A cosine-Gaussian radial polarization beam generating device

Abstract

The present invention discloses a cosine-Gaussian radial polarization beam generating device, which relates to the field of vector light field control. The laser passes through a beam expansion and collimation system, a polarizer, and the first polarization beam splitter in sequence to obtain a first linear polarization component and a second linear polarization component; the first reflector is arranged in the first 4f system; the first linear polarization component is sequentially input into a first spatial light modulator and a first 4f system; the second reflector is arranged in the second 4f system; the second linear polarization component is sequentially input into a second spatial light modulator and a second 4f system; holograms are loaded on both the first spatial light modulator and the second spatial light modulator; the light output from the first 4f system and the light output from the second 4f system are both input into a second polarization beam splitter to obtain a column vector beam; the column vector beam is input into the polarization converter to obtain a cosine-Gaussian radial polarization beam. The present invention can generate a cosine-Gaussian radial polarization beam with any number of periods.

Description

Technical Field

[0001] The invention relates to the field of vector light field regulation, and in particular to a cosine-Gaussian radially polarized light beam generating device. Background Art

[0002] Light is the main carrier of information transmission. Polarization is a basic property of light. The degree of freedom it provides plays an increasingly important role in the application of light field control in the field of information photonics. Vector beams whose polarization states depend on spatial distribution are a classic structured beam. Studies have shown that vector beams have unique properties and novel optical characteristics that are different from scalar light fields, and are widely used in many research fields of light-matter interaction.

[0003] At present, the methods for generating arbitrary vector beams can be mainly divided into two types: active and passive. The active method is to place optical devices such as birefringence and conical prisms in the cavity to generate vector beams; the passive method mainly obtains linearly polarized light through mode superposition or the use of polarization conversion elements. Radially polarized beams are a typical vector beam. After being focused by a high numerical aperture lens, they have a strong longitudinal field component and form a focus that is smaller than the focusing spot size of the scalar light field. This feature is widely used in super-resolution imaging, particle acceleration, surface plasmon excitation, particle capture, and optical micromanipulation. Therefore, studying new vector beams will bring more novel focusing characteristics and further enrich the research methods of the interaction between light and matter.

[0004] At present, people can use digital wavefront shaping devices to quantitatively control the polarization state of vector beams in a diversified and flexible manner, but the generation of traditional vector light fields is mainly aimed at local vector beams with cylindrical symmetry. In recent years, people have proposed many new vector beams with complex polarization state distribution by using the rich and adjustable degrees of freedom in vector light fields. For example, hybrid polarization vector beams with radial changes in the handedness of linear polarization, circular polarization and elliptical polarization in the cylindrical coordinate system, full Poincare spheres based on the superposition of fundamental mode Gaussian light and Laguerre Gaussian light with orthogonal polarization, vector beams on high-order Poincare spheres, vector beams on hybrid-order Poincare spheres and generalized Poincare spheres, array vector beams, multi-singularity vector beams, other non-cylindrical symmetric vector beams and new vector beams on the focal plane, etc. The proposal and generation of these new vector beams further provide new degrees of freedom for light field control and enrich the types of vector beams.

[0005] However, there is no report on the method and device for generating a new type of cosine-Gaussian radial polarization beam with arbitrarily adjustable period number. This new type of structured beam itself has a spatial structure of multiple spots and beam splitting, which has significant advantages in application fields such as optical micromachining of multiple holes, optical micromanipulation of multiple particles, and multi-focus scanning microscopy. Summary of the invention

[0006] The object of the present invention is to provide a cosine-Gaussian radial polarized light beam generating device, which can generate a cosine-Gaussian radial polarized light beam with any period number.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] A cosine-Gaussian radial polarized light beam generating device comprises: a beam expansion and collimation system, a polarizer, a Mach-Zehnder interference system, a first spatial light modulator, a second spatial light modulator, a first 4f system, a second 4f system and a polarization converter; the Mach-Zehnder interference system comprises a first polarization beam splitter, a second polarization beam splitter, a first reflector and a second reflector;

