Slow light device based on rectangular discontinuous graphene metamaterial

Abstract

The utility model relates to a slow light device based on a rectangular discontinuous graphene metamaterial. The slow light device comprises a silicon substrate, square ring continuous graphene, first rectangular discontinuous graphene, second rectangular discontinuous graphene and third rectangular discontinuous graphene. The square ring continuous graphene, the first rectangular discontinuous graphene, the second rectangular discontinuous graphene and the third rectangular discontinuous graphene are respectively arranged on the upper surface of the silicon substrate; the first rectangular discontinuous graphene, the second rectangular discontinuous graphene and the third rectangular discontinuous graphene are sequentially and uniformly arranged along the front-back direction of the slow light device; the square ring continuous graphene is of a rectangular frame structure. According to the utility model, the problems of small refractive index and narrow bandwidth of a slow light device group with a graphene metamaterial structure are solved; the size of the slow light device with the graphene metamaterial structure is reduced, and the problem that the slow light device with the graphene metamaterial structure is not easy to integrate in an on-chip plasmon light path is solved.

Description

Technical Field

[0001] This utility model relates to the field of optical communication technology, specifically to a slow-light device based on rectangular discontinuous graphene metamaterial. Background Technology

[0002] In the field of optical communication, with the increase in transmission capacity, the "electronic bottleneck" phenomenon in optical-electrical-optical data routing and switching methods has become more prominent, becoming a major factor restricting the bandwidth, size, cost, power consumption, and speed of communication networks. To overcome this "electronic bottleneck," all-optical networks have emerged, becoming an inevitable trend in the development of communication networks. All-optical networks rely on the ability to generate and control data buffering, logic conversion, and signal delay. By utilizing slow-optical devices for signal delay and buffering, they can avoid the problems of large size and complex structure of traditional fiber optic delay lines, and can achieve tunable delay.

[0003] Slow light refers to light pulses propagating in a medium at a group velocity less than the speed of light in a vacuum. In all-optical communication networks and all-optical signal processing, slow-light devices are key components for building next-generation information technologies such as all-optical intelligent interconnection and real-time high-speed measurement and control. With the rapid development of integrated slow-light devices based on key technologies such as signal delay, data buffering, and switching, the demand for small size, large delay, wide bandwidth, and dynamic tunability in mid-infrared slow-light devices is becoming increasingly apparent. Therefore, it is crucial to realize slow-light devices with compact device size, large group refractive index, wide bandwidth, dynamic tunability, and easy integration based on new operating mechanisms. The application of such novel slow-light devices in data routing, signal delay, data buffering, and switching technologies in all-optical communication networks and signal processing is becoming increasingly widespread.

[0004] Surface plasmon polaritons (SPPs) are evanescent electromagnetic waves that propagate along the metal-dielectric interface and decay exponentially in the direction perpendicular to the metal surface. SPPs possess the ability to overcome the traditional optical diffraction limit and exhibit strong localized optical field enhancement characteristics, thus enabling the guidance and manipulation of light at the subwavelength level. SPP waves can serve as carriers of energy and information, and they hold significant application value in high-density integrated photonic circuits.

[0005] Currently, slow-light devices based on SPPs have been extensively studied, such as slow-light buffers based on metamaterials and metasurface structures. Due to the strong localized optical field enhancement properties of SPPs and their ability to overcome the traditional diffraction limit, SPP-based slow-light devices exhibit small structural dimensions and wide bandwidths. The propagation direction of SPPs is parallel to the device surface, facilitating chip integration and design. Therefore, realizing SPP metamaterial slow-light devices with compact device size, large group refractive index, wide bandwidth, dynamic tunability, and easy integration is a future development trend.

[0006] Currently, slow-light devices based on plasmon-induced transparency (PIT) in SPPs (Slow-Light Polymers) are attracting increasing attention. The PIT phenomenon is similar to the electromagnetically induced transparency (EIT) effect in atomic gases. However, compared to the EIT phenomenon in atomic gases, which is determined by the absorption characteristics of the material, the EIT-like phenomenon generated by the geometry of a resonant cavity coupled with a plasma waveguide system has greater application prospects due to its advantages such as room-temperature operation, compatibility with chip integration, tunability of the transmission band, and controllable bandwidth. In metamaterial structures, the PIT effect is generated by the mutual coupling interference between bright and dark modes, thereby realizing slow light. Because the PIT effect has a large quality factor in its transparency peak, a relatively steep transmission spectrum, and strong dispersion leading to a large group delay, the PIT effect is suitable for application in slow-light devices.

