Electric control terahertz broadband large-phase-shift dynamic phase shifter based on graphene-metal metasurface

Abstract

The invention relates to an electrically-controlled terahertz broadband large-phase-shift dynamic phase shifter based on a graphene-metal metasurface. The electrically-controlled terahertz broadband large-phase-shift dynamic phase shifter is composed of a high-resistance silicon substrate and a two-dimensional array on the high-resistance silicon substrate. Each array unit comprises three rectangular metal frames arranged side by side in the vertical direction, three graphene rectangular frames embedded in the rectangular metal frames, three sets of rectangular metal blocks and two rectangular metal blocks. Each group comprises four rectangular metal blocks which are arranged on the upper side and the lower side of the graphene rectangular frame in pairs. The two rectangular metal blocks are connected to the middles of the left side and the right side of the array unit respectively. The two extraction electrodes are located on the two sides of the two-dimensional array and connected with the positive electrode and the negative electrode of the direct-current power source respectively. When the bias voltage is increased, a terahertz wave absorption peak generated by the phase shifter gradually moves to low frequency, and broadband and large phase shift can be generated on the right side of the absorption peak. The electrically-controlled terahertz broadband large-phase-shift dynamic phase shifter is low in manufacturing cost and high in response speed, and has potential application value in the fields of terahertz phased array radars, broadband wireless communication and the like.

Description

Technical Field

[0001] The present invention relates to the field of terahertz technology, and in particular to an electrically controlled terahertz broadband large phase shifter based on a graphene-metal super surface. Background Art

[0002] In recent years, terahertz waves have attracted great attention due to their excellent characteristics such as strong penetration, good safety, and ultra-wide bandwidth. They have important application value in the future new radar system, 6G broadband wireless communication and other fields. In these applications, the control of the phase of terahertz waves is indispensable, and the commonly used phase control device is the terahertz phase shifter. At present, the phase of terahertz waves is mainly controlled by designing metasurface structures. However, existing terahertz phase shifters are difficult to achieve wide-band and large phase shift control functions, which greatly limits the application field of terahertz phase shifters. Summary of the invention

[0003] The purpose of the present invention is to disclose an electrically controlled terahertz broadband large phase shifter based on a graphene-metal super surface, comprising a high-resistance silicon substrate, a two-dimensional array located on the high-resistance silicon substrate, each array unit comprising three rectangular metal frames arranged side by side in a vertical direction, three graphene rectangular frames embedded in the rectangular metal frames, three groups of rectangular metal blocks located in the graphene rectangular frames, and two rectangular metal blocks located on the left and right sides of the array unit, respectively. Each group of rectangular metal blocks comprises four metal blocks of equal size, two of which are connected to the upper side of the graphene rectangular frame, and the other two are connected to the lower side of the graphene frame. The two rectangular metal blocks are located on the left and right sides of the unit, respectively, and are connected to the middle of the left and right sides of the middle rectangular metal frame. Two extraction electrodes are located on both sides of the two-dimensional array, and are respectively connected to the positive and negative poles of a direct current power supply. When a terahertz wave polarized in the vertical direction is incident, the terahertz wave passing through the phase shifter generates an absorption peak. When the bias voltage increases, the absorption peak gradually moves to a low frequency, and a broadband and large phase shift is generated on the right side of the absorption peak.

[0004] The invention discloses an electrically controlled terahertz broadband large phase-shifting state phase shifter based on a graphene-metal supersurface, comprising a high-resistance silicon substrate and a two-dimensional array composed of metal-graphene located on the high-resistance silicon substrate. The side length of the two-dimensional array is 1.0 to 1.5 times the diameter of the incident terahertz beam. The length and width of the high-resistance silicon substrate are both greater than the length and width of the two-dimensional array. The terahertz wave is incident from above the two-dimensional array, passes through the two-dimensional array, and then passes through the high-resistance silicon substrate and then exits.

[0005] Each array unit of the two-dimensional array includes three rectangular metal frames arranged side by side in the vertical direction, three graphene rectangular frames embedded in the rectangular metal frames, three groups of rectangular metal blocks located in the graphene rectangular frames, and two rectangular metal blocks located on the left and right sides of the array unit respectively.

[0006] Each metal structure is a metal strip of any one of gold sheet, aluminum sheet or copper sheet.

[0007] The three rectangular metal frames are arranged along the vertical direction, and the upper and lower sides of adjacent rectangular metal frames are connected.