[0009] The laser passes through a beam expansion and collimation system, a polarizer, and the first polarization beam splitter in sequence to obtain a first linear polarization component and a second linear polarization component; the first reflector is arranged in the first 4f system; the first linear polarization component is sequentially input into a first spatial light modulator and a first 4f system; the second reflector is arranged in the second 4f system; the second linear polarization component is sequentially input into a second spatial light modulator and a second 4f system; holograms are loaded on both the first spatial light modulator and the second spatial light modulator; the light output from the first 4f system and the light output from the second 4f system are both input into a second polarization beam splitter to obtain a cylindrical vector beam; the cylindrical vector beam is input into the polarization converter to obtain a cosine-Gaussian radially polarized beam.

[0010] Optionally, the beam expansion and collimation system includes a pinhole filter and a collimating lens;

[0011] The laser light is sequentially input into the pinhole filter and the collimating lens.

[0012] Optionally, the first 4f system includes a first lens and a second lens;

[0013] The first spatial light modulator is arranged on the front focal plane of the first lens; the first reflector is arranged between the first lens and the second lens; and the light passing through the first spatial light modulator is sequentially input into the first lens, the first reflector and the second lens.

[0014] Optionally, the cosine-Gaussian radial polarization light beam generating device further includes a first filter screen; the first filter screen is arranged between the first reflector and the second lens.

[0015] Optionally, the second 4f system includes a third lens and a fourth lens;

[0016] The second spatial light modulator is arranged on the front focal plane of the third lens; the second reflector is arranged between the third lens and the fourth lens; and the light passing through the second spatial light modulator is sequentially input into the third lens, the second reflector and the fourth lens.

[0017] Optionally, the cosine-Gaussian radial polarization light beam generating device further includes a second filter screen; the second filter screen is arranged between the second reflector and the fourth lens.

[0018] Optionally, the cosine-Gaussian radially polarized light beam generating device further includes a first half-wave plate and a second half-wave plate;

[0019] The first half wave plate is arranged between the first 4f system and the second polarization beam splitter;

[0020] The second bifurcated straight wave plate is arranged between the second 4f system and the second polarization beam splitter.

[0021] Optionally, the cosine-Gaussian radial polarization beam generating device further includes an image sensor;

[0022] The image sensor is disposed on the output light beam of the polarization converter.

[0023] Optionally, the hologram loaded on the first spatial light modulator is a first linear polarization component calculated according to a modified off-axis interference hologram encoding method; the hologram loaded on the second spatial light modulator is a second linear polarization component calculated according to a modified off-axis interference hologram encoding method.

[0024] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0025] The cosine-Gaussian radial polarization beam generating device provided by the present invention, the laser passes through the beam expansion and collimation system, the polarizer and the first polarization beam splitter in sequence to obtain the first linear polarization component and the second linear polarization component; the first linear polarization component is sequentially input into the first spatial light modulator and the first 4f system; the second linear polarization component is sequentially input into the second spatial light modulator and the second 4f system; the first spatial light modulator and the second spatial light modulator are both loaded with holograms; the light output from the first 4f system and the light output from the second 4f system are both input into the second polarization beam splitter to obtain a column vector beam; the column vector beam is input into the polarization converter to obtain a cosine-Gaussian radial polarization beam. By introducing two spatial light modulators and a 4f system in a Mach-Zehnder interference system, a hologram is loaded on the spatial light modulator, so that the required column vector beam is obtained on the output surface of the 4f system, and the column vector beam passes through the polarization converter to generate a chord-Gaussian radial polarization beam with any number of periods. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 A schematic diagram of a cosine-Gaussian radially polarized light beam generating device provided by the present invention;

[0028] Figure 2 For holograms;

[0029] Figure 3 The spatial spectrum diagram of the frequency domain of the computer hologram loaded into the spatial light modulator after the first Fourier transform;

[0030] Figure 4 It is the intensity distribution diagram of cosine-Gaussian radially polarized beam.