[0007] In recent years, graphene, a two-dimensional material consisting of a single carbon atom layer, has provided a novel and low-loss method for confining and controlling spatially polarized light particles (SPPs), and is therefore widely used in the design of SPP devices. Considering the unique properties of graphene, graphene-based micro- and nanostructures can generate very strong localized SPPs from the near-infrared region to the terahertz band. The PIT effect is generated in graphene metamaterial structures, and by altering the Fermi level of graphene, the slow light generated by the PIT effect can be dynamically tuned.

[0008] The shortcomings of existing technology are:

[0009] 1. Traditional slow-light devices have low group refractive index and narrow bandwidth, which limits their application and development in all-optical communication networks and all-optical signal processing technologies.

[0010] 2. Traditional slow-light devices based on fiber delay lines or micro-ring resonator structures are large in size, which is not conducive to the large-scale integration of optical devices.

[0011] 3. Traditional graphene metamaterial structures produce a single PIT effect, which can only achieve single-channel slow light. Utility Model Content

[0012] This invention addresses the aforementioned problems by providing a slow-light device based on rectangular discontinuous graphene metamaterials. Its purpose is to achieve a small-size, high-group refractive index, wide-bandwidth, and easily integrated slow-light device using a rectangular discontinuous graphene metamaterial structure; to solve the problems of low group refractive index and narrow bandwidth in graphene metamaterial structure slow-light devices; to reduce the size of the graphene metamaterial structure slow-light device; and to solve the problem of difficulty in integrating the graphene metamaterial structure slow-light device into on-chip plasmon optical paths.

[0013] To solve the above problems, the technical solution provided by this utility model is as follows:

[0014] A slow-light device based on rectangular discontinuous graphene metamaterial comprises a silicon substrate, square ring continuous graphene, a first rectangular discontinuous graphene, a second rectangular discontinuous graphene, and a third rectangular discontinuous graphene, wherein:

[0015] The square ring continuous graphene, comprising the first rectangular discontinuous graphene, the second rectangular discontinuous graphene, and the third rectangular discontinuous graphene, is respectively disposed on the upper surface of the silicon substrate; the first rectangular discontinuous graphene, the second rectangular discontinuous graphene, and the third rectangular discontinuous graphene are uniformly arranged sequentially along the front-back direction of the slow-light device; the square ring continuous graphene has a rectangular frame structure; the square ring continuous graphene is spaced around the first rectangular discontinuous graphene, the second rectangular discontinuous graphene, and the third rectangular discontinuous graphene. The outer side of the graphene; the first rectangular discontinuous graphene, the second rectangular discontinuous graphene, and the third rectangular discontinuous graphene are directly coupled to the incident light, and SPPs are directly excited on the surface of the first rectangular discontinuous graphene, the second rectangular discontinuous graphene, and the third rectangular discontinuous graphene, respectively; the square ring continuous graphene indirectly excites SPPs on the surface of the square ring continuous graphene by near-field coupling with the first rectangular discontinuous graphene, the second rectangular discontinuous graphene, and the third rectangular discontinuous graphene, respectively.

[0016] Preferably, the thickness of the silicon substrate is 300 nm.

[0017] Preferably, the square ring continuous graphene has an outer length of 18 µm, an outer width of 8 µm, an inner length of 16 µm, and an inner width of 6 µm.

[0018] Preferably, the side lengths of the first rectangular discontinuous graphene, the second rectangular discontinuous graphene, and the third rectangular discontinuous graphene are all 4.5 µm.

[0019] Preferably, the spacing between the first rectangular discontinuous graphene and the second rectangular discontinuous graphene is 0.62 µm; the spacing between the second rectangular discontinuous graphene and the third rectangular discontinuous graphene is 0.62 µm.

[0020] Preferably, the thickness of the single-layer graphene used in the slow-light device is 0.2 nm.

[0021] Preferably, the Fermi level of the square ring continuous graphene, the first rectangular discontinuous graphene, the second rectangular discontinuous graphene, and the third rectangular discontinuous graphene is all fixed at 1.1 eV.

[0022] Preferably, the size of the slow-light device is on the order of micrometers.

