阅读说明：本技术 一种径向和角向柱矢量光束的独立位相控制装置及方法 (Independent phase control device and method for radial and angular column vector beams ) 是由 贺炎亮 李灿铭 杨博 谢智强 刘俊敏 田冰冰 李瑛� 范滇元 陈书青 于 2020-12-25 设计创作，主要内容包括：本发明公开了一种径向和角向柱矢量光束的独立位相控制装置及方法,所述装置包括：径向和角向混合柱矢量光束的产生模块、径向和角向柱矢量光束空间分离器件模块和远场检测模块；本发明通过在传统动力学相位超表面的基础上进一步赋予每个超原子空间位置相关的旋转角度来实现对于径向和角向柱矢量光束的独立相位操控,径向和角向柱矢量光束空间分离器件被设计通过在径向和角向偏振方向上集成共轭的梯度光栅相位,相较于传统光学器件,本发明所提出的方法使得对于非均匀偏振光束的任意相位操控成为可能,这使得其在结构光通信、全光互联等领域具有广泛的应用前景。(The invention discloses a device and a method for controlling independent phases of radial and angular column vector beams, wherein the device comprises: the device comprises a radial and angular mixed column vector beam generating module, a radial and angular column vector beam space separation device module and a far field detection module; the invention further endows each super-atom spatial position relative rotation angle on the basis of the traditional dynamic phase super-surface to realize independent phase control on radial and angular column vector beams, and the radial and angular column vector beam spatial separation device is designed to integrate conjugated gradient grating phases in the radial and angular polarization directions.)

1. An independent phase control device for radial and angular column vector beams, comprising:

the device comprises a radial and angular mixed column vector beam generating module, a radial and angular column vector beam space separation device module and a far field detection module;

the generation module of the radial and angular mixed column vector beam comprises:

a first light source and a second light source for generating a gaussian beam;

a first polarizing plate and a second polarizing plate for changing a polarization direction of the Gaussian beam;

a first polarizer and a second polarizer for generating linear polarization light by polarization;

the first polarization conversion element is used for generating a radial column vector light beam, and the second polarization conversion element is used for generating an angular column vector light beam;

a mirror for changing an optical path;

the beam combining mirror is used for combining the radial column vector light beam and the angular column vector light beam into one beam;

the radial and angular column vector beam space separation device module comprises:

a lens for focusing the radial and angular mixed column vector beam;

the plasmon super-structure surface is used for carrying out space separation on the radial and angular mixed column vector beams;

the far-field detection module comprises:

and the light intensity detection device is used for detecting the radial column vector light beams and the angular column vector light beams at different spatial positions.

2. The apparatus for independent phase control of radial and azimuthal cylindrical vector beams according to claim 1, wherein said first light source, said first polarizer, said first polarization transformation element, said beam combiner, said lens and said plasmonic superstructure surface are sequentially arranged on a same optical axis;

the second light source, the second polarizer, the second polarization conversion element and the reflector are sequentially arranged on the same optical axis;

the beam combining mirror is arranged above the reflecting mirror;

the light intensity detection device is arranged below the surface of the plasmon super structure.

3. The apparatus for independent phase control of radial and angular column vector beams according to claim 1, wherein said first and second light sources are lasers with a wavelength of 1550 nm.

4. The apparatus for independent phase control of radial and angular column vector beams according to claim 1, wherein said first and second polarizers are half-wave plates.

5. The apparatus for independent phase control of radial and angular cylindrical vector beams according to claim 1, wherein said first polarizer is a X-direction polarizing glan prism and said second polarizer is a Y-direction polarizing glan prism.

6. The apparatus for independent phase control of radial and angular cylinder vector beams according to claim 1, wherein said first and second polarization transformation elements are Q-plates.

7. The apparatus for independent phase control of radial and angular column vector beams according to claim 1, wherein said mirrors are plane mirrors.

8. The apparatus for independent phase control of radial and angular cylindrical vector beams according to claim 1, wherein said light intensity detection means is a 1550nm CCD camera.

