阅读说明：本技术 电致变焦超透镜及其制备方法和调制方法 (Electro-zoom super lens and preparation method and modulation method thereof ) 是由 林佑昇 林鹏 于 2021-11-22 设计创作，主要内容包括：本发明公开了一种电致变焦超透镜及其制备方法和调制方法,电致变焦超透镜包括衬底及设置于所述衬底上的若干个同心环,每个所述同心环包括相变材料层及分别设置于所述相变材料层的两面的第一电极层和第二电极层,通过调节所述第一电极层和所述第二电极层的电压调节所述同心环的相移以调节所述电致变焦超透镜的焦距。本发明实施例结构简单、易于调节且便于集成化应用,可广泛应用于透镜技术领域。(The invention discloses an electro-zoom super lens and a preparation method and a modulation method thereof, wherein the electro-zoom super lens comprises a substrate and a plurality of concentric rings arranged on the substrate, each concentric ring comprises a phase change material layer and a first electrode layer and a second electrode layer which are respectively arranged on two sides of the phase change material layer, and the phase shift of the concentric rings is adjusted by adjusting the voltage of the first electrode layer and the second electrode layer so as to adjust the focal length of the electro-zoom super lens. The embodiment of the invention has simple structure, easy adjustment and convenient integrated application, and can be widely applied to the technical field of lenses.)

1. An electro-zoom super lens is characterized by comprising a substrate and a plurality of concentric rings arranged on the substrate, wherein each concentric ring comprises a phase change material layer and a first electrode layer and a second electrode layer which are respectively arranged on two sides of the phase change material layer, and the phase shift of the concentric rings is adjusted by adjusting the voltage of the first electrode layer and the second electrode layer so as to adjust the focal length of the electro-zoom super lens.

2. The electro-variable zoom superlens of claim 1, wherein the concentric rings are equally spaced.

3. The electro-variable focus superlens of claim 1, wherein the material of the substrate comprises silicon dioxide.

4. The electro-variable focus superlens of claim 1, wherein the first electrode layer and the second electrode layer are of the same material.

5. The electro-variable focus superlens of claim 1, wherein the material of the first electrode layer and the second electrode layer comprises indium tin oxide.

6. A preparation method of an electro-zoom super lens is characterized in that the electro-zoom super lens comprises a substrate and a plurality of concentric rings arranged on the substrate, and the preparation method comprises the following steps:

providing a substrate;

preparing a first electrode layer, a phase change material layer and a second electrode layer on the substrate in sequence;

preparing a plurality of concentric rings on the surface of the second electrode layer by photoetching and etching; each concentric ring comprises a phase change material layer, and a first electrode layer and a second electrode layer which are respectively arranged on two sides of the phase change material layer.

7. The production method according to claim 5, wherein the first electrode layer, the phase change material layer, and the second electrode layer are successively produced on the substrate by chemical vapor deposition.

8. A modulation method of an electro-zoom super lens is characterized in that the electro-zoom super lens comprises a substrate and a plurality of concentric rings arranged on the substrate, each concentric ring comprises a phase change material layer and a first electrode layer and a second electrode layer which are respectively arranged on two sides of the phase change material layer, and the modulation method comprises the following steps:

acquiring a focal length to be adjusted of the electro-zoom super lens;

determining the phase shift of the concentric ring according to the focal length to be adjusted and a preset first corresponding relation; the first correspondence comprises a calculation formula between phase shift and focal length of the concentric rings;

and determining the voltages of the first electrode layer and the second electrode layer according to the phase shift and a preset second corresponding relation.

9. The modulation method according to claim 8, wherein the calculation formula comprises:

wherein the content of the first and second substances,representing the phase shift of concentric rings with coordinates (x, y), λ representing the wavelength of the incident light, and f representing the focal length.

Technical Field

The invention relates to the technical field of lenses, in particular to an electro-zoom super lens and a preparation method and a modulation method thereof.

Background

Variable focal length is important in optical imaging systems, and conventional zoom schemes typically employ a cascade of conventional lenses, with the distance between the conventional lenses being adjusted to achieve zoom. The traditional lens realizes focusing by changing the phase and polarization of light, and as the refractive index of natural materials is limited, once the size of the device is further reduced to a sub-wavelength scale, enough phase change is difficult to accumulate, so that the zoom system is large and complex, the integration level of the zoom system is greatly reduced, and the application of the zoom system in portable and wearable equipment is limited.

Disclosure of Invention

In view of the above, an object of the embodiments of the present invention is to provide an electro-zoom super lens, a method for manufacturing the same, and a method for modulating the same, wherein the electro-zoom super lens has a simple structure, is easy to adjust, and is convenient for integrated application.