[0023] Compared with the prior art, this utility model has the following advantages:

[0024] 1. This invention realizes a small-size, high-group-refractive-index, wide-bandwidth, and easily integrated rectangular discontinuous graphene metamaterial structure slow-light device in the terahertz band, applying the three-PIT effect generated by the rectangular discontinuous graphene metamaterial structure to the integrated slow-light device. The group refractive indices at the center frequencies of the three transmission windows are 768.3, 953.5, and 612.8, respectively, with a maximum group refractive index of 953.5; the spectral bandwidths of the three transmission windows are 0.90 THz, 0.84 THz, and 1.32 THz, respectively, with a maximum spectral bandwidth of 1.32 THz. This solves the problems of low group refractive index and narrow bandwidth in graphene metamaterial structure slow-light devices.

[0025] 2. The slow-light device based on rectangular discontinuous graphene metamaterial of this invention has a size on the micrometer scale, which can realize an ultra-compact structure, greatly reducing the size of the slow-light device based on graphene metamaterial structure, and solving the problem that the slow-light device based on graphene metamaterial structure is not easy to integrate in on-chip plasmon optical path. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of a slow-light device based on rectangular discontinuous graphene metamaterial, according to a specific embodiment of this utility model.

[0027] Figure 2 This is a schematic diagram of the system transmission spectrum of a slow-light device based on rectangular discontinuous graphene metamaterial, according to a specific embodiment of this utility model.

[0028] Figure 3 This is a schematic diagram of the transmission spectrum phase shift and system group refractive index of a slow-light device based on rectangular discontinuous graphene metamaterial, which is a specific embodiment of this utility model.

[0029] The components are: 1. silicon substrate, 2. square ring continuous graphene, 3. first rectangular discontinuous graphene, 4. second rectangular discontinuous graphene, and 5. third rectangular discontinuous graphene. Detailed Implementation

[0030] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are only for illustrating the present invention and are not intended to limit the scope of the present invention. After reading the present invention, any modifications of the present invention in various equivalent forms by those skilled in the art will fall within the scope defined by the appended claims.

[0031] This utility model application claims protection for a slow-light device based on rectangular discontinuous graphene metamaterial, such as... Figure 1 As shown, it includes a silicon substrate 1, square ring continuous graphene 2, first rectangular discontinuous graphene 3, second rectangular discontinuous graphene 4, and third rectangular discontinuous graphene 5, wherein:

[0032] Square ring continuous graphene 2, first rectangular discontinuous graphene 3, second rectangular discontinuous graphene 4, and third rectangular discontinuous graphene 5 are respectively disposed on the upper surface of silicon substrate 1; the first rectangular discontinuous graphene 3, second rectangular discontinuous graphene 4, and third rectangular discontinuous graphene 5 are uniformly arranged sequentially along the front-back direction of the slow-light device; the square ring continuous graphene 2 has a rectangular frame structure; the square ring continuous graphene 2 is disposed in a spaced manner around the first rectangular discontinuous graphene 3, second rectangular discontinuous graphene 4, and third rectangular discontinuous graphene 5. On the outside of 5; the first rectangular discontinuous graphene 3, the second rectangular discontinuous graphene 4, and the third rectangular discontinuous graphene 5 are directly coupled to the incident light, and SPPs are directly excited on the surface of the first rectangular discontinuous graphene 3, the second rectangular discontinuous graphene 4, and the third rectangular discontinuous graphene 5, respectively; the square ring continuous graphene 2 indirectly excites SPPs on the surface of the square ring continuous graphene 2 by near-field coupling with the first rectangular discontinuous graphene 3, the second rectangular discontinuous graphene 4, and the third rectangular discontinuous graphene 5, respectively.

[0033] It should be noted that this invention utilizes a laser emitted by a laser to vertically irradiate the device structure from the top, and uses a spectrometer to detect the transmission spectrum at the bottom of the device.

[0034] It should be noted that the purpose of this invention is to realize a slow-light device with a small size, large group refractive index, wide bandwidth, and easy integration using a graphene metamaterial structure. This invention employs FDTD-solution software simulation to determine the structural parameters of the slow-light device based on rectangular discontinuous graphene metamaterials.

[0035] In this specific embodiment, the thickness of the silicon substrate 1 is 300 nm.

[0036] In this specific embodiment, the outer length of the square ring continuous graphene 2 is 18 µm, the outer width is 8 µm, the inner length is 16 µm, and the inner width is 6 µm.

[0037] In this specific embodiment, the side lengths of the first rectangular discontinuous graphene 3, the second rectangular discontinuous graphene 4, and the third rectangular discontinuous graphene 5 are all 4.5 µm.

