CN114578586A - Light beam control device - Google Patents

Abstract

An optical beam steering apparatus, comprising: a substrate and a mirror layer, a conductive layer, a dielectric layer, and a sub-wavelength antenna unit stacked on the substrate, wherein the sub-wavelength antenna unit and the mirror layer are configured to apply different voltages; the first bonding layer is arranged between the dielectric layer and the sub-wavelength antenna unit, the light beam control device can realize tight connection between the dielectric layer and the sub-wavelength antenna unit, and can ensure that the deflection angle of refracted light and reflected light can be conveniently controlled.

Description

Beam control device

technical field

Embodiments of the present disclosure relate to a beam steering apparatus.

Background technique

According to the different types of modulated waves, metasurfaces can be divided into optical metasurfaces, acoustic metasurfaces, and mechanical metasurfaces. Optical metasurfaces are the most common type, which can control the polarization, phase, amplitude and frequency of electromagnetic waves through subwavelength microstructures. Metasurface technology is an emerging technology that combines optics and nanotechnology.

Metasurfaces can be considered two-dimensional metamaterials because they are characterized by repeating patterns of subwavelength structures, and because they share many of the same advantages as metamaterials, metasurfaces are even more favorable than metamaterials in many ways. For example, metasurfaces can transmit light more efficiently than metamaterials. In terms of polarization, metasurfaces can realize functions such as polarization conversion, optical rotation, and vector beam generation. In terms of amplitude regulation, metasurfaces can achieve asymmetric light transmission, dereflection, enhanced transmission, and magnetic mirrors. In terms of frequency regulation, the microstructure of the metasurface can achieve strong local field enhancement in the case of resonance. Using these local field enhancement effects, nonlinear signal or fluorescence signal enhancement can be achieved. In the visible light band, light of different frequencies corresponds to different colors, and the frequency-selective properties of metasurfaces can be used to realize structural colors. Using metasurfaces can freely control the color of metasurfaces by changing geometric parameters such as the size and shape of their structural units, which can be used in high-pixel imaging, visual biosensing and other fields.

SUMMARY OF THE INVENTION

At least one embodiment of the present disclosure provides a light beam control device. The light beam control device realizes a better connection between the dielectric layer and the subwavelength antenna unit by arranging a first adhesive layer between the dielectric layer and the subwavelength antenna unit. compact, so as to ensure the stability of the structure of the entire beam control unit.

At least one embodiment of the present disclosure provides a light beam control device, the light beam control device includes: a substrate and a mirror layer, a conductive layer, a dielectric layer and a subwavelength antenna unit stacked on the substrate, wherein the subwavelength antenna unit The antenna unit and the mirror layer are configured to apply different voltages; a first adhesive layer is provided between the dielectric layer and the subwavelength antenna unit.

For example, in the light beam control device provided in at least one embodiment of the present disclosure, between the first adhesive layer and the dielectric layer, and between the first adhesive layer and the subwavelength antenna unit A chemical bond is formed therebetween, and the first adhesive layer is configured to bond the dielectric layer and the subwavelength antenna unit.

For example, in the light beam control device provided in at least one embodiment of the present disclosure, the thickness of the first adhesive layer is 1 nanometer to 50 nanometers, and the material of the first adhesive layer includes titanium metal element, chromium metal element , at least one of tungsten metal element and niobium metal element.

For example, in the light beam control device provided in at least one embodiment of the present disclosure, the first adhesive layer has conductivity, and the orthographic projection of the first adhesive layer on the substrate and the sub-wavelength antenna unit are The orthographic projections on the substrates at least partially overlap.

For example, in the light beam control device provided in at least one embodiment of the present disclosure, the first adhesive layer has insulating properties, and the orthographic projection of the sub-wavelength antenna unit on the substrate is located at the position of the first adhesive layer. within the orthographic projection on the substrate.

For example, in the light beam control device provided by at least one embodiment of the present disclosure, a second adhesive layer is provided between the substrate and the mirror surface layer, and the second adhesive layer is configured to connect the substrate and the mirror layer. The mirror layer is bonded.

For example, in the light beam control device provided by at least one embodiment of the present disclosure, between the second adhesive layer and the substrate, and between the second adhesive layer and the mirror surface layer, there are formed chemical bonds to bond the substrate and the mirror layer.

For example, in the light beam control device provided by at least one embodiment of the present disclosure, the thickness of the second adhesive layer is 1 nanometer to 1000 nanometers, and the material of the second adhesive layer includes titanium metal element, chromium metal element , at least one of tungsten metal element and niobium metal element.

For example, in the light beam control device provided by at least one embodiment of the present disclosure, the material of the first adhesive layer and the material of the second adhesive layer are the same or different.

For example, in the light beam control device provided in at least one embodiment of the present disclosure, the subwavelength antenna unit includes a plurality of antennas, and each of the antennas is in the shape of a rod.

For example, in the light beam control device provided in at least one embodiment of the present disclosure, at least two adjacent antennas are configured to form different voltage differences with the mirror layer.

For example, in the light beam control device provided in at least one embodiment of the present disclosure, the subwavelength antenna unit includes a plurality of antennas, and the plurality of antennas are arranged in an array.

For example, in the light beam control device provided in at least one embodiment of the present disclosure, at least two adjacent antennas in the column direction are configured to form different voltage differences with the mirror layer, and/or in the row direction At least two adjacent said antennas are configured to form different voltage differences with said mirror layer.

For example, in the light beam control device provided in at least one embodiment of the present disclosure, the subwavelength antenna unit includes a plurality of antennas in a loop, and the plurality of antennas are arranged in concentric circles.

For example, in the light beam control device provided by at least one embodiment of the present disclosure, at least two adjacent antennas are configured to form different voltage differences with the mirror layer.

For example, in the light beam control device provided in at least one embodiment of the present disclosure, at least two power lines are further included, the plurality of antennas and the power lines are respectively electrically connected through connecting parts, each of the power lines and one or A plurality of the antennas are electrically connected, and the power line is configured to apply a voltage to the corresponding antennas.

For example, in the light beam control device provided in at least one embodiment of the present disclosure, an insulating layer is provided between the sub-wavelength antenna unit and the power supply line, and the connection portion is provided through the power supply line and the insulating layer. in the via structure of the layer.

