CN115903251A - Lossless programmable arbitrary vector light beam generation system and method - Google Patents

Abstract

The invention discloses a lossless programmable arbitrary vector beam generation system and a method, wherein the system comprises a laser, the output laser of the laser sequentially passes through a polaroid, a first half-wave plate, a polarization beam splitter, a unitary transformation space light conversion system, a polarization beam combiner, a quarter-wave plate, a polarization analyzer and a CCD camera, a second half-wave plate is arranged between the polarization beam splitter and the unitary transformation space light conversion system, and a third half-wave plate is arranged between the unitary transformation space light conversion system and the polarization beam combiner; the unitary transformation space optical conversion system consists of a plurality of phase planes and plane reflectors and is used for converting orthogonally polarized common Gaussian mode laser output by the polarization beam splitter into orthogonally polarized Laguerre Gaussian mode laser; the phase planes are connected to a computer, and a phase mask generated by an algorithm run by the computer is displayed on each phase plane.

Description

Lossless programmable arbitrary vector light beam generation system and method

Technical Field

The present invention relates to the field of vector beams, and more particularly, to a system and method for generating lossless, programmable, and highly accurate arbitrary vector beams.

Background

A vector beam refers to a beam with a non-uniform distribution of spatial polarization states. The common vector light beams have radial polarization and azimuth angle polarization vector light beams, and after being focused by a high numerical aperture lens, strong longitudinal electric field components can be generated on a focal plane of the radial polarization vector light beams to form a focus which is clearer than that of a uniform polarization light beam; and the light intensity on the axis is always zero after the azimuth angle polarization vector light beam is focused, and hollow light field distribution is generated on a focal plane. Due to the special optical properties, the vector beam has wide application in spectroscopy, high-resolution imaging and optical capture. Many methods have been proposed to generate arbitrary vector beams, which can be divided into extra-cavity and intra-cavity generation. The extra-cavity generation method generally generates an arbitrary vector beam by controlling the degree of freedom of polarization using a spatial light modulator or a polarization converter based on liquid crystal; the intracavity method enables a laser to emit a desired vector beam by controlling the structure of a laser resonator. These existing methods generally face the challenges of high loss, low conversion efficiency, and inflexible experimental protocols. In the invention, a lossless, efficient and more flexible generation mode of any vector beam is provided.

Fig. 1 shows a prior art arrangement for generating an arbitrary vector beam in a cavity, see document 1. This device mainly realizes the generation of arbitrary vector light beams by inserting optical elements such as a Quarter Wave Plate (QWP) and a q-plate (QP) in a standard FP cavity, wherein the QWP is used for changing the polarization state of light; QP is an optical phase element that can map polarization control to Orbital Angular Momentum (OAM) control: a left (right) handed circularly polarized gaussian beam with spiral charge number l =0 can be converted into a right (left) handed OAM beam with spiral charge number l = ± q, which is related to the polarization state of the original light, by passing through QP. YAG laser emits horizontal polarization Gaussian beam and is converted into left-handed circular polarization Gaussian beam after passing through quarter wave plate with 45 degrees to axis, QP converts the left-handed circular polarization Gaussian beam into OAM beam with right-handed circular polarization and spiral charge l =1, reflection on a mirror placed with 45 degrees to the optical axis can reverse polarization state and spiral charge number to generate OAM beam with left-handed circular polarization and spiral charge l = -1, and superposition of two OAM beams with opposite polarization states and opposite spiral charge number can generate vector beam with uneven polarization distribution, so that any vector beam can be generated by controlling relative angle between QWP and QP. This technique enables the generation of arbitrary vector beams within the laser cavity by varying the relative angle between the QWP and the QP. However, the generation of a specific vector beam by this device requires precise setting of the rotation angles of the QWP and QP, and if a plurality of vector beams are to be generated, the rotation angles of the QWP and QP need to be manually adjusted one by one, which makes this solution inflexible in generating a plurality of loss beams. In addition, the QP surface is comprised of a series of uneven phase elements, which are more complex to manufacture.

