A FP-cavity-anapole-exciton system for realizing multiple strongly coupled Rabi splits

Abstract

This invention relates to the field of optical technology, specifically to a multi-mode FP-anapole-exciton system that achieves multiple strongly coupled Rabi splits. The system comprises basic units arranged in a two-dimensional periodic pattern, with a square period. Each basic unit includes, from bottom to top, a first dielectric layer, a first metal layer, a composite layer, a second metal layer, and a second dielectric layer. The composite layer includes a transparent dielectric and a heterogeneous disk embedded within it. The heterogeneous disk includes, from top to bottom, a first dielectric disk, a semiconductor disk, and a second dielectric disk. This invention utilizes incident light waves to induce excitation of multiple FP-cavity modes, anapoles, and excitons. Through precise structural design and parameter adjustment, it achieves strong coupling between these multiple FP-cavity modes, anapoles, and excitons, expanding the number of Rabi splits, enhancing the strength of the three-mode coupling, and obtaining multiple large Rabi splitting energies. It has broad application prospects in ultrafast optical switches, Bose-Einstein condensates, and low-threshold lasers.

Description

Technical Field

[0001] This invention relates to the field of optical technology, and more specifically to an FP cavity-anapole-exciton system for realizing multiple strongly coupled Rabi splits. Background Technology

[0002] The interaction between light and matter plays a crucial role in optoelectronics, quantum optics, and nanophotonic devices, and has become the core of modern optics. Strong light-matter interactions can generate novel mixed energy states, showing promising applications in tunable low-threshold semiconductor lasers, low-energy switches, and cutting-edge nanophotonic devices. When the coherent energy exchange rate between light and matter exceeds the average dissipation rate of the mode, strong coupling occurs between two or more stimulated modes in an optical system, leading to the formation of polarons with both optical and material properties, manifested as observable energy level splitting. Strong coupling phenomena are currently widely used in applications such as ultrafast optical switches, Bose-Einstein condensates, and low-threshold lasers.

[0003] Large Rabi splitting implies strong coupling strength in the coupled system, which is crucial for driving the interaction between light and matter. Furthermore, large Rabi splitting helps distinguish coherent light emission from conventional photonic lasers, which is essential for fabricating coherent light sources in integrated optical circuits and studying macroscopic quantum state excitation phenomena. For example, see reference 1 (H. Chen, J. Li, et al, "Room-temperature polariton lasing in GaN microrods with large Rabi splitting," Opt. Express 30, 16794-16801 (2022)).

[0004] To enhance Rabi level splitting, existing literature mainly employs anapole-exciton two-mode coupling, such as reference 2 (S. Liu, J. Fan, et al, "Resonance coupling between molecular excitons and nonradiating anapole modes in silicon nanodisk-J-aggregate heterostructures," ACS Photon. 5, 1628 (2018)) and reference 3 (J. Wang, W. Yang, et al, "Boosting anapole-exciton strong coupling in all-dielectric heterostructures," Photonics Res. 10, 1744 (2022)). Exploring novel coupling modes to enhance Rabi splitting energy is of great significance. Summary of the Invention

[0005] To address the above problems, this invention provides an FP cavity-anapole-exciton system for realizing multiple strongly coupled Rabi splits, which is composed of basic units arranged in a two-dimensional periodic pattern, with the two-dimensional period being a square period. The basic unit includes a first dielectric layer, a first metal layer, a composite layer, a second metal layer, and a second dielectric layer arranged from bottom to top. The composite layer includes a transparent dielectric and a heterogeneous disk embedded in the composite layer. The heterogeneous disk includes a first dielectric disk, a semiconductor disk, and a second dielectric disk arranged from top to bottom.

[0006] In this invention, the first dielectric disk, the semiconductor disk, and the second dielectric disk generate anapoles. The destructive interference caused by the uniform contribution of heterogeneous electric dipoles and ring dipoles generates anapoles, which exhibit near-field enhancement and far-field non-radiative properties. The semiconductor disk generates excitons, possessing a high real part of the relative permittivity and excellent exciton response, which is highly advantageous in enhancing the spatial overlap of the electric field and reducing the mode volume. A Fabry-Pérot (FP) cavity is formed between the first and second metal layers. Multiple optical reflections can excite FP cavity modes and confine the electric field within the cavity. The system of this invention achieves strong three-mode coupling of FP cavity-anapole-exciton, improving the energy value of Rabi splitting.

[0007] Furthermore, the materials of the first dielectric layer and the second dielectric layer are magnesium fluoride or silicon dioxide, the materials of the first metal layer and the second metal layer are silver, gold, palladium, platinum, or rhodium, and the material of the transparent dielectric is magnesium fluoride or silicon dioxide.

