Multi-mode coupling tunable electromagnetically induced transparency-like device based on polarization mode

Abstract

The present invention provides a polarization-based multimode coupling tunable electromagnetically induced transparency-like device, which includes a dielectric plate. The dielectric plate is provided with a double-layer metal resonant structure. The double-layer metal resonant structure includes a circular resonator, an H-shaped resonator, and a split-ring resonator. The top surface of the dielectric plate is provided with the circular resonator and the H-shaped resonator. The H-shaped resonator is arranged inside the circular resonator, and the H-shaped resonator and the circular resonator are in non-contact with each other. The bottom surface of the dielectric plate is provided with the split-ring resonator. By changing the polarization direction of the incident electromagnetic wave, the switching between single-peak and double-peak of the electromagnetically induced transparency-like is realized. This polarization-based multimode coupling tunable electromagnetically induced transparency-like device can realize the switching between single and double transmission windows in the electromagnetically induced transparency-like by changing the polarization direction, and can produce a strong slow light effect accompanied by a large group delay, having potential application value in the field of sensors.

Description

Technical Field

[0001] The present invention relates to a multi-mode coupling tunable electromagnetic-induced transparency-like device based on polarization mode, belonging to the technical field of electromagnetic-induced transparency-like technology. Background Art

[0002] Electromagnetically induced transparency (EIT) is a quantum interference effect and has application prospects in fields such as sensors, slow light, and filtering. After realizing EIT in the terahertz band using electromagnetic metamaterials, due to the fact that it does not require harsh experimental conditions such as high-intensity and low-temperature lasers, electromagnetic-induced transparency-like based on metamaterials has received great attention. Electromagnetic-induced transparency-like can be divided into polarization-insensitive electromagnetic-induced transparency-like, low-loss electromagnetic-induced transparency-like, tunable electromagnetic-induced transparency-like, etc.

[0003] Among them, there are many ways to achieve tunability in tunable electromagnetic-induced transparency-like. For example, materials such as graphene and photosensitive silicon are used for self-variable regulation, and structural modulation is carried out by changing the size and structure. More often, it is the regulation of the amplitude or frequency of a single transmission peak. After the design unit is manufactured, it is difficult to carry out regulation. Currently, it is difficult for the existing tunable electromagnetic-induced transparency-like to achieve the switching between single and double peaks of electromagnetic-induced transparency-like.

[0004] For example, Chinese Patent CN201910193467.5 discloses a double-peak electromagnetic-induced transparency-like device and method based on two coupling modes, and also fails to achieve the switching between single and double peaks of electromagnetic-induced transparency-like.

[0005] The above problems should be considered and solved during the design and processing of tunable electromagnetic-induced transparency-like devices. Summary of the Invention

[0006] The purpose of the present invention is to provide a multi-mode coupling tunable electromagnetic-induced transparency-like device based on polarization mode to solve the problem in the prior art that the tunable method is realized by changing the physical size, and it is difficult to achieve the switching between single and double peaks of electromagnetic-induced transparency-like after being manufactured.

[0007] The technical solution of the present invention is as follows:

[0008] A multi-mode coupling tunable electromagnetic-induced transparency-like device based on polarization mode includes a dielectric plate. The dielectric plate is provided with a double-layer metal resonant structure. The double-layer metal resonant structure includes a circular-ring resonator, an H-shaped resonator, and a double-open-ring resonator. The top surface of the dielectric plate is provided with a circular-ring resonator and an H-shaped resonator. The H-shaped resonator is arranged inside the circular-ring resonator, and the H-shaped resonator and the circular-ring resonator are in non-contact with each other. The bottom surface of the dielectric plate is provided with a double-open-ring resonator. By changing the polarization direction of the incident electromagnetic wave, the switching between single and double peaks of electromagnetic-induced transparency-like is realized.

[0009] Further, the middle horizontal tangent line of the H-shaped resonator is parallel to the opening direction of the double split-ring resonator.

[0010] Further, the double split-ring resonator is formed by combining two split-ring resonators with the same opening direction placed side by side.

[0011] Further, the top and bottom surfaces of the dielectric plate are respectively parallel to the direction of the incident electromagnetic wave.