In a first aspect, an embodiment of the present invention provides an electro-zoom super lens, which includes a substrate and a plurality of concentric rings disposed on the substrate, each of the concentric rings includes a phase change material layer and a first electrode layer and a second electrode layer disposed on two sides of the phase change material layer, respectively, and phase shifts of the concentric rings are adjusted by adjusting voltages of the first electrode layer and the second electrode layer to adjust a focal length of the electro-zoom super lens.

Optionally, the concentric rings are equally spaced.

Optionally, the material of the substrate comprises silicon dioxide.

Optionally, the first electrode layer and the second electrode layer are made of the same material.

Optionally, the material of the first electrode layer and the second electrode layer comprises indium tin oxide.

In a second aspect, an embodiment of the present invention provides a method for manufacturing an electro-zoom super lens, where the electro-zoom super lens includes a substrate and a plurality of concentric rings disposed on the substrate, and the method includes:

providing a substrate;

preparing a first electrode layer, a phase change material layer and a second electrode layer on the substrate in sequence;

preparing a plurality of concentric rings on the surface of the second electrode layer by photoetching and etching; each concentric ring comprises a phase change material layer, and a first electrode layer and a second electrode layer which are respectively arranged on two sides of the phase change material layer.

Optionally, the first electrode layer, the phase change material layer and the second electrode layer are sequentially prepared on the substrate through chemical vapor deposition.

In a third aspect, an embodiment of the present invention provides a modulation method for an electro-zoom super lens, where the electro-zoom super lens includes a substrate and a plurality of concentric rings disposed on the substrate, each of the concentric rings includes a phase change material layer and a first electrode layer and a second electrode layer respectively disposed on two sides of the phase change material layer, and the modulation method includes:

acquiring a focal length to be adjusted of the electro-zoom super lens;

determining the phase shift of the concentric ring according to the focal length to be adjusted and a preset first corresponding relation; the first correspondence comprises a calculation formula between phase shift and focal length of the concentric rings;

and determining the voltages of the first electrode layer and the second electrode layer according to the phase shift and a preset second corresponding relation.

Optionally, the calculation formula includes:

wherein the content of the first and second substances,representing the phase shift of concentric rings with coordinates (x, y), λ representing the wavelength of the incident light, and f representing the focal length.

The implementation of the embodiment of the invention has the following beneficial effects: the electro-zoom super lens comprises a substrate and a plurality of concentric rings arranged on the substrate, wherein each concentric ring comprises a phase change material layer and a first electrode layer and a second electrode layer which are respectively arranged on two sides of the phase change material layer, and the phase shift of the concentric rings is adjusted by adjusting the voltage of the first electrode layer and the second electrode layer so as to adjust the focal length of the electro-zoom super lens; the zoom lens can realize accurate zooming only by one super lens, and has the advantages of small size, simple structure and convenient manufacture and integrated application.

Drawings

FIG. 1 is a schematic structural diagram of an electro-zoom super lens according to an embodiment of the present invention;

FIG. 2 is a simulated graph of phase shift and transmittance versus refractive index for concentric rings in an electro-zoom superlens provided by an embodiment of the present invention;

fig. 3 is a simulation diagram of phase requirements of the electro-zoom super lens with focal lengths of 50um, 60um and 70um at different radii and refractive indexes corresponding to the phases according to the embodiment of the present invention;

FIG. 4 is a simulation diagram of the light intensity of the electro-zoom super lens with focal lengths of 50um, 60um and 70um along the z-axis direction according to the embodiment of the present invention;

FIG. 5 is a schematic flow chart illustrating steps of a method for manufacturing an electro-zoom super lens according to an embodiment of the present invention;

FIG. 6 is a schematic flow chart illustrating steps of another method for manufacturing an electro-variable-focus superlens according to an embodiment of the present invention;

fig. 7 is a flowchart illustrating steps of a modulation method for an electro-zoom super lens according to an embodiment of the present invention.

Detailed Description

The invention is described in further detail below with reference to the figures and the specific embodiments. The step numbers in the following embodiments are provided only for convenience of illustration, the order between the steps is not limited at all, and the execution order of each step in the embodiments can be adapted according to the understanding of those skilled in the art.