[0031] Explanation of symbols:

[0032] Pinhole filter-SF, collimating lens-L1, polarizer-P, first polarization beam splitter-PBS1, second polarization beam splitter-PBS2, first spatial light modulator-SLM1, second spatial light modulator-SLM2, first lens-L2, second lens-L3, third lens-L4, fourth lens-L5, first reflector-M1, second reflector-M2, first filter screen-FA1, second filter screen-FA2, polarization converter-RPC, image sensor-CCD. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] The purpose of the present invention is to provide a cosine-Gaussian radial polarized light beam generating device, which can generate a cosine-Gaussian radial polarized light beam with any period number.

[0035] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] like Figure 1As shown, a cosine-Gaussian radial polarized light beam generating device provided by the present invention comprises: a beam expansion and collimation system, a polarizer P, a Mach-Zehnder interference system, a first spatial light modulator SLM1, a second spatial light modulator SLM2, a first 4f system, a second 4f system and a polarization converter RPC; the Mach-Zehnder interference system comprises a first polarization beam splitter PBS1, a second polarization beam splitter PBS2, a first reflector M1 and a second reflector M2. The polarization converter RPC in the present invention is a radial polarization converter.

[0037] The laser passes through the beam expansion and collimation system, the polarizer P and the first polarization beam splitter PBS1 in sequence to obtain a first linear polarization component and a second linear polarization component; the first reflector M1 is arranged in the first 4f system; the first linear polarization component is sequentially input into the first spatial light modulator SLM1 and the first 4f system; the second reflector M2 is arranged in the second 4f system; the second linear polarization component is sequentially input into the second spatial light modulator SLM2 and the second 4f system; holograms are loaded on the first spatial light modulator SLM1 and the second spatial light modulator SLM2; the light output from the first 4f system and the light output from the second 4f system are both input into the second polarization beam splitter PBS2 to obtain a cylindrical vector beam; the cylindrical vector beam is input into the polarization converter RPC to obtain a cosine-Gaussian radially polarized beam.

[0038] The beam expansion and collimation system includes a pinhole filter SF and a collimating lens L1; the laser is sequentially input into the pinhole filter SF and the collimating lens L1.

[0039] The first 4f system includes a first lens L2 and a second lens L3; the first spatial light modulator SLM1 is arranged on the front focal plane of the first lens L2; ​​the first reflector M1 is arranged between the first lens L2 and the second lens L3; the light passing through the first spatial light modulator SLM1 is sequentially input into the first lens L2, the first reflector M1 and the second lens L3.

[0040] The cosine-Gaussian radial polarized light beam generating device further comprises a first filter screen FA1; the first filter screen FA1 is arranged between the first reflector M1 and the second lens L3.

[0041] The second 4f system includes a third lens L4 and a fourth lens L5; the second spatial light modulator SLM2 is arranged on the front focal plane of the third lens L4; the second reflector M2 is arranged between the third lens L4 and the fourth lens L5; the light passing through the second spatial light modulator SLM2 is sequentially input into the third lens L4, the second reflector M2 and the fourth lens L5.

[0042] The cosine-Gaussian radial polarization beam generating device further includes a second filter screen FA2; the second filter screen FA2 is arranged between the second reflector M2 and the fourth lens L5.

[0043] The cosine-Gaussian radial polarization beam generating device also includes a first half-wave plate and a second half-wave plate; the first half-wave plate is arranged between the first 4f system and the second polarization beam splitter PBS2; the second half-wave plate is arranged between the second 4f system and the second polarization beam splitter PBS2.

[0044] The cosine-Gaussian radially polarized light beam generating device further comprises an image sensor CCD; the image sensor CCD is arranged on the output light beam of the polarization converter RPC.

[0045] The hologram loaded on the first spatial light modulator SLM1 is a first linear polarization component calculated according to the modified off-axis interference hologram encoding method; the hologram loaded on the second spatial light modulator SLM2 is a second linear polarization component calculated according to the modified off-axis interference hologram encoding method.

[0046] A new type of cosine-Gaussian radial polarization beam with an arbitrarily adjustable period number is obtained by using a radial polarization converter RPC through a cylindrical vector beam of arbitrary order; a computer-generated hologram is prepared according to a modified off-axis interferometric computer-generated holographic encoding method, specifically including:

[0047] ① Design of computer-generated hologram: First, theoretically, the arbitrary order cylindrical vector beam to be generated is characterized by two orthogonal polarization linear polarization basis vectors, and the amplitude and phase information of the two orthogonal linear polarization components are calculated respectively; then, the two orthogonal polarization components are encoded using the corrected off-axis computer-generated holographic encoding method.