9. The independent phase control device for radial and angular cylindrical vector beams according to claim 1, wherein said plasmonic super-structured surface is used to diffract a radial and angular mixed cylindrical vector beam.

10. A method for independent phase control of radial and angular column vector beams based on the apparatus for independent phase control of radial and angular column vector beams according to any one of claims 1 to 9, comprising the steps of:

the 1550nm laser generated by the first light source generates linearly polarized light polarized in the X-axis direction through the first polarizer and the first polarizer, and the linearly polarized light is converted into a radial column vector beam through the first polarization conversion element;

the 1550nm laser generated by the second light source is linearly polarized in the Y-axis direction generated by the second polarizer and is converted into an angular column vector beam through the second polarization conversion element;

the angular column vector light beam is reflected to the beam combiner through the reflector, and the beam combiner combines the radial column vector light beam and the angular column vector light beam to obtain a radial and angular mixed column vector light beam;

the radial and angular mixed column vector beams are focused by the lens and then are transmitted to the plasmon super-structure surface, and the plasmon super-structure surface performs space separation on the radial and angular mixed column vector beams;

the light intensity detection device detects the radial column vector light beams and the angular column vector light beams emitted by the plasmon super-structure surface, and independent phase control of the radial column vector light beams and the angular column vector light beams is achieved.

Technical Field

The invention relates to the technical field of optics, in particular to a device and a method for controlling independent phases of radial and angular column vector beams.

Background

Generally, the polarization of light means that the vibration direction of the light vector is not axisymmetric with respect to the propagation direction, and light having a polarization property is called polarized light. According to the spatial distribution of the polarization state in the cross section of the light beam, the polarized light can be divided into uniformly polarized light and non-uniformly polarized light, and the vector light is non-uniformly polarized light. The most specific of the vector beams is a beam with a polarization state in the cross section of the beam in cylindrical symmetry, i.e. a cylindrical vector beam, sometimes also referred to as a vector beam or a vector mode, the most common polarization directions of which are radial polarization and angular polarization. Due to its unique optical properties, cylindrical vector beams have found applications in many fields, such as beam shaping, optical trapping, optical information processing, super resolution technology, optical metrology, and laser material processing. Particularly in the field of optical communications, cylindrical vector beams, which are the natural modes of optical fibers, have good anti-turbulence capability and have been proven to be capable of mode division multiplexing in free space and optical fibers, which can greatly improve communication capacity and frequency utilization, which provides an excellent solution for the upcoming capacity crisis. But the non-uniform distribution of polarization makes new multiplexing techniques more demanding for corresponding information processing devices. Especially the information processing of single vector mode channels in multiplexing, such as channel separation and transformation, has not been solved, and the key of this is how to realize arbitrary independent phase control of radial and angular cylindrical vector light.

Heretofore, various optical elements have been applied to phase control of a cylindrical vector beam, such as a lens, a spiral phase plate, and a spatial light modulator. The phase modulation of the lens and the spiral phase plate depends on light path accumulation, the device is large in size, and the modulation function is single, so that the obvious defect is formed. Spatial light modulators increase the diversity of operation in that they can be reconstructed, but due to their polarization sensitive nature, they often entail the decomposition of a cylindrical vector beam into two orthogonal linear polarization orbital angular momentum modes, often accompanied by a complex optical link. Recently, the super-surface shows excellent phase and polarization manipulation capabilities, which is a material to construct its geometry and alignment direction at a sub-wavelength scale. There have been many studies reporting the use of super-surfaces to manipulate cylindrical vector beams and apply them to all-optical information processing. In previous work, PB phase super surfaces with spin-orbit interaction have been proven to be capable of information processing of cylindrical vector beams. However, conjugate phase modulation of the left and right rotational components of the PB phase super surface can only control the polarization of the cylindrical vector beam. The hybrid phase super-surface proposed later realizes non-conjugate phase modulation of left and right rotational components by adjusting the geometric dimensions of metal atoms while rotating them, thereby making it possible to manipulate the phase of a cylindrical vector beam. Unfortunately, this approach, while achieving phase control, also changes the polarization distribution of the incident beam. The optical lens, the beam splitter and the like are realized by utilizing the polarization insensitive super surface, and the arbitrary phase control of the cylindrical vector light beam can be realized to a certain extent without changing the polarization distribution of the cylindrical vector light beam. However, the polarization insensitivity is such that the phase modulation of the radial and angular cylindrical vector beams is always the same. Therefore, it remains quite challenging for the super-surface to achieve independent phase control of the radial and angular cylindrical vector beams.