Fig. 2 shows a prior art device for generating an arbitrary vector beam outside a cavity, see document [2]. The laser emits x-direction linear polarized light, the beam is expanded by a rotary beam expander and then is converted into an HG mode by a transmission type spatial light modulator, and a 4-time focal length (4-f) system consisting of a pair of same lenses (L1 and L2) with f focal lengths is placed behind the spatial light modulator. A Holographic Grating (HG) on the spatial light modulator can diffract the incident beam into different orders, with only the ± 1 st order diffracted beams being allowed to pass through a spatial filter F located on the fourier plane of the 4-F system, after which the ± 1 st order diffracted light is converted into left and right circularly polarized light, respectively. These two beams recombine on the phase grating G placed at the back focal plane of L2 to generate a vector beam. The technology can generate two Hermite Gaussian (HG) modes with opposite polarization directions and opposite spiral charges by setting the mode pattern of the holographic grating on the SLM through a computer, and the two HG modes are superposed to generate any vector beam, so that the experimental scheme is flexible. However, in this device, the spatial light modulator has non-negligible diffraction loss, the grating G has only 40% diffraction efficiency for the first order diffracted light, and the period mismatch between the SLM generated HG mode and the grating G causes some loss, so this technique has large loss and low mode conversion efficiency.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and solve the technical problems of large loss, low mode conversion efficiency, non-programmable property, inflexible experimental scheme and the like in the conventional device for generating any vector beam. A lossless programmable arbitrary vector beam generation system and method are provided.

The purpose of the invention is realized by the following technical scheme:

a lossless programmable arbitrary vector beam generation system comprises a laser, wherein output laser of the laser sequentially passes through a polarizing plate, a first half-wave plate, a polarization beam splitter, a unitary transformation space optical conversion system, a polarization beam combiner, a quarter-wave plate, a polarization analyzer and a CCD camera, a second half-wave plate is further arranged between the polarization beam splitter and the unitary transformation space optical conversion system, and a third half-wave plate is further arranged between the unitary transformation space optical conversion system and the polarization beam combiner; the unitary transformation space light conversion system consists of a plurality of phase planes and plane reflectors, and is used for converting orthogonally polarized common Gaussian mode laser output by the polarization beam splitter into orthogonally polarized Laguerre Gaussian mode laser; the phase planes are connected to a computer, and a phase mask generated by an algorithm run by the computer is displayed on each phase plane.

Furthermore, the phase plane is divided into an upper part and a lower part, and mode conversion is respectively carried out on the polarized light in the X direction and the polarized light in the Y direction.

Further, the phase mask is obtained by a wave front matching algorithm, and in the unitary transformation space optical conversion system, all the forward propagation input fields and the backward propagation output fields are moved forward to the next plane together or moved backward to the previous plane together by the wave front matching algorithm, and iteration is performed until the error is minimized.

The invention also provides a lossless programmable arbitrary vector beam generation method, wherein a laser emits a linear Gaussian mode laser, and the linear Gaussian mode laser is changed into the arbitrary linear Gaussian mode laser by using the polaroid and the first half-wave plate;

the linear polarization Gaussian mode laser is transmitted to the polarization beam splitter and is divided into vertical and horizontal polarization linear polarization Gaussian mode laser, and the horizontal polarization Gaussian mode laser is changed into a vertical polarization direction which can be modulated by a phase plane through a second half-wave plate; then the two vertical line-biased Laguerre mode lasers respectively enter an upper part and a lower part on a phase plane and are converted into two vertical line-biased Laguerre mode lasers through modes, the two vertical line-biased Laguerre mode lasers have controllable relative phases, one vertical line-biased Laguerre mode laser is converted into a horizontal line-biased Laguerre mode laser through a third half-wave plate to obtain two orthogonal line-biased Laguerre mode lasers, vector beams are generated by superposition on a polarization beam combiner, and then horizontal and vertical line polarization components in the synthesized vector beams are respectively converted into left circular and right circular polarization components through a quarter-wave plate; and finally, detecting the generated vector light beam by a polarization analyzer and a CCD camera.