[0048] ② Prepare a computational hologram corresponding to two orthogonal linear polarization components based on a computer.

[0049] The two prepared computer-generated holograms are respectively loaded onto two spatial light modulators on the front focal plane of the first lens of the 4f system in their respective optical paths. At the same time, a filter aperture is placed on the rear focal plane of the first Fourier lens of the two 4f systems, the diffraction component transmitted along the optical axis is selected, and a second Fourier lens is placed behind the filter aperture to ensure that the filter screen is on the front focal plane of the second Fourier lens; a half-wave plate is placed behind the second Fourier lens to rotate the polarization states of the two light beams by 90 degrees respectively; then a polarization beam splitter is placed close to the two half-wave plates to synthesize the two beams; the synthesized light passes through a radial polarization converter RPC and finally reaches the rear focal plane of the second lens (the CCD surface of the image sensor).

[0050] A collimated Gaussian beam is used to illuminate the system, and the collimating lens L1 is translated a small distance in the direction perpendicular to the optical axis to generate obliquely incident Gaussian light, which is then passed through the polarizer P to generate 45-degree linear polarized light; the 45-degree linear polarized light is decomposed into two vertically vibrating linear polarized components through a polarization beam splitter, and both components are incident on the computer hologram loaded on the spatial light modulator at an oblique angle, so that the light beams passing through the computer hologram are transmitted along the directions of their respective optical axes and enter the 4f systems in their respective optical paths respectively; the light passing through the computer hologram is transformed by the first Fourier lens, and then filtered by the filter aperture and the second Fourier lens, a half-wave plate, and a polarization beam splitter to synthesize a cylindrical vector beam of any order at the output surface of the 4f system, and the first-order diffraction components are respectively selected through a filter screen on the frequency domain surface of the two paths of light, and a cylindrical vector beam of any order is synthesized at the output surface of the 4f system; a radial polarization converter is introduced to obtain a required cosine Gaussian radial polarized beam of any period number at the output surface.

[0051] The collimating lens L1 is slightly offset along the optical axis to produce obliquely incident Gaussian light, and two polarization beam splitters are used to realize the separation and then addition of the light beams; the two computer holograms are set on the front focal plane of the first Fourier lens of the 4f system, and a filter screen is placed on the back focal plane of the first Fourier lens. The light field of the filter screen is Fourier transformed after passing through the second Fourier lens of the 4f system; before synthesizing the two beams, the vibration directions of the two linearly polarized lights are rotated 90 degrees using a half-wave plate, and then synthesized through a polarization beam splitter; after the synthesized light passes through a radial polarization converter, it can generate a required cosine Gaussian radial polarized light beam with any period number on the CCD surface of the image sensor.

[0052] The present invention provides a method for obtaining a cosine-Gaussian radially polarized beam with any period number by using a radial polarization converter through a column vector beam of any order. The radially polarized cosine-Gaussian beam with different period numbers has light spots split twice as many as the period number, and the theoretical results are consistent with the calculation simulation results.

[0053] Combination Figure 1 The main principles of the device provided by the present invention include:

[0054] (1) First, design a traditional cylindrical vector beam. The expression can be expressed as: Here m represents the order of the cylindrical vector beam, is the azimuth, represents a constant phase, and are the unit vectors corresponding to the horizontal and vertical variables in the Cartesian rectangular coordinate system on the x and y axes in the rectangular coordinate system, respectively, and are also called the orthogonal basis vectors of the two linear polarizations.

[0055] (2) Substitute the rectangular coordinates in step (1) and Using polar coordinates and Two unit vectors are used to represent it, where and Represent the unit vectors in the radial direction and angular direction respectively. According to the coordinate transformation relationship, we can get the rectangular coordinate system and The two unit vectors can be expressed as:

[0056]

[0057]

[0058] (3) Substitute the above two equations into the expression in step (1) and use the radial and angular unit vectors and To represent a cylindrical vector beam:

[0059]

[0060] In the formula, n is used to replace m-1, where n represents the number of change cycles of the cosine-Gaussian radial polarized beam in the azimuth direction, and m represents the cylindrical vector beam order.