Therefore, the prior art still needs to be improved and developed to address the above drawbacks.

Disclosure of Invention

The present invention provides a device and a method for controlling independent phases of radial and angular cylindrical vector beams, aiming at achieving independent phase control of radial and angular mixed cylindrical vector beams.

The technical scheme adopted by the invention for solving the technical problem is as follows:

an independent phase control device for radial and angular cylindrical vector beams, wherein the independent phase control device for radial and angular cylindrical vector beams comprises:

the device comprises a radial and angular mixed column vector beam generating module, a radial and angular column vector beam space separation device module and a far field detection module;

the generation module of the radial and angular mixed column vector beam comprises:

a first light source and a second light source for generating a gaussian beam;

a first polarizing plate and a second polarizing plate for changing a polarization direction of the Gaussian beam;

a first polarizer and a second polarizer for generating linear polarization light by polarization;

the first polarization conversion element is used for generating a radial column vector light beam, and the second polarization conversion element is used for generating an angular column vector light beam;

a mirror for changing an optical path;

the beam combining mirror is used for combining the radial column vector light beam and the angular column vector light beam into one beam;

the radial and angular column vector beam space separation device module comprises:

a lens for focusing the radial and angular mixed column vector beam;

the plasmon super-structure surface is used for carrying out space separation on the radial and angular mixed column vector beams;

the far-field detection module comprises:

and the light intensity detection device is used for detecting the radial column vector light beams and the angular column vector light beams at different spatial positions.

The independent phase control device for the radial and angular cylindrical vector beams is characterized in that the first light source, the first polaroid, the first polarizer, the first polarization transformation element, the beam combiner, the lens and the plasmon polariton super-structure surface are sequentially arranged on the same optical axis;

the second light source, the second polarizer, the second polarization conversion element and the reflector are sequentially arranged on the same optical axis;

the beam combining mirror is arranged above the reflecting mirror;

the light intensity detection device is arranged below the surface of the plasmon super structure.

And the first light source and the second light source are lasers with the wavelength of 1550 nm.

And independent phase control means for said radial and angular cylindrical vector beams, wherein said first and second polarizers are half-wave plates.

The independent phase control device of the radial and angular column vector beams is characterized in that the first polarizer is a Glan prism polarized in the X direction, and the second polarizer is a Glan prism polarized in the Y direction.

And the independent phase control device for the radial and angular cylindrical vector beams, wherein the first polarization conversion element and the second polarization conversion element are Q-plates.

And the reflector is a plane reflector.

And the radial and angular column vector light beams are independently phase-controlled, wherein the light intensity detection device is a 1550nm CCD camera.

And the plasmon polariton super-structure surface is used for diffracting the radial and angular mixed column vector beams.

In order to achieve the above object, the present invention further provides a method for controlling independent phases of radial and angular cylindrical vector beams based on the device for controlling independent phases of radial and angular cylindrical vector beams, wherein the method for controlling independent phases of radial and angular cylindrical vector beams comprises the following steps:

the 1550nm laser generated by the first light source generates linearly polarized light polarized in the X-axis direction through the first polarizer and the first polarizer, and the linearly polarized light is converted into a radial column vector beam through the first polarization conversion element;

the 1550nm laser generated by the second light source is linearly polarized in the Y-axis direction generated by the second polarizer and is converted into an angular column vector beam through the second polarization conversion element;

the angular column vector light beam is reflected to the beam combiner through the reflector, and the beam combiner combines the radial column vector light beam and the angular column vector light beam to obtain a radial and angular mixed column vector light beam;

the radial and angular mixed column vector beams are focused by the lens and then are transmitted to the plasmon super-structure surface, and the plasmon super-structure surface performs space separation on the radial and angular mixed column vector beams;

the light intensity detection device detects the radial column vector light beams and the angular column vector light beams emitted by the plasmon super-structure surface, and independent phase control of the radial column vector light beams and the angular column vector light beams is achieved.

