阅读说明：本技术 一种基于石墨烯纳米条超材料结构的慢光器件 (Slow light device based on graphene nano-strip metamaterial structure ) 是由 王波云 余华清 曾庆栋 熊良斌 杜君 于 2019-11-18 设计创作，主要内容包括：本发明涉及了一种基于石墨烯纳米条超材料结构的慢光器件,包括：硅衬底,设置于硅衬底上第一石墨烯纳米条、可与第一石墨烯纳米条直接耦合的若干第二石墨烯纳米条以及可与第一石墨烯纳米条间接耦合的若干第三石墨烯纳米条,各第二石墨烯纳米条分别与第一石墨烯纳米条平行设置,各第二石墨烯纳米条之间可分别发生直接耦合；各第三石墨烯纳米条与第一石墨烯纳米条垂直设置,各第三石墨烯纳米条之间以及各第三石墨烯纳米条与各第二石墨烯纳米条之间可分别发生直接耦合。基于本发明的慢光器件,尺寸小、群延时大、带宽宽、动态可调谐以及易于集成,具有很好的应用前景。(The invention relates to a slow light device based on a graphene nano strip metamaterial structure, which comprises: the graphene nano-strip structure comprises a silicon substrate, a first graphene nano-strip, a plurality of second graphene nano-strips and a plurality of third graphene nano-strips, wherein the first graphene nano-strip, the plurality of second graphene nano-strips can be directly coupled with the first graphene nano-strip, the plurality of third graphene nano-strips can be indirectly coupled with the first graphene nano-strip, each second graphene nano-strip is respectively arranged in parallel with the first graphene nano-strip, and the second graphene nano-strips can be directly coupled with each other; each third graphene nanoribbon is perpendicular to the first graphene nanoribbon, and direct coupling can occur between each third graphene nanoribbon and each second graphene nanoribbon respectively. The slow light device based on the invention has small size, large group delay, wide bandwidth, dynamic tuning, easy integration and good application prospect.)

1. A slow light device based on a graphene nano strip metamaterial structure is characterized by comprising: the graphene nano-strip structure comprises a silicon substrate (4), a first graphene nano-strip (1), a plurality of second graphene nano-strips (2) and a plurality of third graphene nano-strips (3), wherein the first graphene nano-strips (1), the plurality of second graphene nano-strips (2) can be directly coupled with the first graphene nano-strips (1), the plurality of third graphene nano-strips (3) can be indirectly coupled with the first graphene nano-strips (1), the second graphene nano-strips (2) are respectively arranged in parallel with the first graphene nano-strips (1), and the second graphene nano-strips (2) can be directly coupled with each other; each third graphene nanoribbon (3) is perpendicular to each first graphene nanoribbon (1), and direct coupling can occur between each third graphene nanoribbon (3) and each second graphene nanoribbon (2).

2. The graphene nanoribbon metamaterial structure-based slow-light device according to claim 1, wherein the first graphene nanoribbon (1), each second graphene nanoribbon (2), and each third graphene nanoribbon (3) are each composed of single-layer graphene, and the chemical potentials of the first graphene nanoribbon (1), each second graphene nanoribbon (2), and each third graphene nanoribbon (3) are 0.30-0.31 eV respectively.

3. The graphene nanoribbon metamaterial structure-based slow light device according to claim 1, wherein each second graphene nanoribbon (2) and each third graphene nanoribbon (3) are respectively disposed on the same side of the first graphene nanoribbon (1), the distance between the adjacent edges of each second graphene nanoribbon (2) is 8 to 12nm, the distance between the adjacent edges of each third graphene nanoribbon (3) is 6 to 10nm, the distance between the adjacent edges of the first graphene nanoribbon (1) and the adjacent second graphene nanoribbon (2) is 8 to 12nm, the coupling length is 8 to 12nm, the distance between the adjacent edges of the first graphene nanoribbon (1) and the adjacent third graphene nanoribbon (3) is 8 to 12nm, the distance between the adjacent edges of the second graphene nanoribbon (2) and the adjacent third graphene nanoribbon (3) is 8 to 12nm, the coupling length between each third graphene nanoribbon (3) and each second graphene nanoribbon (2) is 8-12 nm.

