As shown, the topological state is spatially localized within the boundary between topologically trivial and non-trivial photonic crystals. Figure 4b and Figure 4c It shows that the topological state has a highly directional vertical emission characteristic, and its far-field field intensity distribution is nearly Gaussian.

[0045] Figure 5a and Figure 5b The high extraction efficiency of the topological single-photon source obtained by three-dimensional simulation is demonstrated. Figure 5aAs shown, the light source radiation field of the device has high directivity, and the far-field divergence angle is only 6.2°; the extraction efficiency can reach 92%, and the extraction efficiency has reached 77% when the numerical aperture (NA) of the collection objective lens is only 0.15. As shown in FIG. 6, the extraction efficiency of the device is also shown to have a large tolerance for the radiation wavelength of the quantum dot: when the excitation wavelength changes from 928 nm to 936 nm, the extraction efficiency can be maintained above 80%. Figure 5b

[0046] The application provides a topological bulk state single photon source device, which deeply explores the bulk state properties of the topological structure, applies it to the design of a single photon source, opens up a new research direction of topological quantum optics, breaks through the limitation of the prior art that only relies on the coupling of topological boundary states or corner states and quantum dots, and effectively improves the coupling efficiency of quantum dots and microcavities by using the large mode volume of topological bulk states. It breaks through the bottleneck of low coupling probability caused by the limited mode volume of traditional modes, and provides a more optimal solution for realizing efficient light-matter interaction. Moreover, the extraction efficiency of the single photon source is significantly improved, the adaptability to the radiation wavelength of the quantum dot is enhanced, and the charge adjustable function is realized.

[0047] The application also provides a quantum light source for quantum communication, optical quantum simulation, optical quantum sensing, optical quantum computing and other quantum information application fields. The quantum light source comprises the topological bulk state single photon source device as described above, and the topological bulk state single photon source device has high extraction efficiency, efficiently and accurately generates single photons as reliable carriers of information, reduces photon loss, and improves the efficiency of information transmission and processing. Moreover, the topological bulk state single photon source device can be compatible with electrical injection, and can realize the charge adjustable function without additional integrated electrical contact bridges, so that the light-emitting characteristics of single photons can be flexibly adjusted to meet the needs of different application scenarios; the robust quantum dot-microcavity interaction realized by coupling a single InAs / GaAs quantum dot to a topological bulk state optical microcavity ensures that single photons can still be stably and reliably generated in complex environments and in the presence of processing defects, thereby providing solid light source support for various quantum information applications.

[0048] It should be clearly understood that the application describes how to form and use specific examples, but the application is not limited to any details of these examples. Instead, based on the teachings of the disclosure of the application, these principles can be applied to many other embodiments.

[0049] In addition, it should be noted that the above figures are only schematic illustrations of the processes included in the method according to the exemplary embodiments of the application, and are not for limiting purposes. It is easy to understand that the processes shown in the above figures do not indicate or limit the time sequence of these processes. In addition, it is also easy to understand that these processes can be executed synchronously or asynchronously, for example, in multiple modules.

[0050] ​The exemplary embodiments of this application are specifically illustrated and described herein. But, it is to be understood that the application is not limited to the details of the illustrated implementations; rather, this application is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A topological single-photon source device, characterized in that: include: GaAs layer; A SiO2 / Au structure, comprising a SiO2 layer and an Au layer, is located below the GaAs layer to act as a reflector to suppress back-photon leakage; A topological microcavity is formed on the GaAs layer; Quantum dots are grown in the GaAs layer and coupled with the topological state of the topological microcavity to generate a topological single-photon source.

2. The topological single-photon source device according to claim 1, characterized in that: The topological microcavity comprises: Hexagonal optical microcavities, including topologically trivial photonic crystals; A topologically nontrivial photonic crystal surrounds the outside of the hexagonal optical microcavity.

3. The topological single-photon source device according to claim 2, characterized in that: The topologically trivial photonic crystal is obtained by shrinking and designing the triangular air hole lattice points in each unit cell of the hexagonal lattice.

4. The topological single-photon source device according to claim 2, characterized in that: The topologically non-trivial photonic crystal is obtained by designing the expansion of triangular air hole lattice points in each unit cell of the hexagonal lattice.

5. The topological single-photon source device according to claim 2, characterized in that: Adjacent to the Γ point, the components of the p and d modes in the energy bands of the topologically trivial photonic crystal and the topologically non-trivial photonic crystal can be reversed, so that the light waves can be reflected by the topological interface and confined in the hexagonal optical microcavity to form the topological state.

6. The topological single-photon source device according to claim 1, characterized in that: The topological microcavity is formed in the GaAs layer through an etching process.

7. The topological single-photon source device according to claim 1, wherein: The quantum dots include In(Ga)As quantum dots.

8. The topological single-photon source device according to claim 7, characterized in that: The quantum dots are grown in the GaAs layer by molecular beam epitaxy.

9. The topological single-photon source device according to claim 7, characterized in that: The thickness of the GaAs layer is 150nm-200nm; The thickness of the SiO2 layer is 250nm-350nm; The thickness of the Au layer is 150nm-250nm.

10. A quantum light source, characterized in that include: The topological single-photon source device according to any one of claims 1 to 9, used to generate single photons.

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