Rotationally non-overlapping metasurface structures based on Fano resonance and their applications

Abstract

A rotationally non-overlapping metasurface structure based on Fano resonance comprises a dielectric substrate and a metal film, wherein the metal film is covered directly above the dielectric substrate, wherein a rotationally non-overlapping unit is etched into the metal film and extends through the thickness of the metal film, wherein the rotationally non-overlapping unit is composed of a plurality of periodically arranged rotationally non-overlapping sub-units; the rotationally non-overlapping sub-units comprise an outer ring and a quasi-ring located within the outer ring, wherein the quasi-ring is concentrically arranged with the outer ring, and an opening is provided on the circumference of the quasi-ring, wherein the angles between the two ends of the opening and the center of the circle are symmetrical about the horizontal axis. The angle of the opening is adjusted to adjust the number of Fano resonances; the outer radius of the outer ring and the inner radius of the quasi-ring, as well as the polarization direction of the incident light, are adjusted respectively to realize the application of plasma sensing and optical switching. The structure of the present invention is simple and easy to manufacture, and the size is nanometer-scale for easy integration. Plasma sensing and switching applications are realized through convenient adjustment, opening up a new path for highly integrated photonic devices.

Description

Technical Field

[0001] The present invention relates to the field of micro-nano optoelectronic technology, in particular to a rotationally non-overlapping metasurface structure based on Fano resonance and applications thereof. Background Art

[0002] In recent years, the manipulation of the optical response of metasurfaces, particularly their spectral response in the near-infrared region, remains a key challenge in developing practical optical devices based on metasurfaces. Artificial digital metasurfaces, typically composed of periodic or quasi-periodic subwavelength artificial unit structures, can be used to modify the transmission characteristics of electromagnetic waves.

[0003] Existing control mechanisms for metasurface design primarily rely on dynamic electromagnetic wave control, including electrical, temperature, and optical methods. For example, Chinese patent publication number CN109612966A discloses an all-dielectric metasurface refractive index sensor based on polarization-insensitive Fano resonance, which generates a high-quality Fano resonance with high sensitivity and high quality factor that is insensitive to polarization state through a combination of three V-shaped dielectric antennas; publication number CN103259098A discloses a multilayer symmetrical metamaterial that can generate Fano resonance enhancement and frequency tunability, which improves and tunes the Fano resonance quality factor through the generation of electric dipole resonance by the multilayer symmetrical metamaterial; and patent publication numbers CN113589406A, CN109683219A, and CN103247862A, among others. However, the structures of these existing modified metasurface Fano resonances may be complex and difficult to process; have low quality factors and large disturbances; or be difficult to tune. Therefore, achieving a metasurface Fano resonance with a simple structure, convenient control, and high quality factor is currently an area that needs improvement. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above-mentioned deficiencies in the prior art and to provide a rotationally non-overlapping metasurface structure based on Fano resonance and its application.

[0005] The technical solution of the present invention is: a rotationally non-overlapping metasurface structure based on Fano resonance, including a dielectric substrate and a metal film, the metal film covering directly above the dielectric substrate, and a rotationally non-overlapping unit structure etched into the metal film that penetrates the thickness of the metal film, and the rotationally non-overlapping unit structure is composed of multiple periodically arranged rotationally non-overlapping sub-unit structures.

[0006] The rotationally non-overlapping subunit structure includes an outer ring and a quasi-circular ring located inside the outer ring. The quasi-circular ring is concentrically arranged with the outer ring, and an opening is provided on the circumference of the quasi-circular ring. The opening angles between the two ends of the opening and the center of the circle are symmetrical about the horizontal axis.

[0007] A further technical solution of the present invention is: the dielectric material of the dielectric substrate is quartz or benzocyclobutene, and the thickness of the dielectric substrate is 225 to 250 nm; the material of the metal film is silver or gold, and the thickness of the metal film is 50 to 60 nm; the period of the multiple rotationally non-overlapping subunits is 400 to 600 nm.

[0008] A further technical solution of the present invention is: the outer radius of the outer ring is 160-190nm, and the width of the outer ring is 20-50nm; the outer radius of the quasi-ring is 100-150nm, the inner radius of the quasi-ring is 95-125nm, and the opening angle is 20°-135°.