For example, in the light beam control device provided by at least one embodiment of the present disclosure, the material of the subwavelength antenna unit includes at least one of conductive metal, conductive metal oxide, and conductive graphene.

For example, in the light beam control device provided by at least one embodiment of the present disclosure, the material of the mirror surface layer includes at least one of reflective and conductive metals, conductive metal oxides, and conductive graphene.

For example, in the light beam control device provided by at least one embodiment of the present disclosure, the material of the conductive layer includes indium tin oxide, indium zinc oxide, or indium gallium zinc oxide.

For example, in the light beam control device provided by at least one embodiment of the present disclosure, the material of the dielectric layer includes an inorganic insulating material or an organic insulating material.

Description of drawings

In order to explain the technical solutions of the embodiments of the present disclosure more clearly, the accompanying drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present disclosure, rather than limit the present disclosure. .

FIG. 1 is a schematic cross-sectional structure diagram of a light beam control device provided by at least one embodiment of the present disclosure;

FIG. 2 is a perspective structural schematic diagram of a light beam control device provided by at least one embodiment of the present disclosure;

FIG. 3 is a schematic plan view of a subwavelength antenna unit according to at least one embodiment of the present disclosure;

FIG. 4 is a graph of the phase change of the reflected light as the electron concentration changes, according to at least one embodiment of the present disclosure;

FIG. 5 is a schematic plan structure diagram of still another subwavelength antenna unit provided by at least one embodiment of the present disclosure;

6 is a schematic plan view of another subwavelength antenna unit provided by at least one embodiment of the present disclosure;

FIG. 7 is a schematic plan view of another subwavelength antenna unit provided by at least one embodiment of the present disclosure;

FIG. 8 is a schematic plan structure diagram of a subwavelength antenna unit and a connecting portion according to at least one embodiment of the present disclosure; and

FIG. 9 is a schematic three-dimensional structural diagram of a subwavelength antenna unit and a connecting portion provided by at least one embodiment of the present disclosure.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are some, but not all, embodiments of the present disclosure. Based on the described embodiments of the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present disclosure.

Unless otherwise defined, technical or scientific terms used in this disclosure shall have the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure belongs. As used in this disclosure, "first," "second," and similar terms do not denote any order, quantity, or importance, but are merely used to distinguish the various components. "Comprises" or "comprising" and similar words mean that the elements or things appearing before the word encompass the elements or things recited after the word and their equivalents, but do not exclude other elements or things. Words like "connected" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "Down", "Left", "Right", etc. are only used to represent the relative positional relationship, and when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

For the case where the incident light is infrared light, near-infrared light or visible light, adjusting the voltage can change the electron concentration in the conductive layer to realize the change of the phase, and then realize the phase plane of the light reflected or transmitted from the surface of the beam control device. manipulation. Taking the reflection of light from the surface of the beam control device as an example, the structure of the beam control device mainly includes a mirror layer, a conductive layer, a dielectric layer, a subwavelength antenna unit, and a power supply that establishes a voltage between the subwavelength antenna unit and the mirror layer. In order to achieve the ultimate goal of controlling the beam direction. However, the inventors of the present disclosure found that when other layer structures are formed on the surface of a certain base material, due to the difference in the chemical properties of the materials of the two-layer layers in contact with each other, it may lead to the difference between the two-layer structures in contact with each other. The bonding force between the two layers is not strong enough, so that the quality of the layer structure formed later is not good, or it is easy to cause the phenomenon of delamination between the two layer structures that are in contact with each other, or it is easy for the layer structure formed later to easily change from the previous one. The phenomenon of peeling off on the formed layer structure, that is, there is a problem of unstable connection between the dielectric layer and the subwavelength antenna unit in the current beam steering device, so that the control of the phase plane of the light is unstable.

The inventors of the present disclosure have noticed that an adhesion layer may be formed on a previously formed layer structure (eg, a dielectric layer), and the material of the adhesion layer is usually selected to be the same as that of the previously formed layer structure (eg, a dielectric layer) A material with strong bonding force with the layer structure formed later (eg subwavelength antenna element). Specifically, the principle of increasing the bonding force between the layer structures mainly includes: increasing the wetting of the layer structure formed later, so as to form a stronger layer between the layer structure formed later and the layer structure previously formed Strong chemical bonds to make the connection between the layer structures in contact with each other tighter. For example, an adhesion layer is formed between the dielectric layer in the beam steering device and the interface of the subwavelength antenna unit, and the material of the adhesion layer includes a metal element such as chromium, tungsten, niobium, chromium or titanium.

At least one embodiment of the present disclosure provides a beam control device, the beam control device includes: a substrate, a mirror layer, a conductive layer, a dielectric layer and a subwavelength antenna unit stacked on the substrate, wherein the subwavelength antenna unit and The mirror layer is configured to apply different voltages, a first adhesive layer is provided between the dielectric layer and the sub-wavelength antenna element, and the beam steering device is provided by the first adhesive layer between the dielectric layer and the sub-wavelength antenna element. The layer can realize a tighter connection between the dielectric layer and the subwavelength antenna unit, thereby ensuring the structural stability of the entire beam steering unit.

For example, FIG. 1 is a schematic cross-sectional structure diagram of a beam control device provided by at least one embodiment of the present disclosure. As shown in FIG. 1 , the beam control device 100 includes: a substrate 101 , a mirror layer 102 stacked on the substrate 101 , the conductive layer 103, the dielectric layer 104 and the subwavelength antenna element 105, the subwavelength antenna element 105 and the mirror layer 102 are configured to apply different voltages so that there is a voltage difference between the subwavelength antenna element 105 and the mirror layer 102, And a first adhesive layer 106 is disposed between the dielectric layer 104 and the subwavelength antenna unit 105 . The entire structure of the beam control device 100 is a metasurface structure, and the conductive layer 103 in the beam control device will cause electrons in the conductive layer 103 to move to the vicinity of the interface between the conductive layer 103 and the dielectric layer 104 due to the change of the voltage applied to the conductive layer 103 (ie The effective area A) gathers, causing the electron concentration of the effective area A of the conductive layer 103 to change, so that the real part of the dielectric constant of the effective area A is close to 0, and then the reflection or transmission from the surface of the beam control device can be realized. It should be noted that in Figure 1, the effective area A is roughly shown by a dotted rectangular frame, but it does not mean that the effective area A is limited to this area, and can also include areas near this area. That is, it may be a larger area than the dashed rectangle shown in FIG. 1 , or a smaller area than the dashed rectangle shown in FIG. 1 .