Has the advantages that: the 1550nm laser generated by the first light source is firstly passed through the first polarizer and the first polarizer to generate linearly polarized light polarized in the X-axis direction, and then is converted into a radial column vector beam by the first polarization conversion element; the 1550nm laser generated by the second light source is linearly polarized in the Y-axis direction generated by the second polarizer and is converted into an angular column vector beam through the second polarization conversion element; the angular column vector light beam is reflected to the beam combiner through the reflector, and the beam combiner combines the radial column vector light beam and the angular column vector light beam to obtain a radial and angular mixed column vector light beam; the radial and angular mixed column vector beams are focused by the lens and then are transmitted to the plasmon super-structure surface, and the plasmon super-structure surface performs space separation on the radial and angular mixed column vector beams; the light intensity detection device detects the radial column vector light beams and the angular column vector light beams emitted by the plasmon super-structure surface, and independent phase control of the radial column vector light beams and the angular column vector light beams is achieved. The invention realizes independent phase control of radial and angular column vector beams by endowing each super-atom with a relevant rotation angle at a spatial position, breaks through the polarization insensitivity of the traditional optical device, and has the advantages of small volume and convenient use.

Drawings

Fig. 1 is a schematic structural diagram of a preferred embodiment of the independent phase control device for radial and angular cylindrical vector beams of the present invention.

FIG. 2 is a flow chart of a preferred embodiment of the method of independent phase control of radial and angular cylindrical vector beams of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer and clearer, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1, fig. 1 is a schematic structural diagram of an independent phase control device for radial and angular column vector beams according to a preferred embodiment of the present invention.

As shown in fig. 1, an embodiment of the present invention provides an apparatus for controlling independent phases of radial and angular cylindrical vector beams, including: the device comprises a radial and angular mixed column vector beam generating module, a radial and angular column vector beam spatial separation device module and a far field detection module.

Specifically, the generation module of the radial and angular mixed column vector beam comprises: a first light source 1 and a second light source 5 for generating a gaussian beam; a first polarizer 2 and a second polarizer 6 for changing the polarization direction of the gaussian beam; a first polarizer 3 and a second polarizer 7 for generating linear polarization by polarization; a first polarization conversion element 4 for generating a radial cylindrical vector light beam and a second polarization conversion element 8 for generating an angular cylindrical vector light beam; a mirror 9 for changing an optical path; a beam combiner 10 for combining the radial and angular cylindrical vector beams into one beam.

Specifically, the radial and angular column vector beam space separation device module includes: a lens 11 for focusing the radial and angular mixed cylindrical vector beam; a plasmonic metamaterial surface 12 for spatially separating the radial and angular mixed cylindrical vector beams.

Specifically, the far-field detection module includes: and the light intensity detection device 13 is used for detecting the radial column vector light beams and the angular column vector light beams at different spatial positions.

Wherein the first light source 1, the first polarizer 2, the first polarizer 3, the first polarization conversion element 4, the beam combiner 10, the lens 11, and the plasmonic superstructure surface 13 are sequentially disposed on the same optical axis; the second light source 5, the second polarizer 6, the second polarizer 7, the second polarization conversion element 8 and the reflector 9 are sequentially arranged on the same optical axis; the beam combiner 10 is arranged above the reflector 9; said light intensity detection means 13 are arranged below said plasmonic superstructure surface 12.

The first light source 1 and the second light source 5 are lasers (devices for emitting laser light) with a wavelength of 1550nm, which are used to generate gaussian beams, and in general, the amplitude distribution of the cross section of the fundamental mode radiation field emitted by the laser resonator follows a gaussian function, so called gaussian beam.