[0009] A further technical solution of the present invention is to adjust the opening angle of the quasi-circular ring in the rotationally non-overlapping subunit structure to adjust the number of Fano resonance peaks.

[0010] A further technical solution of the present invention is: when the polarization direction of the incident light incident on the rotationally non-overlapping metasurface structure is 0°, the opening angle is adjusted from 0° to 180°, so that the number of Fano resonance peaks changes from single to three; when the polarization direction of the incident light incident on the rotationally non-overlapping metasurface structure is 90°, the opening angle is adjusted from 0° to 180°, so that the number of Fano resonance peaks changes from single to two, two to three, and three to two.

[0011] Another technical solution of the present invention is: based on the plasma sensing application of the rotationally non-overlapping metasurface structure of Fano resonance, the outer radius of the outer ring and the inner radius of the quasi-ring in the aforementioned rotationally non-overlapping subunit are adjusted to adjust the optical properties of the Fano resonance.

[0012] A further technical solution of the present invention is: when the outer radius of the outer ring changes from 175nm to 190nm, the resonance center of the Fano resonance blue-shifts according to an exponential function; when the inner circle radius of the quasi-ring changes from 95nm to 125nm, the resonance center of the Fano resonance red-shifts according to an exponential function.

[0013] Another technical solution of the present invention is: based on the application of a plasma optical switch of a rotationally non-overlapping metasurface structure of Fano resonance, the polarization direction of the incident light incident on the metasurface structure is adjusted to adjust the optical properties of the Fano resonance.

[0014] A further technical solution of the present invention is that the polarization direction of the incident light of the metasurface structure is parallel or perpendicular to the direction of the opening angle.

[0015] A further technical solution of the present invention is: the operating wavelength of the metasurface structure is 1207nm and / or 2021nm.

[0016] Compared with the prior art, the present invention has the following characteristics:

[0017] 1. The rotational non-overlapping metasurface structure of the present invention consists only of a dielectric substrate and a metal film with a hole array, is small in size, simple in structure and easy to manufacture.

[0018] 2. The rotational non-overlapping metasurface structure of the present invention can adjust the number of Fano resonances by adjusting the polarization direction of the incident light.

[0019] 3. The rotationally non-overlapping metasurface structure of the present invention has a high switching ratio. By changing the structural parameters of the rotationally non-overlapping metasurface structure, the transmittance of the transmitted light can be effectively adjusted, and it is applied to plasma sensing and plasma optical switching.

[0020] The detailed structure of the present invention is further described below in conjunction with the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the super surface structure of the present invention;

[0022] Figure 2 It is a structural diagram of the rotation non-overlapping subunit;

[0023] Figure 3 It is a two-dimensional cross-sectional schematic diagram of the rotational non-overlapping subunit;

[0024] Figure 4 (a) and 4(b) are the transmittance spectra of a single outer ring and a quasi-ring with the same parameters, respectively;

[0025] Figure 5 This is a transmittance spectrum of the rotationally non-overlapping unit periodic structure in the near-infrared band of Example 1;

[0026] Figure 6(a) 、 6(b) These are the transmittance spectra when the incident light polarization angles are 0° and 90° respectively;

[0027] Figure 7(a) 、 7(b) They are the transmittance spectra when the inner radius of the ring-like unit structure changes;

[0028] Figure 8(a) 、 8(b) They are the transmittance spectra when the radius of the outer ring unit structure changes;

[0029] Figure 9 The polarization directions of the incident light are along the X and Z axis directions, respectively. DETAILED DESCRIPTION

[0030] Example 1, as Figure 1-5As shown, the rotational non-overlapping metasurface structure based on Fano resonance includes a dielectric substrate 1 and a metal film 2, wherein the metal film 2 is covered directly above the dielectric substrate 1.

[0031] The dielectric material of the dielectric substrate 1 is quartz, and the thickness of the dielectric substrate is 225 nm. The dielectric material of the dielectric substrate 1 can also be any other dielectric suitable for processing, such as benzocyclobutene.

[0032] The metal film 2 is made of silver and has a thickness of 50 nm. Silver allows for low absorption loss in the visible and near-infrared regions. The metal film 2 can also be made of other metals similar to silver that can generate surface plasmons, such as gold.