Compared with the prior art, the technical scheme of the invention has the following beneficial effects:

1. the invention mainly utilizes a unitary transformation space optical conversion system, and can carry out lossless and high-accuracy arbitrary space mode conversion. The unitary transformation space optical conversion system consists of a phase plane and a plane mirror, realizes space phase transformation by a series of transverse phase masks separated by Fourier transformation on the phase plane, and can perform arbitrary space transformation between orthogonal input and output mode bases of space modes. The invention adopts a space diversity mode to divide a phase plane in a unitary transformation space optical conversion system into an upper part and a lower part which respectively correspond to polarization in x and y directions. The two parts can convert the orthogonal polarization common Gaussian mode generated after passing through the polarization beam splitter into any orthogonal polarization Laguerre Gaussian (LG) mode, and enable the same to have relative phases, the two orthogonal polarization Laguerre Gaussian modes are respectively changed into the Laguerre Gaussian modes of left-handed and right-handed circular polarization through the quarter-wave plate, and the Laguerre Gaussian modes of the left-handed and right-handed circular polarization with the relative phases are superposed to generate any vector light beam. This mode transformation process is a transformation from one mode base (normal gaussian mode with orthogonal polarization) to another mode base (laguerre gaussian mode with orthogonal polarization), and thus can be regarded as a spatial unitary transformation, and although the spatial characteristics of the optical field are changed, the spatial light transformation system of the unitary transformation does not increase or decrease the energy, and thus has no inherent energy loss.

2. The invention mainly utilizes a unitary transformation space light conversion system, a half wave plate and a quarter wave plate, can convert common orthogonal linear bias Gaussian beams into left and right hand circularly polarized Laguerre Gaussian modes without loss and with high efficiency, realizes the conversion of orthogonal polarization modes, brings controllable relative phases on the orthogonal polarization modes, and can generate any vector beams by overlapping the orthogonal polarization Laguerre Gaussian modes with the relative phases.

3. The phase mask on the phase plane in the unitary transformation space optical conversion system has programmable property. Firstly, respectively setting target modes for polarization diversity phase planes, running MATLAB codes, and acquiring phase mask information on the phase planes through a wavefront matching algorithm, so that common Gaussian beams can be converted into target Laguerre Gaussian modes. The adjustment method is more flexible compared with the traditional q-plate.

4. The unitary transformation space optical conversion system provided by the invention allows to execute the lossless transformation of an arbitrary space mode. It operates as a discrete fourier transform with a continuous transverse phase mask separated by free space propagation, thereby enabling the generation of an arbitrary set of orthogonal spatial modes. This system has a higher conversion efficiency and higher accuracy of mode conversion than a spatial light modulator with only one phase plane.

Drawings

Fig. 1 is a prior art apparatus for generating an arbitrary vector beam within a chamber.

Fig. 2 is a prior art arrangement for generating an arbitrary vector beam outside a cavity.

FIG. 3 is a schematic diagram of the structure of an arbitrary vector beam generating system of the present invention.

FIG. 4 is a schematic diagram of a discretized phase mask on a phase plane for mode conversion in accordance with the present invention.

FIG. 5 is a schematic diagram of four specific first-order linear polarization vector LG light beams generated by the superposition method according to the present invention.

Fig. 6a to 6d are schematic diagrams illustrating experimental simulation results of four specific first-order linearly polarized vector LG light beams according to the present invention. Fig. 6a is an experimental simulation result of a radially polarized LG01 beam, fig. 6b is an experimental simulation result of an azimuthally polarized LG01 beam, fig. 6c is an experimental simulation result of an anti-vortex LG01 beam, and fig. 6d is an experimental simulation result of an anti-vortex LG01 beam rotated by 45 ° clockwise with respect to the anti-vortex LG01 beam in fig. 6 c.

FIGS. 7a and 7b are schematic diagrams of experimental simulation results of two high-order radial polarization vector beams (LG 11, LG 21) respectively by the method of the present invention.

Detailed Description

The invention is described in further detail below with reference to the figures and specific 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.

Fig. 3 shows that the system for generating a lossless programmable arbitrary vector light beam provided by this embodiment includes a laser 1, an output laser of the laser 1 sequentially passes through a polarizer 2, a half-wave plate 3, a polarization beam splitter 4, a unitary transformation spatial light conversion system 6, a polarization beam combiner 8, a quarter-wave plate 9, a polarization analyzer 10 and a CCD camera 11, a half-wave plate 5 is further disposed between the polarization beam splitter 4 and the unitary transformation spatial light conversion system 6, and a half-wave plate 7 is further disposed between the unitary transformation spatial light conversion system 6 and the polarization beam combiner 8; the unitary transformation space light conversion system consists of a plurality of phase planes 601 and a plane mirror 602, and the unitary transformation space light conversion system 6 is used for converting the orthogonally polarized common Gaussian mode laser output by the polarization beam splitter 4 into orthogonally polarized Laguerre Gaussian mode laser; the phase planes 601 are connected to a computer, and a phase mask generated by an algorithm run by the computer is displayed on each phase plane 601.

