Arbitrary polarization state generation method, arbitrary polarization state generator and application of arbitrary polarization state generator

Abstract

The invention discloses an arbitrary polarization state generation method, an arbitrary polarization state generator and application thereof, and solves the problems that an existing polarization calibration system lacks a polarization target construction method, so that polarized light generated after a polarized light source passes through a polaroid or a 1 / 4 wave plate through a laser light source is fully polarized light, partial polarized light cannot be generated, and the polarization calibration precision is poor. And polarized light with a rated polarization share cannot be generated according to design requirements. The diaphragm A and the attenuation slice A are sequentially arranged along a light path where a light beam A is located, and the diaphragm B, the polaroid, the 1 / 4 wave plate, the attenuation slice B and the concave reflector are sequentially arranged along a light path where a light beam B is located. The reflecting surface of the concave reflecting mirror is arranged at the intersection of the light paths of the light beam A and the light beam B, and is used for converging the two light beams, converting the two light beams into parallel light and emitting the parallel light; a beam of polarized light and a beam of non-polarized light are mixed according to different proportions to generate fully polarized light in different polarization states of partially polarized light or fully polarized light.

Description

Technical Field

[0001] The present invention relates to a polarization state generator and a generating method, and in particular to an arbitrary polarization state generating method, an arbitrary polarization state generator and applications thereof. Background Art

[0002] Polarization imaging technology can simultaneously acquire both polarization and intensity information about a target, enabling comprehensive detection and identification of target characteristics. It offers unique advantages in detecting moisture content, roughness, and contour information. It is widely used to improve target-to-background contrast, image in turbid media, and suppress ocean flare. Consequently, polarization imaging holds significant application value in fields such as remote sensing and national defense. Polarization calibration can eliminate systematic errors in the system and improve the accuracy of polarization measurements. In machine vision and industrial inspection, polarization calibration can enhance image contrast, making difficult-to-distinguish objects more distinct. This facilitates the detection of subtle defects such as scratches and dents, improving inspection reliability. Polarization calibration plays a crucial role in polarization imaging systems, improving not only measurement accuracy and reliability but also system functionality and applicability. Polarization calibration can fully leverage the advantages of polarization imaging, providing more accurate and richer information for a variety of applications.

[0003] Currently, there is a lack of methods for constructing polarization targets in polarization calibration systems. Common polarization light sources use lasers or LED light sources to pass through polarizers or quarter-wave plates to generate polarized light of different states. However, this method only generates fully polarized light and cannot produce partially polarized light or polarized light with the rated polarization fraction as required by the design. This affects the polarization linear response of the polarization imaging system and may reduce the calibration accuracy of complex components. Summary of the Invention

[0004] The purpose of the present invention is to solve the problem that due to the lack of a method for constructing a polarization target in the existing polarization calibration system, the polarized light generated by a polarized light source using a laser or an LED light source through a polarizer or a 1 / 4 wave plate is fully polarized light, and cannot generate partially polarized light or polarized light with a rated polarization share as required by the design. The present invention provides a method for generating an arbitrary polarization state, an arbitrary polarization state generator and applications thereof.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for generating an arbitrary polarization state, which is special in that it includes the following steps:

[0007] Step 1: Two light sources are respectively placed on the optical path passing through the virtual focus of the concave reflector, emitting unbiased and parallel uniform plane light, namely beam A and beam B; wherein beam A is used to provide an unpolarized component and beam B is used to provide a polarized component;

[0008] Step 2: Use aperture A to control the passage of light beam A, and use aperture B to control the passage of light beam B. Both apertures A and B can be opened or closed. When closed, no light passes through the light path. When opened, the size of the light beam can be adjusted.

[0009] Step 3: Pass light beam A through attenuation plate A to adjust the light intensity; light beam B passes through the polarizer and 1 / 4 wave plate in sequence, and polarized light of the required polarization state is generated by rotating the polarizer and 1 / 4 wave plate, and then passes through attenuation plate B to adjust the light intensity of the generated polarized light; among them, by rotating the polarizer, linear polarized light of any angle can be obtained, and in combination with the 1 / 4 wave plate, different angles between the two can generate elliptically polarized light of any polarization angle. This light path can generate fully polarized light of all polarization states.