[0012] Further, the dielectric plate is a dielectric plate made of polyimide.

[0013] Further, the polarization direction of the incident electromagnetic wave is changed to vary between parallel and perpendicular to the opening direction of the double split-ring resonator in the electric field direction of the incident electromagnetic wave.

[0014] Further, when the electric field direction of the incident electromagnetic wave is parallel to the opening direction of the double split-ring resonator, the ring resonator and the H-shaped resonator will be excited by the incident electric field to generate resonance. The double split-ring resonator is excited by the near-field coupling of the ring resonator and the H-shaped resonator and cannot be excited by the incident electric field. The ring resonator serves as a bright mode, the H-shaped resonator serves as a bright mode, and the double split-ring resonator serves as a dark mode, forming a bright-bright-dark mode channel. The ring resonator, the H-shaped resonator, and the double split-ring resonator are coupled pairwise to generate two electromagnetically induced transparency-like transmission peaks.

[0015] Further, when the electric field direction of the incident electromagnetic wave is perpendicular to the opening direction of the double split-ring resonator, the ring resonator and the double split-ring resonator are excited by the incident electric field to generate resonance. At this time, the H-shaped resonator cannot be excited by the electric field to generate resonance, nor can it be excited by the near-field coupling of the ring resonator and the double split-ring resonator. Then the ring resonator and the double split-ring resonator form a bright-bright mode channel, generating a single electromagnetically induced transparency-like transmission peak.

[0016] The beneficial effects of the present invention are as follows:

[0017] First, this polarization-based multimode coupling tunable electromagnetically induced transparency-like device can achieve the switching between single and double transmission windows in electromagnetically induced transparency-like by changing the polarization direction of the incident electromagnetic wave, and can produce a strong slow light effect accompanied by a large group delay, having potential application value in the field of sensors.

[0018] Second, this polarization-based multimode coupling tunable electromagnetically induced transparency-like device adopts a double-layer metal resonant structure to obtain electromagnetically induced transparency-like. By respectively arranging the ring resonator, the H-shaped resonator, and the double split-ring resonator on the top and bottom surfaces of the same dielectric plate, miniaturization can be achieved, and the ways to obtain electromagnetically induced transparency-like can be enriched. Description of the Drawings

[0019] Figure 1 FIG. 2 is a schematic structural diagram of a multi-mode coupling tunable electromagnetically induced transparency-like device based on polarization mode according to an embodiment of the present invention;

[0020] Figure 2 FIG. 3 is a schematic bottom surface structure diagram of a dielectric plate of a multi-mode coupling tunable electromagnetically induced transparency-like device based on polarization mode according to an embodiment;

[0021] Figure 3 FIG. 4 is a three-dimensional diagram of generating electromagnetically induced transparency-like by a multi-mode coupling tunable electromagnetically induced transparency-like device based on polarization mode according to an embodiment. Among them, (a) is a three-dimensional diagram of generating electromagnetically induced transparency-like when the electric field of the incident electromagnetic wave is incident along the x-axis direction, and (b) is a three-dimensional diagram of generating electromagnetically induced transparency-like when the electric field of the incident electromagnetic wave is incident along the y-axis direction;

[0022] Figure 4 FIG. 5 is a schematic diagram of the transmission spectrum of a multi-mode coupling tunable electromagnetically induced transparency-like device based on polarization mode according to an embodiment. Among them, (a) is a schematic diagram of the transmission spectrum when the electric field of the incident electromagnetic wave is incident along the x-axis direction, and (b) is a schematic diagram of the transmission spectrum when the electric field of the incident electromagnetic wave is incident along the y-axis direction;

[0023] Figure 5 FIG. 6 is a schematic diagram of the phase change and group delay of an electromagnetically induced transparency-like transmission window generated by a multi-mode coupling tunable electromagnetically induced transparency-like device based on polarization mode according to an embodiment. Among them, (a) is a schematic diagram of the change of the phase slope in the X polarization state, (b) is a schematic diagram of the group delay in the X polarization state, (c) is a schematic diagram of the change of the phase slope in the Y polarization state, and (d) is a schematic diagram of the group delay in the Y polarization state;