For example, when there is no first adhesive layer 106 between the sub-wavelength antenna unit 105 and the dielectric layer 104, the forming process of the dielectric layer 104 and the sub-wavelength antenna unit 105 includes: combining the material of the sub-wavelength antenna unit 105 (for example, Gold) is directly deposited on the surface of the dielectric layer 104 (silicon dioxide) using electron beam evaporation: in the initial stage, gold nanoparticles are formed on the surface of the dielectric layer 104, rather than a continuous gold film layer. As the electron beam evaporation continues, the gold film layer on the surface of the dielectric layer 104 becomes continuous, but due to the coalescence of different crystal grains, the formed gold film layer has a certain degree of surface roughness, so that the final formation The quality of the gold film is poor.

For example, the material of the first adhesive layer 106 is titanium metal element, the material of the sub-wavelength antenna unit 105 is gold, and the material of the dielectric layer 104 is silicon dioxide as an example, when the sub-wavelength antenna unit 105 and the mirror layer are When there is a first adhesive layer 106 between 102, the formation process of the dielectric layer 104, the first adhesive layer 106 and the sub-wavelength antenna unit 105 includes: depositing titanium metal element on the dielectric layer 104, titanium metal element and two Chemical bonds are formed between oxygen atoms on the surface of the dielectric layer 104 formed of silicon oxide material, so as to achieve the purpose of good bonding between titanium metal and silicon dioxide. The addition of titanium metal has a great influence on the grain size and grain orientation of the film formed by the gold material, and at the same time, the first adhesive layer 106 can wet the subwavelength antenna unit 105 formed subsequently, Compared with the example in which pure Au is directly evaporated onto the surface of silica, the nucleation energy barrier is reduced, the number of nucleation sites is increased, and the wettability is enhanced due to the formation of Ti-Au chemical bonds, resulting in Au crystalline The particles are denser and easier to nucleate, and at the same time, the interdiffusion between Au atoms can be promoted, which is more conducive to the formation of a flat and continuous gold film layer.

For example, FIG. 2 is a schematic perspective view of a light beam control device provided by at least one embodiment of the present disclosure. As shown in FIG. 2 , the perspective structure of the light beam control device 100 provides a metasurface on a larger scale to realize reflection The schematic diagram of light control, by establishing different voltage differences between the subwavelength antenna unit 105 and the mirror layer 102, so as to achieve the purpose of manipulating the phase of the reflected light to achieve "abnormal" reflection. For example, as shown in FIG. 2 , the incident light rays are incident perpendicular to the surface of the structure of the beam control device 100 , that is, the incident light is incident along the z direction, but the reflected light rays are not perpendicular to the surface of the structure of the beam control device 100 , but are perpendicular to the surface of the structure of the beam control device 100 . There is a certain angle of deflection on the plane of the main surface of the beam steering device 100 (that is, on the plane where the x-axis and the z-axis are located), and the angle of the deflection can be determined by the metasurface structure and the relationship between the subwavelength antenna unit 105 and the mirror layer 102. The voltage difference between them is controlled together.

For example, referring to FIG. 1 and FIG. 2 , the electron concentration in the conductive layer 103 can be changed by adjusting the voltage difference between the subwavelength antenna unit 105 and the mirror layer 102 . For example, in one example, both the subwavelength antenna element 105 and the mirror layer 102 are made of Au, while the conductive layer 103 is formed of indium tin oxide with a thickness of about 30 nm, and the dielectric layer 104 is formed of aluminum oxide, assuming indium tin oxide If the electron concentration is 6× ^{10 20} cm ⁻³ , the voltage formed between the subwavelength antenna unit 105 and the mirror layer 102 can increase the electron concentration in the effective area A of indium tin oxide, and the higher the voltage, the higher the electron concentration The more, and the closer to the interface portion of the conductive layer 103 and the dielectric layer 104, the higher the electron concentration, with the increase of the distance from the interface of the conductive layer 103 and the dielectric layer 104, the electron concentration gradually decreases. In this way, the electron concentration of the effective area in the conductive layer 103 can be regulated by changing the voltage formed between the subwavelength antenna unit 105 and the mirror layer 102 .

For example, as shown in FIG. 2 , the sub-wavelength antenna unit 105 includes a plurality of antennas 1051, the plurality of antennas 1051 are arranged in sequence, and the plurality of antennas 1051 are arranged at equal intervals or the adjacent antennas 1051 are separated by different intervals. The embodiment does not limit this. In FIG. 2 , the subwavelength antenna unit 105 includes nine antennas 1051 as an example for illustration. The voltage difference formed between each antenna 1051 and the mirror layer 102 may be different, or three antennas may be arranged adjacent to each other in sequence. The antennas 1051 are a group, and the three antennas 1051 in a group have different voltage differences formed between the mirror layer 102 and the three antennas 1051 arranged adjacent to each other are repeated as a repeating unit, and may also be adjacent. Two antennas 1051 are used as a repeating unit, or four antennas 1051 , five antennas 1051 , six antennas 1051 , and seven antennas arranged in sequence are used as a repeating unit.

For example, as shown in FIG. 2, in an example (referred to as example 1), the voltage difference formed between the first antenna 1051, the second antenna 1051, the third antenna 1051 and the mirror layer 102 is V1 in sequence , V2 and V3, V1, V2 and V3 are all different, and use this as a repeating unit. Similarly, the voltage differences formed between the fourth antenna 1051, the fifth antenna 1051, the sixth antenna 1051 and the mirror layer 102 are V4=V1, V5=V2 and V6=V3 in sequence; in the seventh The voltage differences formed between the antenna 1051, the eighth antenna 1051, the ninth antenna 1051 and the mirror layer 102 are V7=V1, V8=V2 and V9=V3 in sequence, so that any two adjacent antennas 1051 and The voltage differences formed between the mirror layers 102 are all different, and the voltage differences change periodically with the three antennas, so that the electron concentration at the interface between the conductive layer 103 and the dielectric layer 104 also changes in the same period, so that the metasurface emits The phase of light undergoes periodic phase changes. The rate of change dФ/dx of this periodic phase transition in the x-axis direction determines the "abnormal" deflection angle of the light exiting the metasurface.