[0010] Step 4: The two beams of light obtained in step 3 are incident on a concave reflector to merge, and then converted into parallel light of arbitrary polarization state by the concave reflector and emitted to obtain a beam of light with the required polarization state.

[0011] In the present invention, the attenuation plate A, the attenuation plate B, and the concave reflector all have polarization-maintaining properties, and do not affect the polarization properties of the light beam itself during the transmission process of light; by combining two beams of light with different polarization properties into one beam of light, a light beam of any polarization state can be obtained.

[0012] When aperture A and aperture B are opened at the same time, light beams A and B pass through the two apertures respectively, and then the light intensities are adjusted by attenuation plates A and B to control the ratio of the two beams, thereby achieving partially polarized light with different polarization ratios; when aperture B is closed, completely non-polarized light can be obtained; when aperture A is closed, completely polarized light is obtained.

[0013] Furthermore, the attenuation plate A and the attenuation plate B are both progressive attenuation plates, which can select the position of the light beam when passing according to the required light intensity.

[0014] Furthermore, in step 3, adjusting the light intensity of the light beam A by passing through the attenuation plate A specifically includes: rotating the attenuation plate A to adjust the position where the light beam A passes through the attenuation plate A to obtain a light beam of the required light intensity;

[0015] The intensity of the polarized light generated by the attenuation plate B is adjusted specifically by rotating the attenuation plate B to adjust the position where the polarized light passes through the attenuation plate B to obtain a polarized light beam of required intensity.

[0016] Furthermore, the light intensities of the light beam A and the light beam B are consistent.

[0017] Furthermore, the light beam A and the light beam B are symmetrical about a line passing through the virtual focus and the real focus of the concave reflecting mirror.

[0018] An arbitrary polarization state generator for implementing the above-mentioned arbitrary polarization state generation method is characterized in that it includes an aperture A and an attenuation plate A arranged in sequence along the optical path of a light beam A; an aperture B, a polarizer, a quarter-wave plate, an attenuation plate B, and a concave reflector arranged in sequence along the optical path of a light beam B; and light beams A and B are both located on an optical path passing through the virtual focus of the concave reflector.

[0019] The reflecting surface of the concave reflecting mirror is arranged at the intersection of the light paths of the light beams A and B, and is used to merge the two light beams and then convert them into parallel light and emit them.

[0020] Furthermore, the attenuation sheet A and the attenuation sheet B are both progressive attenuation sheets.

[0021] Furthermore, the attenuation plate A, polarizer, quarter wave plate, and attenuation plate B are respectively connected to a rotatable wave plate frame, and the position of the light beam passing through the attenuation plate A, polarizer, quarter wave plate, and attenuation plate B can be adjusted through the rotatable wave plate frame.

[0022] The invention discloses an application of an arbitrary polarization state generator, which is special in that it is applied to polarization calibration experiments.

[0023] Beneficial effects of the present invention:

[0024] (1) The present invention provides a method for generating an arbitrary polarization state and an arbitrary polarization state generator, which can generate partially polarized light by mixing a beam of polarized light and a beam of non-polarized light in different proportions, and can also generate fully polarized light with different polarization states.

[0025] (2) The arbitrary polarization state generator provided by the present invention plays an important role in quantitative experiments such as calibration, and provides technical support for precise measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic structural diagram of an arbitrary polarization state generator of the present invention.

[0027] In the figure, 1-light beam A; 2-light beam B; 3-aperture A; 4-aperture B; 5-attenuation plate A; 6-polarizer; 7-1 / 4 wave plate; 8-attenuation plate B; 9-concave reflector. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the accompanying drawings and embodiments. Obviously, the embodiments described 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 making creative efforts are within the scope of protection of the present invention.

[0029] Example

[0030] A method for generating an arbitrary polarization state comprises the following steps:

[0031] Step 1: Place two light sources on the optical path passing through the virtual focus of the concave reflector, emitting unbiased and parallel uniform plane light, beam A1 and beam B2, respectively. Beam A is used to provide an unpolarized component, and beam B is used to provide a polarized component. The light intensities of beams A1 and B2 are consistent.

[0032] The light beam A1 and the light beam B2 are symmetrical about the line passing through the virtual focus and the real focus of the concave reflecting mirror 9 .