4. The graphene nanoribbon metamaterial structure-based slow-light device according to any one of claims 1 to 3, wherein the number of the second graphene nanoribbon (2) and the number of the third graphene nanoribbon (3) are respectively 2, the length of the first graphene nanoribbon (1) is 60-70 nm, the width of the first graphene nanoribbon is 15-25 nm, the length of each second graphene nanoribbon (2) is 45-50 nm, the width of each second graphene nanoribbon is 8-12 nm, the length of each third graphene nanoribbon (3) is 45-50 nm, and the width of each third graphene nanoribbon is 8-14 nm.

5. The graphene nanoribbon metamaterial structure-based slow-light device according to claim 4, wherein the first graphene nanoribbon (1) has a length and a width of 64nm and 20nm, respectively, each second graphene nanoribbon (2) has a length and a width of 48nm and 10nm, respectively, a distance between adjacent sides of each second graphene nanoribbon (2) is 10nm, a coupling length is 48nm, a length and a width of each third graphene nanoribbon (3) are 48nm and 12nm, respectively, a distance between adjacent sides of each third graphene nanoribbon (3) is 8nm, a coupling length is 48nm, a distance between the first graphene nanoribbon and the adjacent side of the adjacent second graphene nanoribbon is 10nm, a coupling length is 10nm, a distance between the adjacent second graphene nanoribbon (2) and the adjacent side of the adjacent third graphene nanoribbon (3) is 8nm, the coupling length was 10 nm.

6. The graphene nanoribbon metamaterial structure-based slow light device of claim 1, wherein the SiO is ₂The thickness of the substrate (4) is 280-320 nm.

Technical Field

The invention belongs to the technical field of photonic devices, and particularly relates to a slow light device based on a graphene nano-strip metamaterial structure.

Background

In the field of optical communication, with the increase of transmission capacity, the electronic bottleneck phenomenon existing in the optical-electrical-optical data routing and switching mode becomes more prominent, and becomes an important factor for restricting the bandwidth, volume, cost, power consumption and speed of a communication network. In order to break through the "electronic bottleneck", all-optical networks have come to be the inevitable trend of communication network development. The all-optical network depends on the capability of generating and controlling data cache, logic conversion and signal delay, and utilizes the slow optical device to delay and cache signals, so that the problems of large volume, complex structure and the like of the traditional optical fiber delay line can be avoided, and the tunable delay can be realized.

Slow light means that the group velocity of light pulses propagating in a medium is less than the speed of light in vacuum. In all-optical communication networks and all-optical signal processing, a slow optical device is a key node device for constructing next-generation information technologies such as all-optical intelligent interconnection, real-time high-speed measurement and control and the like. The traditional slow optical device has small group delay and narrow bandwidth, and limits the application development of the slow optical device in an all-optical communication network and an all-optical signal processing technology. With the rapid development of integrated slow optical devices based on key technologies such as signal delay, data caching and switching, the requirements for small size, large delay, wide bandwidth and dynamic tuning of slow optical devices become more and more obvious, so that the realization of a slow optical device with a new working mechanism such as compact device size, large group delay, wide bandwidth, dynamic tuning and easy integration is very important, and the novel slow optical device is more and more widely applied to all-optical communication networks and data routing, signal delay, data caching and switching technologies of signal processing.

Disclosure of Invention

The technical problem solved by the invention is as follows: the slow light device based on the graphene nano strip metamaterial structure is small in size, large in group delay, wide in bandwidth, dynamically tunable and easy to integrate.

The specific technical scheme is as follows:

the invention provides a slow light device based on a graphene nano strip metamaterial structure, which comprises: the graphene nano-strip structure comprises a silicon substrate, a first graphene nano-strip, a plurality of second graphene nano-strips and a plurality of third graphene nano-strips, wherein the first graphene nano-strip, the plurality of second graphene nano-strips can be directly coupled with the first graphene nano-strip, the plurality of third graphene nano-strips can be indirectly coupled with the first graphene nano-strip, the second graphene nano-strips are respectively arranged in parallel with the first graphene nano-strips, and the second graphene nano-strips can be directly coupled with one another; each third graphene nanoribbon is perpendicular to the first graphene nanoribbon, and direct coupling may occur between the third graphene nanoribbons and the second graphene nanoribbons.

Has the advantages that:

1) the slow light device based on the graphene nano strip metamaterial structure has small size (less than 0.05 mu m) ²) Large group delay, wide bandwidth, dynamic tuning and easy integration. The slow light device based on the invention has good application prospect in all-optical communication network and data routing, signal delay, data caching and switching technology of signal processing.