Similarly, two antennas 1051 , four antennas 1051 , five antennas 1051 , six antennas 1051 , seven antennas 1051 , or eight antennas 1051 , etc. arranged in sequence as a repeating unit may refer to the above-mentioned example based on three antennas 1051 as a repeating unit Relevant descriptions are not repeated here.

For example, in another example (Example 2), still as shown in FIG. 2, the first antenna 1051, the second antenna 1051 and the third antenna 1051 are a group, the first antenna 1051, the second antenna 1051 The voltage difference formed between 1051 and the third antenna 1051 and the mirror layer 102 is the same, which is V1. The fourth antenna 1051, the fifth antenna 1051 and the sixth antenna 1051 are used as a group, and the voltage difference formed between the fourth antenna 1051, the fifth antenna 1051 and the sixth antenna 1051 and the mirror layer 102 is the same. , all are V2; the seventh antenna 1051, the eighth antenna 1051 and the ninth antenna 1051 are as a group, and the seventh antenna 1051, the eighth antenna 1051 and the ninth antenna 1051 and the mirror layer 102 are formed between The voltage difference is equal, both are V3. From the tenth antenna to the eighteenth antenna, the voltage difference between the first antenna to the ninth antenna and the mirror layer 102 is repeated in sequence, and the voltage difference formed between the antenna 1051 and the mirror layer 102 takes nine antennas as a period change, so that the electron concentration at the interface portion of the conductive layer 103 and the dielectric layer 104 also changes periodically, so that the phase of the light emitted from the metasurface undergoes a periodic phase change. It is assumed that the structure, material and incident conditions involved in Example 2 are the same as in Example 1 except for the voltage application method mentioned above, and V1, V2, and V3 in Example 2 are the same as those of V1, V2, and V3 in Example 1. The size is also the same, then the rate of change dФ/dx of the periodic phase transition of Example 2 in the x-axis direction is one-third of the rate of change dФ/dx of the periodic phase transition of Example 1 in the x-axis direction, then " The "abnormal" deflection angle will also be different from that in Example 1.

Similarly, two antennas 1051 , four antennas 1051 , five antennas 1051 , six antennas 1051 , seven antennas 1051 or eight antennas 1051 arranged in sequence are used as a combination. In each combination, the difference between each antenna 1051 and the mirror layer 102 is For an example of the same voltage difference formed between the two antennas, please refer to the above related description based on the three antennas 1051 as a combination. That is, when two antennas 1051 are used as a combination, the voltage differences formed between the antennas 1051 and the mirror layer 102 arranged in sequence are V1, V1, V2, V2, V3, V3, V4, V4, etc.; with four antennas 1051 When it is a combination, the voltage differences formed between the antenna 1051 and the mirror layer 102 arranged in sequence are V1, V1, V1, V1, V2, V2, V2, V2, V3, V3, V3, V3, V4, V4 respectively. , V4, V4, etc., which are not limited in the embodiments of the present disclosure.

For example, as shown in FIG. 1 , in the light beam control device 100 , the material of the first adhesive layer 106 includes titanium metal element, chromium metal element, tungsten metal element, niobium metal element, etc., and the first adhesive layer 106 Chemical bonds are formed between the first adhesive layer 106 and the sub-wavelength antenna unit 105 with the dielectric layer 104 . For example, titanium metal element, chromium metal element, tungsten metal element or niobium metal element can be deposited on the dielectric layer 104 by means of evaporation coating, so that the first adhesive layer 106 is formed on the dielectric layer 104, that is, the first adhesive layer 106 is formed on the dielectric layer 104. The material of an adhesive layer 106 includes at least one of titanium metal element, chromium metal element, tungsten metal element and niobium metal element. The first adhesive layer 106 is configured to connect the dielectric layer 104 and the subwavelength antenna unit 105 bond.

For example, since the size of the entire beam control device 100 is set to be small, the thickness of the first adhesive layer 106 is set to be very thin, for example, the thickness of the first adhesive layer is 1-50 nanometers. The first adhesive layer 106 may have conductivity or insulation, which is not limited in the embodiment of the present disclosure. It should be noted that the thickness of the first adhesive layer 106 is too thin, and the thickness of the first adhesive layer 106 shown in FIG. 2 is thickened.

It should be noted that the first adhesive layer 106 can also be formed of other materials, for example, an adhesive formed of organic materials, etc., as long as the thickness of the formed first adhesive layer 106 is 1-50 nanometers. , which is not limited by the embodiments of the present disclosure.

For example, in one example, the first adhesive layer 106 has conductivity, and the orthographic projection of the first adhesive layer 106 on the substrate 101 and the orthographic projection of the subwavelength antenna unit 105 on the substrate 101 at least partially overlap. The "at least partial overlap" includes the overlapping of a part of the orthographic projection of the first adhesive layer 106 on the substrate 101 and a part of the orthographic projection of the sub-wavelength antenna unit 105 on the substrate 101; alternatively, a part of the first adhesive layer 106 on the substrate The orthographic projection on 101 and the orthographic projection of all subwavelength antenna units 105 on the substrate 101 overlap; The orthographic projections overlap, which is not limited in the embodiments of the present disclosure.

For example, in one example, the orthographic projection of the first adhesive layer 106 on the substrate 101 and the orthographic projection of the sub-wavelength antenna unit 105 on the substrate 101 are completely coincident, so that the sub-wavelength antenna unit 105 passes through the first adhesive layer 106 is completely adhered to the dielectric layer 104, so that the sub-wavelength antenna unit 105 is closely connected on the dielectric layer 104, and the first adhesive layer 106 does not occupy more space.

For example, in an example, the first adhesive layer 106 has conductivity and is formed on the entire surface, the sub-wavelength antenna unit 105 includes a plurality of antennas 1051 spaced apart from each other, and the plurality of antennas 1051 can be formed by a patterning process, that is, The first adhesive layer 106 and the subwavelength antenna unit 105 are formed in different process steps, so that the orthographic projections of the plurality of antennas 1051 on the substrate 101 are completely located between the orthographic projections of the first adhesive layer 106 on the substrate 101 Inside.

For example, the plurality of antennas 1051 included in the subwavelength antenna unit 105 and arranged at intervals may be formed by a patterning process. When the orthographic projection of the first adhesive layer 106 on the substrate 101 and the orthographic projection of the subwavelength antenna unit 105 on the substrate 101 are completely coincident, the first adhesive layer 106 and the plurality of antennas 1051 can be formed by the same patterning process, Thereby, process steps are saved.