[0033] Step 2: Control the passage of light beam A1 through aperture A3, and control the passage of light beam B2 through aperture B4; both apertures A1 and B4 can be opened or closed. When closed, no light passes through the light path; when opened, the size of the light beam can be adjusted;

[0034] Step 3: Rotate the attenuation plate A5 to adjust the position where the light beam A1 passes through the attenuation plate A5 to obtain a light beam of the required intensity. The light beam B2 passes through the polarizer 6 and the quarter-wave plate 7 in sequence. The polarizer 6 is rotated to generate polarized light of the required polarization state. The attenuation plate B8 is then rotated to adjust the position where the polarized light passes through the attenuation plate B8 to obtain a polarized light beam of the required intensity.

[0035] Among them, by rotating the polarizer 6, linear polarized light of any angle can be obtained. In combination with the 1 / 4 wave plate 7, the angle between the two is different, and elliptically polarized light of any polarization angle can be generated. This light path can generate fully polarized light of all polarization states.

[0036] Step 4: The two beams of light are incident on the concave reflector 9 and merged, and then converted into parallel light of arbitrary polarization state by the concave reflector 9 and emitted to obtain a light beam of required polarization state.

[0037] Both the attenuation plate A5 and the attenuation plate B8 are progressive attenuation plates, that is, different degrees of attenuation of light can be obtained through one attenuation plate.

[0038] In this embodiment, the polarization state of the light beam A1 incident on the concave reflector 9 is expressed as I1=[S 01 S 11 S 21 S31 ] T , the polarization state of the beam A2 is expressed as I2=[S 02 S 12 S 22 S 32 ] T The polarization state I of the two beams of light after they are incident on the concave reflector 9 and merged is expressed as:

[0039] I=[S 01 S 11 S 21 S 31 ] T +[S 02 S 12 S 22 S 32 ] T =I1+I2.

[0040] In this embodiment, the attenuation plate A5, the attenuation plate B8, and the concave reflector all have polarization-maintaining properties, and do not affect the polarization properties of the light beam itself during the transmission process of light; the combination of two beams of light in different proportions, that is, the combination of polarized light and non-polarized light, thereby covering partially polarized light with different polarization degrees.

[0041] The Stokes parameter is used to describe the polarization state of the light beam. The Stokes parameter is a 1×4 matrix expressed as [S0 S1 S2 S3] T , where S0 represents the intensity of the light beam, S1 represents the intensity difference between 0° and 90°, S2 represents the intensity difference between 45° and 135°, and S3 represents the intensity difference between right-handed and left-handed light.

[0042] The following effects can be achieved by using the method for generating an arbitrary polarization state in this embodiment:

[0043] (1) When the aperture B4 is closed, completely non-polarized light can be obtained.

[0044] (2) When the aperture A3 is closed, completely polarized light is obtained.

[0045] (3) When aperture A3 and aperture B4 are opened at the same time, light beams A1 and B2 pass through the two apertures respectively, and then the light intensities are adjusted by attenuation plates A and B4 to control the ratio of the two beams, thereby achieving partially polarized light with different polarization ratios.

[0046] (4) By rotating the polarizer and the quarter-wave plate, polarized light of different angles or elliptically polarized light of different polarization angles can be obtained.

[0047] This embodiment also provides an arbitrary polarization state generator, such as Figure 1As shown, it includes an aperture A3, an attenuation plate A5, an aperture B4, a polarizer 6, a quarter wave plate 7, an attenuation plate B8 and a concave reflector 9. Among them, the attenuation plate A5 and the attenuation plate B8 are both progressive attenuation plates.

[0048] The aperture A3 and the attenuation plate A5 are sequentially arranged on the optical path of the light beam A1, wherein the attenuation plate A5 is connected to a rotatable wave plate frame for controlling its rotation. The passage of the light beam A1 is controlled by opening or closing the aperture A3, and the light intensity of the light beam A1 passing through the aperture A3 is adjusted by rotating the attenuation plate A5, and then incident on the concave reflector 9.