[0038] In this specific embodiment, the spacing between the first rectangular discontinuous graphene 3 and the second rectangular discontinuous graphene 4 is 0.62 µm; the spacing between the second rectangular discontinuous graphene 4 and the third rectangular discontinuous graphene 5 is 0.62 µm.

[0039] In this specific embodiment, the thickness of the single-layer graphene used in the slow-light device is 0.2 nm.

[0040] In this specific embodiment, the Fermi levels of the square ring continuous graphene 2, the first rectangular discontinuous graphene 3, the second rectangular discontinuous graphene 4, and the third rectangular discontinuous graphene 5 are all fixed at 1.1 eV.

[0041] In this specific embodiment, the size of the slow-light device is on the order of micrometers, which can reduce the size of the slow-light device in the graphene metamaterial structure.

[0042] It should be noted that, in order to form the triple-PIT effect in the transmission spectrum, the incident light is perpendicular to the device structure, such as... Figure 1 As shown, in the entire structure, the first rectangular discontinuous graphene 3, the second rectangular discontinuous graphene 4, and the third rectangular discontinuous graphene 5 are directly coupled to the incident light. Therefore, the first rectangular discontinuous graphene 3, the second rectangular discontinuous graphene 4, and the third rectangular discontinuous graphene 5 exhibit a wide-bandwidth bright mode in the structure, and SPPs can be directly excited on their surface with only perpendicularly incident light. Since the square ring continuous graphene 2 cannot be directly coupled with perpendicularly incident light, the square ring continuous graphene 2 exhibits a narrow-bandwidth dark mode in the structure. The square ring continuous graphene 2 can indirectly excite SPPs on its surface through near-field coupling with the first rectangular discontinuous graphene 3, the second rectangular discontinuous graphene 4, and the third rectangular discontinuous graphene 5. That is, the incident light is indirectly coupled to the square ring continuous graphene 2 through the first rectangular discontinuous graphene 3, the second rectangular discontinuous graphene 4, and the third rectangular discontinuous graphene 5. Therefore, the destructive interference between the three bright modes and the one dark mode produces the three-PIT effect.

[0043] It needs to be further explained that, such as Figure 2As shown, three significant PIT-effect transmission windows were generated in the transmission spectrum, with transmission depression frequencies of 2.76 THz, 3.66 THz, 4.50 THz, and 5.82 THz, respectively. The spectral bandwidths of the first and second transmission depressions in the transmission spectrum are 0.90 THz, the spectral bandwidths of the second and third transmission depressions are 0.84 THz, and the spectral bandwidths of the third and fourth transmission depressions are 1.32 THz. The generation of the three transmission peaks is related to the near-field coupling between the bright and dark modes in the system. Figure 2 It can be seen that the theoretical calculation results of the coupling mode of the transmission spectrum are completely consistent with the FDTD simulation results.

[0044] According to formulas 1 and 2:

[0045] 1

[0046] 2

[0047] θ(ω) is the phase shift in the transmission spectrum, n g For the group refractive index, v g Let τ be the group velocity. g The group delay of the transmission spectrum is given by denoted by c, where c is the speed of light in a vacuum, and l is the thickness of the graphene system. The slow light performance can be quantitatively characterized using the group refractive index. Figure 3 The transmission spectrum phase shift and system group refractive index of slow-light devices based on rectangular discontinuous graphene metamaterials are presented.

[0048] In this specific embodiment, such as Figure 3 As shown, a slow-light device based on rectangular discontinuous graphene metamaterials can realize three-channel slow light. The group refractive index at the center frequency of the first transmission window is 768.3, the group refractive index at the center frequency of the second transmission window can reach 953.5, and the group refractive index at the center frequency of the third transmission window is 612.8. Therefore, by utilizing the steep dispersion characteristics of the PIT effect, the speed of light can be effectively slowed down, and the maximum group refractive index can reach 953.5, thus realizing an excellent slow-light device.

[0049] It should be noted that this invention realizes a three-channel slow-light device based on the three-PIT effect in the terahertz band. Utilizing the strong local optical field enhancement characteristics of SPPs generated by graphene and the steep dispersion characteristics of the PIT effect, an ultra-compact slow-light device with a large group refractive index graphene metamaterial structure was realized, with a device size on the micrometer scale. This novel slow-light device with a graphene metamaterial structure has significant scientific research value and potential for future application in the field of photonic device integration, playing a supporting role in the development of future all-optical communication networks and all-optical signal processing technologies.