[0061] (4) When the cylindrical vector beam passes through the radial polarization converter, the angular polarization component cannot pass through the radial polarization converter, and only the radial polarization component can pass through the radial polarization converter. At this time, a cosine-Gaussian radial polarization beam with any number of periods can be obtained.

[0062]

[0063] Here n is the number of change cycles of the cosine-Gaussian radially polarized light beam in the azimuth direction, and cosine modulation with any number of cycles in the azimuth direction can be realized, thereby forming a light spot split in the angular direction.

[0064] (5) According to the theoretical analysis of steps (1)-(4), if we want to generate a radially polarized cosine-Gaussian beam with a specific period number n, we can first define a cylindrical vector beam based on orthogonal linear polarization basis vectors:

[0065]

[0066] After passing through a radial polarization converter, a cosine-Gaussian radial polarized light beam with an adjustable period number can be generated. In the present invention, the order m and the period number n satisfy n=m-1, and the period number n of the cosine-Gaussian radial polarized light beam is regulated by controlling the order m. The order m can be quantitatively controlled by a computer-generated hologram loaded on the spatial light modulator.

[0067] The implementation of the present invention mainly comprises the following steps:

[0068] Step 1: Expand the laser beam and convert its polarization state into 45-degree linear polarized light. Specifically, use the pinhole filter SF and collimating lens L1 to expand the laser beam, and use a polarizer to convert its polarization state into polarized light vibrating at 45 degrees. The light field at this time can be defined as Here E x0 and E y0 They are the complex amplitudes of the two linear polarization components vibrating in the x and y directions respectively.

[0069] Step 2: The 45-degree linearly polarized light is incident on the Mach-Zehnder interferometer system composed of two polarization beam splitters PBS1 and PBS2 and two reflectors M1 and M2. x0 and E y0 The two components travel along optical paths 1 and 2 respectively.

[0070] Step 3: Introduce a 4f imaging system into the two light paths 1 and 2 of the Mach-Zehnder interferometer system respectively, including four lenses L2, L3, L4, and L5, and the focal lengths f of the four lenses are equal.

[0071] Step 4: Place a spatial light modulator SLM1 and SLM2 on the input surface of each 4f imaging system, that is, the front focal plane of the first lens, and load the corresponding CGH. Figure 2 As shown, through Figure 2 Holograms can be generated in Figure 4 (b) shows a radially polarized cosine-Gaussian vector beam with a period number equal to 2. The linear polarization components of the two perpendicular vibrations required are calculated according to the expression of the polarized cosine-Gaussian beam, and a hologram is made; the generated computational hologram is loaded on the spatial light modulator, and the collimating lens is moved in the direction perpendicular to the optical axis so that the first-order diffraction components of the two lights can be transmitted along the optical axis, and then the light passes through the half-wave plate and the polarization beam splitter to obtain a cylindrical vector beam at the output surface.

[0072] The specific encoding method of the CGH loaded into the spatial light modulator in step 5 and step 4 is as follows:

[0073] a. In optical path 1, determine the complex amplitude of the linear polarization basis vector vibrating in the x direction The hologram is produced according to the modified off-axis interference hologram encoding method. The specific encoding method of the x-component hologram is:

[0074]

[0075] Among them, u Ris a plane reference light incident at a small angle, tilted by 0.8 rad along the x direction, where m = 3, and the corresponding x-component CGH is shown in the attached figure. Figure 2 As shown in (a) in . is the complex conjugate of the complex amplitude of the linear polarization basis vector vibrating in the x direction, is the complex conjugate of the plane reference light.