[0008] Furthermore, the materials of the first dielectric disk and the second dielectric disk are silicon, germanium, and gallium arsenide, and the materials of the semiconductor disk are tungsten disulfide, molybdenum diselenide, or molybdenum disulfide.

[0009] Furthermore, the basic unit has a period of 360 nanometers, and the heterogeneous disk has a diameter of 160 nanometers.

[0010] Furthermore, the heterogeneous disk has a diameter of 160 nanometers, the first dielectric disk has a thickness of 12 nanometers, the semiconductor disk has a thickness of 5-15 nanometers, and the second dielectric disk has a thickness of 12 nanometers.

[0011] Furthermore, the thickness of the composite layer is 40 nanometers to 1500 nanometers.

[0012] Furthermore, the heterogeneous disk is located in the middle of the composite layer. This allows for the realization of strong three-mode coupling and increased Rabi splitting, since the electric field strength of the FP cavity mode is greatest in the middle of the composite layer.

[0013] Furthermore, the thickness of the first metal layer and the second metal layer is 20 nanometers.

[0014] Furthermore, since the first and second dielectric disks are made of the same material, there is no difference in refractive index contrast, which allows the electric field to be more concentrated in the semiconductor disk, thus increasing the Rabi splitting effect.

[0015] Furthermore, since both the first and second dielectric layers are made of the same material as the transparent medium, changes in the thickness of the composite layer will not cause changes in the effective refractive index of the coupling system. Therefore, there is an advantage in changing the thickness of the composite layer without causing changes in the excitation wavelength of the anapole mode.

[0016] The beneficial effects of this invention are:

[0017] (1) This invention integrates a first dielectric layer, a first metal layer, a composite layer, a heterogeneous disk, a second metal layer, and a second dielectric layer, and uses incident light waves to induce the excitation of multiple FP cavity modes, anapoles, and excitons. Through precise structural design and parameter adjustment, strong coupling of multiple FP cavity modes, anapoles, and excitons is achieved, which expands the number of Rabi splits, enhances the strength of the three-mode coupling, and obtains multiple large Rabi splitting energy values. The largest Rabi splitting energy value is as high as 643 meV, which is much higher than the Rabi splitting energy values ​​shown by other structures reported in existing research.

[0018] (2) The first and second dielectric disks are constructed using high refractive index materials such as silicon, gallium arsenide and germanium, which can interact with light to produce anapole with non-radiative properties.

[0019] (3) The tungsten disulfide bulk structure used in this invention has a relatively high real dielectric constant and excellent exciton response characteristics, which can enhance the spatial overlap of the electric field and reduce the mode volume, thus helping to enhance the coupling strength.

[0020] (4) The FP cavity used in this invention can achieve the excitation of multi-order FP cavity modes and the confinement of electric field energy by adjusting the cavity length. Multiple large Rabi splits are achieved by adjusting the structural size and optimizing the material parameters, and the number of Rabi splits is adjustable, which is different from the single Rabi splits reported in existing research.

[0021] Based on the above beneficial effects, this invention has broad application prospects in fields such as ultrafast optical switches, Bose-Einstein condensation, and low-threshold lasers.

[0022] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a FP cavity-anopole-exciton system that realizes multiple strongly coupled Rabi splits;

[0024] Figure 2 This is the absorption spectrum of the FP cavity-anapole-exciton system in Embodiment 1 of the present invention when the cavity length is 520 nm;

[0025] Figure 3 This is a graph showing the variation of the absorption peak of the third-order FP cavity-anapole-exciton strong coupling of the FP cavity-anapole-exciton system with the cavity length in Embodiment 2 of the present invention.

[0026] Figure 4 This is a contour plot of the absorption spectrum of the multi-order FP cavity-anapole-exciton strong coupling of the FP cavity-anapole-exciton system in Embodiment 3 of the present invention as a function of the cavity length of the FP cavity;

[0027] Figure 5 This is the trend of Rabi splitting energy value caused by strong coupling of first-order FP cavity-anapole-exciton system with oscillator strength in Embodiment 4 of the present invention.

[0028] In the figure: 1. First dielectric layer; 2. First metal layer; 3. Composite layer; 4. Heterogeneous disk; 5. Second metal layer; 6. Second dielectric layer; 41. First dielectric disk; 42. Semiconductor disk; 43. Second dielectric disk. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided with reference to the accompanying drawings and embodiments.