It should be noted that the "patterning process" refers to forming the material of the sub-wavelength antenna unit 105 in the whole layer, then forming a photoresist on the material of the sub-wavelength antenna unit 105 formed in the whole layer, and then using a mask to pass ultraviolet rays to the light. The photoresist is irradiated to pattern the photoresist, and then the material of the subwavelength antenna unit 105 is patterned by using the photoresist as a mask, and the photoresist remaining on the formed plurality of antennas 1051 is removed.

It should also be noted that other layer structures can also be formed by a patterning process. The patterning process includes first applying the material of the film layer to be patterned on the base film layer, and then forming a photoresist layer on the film layer to be patterned, using a mask. The plate irradiates the photoresist with ultraviolet rays to pattern the photoresist, and then uses the photoresist as a mask to pattern the to-be-patterned film layer, and removes the remaining photoresist to form the final layer structure.

For example, in one example, the first adhesive layer 106 has insulating properties, and the orthographic projection of the sub-wavelength antenna unit 105 on the substrate 101 is located within the orthographic projection of the first adhesive layer 106 on the substrate 101 . That is, the area covered by the first adhesive layer 106 can extend beyond the area covered by the sub-wavelength antenna unit 105, and the setting area of the first adhesive layer 106 is larger than the coverage area of the sub-wavelength antenna unit 105, which can reduce preparation The complexity of the process, thereby reducing the difficulty of the process.

For example, as shown in FIG. 1 , a second adhesive layer 107 is provided between the substrate 101 and the mirror layer 102 , and the second adhesive layer 107 is configured to bond the substrate 101 and the mirror layer 102 . The orthographic projection of the second adhesive layer 107 on the substrate 101 and the orthographic projection of the mirror layer 102 on the substrate 101 at least partially overlap. In one example, the orthographic projection of the second adhesive layer 107 on the substrate 101 and the mirror surface The orthographic projections of the layer 102 on the substrate 101 overlap, that is, the second adhesive layer 107 fully adheres the mirror layer 102 on the substrate 101 , so that the mirror layer 102 and the substrate 101 are closely connected.

For example, in one example, chemical bonds are formed between the second adhesive layer 107 and the substrate 101, and between the second adhesive layer 107 and the mirror layer 102. For example, the dielectric layer can be formed by evaporation coating. Titanium metal, chromium metal, tungsten metal or niobium metal is deposited on 104 , so as to bond the substrate 101 and the mirror layer 102 , so that the connection between the substrate 101 and the mirror layer 102 is tighter.

For example, in an example, the thickness of the second adhesive layer 107 is 1 nanometer to 1000 nanometers, and the material of the second adhesive layer 107 includes titanium metal element, chromium metal element, tungsten metal element and niobium metal element. at least one of.

Since the size of the entire beam control device 100 is set to be small, the thickness of the second adhesive layer 107 should be set to be very thin, for example, the thickness of the second adhesive layer 107 is 1 nanometer to 1000 nanometers. The second adhesive layer 107 may have conductivity or insulation, which is not limited in the embodiment of the present disclosure.

It should be noted that the second adhesive layer 107 can also be formed of other materials, for example, an adhesive formed of organic materials, etc., as long as the thickness of the formed second adhesive layer 107 is 1-1000 nanometers, The embodiments of the present disclosure do not limit this.

For example, in one example, the material of the first adhesive layer 106 and the material of the second adhesive layer 107 are the same, so that the same process equipment and the same material can be used to form the first adhesive layer 106 and the second adhesive layer 107, so that the process of preparing the first adhesive layer 106 and the second adhesive layer 107 is simple, and the equipment cost and production cost can be reduced.

For example, in another example, the material of the first adhesive layer 106 and the material of the second adhesive layer 107 may also be different, so that the types of materials used can be more abundant.

For example, FIG. 3 is a schematic plan view of a sub-wavelength antenna unit provided by at least one embodiment of the present disclosure. As shown in FIG. 3 , each antenna 1051 is in the shape of a rod, and one end of each antenna 1051 is provided with a connection terminal , the connection terminals are respectively connected with the external power supply. 100 antennas 1051 are shown in FIG. 3 , and the voltage differences formed between each antenna 1051 and the mirror layer 102 are V1, V2, V3, V4...V99 and V100 in sequence. Here V1-V100 contains at least two different values, and the setting of the voltage difference is periodic. Periodicity refers to two aspects: on the one hand, 1-N adjacent antennas are grouped together, and the voltage difference between the same group of antennas and the mirror layer is the same; the second aspect is that the voltage difference between the antennas and the mirror layer in different groups is A variety of (eg, 2-N) different values, and the voltage difference of these different values should recur periodically. For example, taking two adjacent antennas as a group, there are three different voltage differences between the antennas of different groups and the mirror layer: Va, Vb, Vc, which appear repeatedly. Then the voltage difference between the 100 antennas and the mirror layer can be set as follows: V1=Va, V2=Va, V3=Vb, V4=Vb, V5=Vc, V6=Vc, V7=Va, V8=Va, V9= Vb, V10=Vb, V11=Vc, V12=Vc . . . The total number of periodic antennas 1051 may also be more, which is not limited in this embodiment of the present disclosure. The periodic setting method of the voltage difference between the antenna 1051 and the mirror layer 102 may also include taking 3-N adjacent antennas as a group, and the voltage differences between the antennas and the mirror layer in different groups have 2-N different values. There may be more kinds, which are not limited by the embodiments of the present disclosure.

For example, in one example, at least two antennas 1051 are configured to form different voltage differences with the mirror layer 102 , since the application of the voltage will cause electrons in the conductive layer 103 to move to the vicinity of the interface between the conductive layer 103 and the dielectric layer 104 (called the effective area A) is gathered, so that the real part of the dielectric constant of the effective area A is close to zero, and the difference of the voltage difference causes the electron concentration of the effective area A to be different. By controlling the change of the electron concentration of the effective area A, the metasurface reflects Or the phase and amplitude of the transmitted light is modulated to achieve "anomalous" reflection or transmission.