[0076] b. In optical path 2, determine the complex amplitude of the linear polarization basis vector vibrating in the y direction The hologram is produced according to the modified off-axis interference hologram encoding method, as shown in the attached Figure 2 As shown in (b), is the complex conjugate of the complex amplitude of the linear polarization basis vector vibrating in the y direction. The specific encoding method of the y component hologram is:

[0077]

[0078] Step 6: Place a filter screen FA1 and FA2 on the spectrum plane of the 4f system, that is, between the two Fourier lenses, and select the corresponding spectrum. The specific filtering scheme is shown in the attached Figure 3 , the dotted line is the position of the filter hole; the area inside the dotted line corresponds to the spectrum passing through the filter screen, where the double arrows and dots represent the vibration direction of the polarization state of the light incident on the filter screen. Figure 3 (a) is the specific filtering scheme on the filter screen FA1 in optical path 1. Figure 3 (b) in the figure is a specific filtering scheme on the filter screen FA2 surface in the optical path 2.

[0079] Step 7: Move the collimating lens in a direction perpendicular to the optical axis so that the selected spectra in the two light paths 1 and 2 are transmitted along the optical axis.

[0080] Step 8. Introduce a half wave plate between lens L3 and PBS2, and also introduce a half wave plate between lens L5 and PBS2. The two wave plates each rotate the vibration direction of the polarization state of the incident light by 90 degrees to facilitate light combination through PBS2. Figure 1 In the figure, λ / 2 is used to represent a half-wave plate.

[0081] Step 9: Place an image sensor CCD on the output surface of the 4f system. The final cylindrical vector light field can be obtained in the image sensor. The complex amplitudes of the two linear polarization components vibrating in the x and y directions are E x0 and E y0 They have the same amplitude and phase and can be viewed as two equal constant complex coefficients.

[0082] Step 10: A radial polarization converter is introduced between the output surface and PBS2. The cylindrical vector beam passes through the radial polarization converter to obtain a cosine-Gaussian radial polarized beam, as shown in the attached figure. Figure 4 As shown in (b); by regulating the value of m in the two linear polarization components of the vertical vibration, a high-order cylindrical vector beam of any order is generated, and a cosine-Gaussian radial polarized beam of any period number is obtained through a radial polarizer.

[0083] Step 11: Control the order of the column vector beam and re-encode it to generate a cosine-Gaussian radial polarized beam with any period number using this system. Figure 4 (a)-(d) show the light intensity distribution diagrams of radially polarized cosine-Gaussian beams with period numbers of 0, 2, 5, and 8, respectively, calculated based on the present invention. The calculated results are consistent with the theoretical analysis.

[0084] The present invention determines a method for generating a new type of cosine-Gaussian radially polarized beam by using a high-order cylindrical vector beam through a radial polarization converter. The method can realize the generation of a new type of cosine-Gaussian radially polarized beam with an arbitrary number of periods by quantitatively controlling the order of the cylindrical vector beam. Specific implementation: By introducing a spatial light modulator and a 4f system into each of the two paths of light in the Mach-Zehnder interference system, a computational hologram is loaded on the spatial light modulator, and the required cylindrical vector beam can be obtained on the output surface of the 4f system; the cylindrical vector beam then passes through a radial polarization converter to generate a cosine-Gaussian radially polarized beam with an arbitrary number of periods. The present invention can generate a new type of cosine-Gaussian radially polarized beam with an arbitrarily adjustable number of periods, which is conducive to the related applications of structured light in the fields of lithography, optical super-resolution imaging, laser micromachining, and optical micromanipulation.