[0049] The aperture B4, polarizer 6, 1 / 4 wave plate 7, and attenuation plate B8 are arranged in sequence on the optical path of the light beam B2, among which the polarizer 6, 1 / 4 wave plate 7, and attenuation plate B8 are respectively connected to a rotatable wave plate frame for controlling rotation. The passage of the light beam B2 is controlled by opening or closing the aperture B4, and polarized light of different angles or elliptically polarized light of different polarization angles is obtained by rotating the polarizer 6 and the 1 / 4 wave plate 7, and the light intensity is adjusted by the attenuation plate B8, and then incident on the concave reflector 9 for convergence, and then converted into parallel light of any polarization state through the concave reflector 9 and emitted to obtain a light beam of the required polarization state.

[0050] The reflecting surface of the concave reflector 9 is set at the intersection of the light paths of the light beams A1 and B2, and is used to merge the two light beams, convert them into parallel light and emit them to obtain a light beam with a required polarization state.

[0051] In the calibration of polarization products, especially in the linear polarization measurement capability of polarization cameras, a standardized polarization light source is particularly important. The arbitrary polarization state generator of this embodiment can be applied to polarization calibration experiments.

[0052] The above description is merely a specific embodiment of the present invention, and a comparison of the effects of the specific embodiment with the relevant comparative examples. However, the scope of protection of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present invention shall be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope of protection of the claims.

Claims

1. A method for generating an arbitrary polarization state, characterized in that: The following steps are involved: Step 1: two light sources are respectively arranged on the optical path passing through the virtual focus of the concave reflector (9), emitting unbiased and parallel uniform plane light, namely light beam A (1) and light beam B (2); Step 2: Control light beam A (1) to pass through aperture A (3), and control light beam B (2) to pass through aperture B (4); Step 3: Light beam A (1) is passed through attenuation plate A (5) to adjust the light intensity; light beam B (2) is passed through polarizer (6) and quarter wave plate (7) in sequence, and polarized light of the required polarization state is generated by rotating polarizer (6) and quarter wave plate (7), and then the intensity of the generated polarized light is adjusted by passing through attenuation plate B (8); Step 4: The two beams of light obtained in step 3 are incident on the concave reflector (9) to merge, and then converted into parallel light of arbitrary polarization state through the concave reflector (9) and emitted to obtain a light beam of required polarization state.

2. The method for generating an arbitrary polarization state according to claim 1, wherein: The attenuation plate A (5) and the attenuation plate B (8) are both progressive attenuation plates.

3. The method for generating an arbitrary polarization state according to claim 2, wherein: In step 3: The light intensity of the light beam A (1) is adjusted by passing through the attenuation plate A (5) by rotating the attenuation plate A (5) to adjust the position of the light beam A (1) passing through the attenuation plate A (5) to obtain a light beam of the required light intensity; The intensity of the polarized light generated by the attenuation plate B (8) is adjusted specifically by rotating the attenuation plate B (8) to adjust the position of the polarized light passing through the attenuation plate B (8) to obtain a polarized light beam of the required intensity.

4. The method for generating an arbitrary polarization state according to claim 1, wherein: The light intensity of the light beam A (1) and the light beam B (2) are consistent.

5. The method for generating an arbitrary polarization state according to claim 1, wherein: The light beam A (1) and the light beam B (2) are symmetrical about a line passing through the virtual focus and the real focus of the concave reflector (9).

6. An arbitrary polarization state generator, used to implement the arbitrary polarization state generation method according to any one of claims 1 to 5, characterized in that: include: An aperture A (3) and an attenuation plate A (5) are sequentially arranged along the optical path of the light beam A (1); and an aperture B (4), a polarizing plate (6), a quarter wave plate (7), an attenuation plate B (8), and a concave reflector (9) are sequentially arranged along the optical path of the light beam B (2); the light beam A (1) and the light beam B (2) are both located on an optical path passing through the virtual focus of the concave reflector (9); The reflecting surface of the concave reflecting mirror (9) is arranged at the intersection of the light paths of the light beam A (1) and the light beam B (2), and is used to merge the two light beams and then convert them into parallel light for emission.

7. The arbitrary polarization state generator according to claim 6, characterized in that: The attenuation plate A (5) and the attenuation plate B (8) are both progressive attenuation plates.

8. The arbitrary polarization state generator according to claim 6, characterized in that: The attenuation plate A (5), polarizing plate (6), quarter wave plate (7), and attenuation plate B (8) are respectively connected to a rotatable wave plate frame.

9. An application of the arbitrary polarization state generator according to any one of claims 6 to 8, characterized in that: Used in polarization calibration experiments.

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