[0024] Figure 6 FIG. 7 is an explanatory schematic diagram of the transmission spectra of a split-ring resonator (SR), an H-shaped resonator (MH), and a double split-ring resonator (SRRs), and the transmission spectra of pairwise combinations of the split-ring resonator, the H-shaped resonator, and the double split-ring resonator when the electric field direction of the incident electromagnetic wave is along the x-axis in the embodiment; where SR+MH is the transmission spectrum when the split-ring resonator and the H-shaped resonator are combined, SR+SRR is the transmission spectrum when the split-ring resonator and the double split-ring resonator are combined, MH+SRR is the transmission spectrum when the H-shaped resonator and the double split-ring resonator are combined, and Double EIT is the transmission spectrum when two transmission peaks are generated by the combination of the split-ring resonator (SR), the H-shaped resonator (MH), and the double split-ring resonator;

[0025] Figure 7It is a schematic illustration of the transmission spectra of a split-ring resonator (SR), an H-shaped resonator (MH), and split-ring resonators (SRRs) when the electric field direction of the incident electromagnetic wave is along the y-axis in the embodiment, as well as the transmission spectra of combinations of the split-ring resonator, the H-shaped resonator, and the split-ring resonators taken two at a time; among them, SR+MH is the transmission spectrum when the split-ring resonator and the H-shaped resonator are combined, SR+SRR is the transmission spectrum when the split-ring resonator and the split-ring resonator are combined, MH+SRR is the transmission spectrum when the H-shaped resonator and the split-ring resonator are combined, and Single EIT is the transmission spectrum when a single transmission peak is generated when the split-ring resonator (SR), the H-shaped resonator (MH), and the split-ring resonator are combined;

[0026] Figure 8 It is a schematic diagram of the transmission spectra of the double-layer metal resonant structure in different polarization directions in the embodiment;

[0027] Wherein: 1 - dielectric plate, 2 - split-ring resonator, 3 - H-shaped resonator, 4 - split-ring resonator. Detailed implementation manners

[0028] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Embodiment

[0029] A polarization-based multimode coupling tunable electromagnetically induced transparency-like device, as Figure 1 and Figure 2 , includes a dielectric plate 1. The dielectric plate 1 is provided with a double-layer metal resonant structure. The double-layer metal resonant structure includes a split-ring resonator 2, an H-shaped resonator 3, and a split-ring resonator 4. The top surface of the dielectric plate 1 is provided with the split-ring resonator 2 and the H-shaped resonator 3. The H-shaped resonator 3 is arranged inside the split-ring resonator 2, and the H-shaped resonator 3 and the split-ring resonator 2 are not in contact with each other. The bottom surface of the dielectric plate 1 is provided with the split-ring resonator 4. By changing the polarization direction of the incident electromagnetic wave, the switching between single and double peaks of electromagnetically induced transparency-like is realized.

[0030] This polarization-based multimode coupling tunable electromagnetically induced transparency-like device can realize the switching between single and double transmission windows in electromagnetically induced transparency-like by changing the polarization direction of the incident electromagnetic wave, and can produce a strong slow light effect accompanied by a large group delay, having potential application value in the field of sensors.

[0031] As Figure 1 and Figure 2 , the middle horizontal tangent of the H-shaped resonator 3 is parallel to the opening direction of the split-ring resonator 4. The split-ring resonator 4 is formed by combining two split-ring resonators with the same opening direction placed side by side.

[0032] In this polarization-based multimode coupling tunable electromagnetically induced transparency (EIT)-like device, the top and bottom surfaces of dielectric plate 1 are parallel to the electromagnetic field direction. Dielectric plate 1 is made of polyimide.

[0033] In this polarization-based multimode coupling tunable EIT-like device, the polarization direction of the incident electromagnetic wave is changed between parallel and perpendicular to the opening direction of the double split-ring resonator 4 in the electric field direction of the incident electromagnetic wave. During the change of the incident electromagnetic wave direction, the switching of the number of EIT-like transmission peaks is achieved.