The first polarizer 2 and the second polarizer 6 are half-wave plates, the wave plate is an optical device capable of generating an additional optical path difference (or phase difference) between two light vibrations perpendicular to each other, the half-wave plate is a birefringent crystal with a certain thickness, when the normally incident light is transmitted, the phase difference between the ordinary light (o light) and the extraordinary light (e light) is equal to pi or an odd multiple thereof, and such a wafer is called as a half-wave plate, which is called as a half-wave plate for short.

The first polarizer 3 is a glan prism polarized in the X direction, the second polarizer 7 is a glan prism polarized in the Y direction, the glan prism is one of polarizing prisms, the polarizing prism is a polarizing device made by using birefringence of a crystal, and the natural light or the polarized light becomes linearly polarized light with the vibration direction determined by the polarization direction of the prism after passing through the polarizing prism.

Wherein the first polarization conversion element 4 and the second polarization conversion element 8 are Q-plates (Q-plates, also called variable vortex plates, Q in Q-plates refers to spatial rotation rate).

Wherein the reflector 9 is a plane reflector

Wherein the plasmonic superstructure surface 12 is designed to achieve spatial separation of radial and angular cylindrical vector beams by integrating conjugated gradient grating phases in radial and angular polarization directions.

The light intensity detection device 14 is a 1550nm CCD camera, and has the advantages of strong environment adaptability, and stable and reliable performance.

The above-described apparatus is not limited to these devices, and may be replaced with devices having corresponding functions.

Further, based on the device for controlling independent phases of radial and angular cylindrical vector beams provided by the above embodiments, the present invention further provides a method for controlling independent phases of radial and angular cylindrical vector beams, please refer to fig. 2, and fig. 2 is a flowchart of a preferred embodiment of the method for controlling independent phases of radial and angular cylindrical vector beams according to the present invention.

According to the light path structure of the independent phase control device of the radial and angular column vector beams, the specific implementation process is as follows:

step S100, 1550nm laser light generated by the first light source 1 passes through the first polarizer 2 and the first polarizer 3 to generate linearly polarized light polarized in the X-axis direction, and then passes through the first polarization transformation element 4 to be converted into a radial cylindrical vector beam;

step S200, 1550nm laser generated by the second light source 5, the second polarizer 6 and the second polarizer 7 generate linearly polarized light polarized in the Y-axis direction, and the linearly polarized light is converted into an angular cylindrical vector light beam by the second polarization conversion element 8;

step S300, the angular column vector light beam is reflected to the beam combiner 10 through the reflector 9, and the beam combiner 10 combines the radial column vector light beam and the angular column vector light beam to obtain a radial and angular mixed column vector light beam;

step S400, the radial and angular mixed column vector beams are focused by the lens 11 and then transmitted to the plasmon super-structure surface 12, the plasmon super-structure surface 12 is respectively subjected to diffraction, and the radial and angular mixed column vector beams are subjected to space separation by the plasmon super-structure surface 12;

step S500, the light intensity detection device 13 detects the radial column vector light beam and the angular column vector light beam emitted by the plasmon surface 12, and realizes independent phase control of the radial column vector light beam and the angular column vector light beam.

Specifically, the principle of independent phase control of the plasmon meta-structure surface 12 on the radial and angular mixed column vector beams specifically includes: the phase manipulation of incident polarized light is realized by utilizing the advantages of the traditional dynamic phase and adjusting the geometric dimension of a unit structure, and meanwhile, due to the polarization nonuniformity of vector light, a rotation angle theta is introduced to the super-atoms at each specific spatial position, so that the independent phase manipulation of radial direction and angular direction is realized. For coaxially transmitted radial and angular cylindrical vector beams, it is in position (x)_i，y_i) The local linear polarization of (a) can be expressed as:

E_u＝[cosθ_i sinθ_i]^T；

E_v＝[-sinθ_i cosθ_i]^T；

where T denotes transposing the matrix, E_uAnd E_vRespectively representing radial and angular cylindrical vector beams in their light fieldsLocal position (x)_i，y_i) A polarization Jones matrix of, and<E_u|E_v>0 denotes that they are orthogonal to each other, θ_i＝arctan(y_i/x_i) And the included angle between the local polarization direction of the cylindrical vector beam and the direction of the x axis is shown, and i represents the local position.