To meet the increasing demands for device miniaturization and system integration, the super-surface becomes a common platform for wavefront shaping. The super surface is an artificial material consisting of a two-dimensional periodic sub-wavelength structure array and has high flexible light response capability. The phase, amplitude or polarization state of incident light can be controlled at will by designing a proper subwavelength structure. As an important application of the super-surface, the basic concept of the super-lens is: an incident plane wave is converted to a spherical wave by introducing different phase shifts along its transverse axis. Compared with the traditional lens, the super lens has the characteristics of small size, integration, off-axis focusing and the like, and has great potential in the field of optical imaging.

As shown in fig. 1, an embodiment of the present invention provides an electro-zoom super lens, which includes a substrate and a plurality of concentric rings disposed on the substrate, each of the concentric rings includes a phase change material layer and a first electrode layer and a second electrode layer disposed on two sides of the phase change material layer, respectively, and a phase shift of the concentric ring is adjusted by adjusting voltages of the first electrode layer and the second electrode layer to adjust a focal length of the electro-zoom super lens. Fig. 1(a) shows a plan view of the electro-zoom super lens, and fig. 1(b) shows a side sectional view of the electro-zoom super lens.

The phase change material is a substance which changes the state of a substance and can provide latent heat under the condition of constant temperature; the process of changing physical properties is called a phase change process, and in this case, the phase change material absorbs or releases a large amount of latent heat. In this embodiment, the refractive index of the phase change material layer is adjusted by adjusting the voltages of the first electrode layer and the second electrode layer, different refractive indexes correspond to different phases and transmittances, and then the focal length is adjusted according to the correspondence between the phase shift and the focal length.

When a plane wave is perpendicularly incident to the superlens, it is necessary to deflect the incident light at a certain angle at a specific position of the superlens. It can be formulated as:

wherein the content of the first and second substances,representing the phase shift in rad for concentric rings of coordinates (x, y); λ represents the wavelength of the incident light, in m; f represents the focal length in m; and x and y are coordinate points in a plane coordinate system established by taking the central point of the super lens as a coordinate origin, and the unit is m.

From the above equation, the phase shift of the incident light is a function of the meta-lens coordinates, assuming that the wavelength of the incident light and the focal length of the meta-lens are constant. The phases of concentric rings with different radiuses are different, but the phase of any point on one concentric ring is the same; therefore, the phase requirement of the above formula can be satisfied by applying a voltage to the electrodes such that the refractive indices of the different rings are changed.

According to the refractive index change of the phase-change material, the phase and the transmissivity of the structure under different refractive indexes are simulated through FDTD, and the simulation result is shown in FIG. 2, wherein the incident wavelength is 580 nm; as can be seen from fig. 2, the phase shift of the phase change material is positively correlated with the refractive index, and the transmittance of the phase change material changes periodically with the increase of the refractive index.

Specifically, according to the above formula, the phase requirements of the superlens with the focal lengths of 50um, 60um and 70um at different radii of the lens when the incident wavelength is 580nm and the refractive indexes corresponding to the phases are calculated, and the result is shown in fig. 3. By setting different ring refractive indexes, the light intensity of the superlens with the set focal lengths of 50um, 60um and 70um along the z-axis direction is simulated by FDTD simulation, as shown in FIG. 4. The vertex of the intensity curve shown in fig. 4 is the position of the focal point, so the simulated focal points are 50um, 58um and 67um, respectively, which are very close to the set focal distance. Therefore, the phase of the superlens with different focal lengths can be calculated, and the refractive index of the phase change material can be changed by applying corresponding voltages to different circular rings, so that the aim of artificially controlling the focal length of the superlens is fulfilled.

Optionally, the concentric rings are equally spaced.

It will be appreciated by those skilled in the art that equal spacing between concentric rings facilitates connection.

Optionally, the material of the substrate comprises silicon dioxide.

It should be noted that silicon dioxide is a conventional substrate material and is readily available.

Optionally, the first electrode layer and the second electrode layer are made of the same material.

Optionally, the material of the first electrode layer and the second electrode layer comprises indium tin oxide.

It will be appreciated by those skilled in the art that the materials of the first and second electrode layers are the same for ease of tuning, and that indium tin oxide is also highly conductive.

The implementation of the embodiment of the invention has the following beneficial effects: the electro-zoom super lens comprises a substrate and a plurality of concentric rings arranged on the substrate, wherein each concentric ring comprises a phase change material layer and a first electrode layer and a second electrode layer which are respectively arranged on two sides of the phase change material layer, and the phase shift of the concentric rings is adjusted by adjusting the voltage of the first electrode layer and the second electrode layer so as to adjust the focal length of the electro-zoom super lens; the zoom lens can realize accurate zooming only by one super lens, and has the advantages of small size, simple structure and convenient manufacture and integrated application.