[0034] When the electric field direction of the incident electromagnetic wave is parallel to the opening direction of the double split-ring resonator 4, that is, when the incident electromagnetic wave is along the x-axis, the ring resonator 2 and the H-shaped resonator 3 will be excited by the incident electric field. The ring resonator 2 and the H-shaped resonator 3 are selected as bright modes, while the double split-ring resonator 4 will be coupled and excited but not excited by the incident electric field. The double split-ring resonator 4 is selected as the dark mode. And because the three designed resonant units have similar resonant frequencies, the mutual interference of the three constitutes a bright-bright-dark mode coupling channel, inducing two EIT-like transmission peaks.

[0035] When the electric field direction of the incident electromagnetic wave is perpendicular to the opening direction of the double split-ring resonator 4, that is, when the incident electromagnetic wave is along the y-axis, the ring resonator 2 and the double split-ring resonator 4 will be excited by the incident electric field. Then the ring resonator 2 and the double split-ring resonator 4 are used as bright modes, while the H-shaped resonator 3 will not be excited and will not be coupled and excited by other resonators. Because the two designed resonant units have similar resonant frequencies, the mutual interference of the two constitutes a bright-bright mode coupling channel, inducing one EIT-like transmission peak.

[0036] In this polarization-based multimode coupling tunable EIT-like device, the double-layer metal resonant structure exhibits different characteristics under different polarization directions, thus achieving tunable characteristics when the polarization direction changes. The ring resonator 2, the H-shaped resonator 3, and the double split-ring resonator 4 of the double-layer metal resonant structure are respectively located on the upper and lower surfaces of the same dielectric plate 1, realizing a double-layer EIT-like structure and enabling the miniaturization of the structure.

[0037] In this polarization-based multimode coupling tunable EIT-like device, the double-layer metal resonant structure etched on the upper and lower surfaces of dielectric plate 1 includes a silver circular resonator, the H-shaped resonator 3, and the double split-ring resonator 4. Due to the central symmetry of the unit structure of the circular resonator, it has polarization-insensitive characteristics. While the unit structures of the H-shaped resonator 3 and the double split-ring resonator are not centrally symmetric, so they will exhibit different characteristics under different polarizations.

[0038] Figure 3The three-dimensional schematic diagram of the multi-mode coupling adjustable electromagnetically induced transparency (EIT)-like device based on the polarization method in the embodiment for generating EIT-like effect is shown. As Figure 3 shown in (a) therein, when the opening direction of the double split ring is parallel to the electric field direction of the incident electromagnetic wave, that is, when the electric field direction of the incident electromagnetic wave is along the x-axis direction, the circular resonator and the H-shaped resonator 3 will be excited by the incident electric field and are accompanied by a relatively large Q value, while the double split ring resonator is in a non-excited state. At this time, the circular ring resonator 2 serves as the bright mode, the H-shaped resonator 3 serves as the bright mode, and the double split ring resonator 4 serves as the dark mode, thus having a bright-bright-dark mode channel coupling method. The three-part metal resonator structure generates an EIT-like phenomenon with two transparency windows through pairwise coupling, and a double-transmission-peak EIT-like effect with a large group delay is obtained. As Figure 3 shown in (b) therein, by changing the polarization direction to make the electromagnetic direction of the electromagnetic field perpendicular to the opening direction of the double split ring, that is, when the incident electric field direction is along the y-axis direction, there is a bright-bright mode channel coupling method. The circular ring resonator 2 serves as the bright mode, and the double split ring resonator 4 serves as the bright mode. At this time, the H-shaped resonator 3 is no longer excited by the electric field and is not affected by the coupling of other resonators. The circular ring resonator 2 and the double split ring resonator 4 generate a single-transmission-peak EIT-like effect through bright mode-bright mode coupling. By using the change of the polarization direction, the change in the number of transmission peaks of the EIT-like effect is realized.

[0039] Figure 4 The schematic diagram of the transmission spectrum of the multi-mode coupling adjustable electromagnetically induced transparency (EIT)-like device based on the polarization method in the embodiment is shown. As can be seen from Figure 4 (a) therein, when the electric field of the incident electromagnetic wave is incident along the x-axis direction, obvious EIT-like transmission windows appear in the transmission spectra of 0.878 - 1.255 THz and 1.255 - 1.43 THz respectively. As can be seen from Figure 4 (b) therein, when the electric field of the incident electromagnetic wave is incident along the y-axis direction, an obvious EIT-like transmission window appears in the transmission spectrum of 0.916 - 1.382 THz.