[0050] In the above detailed description, various features are combined together in a single embodiment to simplify this disclosure. This approach to disclosure should not be construed as reflecting an intention that embodiments of the claimed subject matter require more features than are explicitly stated in each claim. Rather, as reflected in the appended claims, the present invention is in a state with fewer features than all of the disclosed individual embodiments. Therefore, the appended claims are hereby clearly incorporated into the detailed description, wherein each claim stands alone as a preferred embodiment of the present invention.

[0051] The disclosed embodiments have been described above to enable any person skilled in the art to implement or use this invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the spirit and scope of this disclosure. Therefore, this disclosure is not limited to the embodiments given herein, but is consistent with the widest scope of the principles and novel features disclosed in this application.

[0052] The foregoing description includes examples of one or more embodiments. It is certainly impossible to describe all possible combinations of components or methods in order to describe the above embodiments, but those skilled in the art will recognize that further combinations and arrangements of the various embodiments are possible. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of the appended claims. Furthermore, the term "comprising" as used in the specification or claims is interpreted in a manner similar to the term "including," as interpreted when used as a conjunction in the claims. Additionally, the use of any term "or" in the specification of the claims is intended to mean "non-exclusive or."

[0053] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above description is only a specific embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A slow-light device based on rectangular discontinuous graphene metamaterial, characterized in that: It comprises a silicon substrate (1), square ring continuous graphene (2), a first rectangular discontinuous graphene (3), a second rectangular discontinuous graphene (4), and a third rectangular discontinuous graphene (5), wherein: The square ring continuous graphene (2), the first rectangular discontinuous graphene (3), the second rectangular discontinuous graphene (4), and the third rectangular discontinuous graphene (5) are respectively disposed on the upper surface of the silicon substrate (1); the first rectangular discontinuous graphene (3), the second rectangular discontinuous graphene (4), and the third rectangular discontinuous graphene (5) are arranged uniformly in sequence along the front-back direction of the slow light device; the square ring continuous graphene (2) has a rectangular frame structure; the square ring continuous graphene (2) is disposed in a spaced manner around the first rectangular discontinuous graphene (3), the second rectangular discontinuous graphene (4), and the third rectangular discontinuous graphene (5). The outer side of graphene (5); the first rectangular discontinuous graphene (3), the second rectangular discontinuous graphene (4), and the third rectangular discontinuous graphene (5) are directly coupled to the incident light, and SPPs are directly excited on the surface of the first rectangular discontinuous graphene (3), the second rectangular discontinuous graphene (4), and the third rectangular discontinuous graphene (5); the square ring continuous graphene (2) indirectly excites SPPs on the surface of the square ring continuous graphene (2) by having near-field coupling with the first rectangular discontinuous graphene (3), the second rectangular discontinuous graphene (4), and the third rectangular discontinuous graphene (5).

2. The slow-light device based on rectangular discontinuous graphene metamaterial according to claim 1, characterized in that: The thickness of the silicon substrate (1) is 300 nm.

3. The slow-light device based on rectangular discontinuous graphene metamaterial according to claim 2, characterized in that: The square ring continuous graphene (2) has an outer length of 18 µm and an outer width of 8 µm, an inner length of 16 µm and an inner width of 6 µm.

4. The slow-light device based on rectangular discontinuous graphene metamaterial according to claim 3, characterized in that: The side lengths of the first rectangular discontinuous graphene (3), the second rectangular discontinuous graphene (4), and the third rectangular discontinuous graphene (5) are all 4.5 µm.

5. The slow-light device based on rectangular discontinuous graphene metamaterial according to claim 4, characterized in that: The spacing between the first rectangular discontinuous graphene (3) and the second rectangular discontinuous graphene (4) is 0.62 µm; the spacing between the second rectangular discontinuous graphene (4) and the third rectangular discontinuous graphene (5) is 0.62 µm.

6. The slow-light device based on rectangular discontinuous graphene metamaterial according to claim 5, characterized in that: The slow-light device uses a single layer of graphene with a thickness of 0.2 nm.

7. The slow-light device based on rectangular discontinuous graphene metamaterial according to claim 6, characterized in that: The Fermi level of the square ring continuous graphene (2), the first rectangular discontinuous graphene (3), the second rectangular discontinuous graphene (4), and the third rectangular discontinuous graphene (5) is fixed at 1.1 eV.

8. The slow-light device based on rectangular discontinuous graphene metamaterial according to claim 7, characterized in that: The size of the slow-light device is on the order of micrometers.

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