2) The device structure can generate double-PIT effect, can realize double-channel slow light, and the chemical potential of the graphene can be adjusted by controlling the external bias voltage or chemical doping and other methods, so that the dynamically tunable double-PIT effect double-channel slow light device can be realized.

On the basis of the scheme, the invention can be further improved as follows:

further, the first graphene nanoribbon, each second graphene nanoribbon and each third graphene nanoribbon are all composed of single-layer graphene, and the chemical potentials of the first graphene nanoribbon, each second graphene nanoribbon and each third graphene nanoribbon are respectively 0.30-0.31 eV.

The size of the device can be effectively reduced by adopting a single-layer graphene nano-strip structure, and the single-layer graphene nano-strip has strong constraint on SPPs (spin particles), has strong local optical field enhancement characteristic and steep dispersion characteristic of PIT (particle induced transient) effect, and can better realize the ultra-compact and large-group delay effect of a slow-light device.

Further, each second graphene nanoribbon and each third graphene nanoribbon are respectively arranged on the same side of the first graphene nanoribbon, the distance between the adjacent edges of each second graphene nanoribbon is 8-12 nm, the distance between the adjacent edges of each third graphene nanoribbon is 6-10 nm, the distance between the adjacent edges of the first graphene nanoribbon and the adjacent second graphene nanoribbon is 8-12 nm, the coupling length is 8-12 nm, the distance between the adjacent edges of the first graphene nanoribbon and the adjacent third graphene nanoribbon is 8-12 nm, the distance between the adjacent edges of the adjacent second graphene nanoribbon 2 and the adjacent third graphene nanoribbon 3 is 8-12 nm, and the coupling length between each third graphene nanoribbon and each second graphene nanoribbon is 8-12 nm respectively.

Further, the number of the second graphene nanoribbons and the number of the third graphene nanoribbons are respectively 2, the length of the first graphene nanoribbons are 60-70 nm, the width of the first graphene nanoribbons are 15-25 nm, the length of each second graphene nanoribbon is 45-50 nm, the width of each second graphene nanoribbon is 8-12 nm, the length of each third graphene nanoribbon is 45-50 nm, and the width of each third graphene nanoribbon is 8-14 nm.

Further, the length and the width of each first graphene nanoribbon are 64nm and 20nm respectively, the length and the width of each second graphene nanoribbon are 48nm and 10nm, the distance between adjacent edges of each second graphene nanoribbon is 10nm, the coupling length is 48nm, the length and the width of each third graphene nanoribbon are 48nm and 12nm respectively, the distance between adjacent edges of each third graphene nanoribbon is 8nm, the coupling length is 48nm, the distance between each first graphene nanoribbon and the adjacent edge of the adjacent second graphene nanoribbon is 10nm, the coupling length is 10nm, the distance between each adjacent second graphene nanoribbon and the adjacent edge of the adjacent third graphene nanoribbon is 8nm, and the coupling length is 10 nm.

The slow light device based on the structure has small size, larger group delay and smaller loss.

Further, in the present invention,the SiO ₂The thickness of the substrate is 280-320 nm.

Using SiO ₂The substrate can reduce the light absorption and light transmission loss of the middle infrared band.

According to the slow light device based on the metamaterial structure, each structural unit is composed of five graphene nano-strips, and a double-channel slow light device based on a double-PIT effect is realized in a middle infrared band. The SPPs generated by the graphene have strong local optical field enhancement property and steep dispersion property of PIT effect, so that the ultra-compact and large-group-delay slow light device with the graphene metamaterial structure is realized, and the size of the device is less than 0.05 mu m ². The slow light device with the graphene metamaterial structure with the new working mechanism has great scientific research value, has application development potential in the field of future photonic device integration, and plays a supporting role in the development of future all-optical communication networks and all-optical signal processing technologies.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

Fig. 1 is a schematic structural diagram of a slow light device based on a graphene nano-strip metamaterial structure.

Fig. 2 is a system transmission spectrum of a slow light device based on a graphene nano strip metamaterial structure.

Fig. 3 is a system group delay of a slow light device based on a graphene nano-strip metamaterial structure.