[0040] Figure 5 The schematic diagram of the phase change and group delay of the EIT-like transmission window generated by the multi-mode coupling adjustable electromagnetically induced transparency (EIT)-like device based on the polarization method in the embodiment is shown. As Figure 5 shown in (a) therein, in the x-polarization state, due to the rapid change of the phase slope, a steep peak appears in the position of the first transparency window in the group delay spectrum, and the maximum value reaches 7.41 ps at 0.923 THz. In the second transparency window, the group delay changes drastically compared with the previous one, and the maximum value reaches 8.5 ps at 1.284 THz. From Figure 5In (b), the maximum group index values of the two windows are 938.1 and 1276.2 respectively, which means that when electromagnetic waves pass through the EIT-like metamaterial with the same thickness, the group velocity of 938.1 (1276.2) is several times slower than that through vacuum. Figure 5 (c) and (d) in show the phase change and group delay in the y-polarization state. The group delay reaches a peak of 5.88 ps at 0.952 THz, and the peak group index reaches 881.7. The group index values in the above two different polarization directions show good slow-wave performance of the EIT effect. As Figure 5 shown, within each transmission window, the phase changes steeply and is accompanied by a large group delay. Therefore, this polarization-based multimode coupling tunable electromagnetic-induced transparency device can be used in slow-light devices and sensor fields.

[0041] As Figure 6 shown, when the electric field of the incident electromagnetic wave is along the x-axis and the incident magnetic field is along the y-axis, the ring resonator 2 and the H-shaped resonator 3 can be excited to resonate. Therefore, the ring resonator 2 and the H-shaped resonator 3 are selected as the bright modes. At this time, the double split-ring metallic resonator is not resonated by the incident electromagnetic wave, but can be resonated by the near-field coupling of the ring resonator 2 and the H-shaped resonator 3, and is selected as the dark mode. Therefore, the transmission spectrum of the electromagnetic-induced transparency at this time is generated by the mutual coupling between the ring resonator 2, the H-shaped resonator 3, and the double split-ring resonator 4. From Figure 6 the transmission spectra generated by pairwise combinations of the resonators, it can be seen that the first transmission peak is generated by the mutual coupling between the ring resonator 2 and the H-shaped resonator 3, the second transmission peak is generated by the mutual coupling between the ring resonator 2 and the double split-ring resonator 4, and the transmission valley between the two transmission peaks is generated by the interference of the two transmission peaks after the mutual coupling between the H-shaped resonator 3 and the double split-ring resonator 4. Therefore, the generation of the two transmission peaks is caused by the pairwise mutual coupling between the resonators. Combining Figure 6 with the EIT curve, it can be seen that the two transparent windows appear in a relatively wide frequency range because the resonance frequencies of the ring resonator 2 and the H-shaped resonator 3 are relatively close and the Q factors have an order-of-magnitude difference. The double split-ring resonator 4 can be resonated by the near-field coupling of the ring resonator 2 and the H-shaped resonator 3, and the resonance frequency is close to the resonance frequencies of the above two metallic resonators. Therefore, it has the necessary conditions to obtain a double-peak electromagnetic-induced transparency.

[0042] As Figure 7 shown, when the electric field of the incident electromagnetic wave is along the y-axis and the incident magnetic field is along the x-axis, the ring resonator 2 and the double split-ring resonator 4 can be excited to resonate. At this time, the H-shaped resonator 3 cannot be resonated and cannot be resonated by near-field coupling either. Therefore, the ring resonator 2 and the double split-ring resonator 4 are selected as the bright modes. Combining Figure 7It can be seen from the EIT curve that the resonance frequencies of the ring resonator 2 and the double split-ring resonator 4 are relatively close, and there is an order-of-magnitude difference in the Q factor. Therefore, it has the necessary conditions to obtain single-peak-like electromagnetically induced transparency.