[0030] Example 1

[0031] The first metal layer 2 and the second metal layer 5 are made of silver, both with a thickness of 20 nm; the heterostructure disk 4 has a diameter of 160 nm; the first dielectric disk 41 and the second dielectric disk 43 are both made of silicon and both have a thickness of 12 nm; the semiconductor disk 42 is made of tungsten disulfide, has a thickness of 10 nm, and an oscillator strength of 0.2; the period of the basic unit is 360 nm; the transparent dielectric is made of magnesium fluoride with a refractive index of 1.38; the distance between the first metal layer 2 and the second metal layer 5 is 520 nm; the first dielectric layer 1 and the second dielectric layer 6 are made of magnesium fluoride. Incident light is perpendicularly incident on the surface of the second dielectric layer 6. Figure 2 The absorption spectrum of the FP cavity-anapole-exciton system in this embodiment. From Figure 2 It can be seen that in the wavelength range of 550nm-700nm, three distinct absorption peaks appear in the absorption spectrum of the system, which are the high-energy branch, the medium-energy branch and the low-energy branch from left to right.

[0032] Example 2

[0033] The first metal layer 2 and the second metal layer 5 are made of silver, both with a thickness of 20 nm; the heterostructure disk 4 has a diameter of 160 nm; the first dielectric disk 41 and the second dielectric disk 43 are both made of silicon and both have a thickness of 12 nm; the semiconductor disk 42 is made of tungsten disulfide, has a thickness of 10 nm, and an oscillator strength of 0.2; the period of the basic unit is 360 nm; the transparent dielectric is made of magnesium fluoride with a refractive index of 1.38; the distance between the first metal layer 2 and the second metal layer 5 is 405-636 nm; the first dielectric layer 1 and the second dielectric layer 6 are made of magnesium fluoride. Incident light is perpendicularly incident on the surface of the second dielectric layer 6. Figure 3 This embodiment shows the absorption spectrum peaks of the third-order FP-anapole-exciton strongly coupled system as a function of the FP cavity length. Triangles represent high-energy branches, spheres represent medium-energy branches, stars represent low-energy branches, short lines represent anapole and exciton energies, and dashed lines represent third-order FP cavity mode energies. Figure 3It can be seen that when the cavity length of the FP cavity increases from 405 nm to 636 nm, a significant anti-crossover behavior emerges between the high-energy and low-energy branches. This anti-crossover characteristic indicates that the anapole and exciton responses of the heterodisk are strongly coupled with the third-order FP cavity mode. The arrows indicate the Rabi splitting energy corresponding to a cavity length of 520 nm, which is 216.3 meV, much higher than the Rabi splitting energy induced by coupling between the third-order FP cavity mode and other modes reported in previous studies.

[0034] Example 3

[0035] The first metal layer 2 and the second metal layer 5 are made of silver, both with a thickness of 20 nm; the heterostructure disk 4 has a diameter of 160 nm; the first dielectric disk 41 and the second dielectric disk 43 are both made of silicon and both have a thickness of 12 nm; the semiconductor disk 42 is made of tungsten disulfide, has a thickness of 10 nm, and an oscillator strength of 0.2; the period of the basic unit is 360 nm; the transparent dielectric is made of magnesium fluoride with a refractive index of 1.38; the distance between the first metal layer 2 and the second metal layer 5 is 40-1500 nm; the first dielectric layer 1 and the second dielectric layer 6 are made of magnesium fluoride. Incident light is perpendicularly incident on the surface of the second dielectric layer 6. Figure 4 This is a contour plot of the absorption spectrum of the multi-order FP-anapole-exciton strongly coupled FP-cavity system in this embodiment, varying with the cavity length of the FP cavity. Figure 4 As can be seen, when the cavity length of the FP cavity increases from 40 nm to 1500 nm, four distinct anti-crossing behaviors appear in the contour plot of the absorption spectrum. These four anti-crossing features from left to right indicate that the anapole and exciton responses of the heterogeneous nanodisk are strongly coupled with the first, third, fifth, and seventh-order FP cavity modes, leading to four large Rabi splits, far exceeding the number of Rabi splits reported in existing three-mode coupled systems. The Rabi splitting energies induced by the coupling of the first, third, fifth, and seventh-order FP cavity modes are 562 meV, 216.3 meV, 178.6 meV, and 156.6 meV, respectively, significantly better than those reported in previous studies.

[0036] Example 4

[0037] The first metal layer 2 and the second metal layer 5 are made of silver, both with a thickness of 20 nm; the heterostructure disk 4 has a diameter of 160 nm; the first dielectric disk 41 and the second dielectric disk 43 are both made of silicon and both have a thickness of 12 nm; the semiconductor disk 42 is made of tungsten disulfide, has a thickness of 10 nm, and an oscillator strength of 0.2-1.5; the period of the basic unit is 360 nm; the transparent dielectric is made of magnesium fluoride with a refractive index of 1.38; the distance between the first metal layer 2 and the second metal layer 5 is 86 nm; the first dielectric layer 1 and the second dielectric layer 6 are made of magnesium fluoride. Incident light is perpendicularly incident on the surface of the second dielectric layer 6. Figure 5 This figure shows the trend of Rabi splitting energy induced by strong coupling of the first-order FP-cavity-anapole-exciton system in this embodiment as a function of oscillator strength. Figure 5 It can be seen that as the oscillator strength of tungsten disulfide increases from 0.2 to 1.5, the Rabi splitting energy induced by strong coupling of the first-order FP cavity mode shows a slow increasing trend, from 562 meV to 643 meV, which is much higher than that reported in existing studies.