[0008] The three graphene rectangular frames are respectively embedded in three rectangular metal frames.

[0009] Each of the three groups of rectangular metal blocks includes four metal blocks of equal size, two of which are connected to the upper side of the graphene rectangular frame, and the other two are connected to the lower side of the graphene frame.

[0010] The two rectangular metal blocks are respectively located on both sides of the unit and are connected to the middle parts of the left and right sides of the middle rectangular metal frame.

[0011] Two extraction electrodes are located on both sides of the two-dimensional array, respectively connected to the positive and negative electrodes of the DC power supply, and there is a switch on the connection line. The electrodes on both sides are respectively connected to the leftmost rectangular metal block in the first column on the left side of the two-dimensional array and the rightmost rectangular metal block in the last column on the right side.

[0012] When the switch connecting the electrode to the DC power supply is turned on, the three graphene patches are all low in conductivity, that is, the rectangular metal frame of the array unit is blocked from the square metal blocks connected to the upper and lower sides of the graphene rectangular frame. When the switch connecting the electrode to the DC power supply is closed, the Fermi level of graphene changes, and the conductivity of the graphene frame increases, that is, the rectangular metal frame is connected to the rectangular metal blocks connected to the upper and lower sides of the graphene rectangular frame. At this time, the phase shifter works in the phase control state.

[0013] The voltage of the DC power supply is 12V to 24V.

[0014] The longitudinal and lateral widths of an array unit in the two-dimensional array are consistent, and are 100 micrometers to 104 micrometers.

[0015] The rectangular metal frame and the rectangular metal block are metal strips made of any one of gold, aluminum or copper sheets, and have a thickness of 0.2 micrometers to 0.8 micrometers.

[0016] The longitudinal length of the rectangular metal frame is 29 micrometers to 31 micrometers, the lateral length is 90 micrometers to 94 micrometers, and the width of the four sides of the rectangular metal frame is 3 micrometers to 5 micrometers.

[0017] The graphene rectangular frame is a single-layer graphene material with a thickness of 1 nanometer, a longitudinal length of 23 micrometers to 25 micrometers, a transverse length of 80 micrometers to 88 micrometers, and a width of 3 micrometers to 5 micrometers on the four sides of the rectangular frame.

[0018] The rectangular metal block located in the graphene rectangular frame has a longitudinal length of 5.5 microns to 7.5 microns and a lateral length of 4 microns to 18 microns.

[0019] The rectangular metal blocks respectively located on the left and right sides of the array unit have a longitudinal length of 6 microns to 10 microns and a lateral length of 3 microns to 5 microns.

[0020] Compared with the prior art, the electrically controlled terahertz broadband large phase shifter based on graphene-metal metasurface of the present invention has the following advantages: 1. By controlling the closing of the DC power switch, a broadband and large phase shift modulation effect can be achieved, which is suitable for different occasions; 2. Its structure is not much different from the existing general terahertz modulation device, and only electrodes and DC power supply are added, which is easy to implement and convenient to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the three-dimensional structure of the electrically controlled terahertz broadband large phase-shifting state phase shifter based on graphene-metal metasurface;

[0022] Figure 2 for Figure 1 Schematic diagram of the AA section;

[0023] Figure 3 is a schematic diagram of an array unit structure;

[0024] Figure 4 for Figure 1 Top view of the two-dimensional array;

[0025] Figure 5 The present invention shows a transmittance change spectrum diagram and a phase change spectrum diagram of the terahertz wave passing through the phase shifter when the terahertz wave polarized along the vertical direction is incident before and after the DC power switch is closed.

[0026] Numbers in the figure: 1, high-resistance silicon substrate; 2, two-dimensional array; 21, rectangular metal frame; 22, graphene rectangular frame; 23, rectangular metal block located in the graphene rectangular frame; 24, rectangular metal blocks located on the left and right sides of the array unit; 25, lead-out metal electrode structure. DETAILED DESCRIPTION

[0027] The following describes in detail a scheme of an electrically controlled terahertz broadband large phase-shifting state phase shifter based on a graphene-metal metasurface according to the present invention in conjunction with the accompanying drawings and specific embodiments.

[0028] The schematic diagram of the embodiment of the electrically controlled terahertz broadband large phase shifter based on the graphene-metal metasurface is shown in FIG. Figure 1 and Figure 2 As shown, it includes a high-resistance silicon substrate 1 and a two-dimensional array 2 located on the high-resistance silicon substrate 1. In this example, the diameter of the incident terahertz beam is 500 microns.