For example, if the real part of the permittivity of the active area A of the conductive layer 103 is close to zero, then according to the continuity boundary condition of the electrical displacement at the boundary of the two materials, it is possible to make the effective area of the conductive layer perpendicular to the conductive layer The electric field component Ez in the direction of 103 is greatly enhanced. The coupling of the resonance in the region where the dielectric constant of indium tin oxide tends to zero and the plasmon resonance of the metasurface enables the metasurface structure to have the ability to control the phase and amplitude voltage of incident light of a specific wavelength.

To achieve phase and amplitude voltage modulation for a specific wavelength, not only the subsurface needs to have a specific geometry, such as the thickness of each layer, the shape, width, height, and arrangement period of the antenna, etc., but also needs to be able to conduct electricity through voltage modulation. The dielectric constant of the layer. For example, for the metasurface of the conductive layer formed by indium tin oxide, the electron concentration in the active area of indium tin oxide can be adjusted by voltage. According to the Drude model, the change of the electron concentration in indium tin oxide can make the dielectric constant of indium tin oxide also change, and then the phases of the refracted light and the reflected light can also change differently. For example, FIG. 4 provides a graph of the phase change of the reflected light with the change of the electron concentration according to at least one embodiment of the present disclosure, as shown in FIG. 4 . As shown, the phase change of the reflected light received at a position above the metasurface structure when varying the electron concentration in the active area in the conductive layer under all antennas from 2.5x10 ²⁰ cm ^-3 to 2x10 ²¹ cm ^-3 can reach about 600°.

For example, FIG. 5 is a schematic plan view of another subwavelength antenna unit provided by at least one embodiment of the present disclosure. As shown in FIG. 5 , each antenna is a group, and different groups of antennas and the mirror layer have 7 different voltages Poor: V1, V2, V3, V4, V5, V6, and V7, and occur periodically, and the total number of antennas is not limited. Assuming that the metasurface structure is used for the manipulation of the transmission angle of the transmitted light, according to the generalized Snell's law to explain the "abnormal" refraction of the refracted light caused by the metasurface, n ₂ sinβ ₂ -n ₁ sinβ ₁ =(λ ₀ /2π )dФ/dx, where n ₁ is the refractive index of the first dielectric layer through which the incident light passes, n ₂ is the refractive index of the second dielectric layer through which the refracted light passes, β ₁ is the incident angle of the incident light, and β ₂ is the refraction The refraction angle of light, dФ/dx represents the rate of change of the additional phase transition in the periodic direction of the antenna array caused by the subwavelength units on the metasurface after the incident light hits the metasurface.

Assuming that the metasurface structure is used for the manipulation of the reflection angle of the reflected light, the periodic way of setting the voltage difference is still as shown in Figure 5. Taking each antenna as a group, there are 7 different voltage differences between different groups of antennas and the mirror layer: V1, V2, V3, V4, V5, V6 and V7 appear periodically, and the total number of antennas is not limited. According to the generalized Snell's law to explain the "abnormal" reflection of the reflected light caused by the metasurface, the same is true: sinβ ₃ -sinβ ₁ =(λ ₀ /2πn ₁ )dФ/dx, where β ₃ is the reflection angle of the reflected light . If the wavelength λ ₀ of the incident light is 1400 nm, n ₁ =1, the incident angle of the light is 0 degrees, and the period of the antenna along the x-axis direction is 400 nm each. By setting the voltage difference between each antenna and the mirror layer, for example, the first antenna 1051, the second antenna 1051, the third antenna 1051, the fourth antenna 1051, the fifth antenna 1051, the sixth antenna 1051, the voltage differences formed between the seventh antenna 1051 and the mirror layer 102 are V1, V2, V3, V4, V5, V6, and V7 in sequence. In the case of more antennas 1051, V1-V7 is one Periodically applying a voltage difference in turn makes the electron concentration in the effective area of the conductive layer under each antenna change periodically, so that the reflected light near each antenna undergoes a periodic phase change: 0, 2π/7, 4π/ 7, 6π/7, 8π/7, 10π/7, 12π/7, 0, 2π/7, 4π/7, 6π/7, …. Then it can be calculated that dФ/dx is equal to π/1400nm ^-1 , and the reflection angle β ₃ can be obtained according to the above formula, which is approximately equal to 30 degrees. Therefore, this metasurface realizes "abnormal" reflection for vertically incident light, that is, the reflection angle is 30 degree rather than 0 degrees, that is, by setting an appropriate voltage difference (including the magnitude of the voltage difference and the period of the voltage difference change), the phase transition period can be controlled, and then the exit angle of the reflected light can be controlled to realize the "abnormal" of the reflected light. "reflection.

For example, in another example, if the wavelength λ ₀ of the incident light is 1400 nm, n ₂ =1, the incident angle of the light is 0 degrees, and the period of the antenna along the x-axis direction is 400 nm each. By setting the voltage difference between each antenna and the mirror layer, for example, the first antenna 1051, the second antenna 1051, the third antenna 1051, the fourth antenna 1051, the fifth antenna 1051, the sixth antenna 1051, seventh antenna 1051, eighth antenna 1051, ninth antenna 1051, tenth antenna 1051, eleventh antenna 1051, twelfth antenna 1051, thirteenth antenna 1051 and fourteenth The voltage differences formed between the strip antennas 1051 and the mirror layer 102 are V1, V1, V2, V2, V3, V3, V4, V4, V5, V5, V6, V6, V7, and V7 in sequence, so that the The electron concentration in the active area in the conductive layer changes periodically, resulting in a periodic phase transition of the reflected light near each antenna: 0, 0, 2π/7, 2π/7, 4π/7, 4π/7, 6π /7, 6π/7, 8π/7, 8π/7, 10π/7, 10π/7, 12π/7, 12π/7, 0, 0, 2π/7, 2π/7, 4π/7, 4π/7 , 6π/7, 6π/7, 8π/7, 8π/7, 10π/7, 10π/7, 12π/7, 12π/7,… then dФ/dx can be calculated as π/2800nm ^-1 , then according to The above formula obtains that the reflection angle β ₃ is equal to 14.5 degrees. Therefore, this metasurface realizes "abnormal" reflection for the light of normal incidence, that is, the reflection angle is approximately equal to 14.5 degrees instead of 0 degrees, that is, by setting a suitable voltage difference (including The magnitude of the voltage difference and the period of the voltage difference change), the phase transition period can be controlled, and then the exit angle of the reflected light can be controlled to realize the "abnormal" reflection of the reflected light.