[0038] In this invention, the presence and strength of excitons are adjusted by regulating the oscillator strength of the semiconductor disk. When the oscillator strength is 0, the semiconductor acts as a dielectric, and the exciton count is zero. When the oscillator strength is not 0, the semiconductor material becomes an exciton material, and an exciton response can be generated. Because this invention discusses exciton performance, the oscillator strength is discussed within the range of 0.2-1.5. In the experiment, the oscillator strength is adjusted by applying an external bias voltage.

[0039] In addition, the semiconductor disk in this invention can also be made of molybdenum disulfide or molybdenum diselenide. Since these two materials also have high refractive index and exciton response characteristics, the disks formed by them can also produce similar three-mode strong coupling effects and multiple large Rabi splitting phenomena.

[0040] Furthermore, since the anapole mode has a large electric field localization effect in the middle position of the heterogeneous disk 4 and the FP cavity mode has a large electric field localization effect in the middle position of the composite layer 3, in this invention, the semiconductor disk 42 is located in the middle layer position of the heterogeneous disk 4, which facilitates the overlap between the electric field excited by the coupling system mode and the large electric field space of the semiconductor disk 42 itself, thereby further enhancing the three-mode coupling and increasing the energy value of Rabi splitting.

[0041] Furthermore, the semiconductor disk 42 is thicker in the middle and thinner at the edges, which allows the electric field of the anapole mode to be more distributed in the semiconductor disk. This increases the spatial overlap between the electric field of the anapole mode and the semiconductor disk, ultimately enhancing the coupling between the excitons in the semiconductor disk and the anapole mode, as well as the external FP cavity, and increasing the energy value of Rabi splitting.

[0042] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A multi-cavity anapole-exciton system for realizing multiple strongly coupled Rabi splits, comprising basic units arranged in a two-dimensional periodic pattern, wherein the two-dimensional period is a square period, characterized in that, The basic unit includes a first dielectric layer, a first metal layer, a composite layer, a second metal layer, and a second dielectric layer arranged from bottom to top. The composite layer includes a transparent dielectric and a heterogeneous disk embedded in the composite layer. The heterogeneous disk includes a first dielectric disk, a semiconductor disk, and a second dielectric disk arranged from top to bottom. The diameter of the heterogeneous disk is 160 nanometers. The thickness of the composite layer is 40 nanometers to 1500 nanometers.

2. The FP-cavity-anapole-exciton system for realizing multiple strongly coupled Rabi splitting as described in claim 1, characterized in that: The first dielectric layer and the second dielectric layer are made of magnesium fluoride or silicon dioxide, the first metal layer and the second metal layer are made of silver, gold, palladium, platinum, or rhodium, and the transparent dielectric is made of magnesium fluoride or silicon dioxide.

3. The FP-cavity-anapole-exciton system for realizing multiple strongly coupled Rabi splitting as described in claim 2, characterized in that: The first dielectric disk and the second dielectric disk are made of silicon, germanium, or gallium arsenide, and the semiconductor disk is made of tungsten disulfide, molybdenum diselenide, or molybdenum disulfide.

4. The FP-cavity-anapole-exciton system for realizing multiple strongly coupled Rabi splitting as described in any one of claims 1-3, characterized in that: The period of the basic unit is 360 nanometers.

5. The FP-cavity-anapole-exciton system for realizing multiple strongly coupled Rabi splitting as described in claim 4, characterized in that: The first dielectric disk has a thickness of 12 nanometers, the semiconductor disk has a thickness of 5-15 nanometers, and the second dielectric disk has a thickness of 12 nanometers.

6. The FP-cavity-anapole-exciton system for realizing multiple strongly coupled Rabi splitting as described in claim 5, characterized in that: The heterogeneous disk is located in the middle of the composite layer.

7. The FP-cavity-anapole-exciton system for realizing multiple strongly coupled Rabi splitting as described in claim 6, characterized in that: The thickness of the first metal layer and the second metal layer is 20 nanometers.

8. The FP-cavity-anapole-exciton system for realizing multiple strongly coupled Rabi splitting as described in claim 7, characterized in that: The first medium disk and the second medium disk are made of the same material.

9. The FP-cavity-anapole-exciton system for realizing multiple strongly coupled Rabi splitting as described in claim 8, characterized in that: Both the first dielectric layer and the second dielectric layer are made of the same material as the transparent medium.

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