The electro-zoom super lens in the embodiment of the invention can realize the focusing function of the target focal length only by applying corresponding voltages on different ring electrodes, and the focal length can be adjusted by adjusting the voltage. The adjustable focal length can be realized only by a single-layer lens, and the integration level is greatly improved. Therefore, the super lens can be integrated into a circuit chip and can be integrated into various imaging devices such as mobile phones, cameras and the like as a zoom lens; meanwhile, the function of variable focal length can be applied to holographic projection and VR glasses, and three-dimensional imaging and the like are realized.

As shown in fig. 5, an embodiment of the present invention provides a method for manufacturing an electro-zoom super lens, where the electro-zoom super lens includes a substrate and a plurality of concentric rings disposed on the substrate, and the method includes:

s1, providing a substrate;

s2, sequentially preparing a first electrode layer, a phase change material layer and a second electrode layer on the substrate;

s3, preparing a plurality of concentric rings on the surface of the second electrode layer through photoetching and etching; each concentric ring comprises a phase change material layer, and a first electrode layer and a second electrode layer which are respectively arranged on two sides of the phase change material layer.

Optionally, the first electrode layer, the phase change material layer and the second electrode layer are sequentially prepared on the substrate through chemical vapor deposition. The chemical vapor deposition method is simple to operate and relatively low in equipment cost.

Specifically, referring to fig. 6, the first step: selecting a substrate meeting the requirement, and sequentially depositing a first ITO (Indium tin oxide) layer, a phase change material layer and a second ITO layer on the substrate by adopting a chemical vapor deposition method; the second step is that: coating photoresist on the surface of the second ITO layer, and photoetching to form a concentric ring structure; the third step: etching according to the photoetching concentric ring structure to obtain concentric rings of the electro-zoom super lens; the fourth step: carrying out photoresist removing operation; the fifth step: and removing the photoresist to obtain the electro-zoom super lens of the embodiment of the invention.

The implementation of the embodiment of the invention has the following beneficial effects: the electro-zoom super lens comprises a substrate and a plurality of concentric rings arranged on the substrate, wherein each concentric ring comprises a phase change material layer and a first electrode layer and a second electrode layer which are respectively arranged on two sides of the phase change material layer, and the phase shift of the concentric rings is adjusted by adjusting the voltage of the first electrode layer and the second electrode layer so as to adjust the focal length of the electro-zoom super lens; the zoom lens can realize accurate zooming only by one super lens, and has the advantages of small size, simple structure and convenient manufacture and integrated application.

As shown in fig. 7, an embodiment of the present invention provides a modulation method for an electro-zoom super lens, where the electro-zoom super lens includes a substrate and a plurality of concentric rings disposed on the substrate, each of the concentric rings includes a phase change material layer and a first electrode layer and a second electrode layer respectively disposed on two sides of the phase change material layer, and the modulation method includes:

s4, acquiring a focal length to be adjusted of the electro-zoom super lens;

s5, determining the phase shift of the concentric ring according to the focal length to be adjusted and a preset first corresponding relation; the first correspondence comprises a calculation formula between phase shift and focal length of the concentric rings;

and S6, determining the voltages of the first electrode layer and the second electrode layer according to the phase shift and a preset second corresponding relation.

Optionally, the calculation formula includes:

wherein the content of the first and second substances,concentric rings with coordinates (x, y)In rad; λ represents the wavelength of the incident light, in m; f represents the focal length in m; and x and y are coordinate points in a plane coordinate system established by taking the central point of the super lens as a coordinate origin, and the unit is m.

The process of the modulation method of the electro-zoom super lens in the embodiment is as follows: the method comprises the steps of firstly obtaining a focal length required to be adjusted of the electro-zoom super lens, then determining a phase shift required to be adjusted according to the focal length required to be adjusted and the relation between the focal length and the phase shift, and finally determining an adjusted voltage according to the relation between the phase shift required to be adjusted and the refractive index of a phase-change material, the relation between the refractive index of the phase-change material and the voltage, and the like.

The implementation of the embodiment of the invention has the following beneficial effects: the electro-zoom super lens comprises a substrate and a plurality of concentric rings arranged on the substrate, wherein each concentric ring comprises a phase change material layer and a first electrode layer and a second electrode layer which are respectively arranged on two sides of the phase change material layer, and the phase shift of the concentric rings is adjusted by adjusting the voltage of the first electrode layer and the second electrode layer so as to adjust the focal length of the electro-zoom super lens; the zoom lens can realize accurate zooming only by one super lens, and has the advantages of small size, simple structure and convenient manufacture and integrated application.

While the preferred embodiments of the present invention have been illustrated and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.