For example, FIG. 6 is a schematic plan view of another subwavelength antenna unit provided by at least one embodiment of the present disclosure. As shown in FIG. 6 , the subwavelength antenna unit 105 includes a plurality of antennas 1051, and the plurality of antennas 1051 are arranged in an array . For example, a plurality of antennas 1051 are arranged in a matrix, and the planar shape of each antenna 1051 is a rectangle, a square, or a circle.

As shown in FIG. 6, at least two adjacent antennas 1051 in the column direction are configured to form different voltage differences with the mirror layer 102, or at least two adjacent antennas 1051 in the row direction are configured to form a different voltage difference with the mirror layer 102 form a different voltage difference, or at least two adjacent antennas 1051 in the column direction are configured to form a different voltage difference with the mirror layer 102, and at least two adjacent antennas 1051 in the row direction are configured to The mirror layer 102 forms different voltage differences, so that the antenna 1051 is configured to form different voltage differences with the mirror layer 102 in the row direction and/or the column direction.

For example, in one example, along the first row, the voltage differences between the antenna 1051 and the mirror layer 102 are sequentially V11, V12, V13, V14, and V15, and the magnitudes of V11, V12, V13, V14, and V15 may be V11=V12=V15, V13=V14, but V11 and V13 are not equal in size, or V11, V12, V13, V14, and V15 are all different, the embodiment of the present disclosure does not limit the number of antennas 1051 .

As shown in FIG. 1 and FIG. 6 , the multiple antennas 1051 have subwavelength periodic structures on the x-axis and the y-axis, and the z-axis is perpendicular to the plane where the x-axis and the y-axis are located. The plane controls the exit angle of the reflected light on these two planes to realize the "abnormal" reflection of the reflected light.

For example, FIG. 7 is a schematic plan view of another sub-wavelength antenna unit provided by at least one embodiment of the present disclosure. As shown in FIG. 7 , the sub-wavelength antenna unit 105 includes a plurality of looped antennas 1051 , and the plurality of antennas 1051 are Concentric circle arrangement, the voltage difference V between different antennas 1051 and mirror layer 102 is different, which causes different phase transitions of reflected or transmitted light at different positions of the metasurface. According to the speed of the phase transition dФ/dx, reflected light at different angles will be obtained. or transmitted light. For example, FIG. 7 shows a plurality of antennas 1051, the voltage difference formed between the first antenna and the mirror layer 102 and between the fifth antenna and the mirror layer 102 in the direction from close to the center of the circle to the direction away from the center of the circle are equal in size, both are V1; the magnitude of the voltage difference formed between the second antenna and the mirror layer 102 and the voltage difference formed between the sixth antenna and the mirror layer 102 are equal, both are V2; The magnitude of the voltage difference formed between the layers 102 and between the seventh antenna and the mirror layer 102 is equal to V3; between the fourth antenna and the mirror layer 102 and between the eighth antenna and the mirror layer 102 The magnitudes of the voltage differences formed between them are equal, and they are all V4, so that the four voltage differences V1, V2, V3 and V4 are used as one cycle to perform the cyclic operation. The voltage difference formed between the first antenna and the mirror layer 102 and between the fifth antenna and the mirror layer 102 can be V1 with the same power line; the same power line can be used between the second antenna and the mirror layer The voltage difference formed between 102 and between the sixth antenna and the mirror layer 102 is V2; the same power line can be used between the third antenna and the mirror layer 102 and between the seventh antenna and the mirror layer 102 The voltage difference formed between them is V3; the voltage difference formed between the fourth antenna and the mirror layer 102 and the voltage difference formed between the eighth antenna and the mirror layer 102 are both V4 with the same power line, thereby saving number of power cords. Of course, two voltage differences V1 and V2 may be used as a cycle to perform cyclic operation, or three voltage differences V1, V2, V3 may be used as a cycle to perform cyclic operation, which is not limited in the embodiment of the present disclosure.

For example, FIG. 8 is a schematic plan view of a sub-wavelength antenna unit and a connection part provided by at least one embodiment of the present disclosure. As shown in FIG. 8 , the sub-wavelength antenna unit 105 includes a plurality of antennas 1051, and the antennas 1051 along the x-axis are direction, the voltage differences between the first antenna, the second antenna, the third antenna and the fourth antenna and the mirror layer are V1, V2, V3 and V4 respectively, and V1, V2, V3 and V4 are used as a Repeating units, the voltage differences between the fifth antenna, the sixth antenna, the seventh antenna, the eighth antenna and the mirror layer are V1, V2, V3 and V4 respectively, thus forming a new cycle. And each antenna 1051 included in the sub-wavelength antenna unit 105 is electrically connected to the power line 108 through the connecting portion 109 .

For example, FIG. 9 is a schematic three-dimensional structural diagram of a subwavelength antenna unit and a connecting portion provided by at least one embodiment of the present disclosure. As shown in FIG. 9 , the subwavelength antenna unit 105 and the power line 108 are electrically connected through the connecting portion 109 . The power lines 108 are configured to apply a voltage to the corresponding antennas 1051, eg, each power line 108 is connected to at least two antennas 1051 to apply the same voltage to the antennas 1051 connected thereto.

For example, as shown in FIG. 9 , an insulating layer 110 is provided between the subwavelength antenna unit 105 and the power supply line 108 , and the entire insulating layer 110 is formed on the plane where the antenna 1051 is formed. The connecting portion 109 is disposed in the via structure 110 a penetrating the power line 108 and the insulating layer 110 , so that the antenna 1051 and the corresponding power line 108 are electrically connected through the connecting portion 109 .

For example, referring to FIG. 1 to FIG. 9 , the material of the subwavelength antenna unit 105 only needs to satisfy the plasmon electromagnetic response to light of the corresponding wavelength and has electrical conductivity. The material of the sub-wavelength antenna unit 105 includes conductive metal, and the conductive metal includes gold, silver, aluminum or copper, etc. The material of the sub-wavelength antenna unit 105 may also include at least one of conductive metal oxide and conductive graphene, The embodiments of the present disclosure do not limit this.