For better illustration, (x, y) and (u, v) are defined as the laboratory coordinates and the hyper-surface unit structure coordinates, respectively, so the jones matrix for the hyper-surface unit structure can be expressed as:

wherein r represents the reflectivity of the structure,andrespectively, representing the response of the super-surface unit structure to linearly polarized reflected light in the u-axis and v-axis.

When E is_uAnd E_vWhen incident simultaneously on a super-surface, the reflected light can be expressed as:

as can be seen from the above formula, for E_uAnd E_vIntroduction of differencesAndcan realize the pair E_uAnd E_vIndependent phase steering.

In the generation module of the radial and angular mixed column vector light beams, gaussian light is generated by a first light source 1(1550nm laser) and a second light source 5(1550nm laser), and passes through a first polarizer 2 (half-wave plate), a second polarizer 6 (half-wave plate), a first polarizer 3 (Glan prism) and a second polarizer 7 (Glan prism) respectively to generate linearly polarized light in the X direction and the Y direction respectively, two linearly polarized light passes through a first polarization transformation element 4(Q plate) and a second polarization transformation element (Q plate) respectively to generate radial and angular column vector light beams respectively, and after the angular column vector light passes through a reflector 9 (plane reflector), two linearly polarized light passes through a beam combiner to finally be mixed radial and angular column vector light beams.

In the radial and angular hybrid cylinder vector beam spatial separation module, according to the principle that the plasmon meta-structure surface 12 operates the independent phases of the radial and angular hybrid cylinder vector beams, the plasmon meta-structure surface 12 is designed to integrate conjugated gradient grating phases in the radial and angular polarization directions, which are respectively:

where λ represents the wavelength of incident light and α represents the diffraction angle in the x-axis direction.

Thereby realizing the separation of the radial and angular mixed column vector beam space, and simultaneously carrying out the detection in the far-field detection module (light intensity detection device 13).

The invention has the following advantages:

(1) the invention realizes independent phase control of radial and angular column vector beams depending on polarization distribution of incident light, breaks through polarization insensitivity of the traditional optical device, and provides a realization method for limited phase control.

(2) The device designed by the invention has the characteristics of small volume and convenient use, and is expected to be applied to all-optical information processing for realizing high-speed vector optical communication.

In summary, the present invention provides an apparatus and a method for independent phase control of radial and angular column vector beams, wherein the apparatus includes: the device comprises a radial and angular mixed column vector beam generating module, a radial and angular column vector beam space separation device module and a far field detection module; the generation module of the radial and angular mixed column vector beam comprises: a first light source and a second light source for generating a gaussian beam; a first polarizing plate and a second polarizing plate for changing a polarization direction of the Gaussian beam; a first polarizer and a second polarizer for generating linear polarization light by polarization; the first polarization conversion element is used for generating a radial column vector light beam, and the second polarization conversion element is used for generating an angular column vector light beam; a mirror for changing an optical path; the beam combining mirror is used for combining the radial column vector light beam and the angular column vector light beam into one beam; the radial and angular column vector beam space separation device module comprises: a lens for focusing the radial and angular mixed column vector beam; the plasmon super-structure surface is used for carrying out space separation on the radial and angular mixed column vector beams; the far-field detection module comprises: and the light intensity detection device is used for detecting the radial column vector light beams and the angular column vector light beams at different spatial positions. The invention realizes independent phase control of radial and angular column vector beams by endowing each super-atom with a relevant rotation angle at a spatial position, breaks through the polarization insensitivity of the traditional optical device, and has the advantages of small volume and convenient use.

It is to be understood that the invention is not limited to the examples described above, but that modifications and variations may be effected thereto by those of ordinary skill in the art in light of the foregoing description, and that all such modifications and variations are intended to be within the scope of the invention as defined by the appended claims.