In the drawings, the names of the components represented by the respective reference numerals are:

a first graphene nanoribbon 1; a second graphene nanoribbon 2; a third graphene nanoribbon 3; a silicon substrate 4.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

With reference to fig. 1, the specific solution provided by the present invention comprises the following steps:

the slow light device based on the graphene nano strip metamaterial structure comprises: the graphene structure comprises a silicon substrate 4, a first graphene nanoribbon 1, a plurality of second graphene nanoribbons 2 and a plurality of third graphene nanoribbons 3, wherein the first graphene nanoribbon 1, the plurality of second graphene nanoribbons 2 can be directly coupled with the first graphene nanoribbon 1, the plurality of third graphene nanoribbons 3 can be indirectly coupled with the first graphene nanoribbon 1, the second graphene nanoribbons 2 are respectively arranged in parallel with the first graphene nanoribbon 1, and the second graphene nanoribbons 2 can be directly coupled with one another; each third graphene nanoribbon 3 is perpendicular to the first graphene nanoribbon 1, and direct coupling may occur between each third graphene nanoribbon 3 and each second graphene nanoribbon 2, respectively.

Surface Plasmon Polaritons (SPPs) are Surface electromagnetic evanescent waves that propagate along a metal-dielectric interface and decay exponentially in a direction perpendicular to the metal Surface. SPPs have the characteristic of breaking through the traditional optical diffraction limit and strong local optical field enhancement, so that the guidance and control of light in the sub-wavelength level can be realized. At present, SPPs slow light devices based on Plasmon Induced Transparency (PIT) effect attract more and more attention. The generation of the PIT phenomenon is similar to an Electromagnetically Induced Transparency (EIT) effect in atomic gas, but compared with the EIT effect in atomic gas which is determined by the absorption characteristics of materials, the PIT phenomenon generated by the geometric structure of the resonant cavity coupling plasma waveguide system has a wider application prospect due to the characteristics of room-temperature operation, chip integration compatibility, tunability of a transmission waveband, controllability of bandwidth and the like. In the metamaterial structure, the PIT effect can be generated by utilizing the mutual coupling interference effect between a bright mode and a dark mode, so that slow light is realized, and the PIT effect is suitable for being applied to a slow light device because the transparent peak of the PIT effect has the characteristics of large quality factor, steeper transmission spectrum, large group delay caused by strong dispersion and the like.

According to the slow light device, the unique electronic structure of the graphene and the excellent performances of unique electrical adjustability, low intrinsic loss, high optical field local area and the like of the graphene plasmon polariton are utilized, and the slow light device is applied to the design of SPPs devices. According to the device, the graphene layer covers the surface of the metamaterial, so that the PIT effect can be generated. According to the slow light device based on the metamaterial structure, each structural unit is composed of five graphene nano-strips, and a double-channel slow light device based on a double PIT effect is realized in a middle infrared band; the slow light device with the ultra-compact and large group delay graphene metamaterial structure is realized by utilizing strong local optical field enhancement SPPs generated by graphene and steep dispersion characteristics of PIT effect, and the size of the device is less than 0.05 mu m ²And the PIT effect slow light can be dynamically regulated and controlled by changing the chemical potential of the graphene.

Specifically, direct coupling may occur between the first graphene nanoribbon 1 and each second graphene nanoribbon 2, and between each second graphene nanoribbon 2, and direct coupling may occur between each third graphene nanoribbon 3, and between each third graphene nanoribbon 3 and each second graphene nanoribbon 2, that is, indirect coupling may occur between the first graphene nanoribbon 1 and each third graphene nanoribbon 3 through each second graphene nanoribbon 2. Therefore, when an incident light beam carrying a signal vertically irradiates each graphene nanoribbon, the incident light beam with an electric field direction parallel to the length direction of each first graphene nanoribbon 1 and each second graphene nanoribbon 2 directly excites the surfaces of the first graphene nanoribbon 1 and each second graphene nanoribbon 2 to generate SPPs, and the direct coupling interference effect between the SPPs of the first graphene nanoribbon 1 and each second graphene nanoribbon 2 generates a PIT effect (first PIT transmission peak). Each third graphene nanoribbon 3 cannot directly excite to generate SPPs by incident light, but excites to generate SPPs in the third graphene nanoribbon 3 by the near-field coupling effect between each second graphene nanoribbon 2 and each third graphene nanoribbon 3, and the coupling interference effect of the SPPs in each second graphene nanoribbon 2 and the SPPs in each third graphene nanoribbon 3 generates a PIT effect (second PIT transmission peak).

And detecting the device transmission spectrum through a spectrometer to obtain a transmittance spectrum, and then processing the transmittance spectrum through the following formula to obtain the system group delay.

t is the transmission, phi (omega) is the transmission spectral phase shift, tau _gFor group delay, the slow light performance can be quantitatively represented by using the group delay.