In particular, lossless conversion for any desired spatial mode between the input and output planes can be achieved by a series of transverse phase masks separated by an optical fourier transform. The unitary transform spatial light transform system 6 in this embodiment allows to perform lossless transform of arbitrary spatial modes and is composed of a series of phase planes 601, each of which shows a phase mask generated by an algorithm, and a plane mirror 602. The unitary transformation space optical conversion system operates as a discrete Fourier transform through continuous transverse phase masks separated by free space propagation, thereby realizing the generation of an arbitrary set of orthogonal space modes.

For a given mode conversion, the phase mask on the phase plane in unitary transform spatial light conversion systems can be obtained by wavefront matching algorithm (WFM), see document [3]. As shown in fig. 4, the wavefront matching algorithm is implemented by a forward input field and a backward output field in the unitary transform space optical transform system, and the only implementation method for one input to excite one corresponding output is that the phases of the forward input field fi and the backward output field bi are completely matched on each spatial coordinate. When the phases of the input and output fields do not match, the phase error at each spatial coordinate can be calculated and corrected at the phase plane corresponding to each spatial position coordinate, which is the phase mask optimization process. In a unitary transform spatial light conversion system, the wavefront matching algorithm moves all fi and bi forward to the next plane together or backward to the previous plane together and iterates until the error is minimized.

Phase error applied to each plane _k (x, y) can be calculated from the field overlap matrix in the k-th plane:

overlap integral matrix O _k With the term O _kij The degree of coupling of each input and output mode can be quantified:

O _kij (z)＝∫∫o _kij (x,y)dxdy

in order to achieve the maximum mode conversion efficiency in a unitary transform spatial light conversion system, it is necessary to minimize the Mode Dependent Loss (MDL) and the Insertion Loss (IL) of the system and determine the optimal phase mask profile. MDL is defined as the matrix O _k IL is the mean of the squares of the singular values. Since the phase mask and free space propagation are lossless transformations, O _kij (z) the magnitude remains constant with z; however, the spatial profile of okij (x, y) may be very different at each z, which means that local phase optimization can minimize global errors. The phase optimization technique finds the best phase mask profile by taking a weighted average of all field overlaps.

Wherein

Is O _kii Average phase of (1), O _kii An overlap matrix representing a forward propagating input field fi and a backward propagating output field bi; o is _kij An overlap matrix representing a forward propagation input field fi and a backward propagation output field bj; once phase mask phi on kth plane _k (x, y) are updated, fi and bi propagate forward or backward together to the next plane through the unitary transform spatial light conversion system, convergence is achieved by continuously forcing phase matching in each iteration step, and finally the phase mask profile on the phase plane in the unitary transform spatial light conversion system is determined.

In order to realize the generation of any vector light beam, the unitary transformation space optical conversion system of the polarization diversity provided by the invention respectively generates corresponding phase mask outlines on phase planes in two polarization directions by utilizing a wave front matching algorithm according to specific mode conversion, and realizes the mode transformation in the two polarization directions by utilizing the generated phase masks.

The principle of converting the orthogonal polarization common gaussian mode output by the polarization beam splitter into the orthogonal polarization laguerre gaussian mode by using the polarization diversity unitary transformation space optical conversion system is as follows:

for the sake of simplicity of description, the laguerre gaussian mode laser will be hereinafter simply referred to as LG mode laser.