[0033] The metal film 2 is etched with a rotationally non-overlapping unit 3 that penetrates the thickness of the metal film. The rotationally non-overlapping unit 3 is composed of a plurality of periodically arranged rotationally non-overlapping sub-units 4. The period of the plurality of rotationally non-overlapping sub-units is 600 nm.

[0034] The rotational non-overlapping subunit 4 includes an outer ring 4-1 and a quasi-circular ring 4-2 located inside the outer ring. The quasi-circular ring 4-2 is concentrically arranged with the outer ring 4-1, and an opening 4-3 is provided on the circumference of the quasi-circular ring 4-2. The opening angle α between the two ends of the opening 4-3 and the center 0 is symmetrical about the horizontal axis.

[0035] The Fano resonance-based rotationally non-overlapping metasurface structure is defined in an X, Y, and Z Cartesian coordinate system, where the X and Z axes are the transverse and longitudinal array periodicity directions, respectively, and the Y axis is perpendicular to the plane formed by the X and Z axes. Incident light is incident perpendicularly from the dielectric substrate 1 onto the bottom side of the metal film 2 and is transmitted through the other side of the metal film 2 to form transmitted light.

[0036] In order to observe the tuning changes of the Fano resonance of the rotationally non-overlapping metasurface structure, the incident light field is set to select an ultrashort Gaussian modulated pulse with a central wavelength of 1550 nm. The pulse width and center time are 5fs and 16fs respectively. The pulse acts perpendicularly to the dielectric substrate 1 and propagates along the positive direction of the Y axis. The polarization direction of the incident light field is fixed along the X axis. The outer radius R2 of the quasi-circular ring 4-2 is 130nm, the inner radius R1 of the quasi-circular ring is 100nm, the opening angle α is 20°, the outer radius R3 of the outer ring 4-1 is 175nm, and the width w of the outer ring 4-1 is 20nm. In order to observe the influence of the incident light field on the rotationally non-overlapping metasurface structure, the 3D-FDTD method is used to numerically simulate the incident light transmission in the rotationally non-overlapping metasurface structure, and a single outer ring unit structure and a single quasi-circular ring unit structure with the same parameters are set respectively for comparison, and the following results are obtained: Figure 4 (a) and (b) are the transmittance spectra shown in Figure 4. The transmittance spectra of the composite rotational non-overlapping metasurface structure are obtained by setting the outer ring unit structure and the quasi-ring unit structure with the same parameters. Figure 5 shown.

[0037] from Figure 4 As can be seen in (a), during the interaction between light and matter, a ring-like structure is formed by breaking a single ring structure at a small angle, which can generate a single Fano resonance in the near-infrared band and induce the generation of bonding mode and antibonding mode. Figure 4 As can be seen in (b), a single ring structure can produce selectively excited bonding modes. Figure 5 It can be seen that compared with the metasurface of a single outer ring unit periodic structure and a single quasi-ring unit periodic structure with small-angle breaking, the rotationally non-overlapping subunit structure formed by the periodic hole array composed of the outer ring and the quasi-ring can cause double Fano resonance. This is because there is spectral overlap in the transmission spectrum between the bonding mode of the single quasi-ring unit structure and the effective electric dipole mode of the single outer ring unit structure, which causes the generation of plasma Fano resonance and generates two new hybrid double bonding modes and double anti-bonding modes in the composite metasurface composed of the outer ring and the quasi-ring. At the same time, the anti-bonding mode in the quasi-ring unit structure interacts with the effective electric dipole mode in the outer ring unit structure, resulting in the selective excitation of the double anti-bonding mode.

[0038] Example 2, as Figure 1-3 As shown in , 6 , the rotational non-overlapping metasurface structure based on Fano resonance includes a dielectric substrate 1 and a metal film 2 , wherein the metal film 2 is covered directly above the dielectric substrate 1 .

[0039] The dielectric material of the dielectric substrate 1 is quartz, and the thickness of the dielectric substrate is 250 nm. The dielectric material of the dielectric substrate 1 can also be any other dielectric suitable for processing, such as benzocyclobutene.

[0040] The metal film 2 is made of silver and has a thickness of 60 nm. Silver allows for low absorption loss in the visible and near-infrared regions. The metal film 2 can also be made of other metals similar to silver that can generate surface plasmons, such as gold.