For example, referring to FIG. 1 to FIG. 9 , the material of the mirror layer 102 is a metal with high reflectivity for light of a specific wavelength and conductivity. For example, the material of the mirror surface layer 102 includes gold, silver, aluminum or copper, etc. The material of the mirror surface layer 102 may also include at least one of conductive metal oxide and conductive graphene, which is not limited in the embodiments of the present disclosure .

For example, in one example, the material of the conductive layer 103 includes indium tin oxide, zinc oxide doped with aluminum or gallium, indium zinc oxide, indium gallium zinc oxide, graphene or conductive nitride, and the like. As long as the material of the conductive layer 103 can generate plasmonic electromagnetic response to light of the corresponding wavelength, the existence of a voltage difference in the conductive layer 103 can cause the electron concentration in the conductive layer 103 to change regionally, thereby regulating the material in the region The real part of the dielectric constant is sufficient.

For example, in one example, the electron concentration of the conductive layer 103 will change with the applied voltage, and the real part of the dielectric constant may be close to 0.

For example, the material of the dielectric layer 104 includes an inorganic insulating layer material or an organic insulating layer material, and the material of the inorganic insulating layer can ensure the adhesion between the dielectric layer 104 and the conductive layer 103, so that the dielectric layer 104 and the conductive layer The connections between layers 103 are tighter.

The light beam control device provided by at least one embodiment of the present disclosure has at least one of the following beneficial technical effects:

(1) In the light beam control device provided by at least one embodiment of the present disclosure, a first adhesive layer is provided between the dielectric layer and the sub-wavelength antenna unit, so as to realize a better connection between the dielectric layer and the sub-wavelength antenna unit. compact, so as to ensure the stability of the structure of the entire beam control unit.

(2) The light beam control device provided by at least one embodiment of the present disclosure can adjust the electron concentration of the effective region in the conductive layer by changing the voltage difference formed by the subwavelength antenna unit and the mirror layer.

The following points need to be noted:

(1) The drawings of the embodiments of the present disclosure only relate to the structures involved in the embodiments of the present disclosure, and other structures may refer to general designs.

(2) In the drawings for describing the embodiments of the present disclosure, the thicknesses of layers or regions are exaggerated or reduced for clarity, ie, the drawings are not drawn on actual scale.

(3) The embodiments of the present disclosure and the features in the embodiments may be combined with each other to obtain new embodiments without conflict.

The above descriptions are only specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto, and the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims (21)

1. An optical beam steering apparatus comprising: a substrate, and a mirror layer, a conductive layer, a dielectric layer and a sub-wavelength antenna unit laminated on the substrate,

wherein the sub-wavelength antenna elements and the mirror layer are configured to apply different voltages;

a first adhesive layer is disposed between the dielectric layer and the sub-wavelength antenna element.

2. The optical beam steering device of claim 1, wherein a chemical bond is formed between the first adhesive layer and the dielectric layer and between the first adhesive layer and the sub-wavelength antenna element, the first adhesive layer configured to bond the dielectric layer and the sub-wavelength antenna element.

3. The light beam control device according to claim 1 or 2, wherein the thickness of the first bonding layer is 1 nm to 50 nm, and the material of the first bonding layer includes at least one of a simple metal of titanium, a simple metal of chromium, a simple metal of tungsten, and a simple metal of niobium.

4. The optical beam steering device of claim 1, wherein the first adhesive layer has an electrical conductivity, and an orthographic projection of the first adhesive layer on the substrate and an orthographic projection of the sub-wavelength antenna element on the substrate at least partially overlap.

5. The light beam steering device of claim 1, wherein the first adhesive layer is insulative, and an orthographic projection of the sub-wavelength antenna element on the substrate is within an orthographic projection of the first adhesive layer on the substrate.

6. The optical beam control device of claim 1, wherein a second adhesive layer is disposed between the substrate and the mirror layer, the second adhesive layer configured to adhere the substrate and the mirror layer.

7. The light beam control device of claim 6, wherein a chemical bond is formed between the second adhesive layer and the substrate and between the second adhesive layer and the mirror layer to bond the substrate and the mirror layer.

8. The optical beam control apparatus according to claim 6, wherein the thickness of the second adhesive layer is 1 nm to 1000 nm, and the material of the second adhesive layer includes at least one of a simple metal of titanium, a simple metal of chromium, a simple metal of tungsten, and a simple metal of niobium.

9. The light beam control device according to any one of claims 6 to 8, wherein a material of the first adhesive layer and a material of the second adhesive layer are the same or different.

10. The beam steering apparatus of claim 1, wherein the sub-wavelength antenna unit comprises a plurality of antennas, each of the antennas being rod-shaped.

11. The beam control device of claim 10, wherein at least two adjacent antennas are configured to form different voltage differences with the mirror layer.

12. The beam steering device of claim 1, wherein the sub-wavelength antenna unit comprises a plurality of antennas arranged in an array.

13. Optical beam control device according to claim 12, wherein at least two adjacent antennas in the column direction are arranged to form a different voltage difference with the mirror layer and/or at least two adjacent antennas in the row direction are arranged to form a different voltage difference with the mirror layer.

14. The beam steering apparatus of claim 1, wherein the sub-wavelength antenna unit comprises a plurality of antennas in a shape of a loop, the plurality of antennas being arranged in concentric circles.

15. The beam control device of claim 14, wherein at least two adjacent antennas are configured to form different voltage differences with the mirror layer.

16. A beam control apparatus according to any one of claims 10 to 15, further comprising at least two power lines, the plurality of antennas and the power lines being electrically connected by respective connection portions, each power line being electrically connected to one or more of the antennas, the power lines being configured to apply a voltage to the corresponding antenna.

17. The beam steering arrangement of claim 16, wherein an insulating layer is disposed between the sub-wavelength antenna element and the power line, the connection being disposed in a via structure that extends through the power line and the insulating layer.

18. The beam steering device of claim 1, wherein the material of the sub-wavelength antenna element comprises at least one of a conductive metal, a conductive metal oxide, and conductive graphene.

19. The optical beam steering apparatus of claim 1, wherein the material of the mirror layer comprises at least one of a metal having reflectivity and conductivity, a conductive metal oxide, and conductive graphene.

20. A beam control device according to claim 1, wherein the material of the conductive layer comprises indium tin oxide, indium zinc oxide or indium gallium zinc oxide.

21. The optical beam steering apparatus of claim 1, wherein the material of the dielectric layer comprises an inorganic insulating material or an organic insulating material.

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