[0029] The length and width of the high-resistance silicon substrate 1 in this example are greater than the length and width of the two-dimensional array 2. The thickness of the high-resistance silicon substrate 1 in this example is 500 microns. The terahertz wave incident from above the two-dimensional array 2 passes through the two-dimensional array 2 and the high-resistance silicon substrate 1 and then exits.

[0030] like Figure 3 and 4 As shown, each array unit of the two-dimensional array 2 of this example includes three rectangular metal frames 21 arranged side by side in the vertical direction, three graphene rectangular frames 22 embedded in the rectangular metal frames, three groups of rectangular metal blocks 23 located on the inner sides of the graphene rectangular frames, and two rectangular metal blocks 24 located on the left and right sides of the array unit. The length and width of one array unit are L = 100 microns.

[0031] In this example, the rectangular metal frames 21 are arranged in the vertical direction, and adjacent rectangular metal frames 21 are connected and share a side. The longitudinal length of each rectangular metal frame 21 is a=33 microns, the lateral length is b=92 microns, and the width w1 of the four sides of the rectangular metal frame 21 is 4 microns.

[0032] In this example, the graphene rectangular frames 22 are respectively embedded in three rectangular metal frames 21. Each graphene rectangular frame 22 has a longitudinal length of 25 microns and a lateral length of 84 microns. The width w2 of the four sides of the graphene rectangular frame 22 is 4 microns, and the thickness is 1 nm.

[0033] In this example, a group of rectangular metal blocks 23 of the same size are located at the center of the inner side of the graphene rectangular frame 22, two of which are connected to the upper side of the graphene rectangular frame 22, and the other two are connected to the lower side of the graphene frame 22. Each metal block located in the graphene rectangular frame 22 has a longitudinal length w3=6.5 microns and a transverse length w4=8 microns. The transverse gap i=8 microns between the two rectangular metal blocks located on the same side, and the longitudinal gap g=4 microns between the rectangular metal blocks located on the upper and lower sides.

[0034] In this example, two rectangular metal blocks 24 are located on the left and right sides of the array unit and connected to the middle of the left and right sides of the middle rectangular metal frame 21. Each metal block 24 has a longitudinal length of 8 microns and a lateral length of 4 microns.

[0035] In this example, there is an electrode 25 on each of the left and right sides of the two-dimensional array 2, which is connected to the positive and negative electrodes of the DC power supply, and there is a switch on the connection line. The electrodes 25 on both sides are respectively connected to the leftmost rectangular metal block 24 in the first column on the left side of the two-dimensional array 2 and the rightmost rectangular metal block 24 in the last column on the right side.

[0036] When the switch connecting the electrode 25 to the DC power supply is turned on, the three graphene patches 22 are all of low conductivity, that is, the rectangular metal frame 21 of the array unit is blocked from the rectangular metal block 23 connected to the upper and lower sides of the graphene rectangular frame 22. When the switch connecting the electrode 25 to the DC power supply is closed, the Fermi level of the graphene changes, and the conductivity of the graphene frame 22 increases, that is, the rectangular metal frame 21 is connected to the rectangular metal block 23 connected to the upper and lower sides of the graphene rectangular frame 22. At this time, the phase shifter works in a phase control state. At this time, the transmittance diagram of the terahertz wave incident and passing through the phase shifter and the curve of the phase changing with frequency are shown as the solid line curve in the figure.

[0037] The above embodiments are only specific examples for further describing the purpose, technical solutions and beneficial effects of the present invention, and the present invention is not limited thereto. Any modification, equivalent replacement, improvement, etc. made within the scope of the disclosure of the present invention are included in the protection scope of the present invention.