[0043] Figure 8 It is a schematic diagram of the transmission spectrum of the double-layer metal resonant structure in the embodiment under different polarization directions. Figure 8 In it, DipⅠ, DipⅡ, and DipⅢ are peak valley 1, peak valley 2, and peak valley 3 respectively. From Figure 8 It can be seen that as the polarization direction changes continuously from 0° (i.e., along the X-axis direction), 30°, 60°, to 90° (i.e., along the Y-axis direction), the number of transmission peaks in the transmission spectrum of the electromagnetically induced transparency-like in the embodiment will change, having the characteristic of single-double peak switching.

[0044] For this multi-mode coupling tunable electromagnetically induced transparency-like device based on the polarization method, the double-layer metal resonant structure has different states under different polarization directions, and the coupling effect between them realizes the change of single-double peaks under the switching of the polarization direction, which can produce a significant slow light effect and group refractive index. At the same time, through the structural design, it can be applied in the field of sensors.

[0045] The above are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. Any equivalent modifications or changes made by those of ordinary skill in the art according to the content disclosed in the present invention shall be included in the protection scope recorded in the claims.

Claims

1. A multimode coupling adjustable electromagnetically induced transparency-like device based on polarization mode, comprising a dielectric plate, characterized in that: The dielectric plate is provided with a double-layer metal resonant structure. The double-layer metal resonant structure includes a circular resonator, an H-shaped resonator, and a double split-ring resonator. The top surface of the dielectric plate is provided with the circular resonator and the H-shaped resonator. The H-shaped resonator is arranged inside the circular resonator, and the H-shaped resonator and the circular resonator are in non-contact with each other. The bottom surface of the dielectric plate is provided with the double split-ring resonator. The double split-ring resonator is a double split-ring resonator formed by a combination of two split-rings with the same opening direction placed side by side; the middle tangent line of the H-shaped resonator is parallel to the opening direction of the double split-ring resonator; by changing the polarization direction of the incident electromagnetic wave, the single-peak and double-peak switching of the electromagnetic-induced transparency-like is realized.

2. The multimode coupling adjustable electromagnetic-induced-transparency-like device based on polarization mode as claimed in claim 1, wherein: The top surface and the bottom surface of the dielectric plate are respectively parallel to the direction of the incident electromagnetic wave.

3. The multimode coupling tunable electromagnetically induced transparency-like device based on polarization mode as claimed in claim 1, wherein: The dielectric plate is a dielectric plate made of polyimide.

4. The multimode coupling adjustable electromagnetic induced transparency-like device based on polarization mode according to any one of claims 1-3, characterized in that: Changing the polarization direction of the incident electromagnetic wave means changing between parallel and perpendicular of the electric field direction of the incident electromagnetic wave and the opening direction of the double split-ring resonator.

5. The multimode coupling tunable electromagnetically induced transparency-like device based on polarization mode as claimed in claim 4, wherein: When the electric field direction of the incident electromagnetic wave is parallel to the opening direction of the double split-ring resonator, the circular resonator and the H-shaped resonator will be excited by the incident electric field to generate resonance. The double split-ring resonator is excited by the near-field coupling of the circular resonator and the H-shaped resonator and cannot be excited by the incident electric field. The circular resonator serves as a bright mode, the H-shaped resonator serves as a bright mode, and the double split-ring resonator serves as a dark mode, constituting a bright-bright-dark mode channel. The circular resonator, the H-shaped resonator, and the double split-ring resonator are coupled pairwise to generate two electromagnetic-induced transparency-like transmission peaks.

6. The multimode coupling tunable electromagnetically induced transparency-like device based on polarization mode as claimed in claim 4, wherein: When the electric field direction of the incident electromagnetic wave is perpendicular to the opening direction of the double split-ring resonator, the circular resonator and the double split-ring resonator are excited by the incident electric field to generate resonance. At this time, the H-shaped resonator cannot be excited by the electric field to generate resonance, nor can it be resonated by the near-field coupling of the circular resonator and the double split-ring resonator. Then the circular resonator and the double split-ring resonator constitute a bright-bright mode channel, generating a single electromagnetic-induced transparency-like transmission peak.

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