The phase plane in the unitary transformation space optical conversion system is divided into an upper part and a lower part, and mode conversion is respectively carried out on polarized light in the x direction and the y direction. According to the method for generating any vector beam by superposing the LG mode lasers, in order to generate a target vector beam, firstly, the LG mode lasers to be superposed, namely target output modes in two directions are set respectively, and the input in the two directions is line offset coherent common Gaussian mode lasers. For the given mode conversion, MATLAB codes are operated to respectively obtain an upper group of phase masks and a lower group of phase masks, and then the information of the upper group of phase masks and the information of the lower group of phase masks are respectively led into x-direction phase plates and y-direction phase plates in a unitary transformation optical conversion system; common linearly polarized gaussian mode laser light emitted by the laser is converted into vertical and horizontal linearly polarized mode laser light through the polarization beam splitter, and as the phase plane in the embodiment can only perform mode conversion aiming at vertical linearly polarized light, the horizontal polarized light firstly passes through the half-wave plate in front of the phase plane, rotates the horizontal polarization to the vertical polarization state, and then respectively irradiates the horizontal polarization and the vertical polarization to the upper part and the lower part of the unitary transformation space light conversion system. At this time, the phase mask on the polarization diversity phase plane can convert the two vertical line biased ordinary Gaussian mode lasers into two vertical line biased LG mode lasers with controllable relative phases, wherein one vertical line biased LG mode laser is converted into a horizontal line biased LG mode laser through a half-wave plate; the polarization beam combiner recombines the two vertically and horizontally polarized LG mode lasers into a single beam, maintaining their respective horizontal and vertical polarization states, thereby forming a vector beam with a non-uniform spatial polarization distribution. To create a special class of linearly polarized vector beams (i.e. linearly polarized at each local location, but with the direction of linear polarization varying with spatial location), a quarter-wave plate is placed after the polarization beam combiner. The method converts horizontal and vertical linear polarization components in the synthesized vector light beam into left and right circular polarization components respectively, so that special linear polarization vector light beams can be generated by a superposition method.

In theory, coherent superposition of orthogonal modes can produce an arbitrary amount of lost light beam, see document [4]. Specifically, in this embodiment, an LG superposition method of left-handed and right-handed circular polarization is adopted, and an arbitrary vector beam is generated by superposing two left-handed and right-handed circular polarization LG mode lasers with relative phases. FIG. 5 is a theoretical schematic diagram of the superposition of two left-and right-handed circularly polarized LG modes to generate four types of special first-order linearly polarized vector light beams. The first row represents the coherent superposition of the left-handed circularly polarized LG01 mode laser and the right-handed circularly polarized LG0-1 mode laser with the relative phase of 0 (namely the corresponding electric field amplitude reaches the corresponding maximum value and minimum value at the same time), and the superposition generates a vector LG01 light beam with radial polarization; in the second row, LG0-1 mode lasers have a phase shift pi and are superposed to generate an azimuth-polarized vector LG01 beam; the third row shows the coherent superposition of the left-handed circular polarization LG0-1 mode laser and the right-handed circular polarization LG01 mode laser with the relative phase of 0 (namely the corresponding electric field amplitude reaches the corresponding maximum value and minimum value at the same time), so as to generate an anti-vortex vector LG01 light beam; the LG0-1 mode lasers in the last row have a phase shift of π, and the superposition still produces an anti-vortex vector LG01 beam, but rotated 45 degrees with respect to the result in the third row. More complex higher order vector beams can also be obtained by superposition of higher order orthogonal LG modes.

Specifically, the method for generating an arbitrary vector light beam based on the light beam generation system includes the following steps:

the laser 1 emits a linear polarization basic Gaussian mode laser, and can be changed into any linear polarization Gaussian mode laser by utilizing the polarizing film 2 and the half-wave plate 3;

then, the linear partially gaussian mode laser light propagates to a polarization beam splitter 4 and is divided into vertically and horizontally polarized linear partially gaussian mode laser light, wherein the horizontal linear partially gaussian mode laser light is changed into the linear partially gaussian mode laser light in the vertical polarization direction that can be modulated by the phase plane through a half-wave plate 5. Then, the two vertical line partially Gaussian mode lasers are respectively incident to an upper part and a lower part on the polarization diversity phase plane 601, the two vertical line partially Gaussian mode lasers are respectively changed into vertical line partially Laguerre Gaussian mode lasers through mode conversion, the lasers have controllable relative phases, one vertical line partially Laguerre Gaussian mode laser is changed into a horizontal line partially Laguerre Gaussian mode laser through a half-wave plate 7, and therefore conversion of an orthogonal mode is achieved through the unitary conversion optical conversion system 6;

then the two orthogonal linear polarization Laguerre mode lasers are superposed on a polarization beam combiner 8 to generate vector beams, and horizontal and vertical linear polarization components in the synthesized vector beams are converted into left circular and right circular polarization components respectively by utilizing a quarter-wave plate 9; finally, the generated vector light beam is detected by a polarization analyzer 10 and a CCD camera 11.