Claims

1. An electrically controlled terahertz broadband large phase-shifting state phase shifter based on a graphene-metal metasurface, comprising a high-resistance silicon substrate (1) and a two-dimensional array (2) located on the upper surface of the high-resistance silicon substrate (1); the side length of the two-dimensional array (2) is 1.0 to 1.5 times the diameter of the incident terahertz wave beam; the length and width of the high-resistance silicon layer (1) are both greater than the length and width of the two-dimensional array (2); the terahertz wave is incident from above the two-dimensional array (2), passes through the two-dimensional array (2) to be modulated, and then passes through the high-resistance silicon substrate (1) before being emitted; characterized in that: Each array unit of the two-dimensional array (2) comprises three rectangular metal frames (21) arranged side by side in a vertical direction, three graphene rectangular frames (22) embedded in the rectangular metal frames, three groups of rectangular metal blocks (23) located in the graphene rectangular frames, and two rectangular metal blocks (24) located on the left and right sides of the array unit respectively; The three rectangular metal frames (21) are arranged in a vertical direction, and the upper and lower sides of adjacent rectangular metal frames (21) are connected; The three graphene rectangular frames (22) are respectively embedded in three rectangular metal frames; Each of the three groups of rectangular metal blocks (23) comprises four metal blocks of equal size, two of which are connected to the upper side of the graphene rectangular frame (22), and the other two are connected to the lower side of the graphene frame (22); The two rectangular metal blocks (24) are respectively located on both sides of the unit and connected to the middle of the left and right sides of the middle rectangular metal frame (21); Two extraction electrodes (25) are located on both sides of the two-dimensional array and are respectively connected to the positive and negative electrodes of the DC power supply, and a switch is provided on the connection line. The electrodes (25) on both sides are respectively connected to the leftmost rectangular metal block (24) in the first column on the left side of the two-dimensional array (2) and the rightmost rectangular metal block (24) in the last column on the right side; When the switch for connecting the electrode (25) to the DC power supply is turned on, the three graphene patches (22) all have low conductivity, that is, the rectangular metal frame (21) of the array unit and the square metal block (23) connected to the upper and lower sides of the graphene rectangular frame (22) are blocked; when the switch for connecting the electrode to the DC power supply is closed, the Fermi level of the graphene changes, and the conductivity of the graphene frame (22) increases, that is, the rectangular metal frame (21) is connected to the rectangular metal block (23) connected to the upper and lower sides of the graphene rectangular frame (22), and the phase shifter works in a phase control state.

2. The electrically controlled terahertz broadband large phase shifter based on graphene-metal supersurface according to claim 1, characterized in that: The voltage of the DC power supply is 12V to 24V.

3. The electrically controlled terahertz broadband large phase shifter based on graphene-metal supersurface according to claim 1, characterized in that: The longitudinal and lateral lengths of an array unit in the two-dimensional array (2) are both 100 micrometers to 104 micrometers.

4. The electrically controlled terahertz broadband large phase shifter based on graphene-metal supersurface according to claim 1, characterized in that: The rectangular metal frame (21) and the rectangular metal block are metal strips made of any one of gold, aluminum or copper sheets, and have a thickness of 0.2 micrometers to 0.8 micrometers.

5. The electrically controlled terahertz broadband large phase shifter based on graphene-metal supersurface according to claim 1, characterized in that: The graphene rectangular frame patch (22) is a single-layer graphene with a thickness of 1 nanometer.

6. The electrically controlled terahertz broadband large phase shifter based on graphene-metal supersurface according to claim 4, characterized in that: The longitudinal length of the rectangular metal frame (21) is 29 micrometers to 31 micrometers, the transverse length is 90 micrometers to 94 micrometers, and the widths of the four sides of the rectangular metal frame (21) are 3 micrometers to 5 micrometers.

7. The electrically controlled terahertz broadband large phase shifter based on graphene-metal supersurface according to claim 5, characterized in that: The graphene rectangular frame (22) is a single-layer graphene material with a thickness of 1 nanometer, a longitudinal length of 23 micrometers to 25 micrometers, a transverse length of 80 micrometers to 88 micrometers, and a width of 3 micrometers to 5 micrometers on the four sides constituting the rectangular frame.

8. The electrically controlled terahertz broadband large phase shifter based on graphene-metal supersurface according to claim 4, characterized in that: The rectangular metal block (23) located in the graphene rectangular frame (22) has a longitudinal length of 5.5 micrometers to 7.5 micrometers and a lateral length of 4 micrometers to 18 micrometers. The lateral gap width between two rectangular metal blocks (23) located on the same side is 4 micrometers to 16 micrometers, and the longitudinal gap width between the rectangular metal blocks (23) located on the upper and lower sides is 4 micrometers to 5 micrometers.

9. The electrically controlled terahertz broadband large phase shifter based on graphene-metal supersurface according to claim 4, characterized in that: The rectangular metal blocks (24) respectively located on the left and right sides of the array unit have a longitudinal length of 6 micrometers to 10 micrometers and a lateral length of 3 micrometers to 5 micrometers.

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