[0041] The metal film 2 is etched with a rotationally non-overlapping unit 3 that penetrates the thickness of the metal film. The rotationally non-overlapping unit 3 is composed of a plurality of periodically arranged rotationally non-overlapping sub-units 4. The period of the plurality of rotationally non-overlapping sub-units is 550 nm.

[0042] The rotational non-overlapping subunit 4 includes an outer ring 4-1 and a quasi-circular ring 4-2 located inside the outer ring. The quasi-circular ring 4-2 is concentrically arranged with the outer ring 4-1, and an opening 4-3 is provided on the circumference of the quasi-circular ring 4-2. The opening angle α between the two ends of the opening 4-3 and the center 0 is symmetrical about the horizontal axis.

[0043] The Fano resonance-based rotationally non-overlapping metasurface structure is defined in an X, Y, and Z Cartesian coordinate system, where the X and Z axes are the transverse and longitudinal array periodicity directions, respectively, and the Y axis is perpendicular to the plane formed by the X and Z axes. Incident light is incident perpendicularly from the dielectric substrate 1 onto the bottom side of the metal film 2 and is transmitted through the other side of the metal film 2 to form transmitted light.

[0044] In order to observe the changes in the number of Fano resonances of the rotating non-overlapping metasurface structure, the incident light field is set to select an ultrashort Gaussian modulated pulse with a central wavelength of 1550 nm. The pulse width and center time are 5fs and 16fs respectively. The pulse acts perpendicularly to the dielectric substrate 1 and propagates along the positive direction of the Y axis. The polarization direction of the incident light field is fixed along the X axis. The outer circle radius R2 of the quasi-circular ring 4-2 is 130nm, the inner circle radius R1 of the quasi-circular ring is 100nm, the outer circle radius R3 of the outer ring 4-1 is 175nm, and the width w of the outer ring 4-1 is 20nm. In order to observe the influence of the incident light field on the rotationally non-overlapping metasurface structure, the 3D-FDTD method is used to numerically simulate the incident light transmission in the rotationally non-overlapping metasurface structure, and it is set that when the polarization angle of the incident light is fixed at 0°, the opening angle α between the two ends of the opening 4-3 on the circumference of the quasi-circular ring 4-2 and the center 0 increases from 0° to 180° in increments of 45°, and the transmittance spectrum shown in Figure 6(a) is obtained; when the polarization angle of the incident light is fixed at 90°, the opening angle α between the two ends of the opening 4-3 on the circumference of the quasi-circular ring 4-2 and the center 0 increases from 0° to 180° in increments of 45°, and the transmittance spectrum shown in Figure 6(b) is obtained.

[0045] As shown in Figure 6(a), when the opening angle α is 0°, only a single Fano resonance exists. At 45°, a new Fano resonance peak-iii appears near 956 nm, along with a new Fano resonance peak-iv, indicating that a triple Fano resonance is achieved due to the change in opening angle α. As the opening angle α continues to increase, the degree of structural symmetry breaking increases, causing the Fano resonance peak-iv to become increasingly stronger and blue-shift. Meanwhile, peak-i gradually weakens and continues to blue-shift. When the opening angle increases to 90°, the resonance intensities of Fano resonance peaks-i and -iv are comparable. As the opening angle increases to 160° and even 180°, peaks-i and -iii undergo degenerate coupling near 886 nm, resulting in a triple Fano resonance in the transmission spectrum.

[0046] As can be seen from Figure 6(b), when the opening angle α is 0°, there is only a single Fano resonance; when the opening angle increases from 0° to 45°, the positive and negative electric fields along the polarization direction of the incident light are asymmetrically distributed, resulting in an obvious double Fano resonance effect; when the opening angle increases from 45° to 90°, the Fano resonance peak-I and Fano resonance peak-II continue to blue-shift, but the resonance intensity of the former continues to weaken, while the resonance intensity of the latter increases; when the opening angle is 90°, Fano resonance peak-IV appears near 3326 nm, indicating that the change in the opening angle α causes the realization of a triple Fano resonance; when the opening angle increases from 90° to 135° or even to 180°, the resonance intensity of Fano resonance peak-I becomes weaker and weaker until it disappears, the resonance intensity of Fano resonance peak-III gradually decreases and turns into a double Fano resonance effect, and the resonance intensity of Fano resonance peak-II and Fano resonance peak-IV continues to increase.