The experimental simulation results of the present invention for four specific first-order linearly polarized vector LG mode beams and two high-order vector beams are shown in fig. 6a to 7 b. The unitary transformation optical conversion system can realize lossless transformation of an orthogonal mode, and the phase mask on the phase plane has the programmable characteristic.

Finally, it should be pointed out that: the above examples are merely illustrative of the computational process of the present invention and are not limiting thereof. Although the present invention has been described in detail with reference to the foregoing examples, those skilled in the art will appreciate that the computing processes described in the foregoing examples can be modified or equivalent substituted for some of the parameters without departing from the spirit and scope of the computing method.

The present invention is not limited to the above-described embodiments. The foregoing description of the specific embodiments is intended to describe and illustrate the technical solutions of the present invention, and the above specific embodiments are merely illustrative and not restrictive. Those skilled in the art can make many changes and modifications to the invention without departing from the spirit and scope of the invention as defined in the appended claims.

Reference documents:

[1]Naidoo，Darryl，et al."Controlled generation of higher-order Poincarésphere beams from a laser."Nature Photonics 10.5(2016):327-332.

[2]Xi-Lin，et al."Generation of arbitrary vector beams with a spatial light modulator and a common path interferometric arrangement."Optics letters 32.24(2007):3549-51.

[3]Sakamaki，Y.，et al."New Optical Waveguide Design Based on Wavefront Matching Method."Journal of Lightwave Technology 25.11(2007):3511-3518.

[4]Shizhen，et al."Generation of arbitrary cylindrical vector beams on the higher order Poincarésphere."Optics Letters(2014)。

Claims (4)

1. a lossless programmable arbitrary vector beam generation system comprises a laser, and is characterized in that output laser of the laser sequentially passes through a polarizing plate, a first half-wave plate, a polarization beam splitter, a unitary transformation space light conversion system, a polarization beam combiner, a quarter-wave plate, a polarization analyzer and a CCD camera, a second half-wave plate is further arranged between the polarization beam splitter and the unitary transformation space light conversion system, and a third half-wave plate is further arranged between the unitary transformation space light conversion system and the polarization beam combiner; the unitary transformation space light conversion system consists of a plurality of phase planes and plane reflectors, and is used for converting orthogonally polarized common Gaussian mode laser output by the polarization beam splitter into orthogonally polarized Laguerre Gaussian mode laser; the phase planes are connected to a computer, and a phase mask generated by an algorithm run by the computer is displayed on each phase plane.

2. The system of claim 1, wherein the phase plane is divided into an upper portion and a lower portion, and the mode conversion is performed on the polarized light in the X and Y directions.

3. A lossless and programmable arbitrary vector beam generation system as claimed in claim 1, wherein the phase mask is obtained by a wave front matching algorithm, and all the forward propagating input field and backward propagating output field are moved forward to the next plane together or moved backward to the previous plane together by the wave front matching algorithm in the unitary transform spatial light transform system, and iterated until the error is minimized.

4. A lossless programmable arbitrary vector beam generation method is based on any beam generation system of claims 1-3, and is characterized in that a laser emits a linear partial Gaussian mode laser, and the linear partial Gaussian mode laser is changed into an arbitrary linear partial Gaussian mode laser by using a polarizing plate and a first half wave plate;

the linear polarization Gaussian mode laser is transmitted to the polarization beam splitter and is divided into vertical and horizontal polarization linear polarization Gaussian mode laser, and the horizontal linear polarization Gaussian mode laser is changed into a vertical polarization direction which can be modulated by a phase plane through a second half-wave plate; then the two vertical line-biased Laguerre mode lasers respectively enter an upper part and a lower part on a phase plane and are converted into two vertical line-biased Laguerre mode lasers through modes, the two vertical line-biased Laguerre mode lasers have controllable relative phases, one vertical line-biased Laguerre mode laser is converted into a horizontal line-biased Laguerre mode laser through a third half-wave plate to obtain two orthogonal line-biased Laguerre mode lasers, vector beams are generated by superposition on a polarization beam combiner, and then horizontal and vertical line polarization components in the synthesized vector beams are respectively converted into left circular and right circular polarization components through a quarter-wave plate; and finally, detecting the generated vector light beam by a polarization analyzer and a CCD camera.

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