According to the slow light device based on the graphene nanoribbon metamaterial structure, the first graphene nanoribbon 1, the second graphene nanoribbons 2 and the third graphene nanoribbons 3 are all composed of single-layer graphene, the chemical potential of the first graphene nanoribbon 1 is 0.31eV, and the chemical potentials of the second graphene nanoribbon 2 and the third graphene nanoribbons 3 are 0.30eV respectively.

The size of the device can be effectively reduced by adopting a single-layer graphene nano-strip structure, and the single-layer graphene nano-strip has strong constraint on SPPs (spin particles), has strong local optical field enhancement characteristic and steep dispersion characteristic of PIT (particle induced diffraction) effect, and can better realize the ultra-compact and large-group delay effect of the slow-light device. By adopting a single-layer graphene nano-strip metamaterial structure, the SPPs slow-light device with larger group delay, wide bandwidth, small size and dynamic tuning is obtained.

According to the slow light device based on the graphene nanoribbon metamaterial structure, the second graphene nanoribbons 2 and the third graphene nanoribbons 3 are respectively arranged on the same side of the first graphene nanoribbons 1, the distance between the adjacent edges of the second graphene nanoribbons 2 is 8-12 nm, the distance between the adjacent edges of the third graphene nanoribbons 3 is 6-10 nm, the distance between the adjacent edges of the first graphene nanoribbons 1 and the adjacent second graphene nanoribbons 2 is 8-12 nm, the coupling length is 8-12 nm, the distance between the adjacent edges of the first graphene nanoribbons 1 and the adjacent third graphene nanoribbons 3 is 8-12 nm, the distance between the adjacent edges of the adjacent second graphene nanoribbons 2 and the adjacent edges of the third graphene nanoribbons 3 is 8-12 nm, and the coupling length between each third graphene nanoribbon 3 and each second graphene nanoribbon 2 is 8-12 nm.

According to the slow light device based on the graphene nano-strip metamaterial structure, the number of the second graphene nano-strips and the number of the third graphene nano-strips are respectively 2, the length of the first graphene nano-strips is 60-70 nm, the width of the first graphene nano-strips is 15-25 nm, the length of each second graphene nano-strip is 45-50 nm, the width of each second graphene nano-strip is 8-12 nm, the length of each third graphene nano-strip is 45-50 nm, and the width of each third graphene nano-strip is 8-14 nm.

According to the slow light device based on the graphene nanoribbon metamaterial structure, the length and the width of a first graphene nanoribbon 1 are 64nm and 20nm respectively, the length and the width of each second graphene nanoribbon 2 are 48nm and 10nm, the distance between adjacent edges of each second graphene nanoribbon 2 is 10nm, the coupling length is 48nm, the length and the width of each third graphene nanoribbon 3 are 48nm and 12nm respectively, the distance between adjacent edges of each third graphene nanoribbon 3 is 8nm, the coupling length is 48nm, the distance between adjacent edges of the adjacent second graphene nanoribbons 2 and the adjacent edges of the third graphene nanoribbons 3 is 8nm, the coupling length is 10nm, the distance between adjacent edges of the first graphene nanoribbon 1 and the adjacent edges of the adjacent second graphene nanoribbons 2 is 10nm, and the coupling length is 10 nm.

Specifically, the system structure is as shown in fig. 1, when the incident light is vertically irradiated from above the slow light device, the direction of the electric field is parallel to the incident light beams in the length direction of the first graphene nanoribbon 1 and each second graphene nanoribbon 2, the surfaces of the first graphene nanoribbons 1 and the second graphene nanoribbons 2 are directly excited to generate SPPs, the first graphene nanoribbons 1 and the second graphene nanoribbons 2 are expressed in a bright mode in the structure, since each third graphene nanoribbon 3 cannot directly generate a coupling effect with the vertically incident light, each third graphene nanoribbon 3 shows a dark mode in the structure, however, each third graphene nanoribbon 3 can indirectly excite the SPPs on the surface thereof by generating a near-field coupling effect with each second graphene nanoribbon 2, that is, the incident light generates an indirect coupling effect with the third graphene nanoribbon 3 through the first graphene nanoribbon 1, each second graphene nanoribbon 2. The coupling interference effect of the SPPs in the first graphene nanoribbon 1, each second graphene nanoribbon 2, and each third graphene nanoribbon 3 causes the generation of the double PIT effect.

According to the slow light device based on the graphene nano strip metamaterial structure, SiO ₂The thickness of the substrate 4 is 280 to 320 nm.