[0047] Example 3, as Figure 1-3 As shown in 7-8, the plasma sensing application of the rotational non-overlapping metasurface structure based on Fano resonance is shown, wherein the rotational non-overlapping metasurface structure based on Fano resonance is similar to the structure of Example 1, and the difference is that the specific values ​​of the outer radius of the outer ring and the inner radius of the quasi-ring in the rotational non-overlapping subunit are different.

[0048] The polarization direction of the incident light field was fixed along the X-axis, the outer radius R2 of the quasi-annular ring 4-2 was 130 nm, the inner radius R1 of the quasi-annular unit structure was increased from 95 nm to 125 nm, and other parameters were the same as in Example 2, resulting in the transmittance spectrum shown in Figure 7(a). The outer radius R3 of the outer annular unit structure was increased from 160 nm to 190 nm, and other parameters were the same as in Example 2, resulting in the transmittance spectrum shown in Figure 8(a).

[0049] As can be seen from Figure 7(a), as the inner radius of the ring-like unit structure gradually increases, the resonance intensity of peak-I and peak-II continues to increase, while the resonance intensity of peak-III continues to weaken. Fd1 and D Fd2 Gradually increase, the inner circle radius R1 increases from 105nm to 125nm, the depth of the resonance peak valley D Fd1 and D Fd2The intensity of the resonances gradually becomes shallower. This is because, within a certain range, as the inner radius R1 of the ring-like unit structure increases, the width of the ring-like unit structure decreases, and the interaction between the bonding modes becomes increasingly stronger. When the critical point is exceeded, that is, when the inner radius R1 is greater than 105nm, the bonding and antibonding modes of the ring-like unit structure gradually weaken. Furthermore, the resonance peaks I, II, and III all redshift according to different exponential functions, as shown in Figure 7(b).

[0050] As can be seen from Figure 8(a), as the outer radius R3 of the outer ring 4-1 gradually increases, the resonance intensity of the resonance peak-I remains almost unchanged, while the resonance intensities of peak-II and peak-III continue to increase. Fd1 Gradually increases, the outer radius R3 increases from 160nm to 180nm, D Fd2 Gradually deepens, when R3 increases from 180 nm to 190 nm, D Fd2 It gradually becomes shallower. This is because within a certain range, as the outer radius R3 of the outer ring 4-1 continues to increase, the resonance center of the effective electric dipole mode generated continues to blueshift, causing the double antibonding mode to become stronger and stronger. When the resonance intensity of the double antibonding mode is stronger than that of the selectively excited double antibonding mode, D Fd2 And the resonance peaks-I,-II and-III all blue-shift according to different exponential functions, as shown in Figure 8(b).

[0051] Therefore, by regulating the specific values ​​of the outer radius of the outer ring and the inner radius of the quasi-ring of the rotating non-overlapping metasurface structure based on Fano resonance, the exponential function of the Fano resonance peak can be varied, thereby realizing plasma optical sensing, which can be applied to plasma nano-detection, as well as monitoring and analysis of biological molecules.

[0052] Example 4, as Figure 1-3 As shown in FIG9 , a plasma optical switch application of a rotationally non-overlapping metasurface structure based on Fano resonance is shown. The rotationally non-overlapping metasurface structure based on Fano resonance is similar to the structure of Example 1. The difference is that the polarization direction of the incident light is adjusted along the Z-axis and along the X-axis, respectively, to obtain the following: Figure 9 The transmittance spectrum is shown.

[0053] from Figure 9 It can be seen that under different polarization directions of the incident light, the rotating non-overlapping metasurface structure exhibits different transmission optical properties, which can realize a dual-wavelength optical switch that is turned on and off in the near-infrared band.

[0054] When the optical switch operates at 1207nm, the transmittances of the switch in the “ON” and “OFF” states are T ON =0.8887 and T OFF =0.02073. Using the on / off ratio calculation formula, the ON / OFF ratio is 16.32 dB. In the "ON" state of the 1207 nm plasmonic optical switch, when the polarization direction of the incident light is along the Z axis, that is, parallel to the opening of the quasi-ring unit structure, coupling with the mode generated by the outer ring structure leads to a Fano resonance. In the "OFF" state of the 1207 nm plasmonic optical switch, when the polarization direction of the incident light is along the X axis, that is, perpendicular to the opening of the quasi-ring unit structure, a plasmonic double Fano resonance is observed in the rotationally non-overlapping metasurface structure.