[0085] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for those of ordinary skill in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and scope of application. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A cosine-Gaussian radial polarization beam generating device, characterized in that: include: A beam expansion and collimation system, a polarizer, a Mach-Zehnder interference system, a first spatial light modulator, a second spatial light modulator, a first 4f system, a second 4f system and a polarization converter; the Mach-Zehnder interference system includes a first polarization beam splitter, a second polarization beam splitter, a first reflector and a second reflector; The laser passes through a beam expansion and collimation system, a polarizer, and the first polarization beam splitter in sequence to obtain a first linear polarization component and a second linear polarization component; the first reflector is arranged in the first 4f system; the first linear polarization component is sequentially input into a first spatial light modulator and a first 4f system; the second reflector is arranged in the second 4f system; the second linear polarization component is sequentially input into a second spatial light modulator and a second 4f system; holograms are loaded on both the first spatial light modulator and the second spatial light modulator; the light output from the first 4f system and the light output from the second 4f system are both input into a second polarization beam splitter to obtain a cylindrical vector beam; the cylindrical vector beam is input into the polarization converter to obtain a cosine-Gaussian radially polarized beam; The principle of the cosine-Gaussian radial polarization beam generating device is: Design the cylindrical vector beam, the cylindrical vector beam The expression is expressed as: Where m represents the order of the cylindrical vector beam, is the azimuth, represents a constant phase, and are the unit vectors corresponding to the horizontal and vertical variables in the Cartesian coordinate system on the x and y axes, respectively; The unit vectors corresponding to the horizontal and vertical variables in the Cartesian coordinate system and Using polar coordinates and Two unit vectors are used to represent and Represent the unit vectors in the radial direction and angular direction respectively. According to the coordinate transformation relationship, the rectangular coordinate system is obtained. and The two unit vectors are represented as: The polar coordinate system will be used and Two unit vectors are used to represent the rectangular coordinate system and Two unit vectors are introduced into the cylindrical vector beam In the expression of and To represent a cylindrical vector beam: In the formula, n is used to replace m-1, where n represents the number of cycles of change in the azimuth direction of the cosine-Gaussian radially polarized beam; When the cylindrical vector beam passes through the radial polarization converter, the angular polarization component cannot pass through the radial polarization converter, and only the radial polarization component can pass through the radial polarization converter. At this time, a cosine-Gaussian radial polarization beam with any number of periods is obtained. The order m of the column vector beam and the number of change periods n in the azimuthal direction of the cosine-Gaussian radial polarized beam satisfy n=m-1. The number of change periods n in the azimuthal direction of the cosine-Gaussian radial polarized beam is regulated by controlling the order m of the column vector beam. The order m of the column vector beam is quantitatively controlled by a hologram loaded onto the first spatial light modulator and the second spatial light modulator.

2. The cosine-Gaussian radial polarization beam generating device according to claim 1, characterized in that: The beam expansion and collimation system includes a pinhole filter and a collimating lens; The laser light is sequentially input into the pinhole filter and the collimating lens.

3. The cosine-Gaussian radial polarization beam generating device according to claim 1, characterized in that: The first 4f system includes a first lens and a second lens; The first spatial light modulator is arranged on the front focal plane of the first lens; the first reflector is arranged between the first lens and the second lens; and the light passing through the first spatial light modulator is sequentially input into the first lens, the first reflector and the second lens.

4. The cosine-Gaussian radial polarization beam generating device according to claim 3, characterized in that: It also includes a first filter screen; the first filter screen is arranged between the first reflector and the second lens.

5. The cosine-Gaussian radial polarization beam generating device according to claim 1, characterized in that: The second 4f system includes a third lens and a fourth lens; The second spatial light modulator is arranged on the front focal plane of the third lens; the second reflector is arranged between the third lens and the fourth lens; and the light passing through the second spatial light modulator is sequentially input into the third lens, the second reflector and the fourth lens.

6. The cosine-Gaussian radial polarization beam generating device according to claim 5, characterized in that: It also includes a second filter screen; the second filter screen is arranged between the second reflector and the fourth lens.

7. The cosine-Gaussian radial polarization beam generating device according to claim 1, characterized in that: Also included is a first half wave plate and a second half wave plate; The first half wave plate is arranged between the first 4f system and the second polarization beam splitter; The second bifurcated straight wave plate is arranged between the second 4f system and the second polarization beam splitter.

8. The cosine-Gaussian radial polarization beam generating device according to claim 1, characterized in that: Also included is an image sensor; The image sensor is disposed on the output light beam of the polarization converter.

9. The cosine-Gaussian radial polarization beam generating device according to claim 1, characterized in that: The hologram loaded on the first spatial light modulator is a first linear polarization component calculated according to the modified off-axis interference hologram encoding method; the hologram loaded on the second spatial light modulator is a second linear polarization component calculated according to the modified off-axis interference hologram encoding method.

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