[0055] When the optical switch operates at 2021nm, the transmittances of the switch in the “ON” and “OFF” states are T ON =0.492 and T OFF =0.05017. Using the on / off ratio calculation formula, an ON / OFF ratio of 9.92 dB was obtained. When the incident light is polarized along the X-axis, the plasmonic optical switch at 2021 nm is in the "ON" state. Due to the strong coupling between the quasi-ring and outer ring unit structures, a plasmonic double Fano resonance occurs in the rotationally non-overlapping metasurface structure. When the incident light is polarized along the Z-axis, in the "OFF" state of the plasmonic optical switch at 2021 nm, the interaction between the quasi-ring and outer ring unit structures in the rotationally non-overlapping metasurface structure only leads to the generation of a Fano resonance.

Claims

1. A rotationally non-overlapping metasurface structure based on Fano resonance includes a dielectric substrate and a metal film, wherein the metal film is covered directly above the dielectric substrate and is characterized by: A rotationally non-overlapping unit structure is etched into the metal film and penetrates the thickness of the metal film. The rotationally non-overlapping unit structure is composed of a plurality of periodically arranged rotationally non-overlapping sub-unit structures. The dielectric material of the dielectric substrate is quartz or benzocyclobutene, and the thickness of the dielectric substrate is 225-250 nm; the material of the metal film is silver or gold, and the thickness of the metal film is 50-60 nm; the period of the multiple rotationally non-overlapping subunits is 400-600 nm; The rotationally non-overlapping subunit structure includes an outer ring and a quasi-circular ring located inside the outer ring. The quasi-circular ring is concentrically arranged with the outer ring, and an opening is provided on the circumference of the quasi-circular ring. The angles between the two ends of the opening and the center of the circle are symmetrical about the horizontal axis. The number of Fano resonance peaks is adjusted by adjusting the opening angle of the quasi-circular ring in the rotationally non-overlapping subunit structure.

2. The rotational non-overlapping metasurface structure based on Fano resonance according to claim 1, wherein: The outer circle radius of the outer ring is 160-190 nm, and the width of the outer ring is 20-50 nm; the outer circle radius of the quasi-circular ring is 100-150 nm, the inner circle radius of the quasi-circular ring is 95-125 nm, and the opening angle is 20°-135°.

3. The rotational non-overlapping metasurface structure based on Fano resonance according to claim 1, wherein: When the polarization direction of the incident light incident on the rotationally non-overlapping metasurface structure is 0°, the opening angle is adjusted from 0° to 180°, and the number of Fano resonance peaks changes from single to three; when the polarization direction of the incident light incident on the rotationally non-overlapping metasurface structure is 90°, the opening angle is adjusted from 0° to 180°, and the number of Fano resonance peaks changes from single to two, two to three, and three to two.

4. The plasma sensing application of the Fano resonance-based rotational non-overlapping metasurface structure according to any one of claim 1, characterized in that: The outer radius of the outer ring and the inner radius of the quasi-ring in the rotationally non-overlapping subunit are adjusted to adjust the optical properties of the Fano resonance.

5. The plasma sensing application of the Fano resonance-based rotational non-overlapping metasurface structure according to claim 4, characterized in that: When the outer radius of the outer ring changes from 175 nm to 190 nm, the resonance center of the Fano resonance blue-shifts according to an exponential function; when the inner radius of the quasi-ring changes from 95 nm to 125 nm, the resonance center of the Fano resonance red-shifts according to an exponential function.

6. Application of the plasmon optical switch of the Fano resonance-based rotationally non-overlapping metasurface structure according to any one of claim 1, characterized in that: The polarization direction of the incident light incident on the metasurface structure is adjusted to adjust the optical properties of the Fano resonance.

7. The application of the plasma optical switch of the Fano resonance-based rotationally non-overlapping metasurface structure according to claim 6 is characterized by: The polarization direction of the incident light of the metasurface structure is parallel or perpendicular to the direction of the opening angle.

8. Application of the plasma optical switch of the Fano resonance-based rotationally non-overlapping metasurface structure according to claim 6 or 7, characterized in that: The operating wavelength of the metasurface structure is 1207 nm and / or 2021 nm.

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