CN202648799U

CN202648799U - Light beam Stokes parameter measuring device

Info

Publication number: CN202648799U
Application number: CN 201220244241
Authority: CN
Inventors: 汤飞龙; 李中梁; 王向朝; 步扬; 曹绍谦
Original assignee: Shanghai Institute of Optics and Fine Mechanics of CAS
Current assignee: Shanghai Institute of Optics and Fine Mechanics of CAS
Priority date: 2012-05-28
Filing date: 2012-05-28
Publication date: 2013-01-02
Anticipated expiration: 2022-05-28

Abstract

A light beam Stokes parameter measurement device, the polarization measurement device is composed of a beam splitting prism group, a phase retarder array, a polarizer, a photodetector array and a signal processing system, each unit of the photodetector array and the phase retarder array Each unit corresponds to each other. The utility model can measure the Stokes parameters of the light beam in real time, and reduces the phase delay error of the phase delay device, the fast axis direction error, the light transmission axis direction error of the polarizer, and the extinction ratio error to the measurement accuracy of the polarization state of the light beam. Impact.

Description

Beam Stokes Parameter Measuring Device

技术领域 technical field

本发明涉及光束斯托克斯参量的测量，特别是一种光束斯托克斯参量测量装置。The invention relates to the measurement of beam Stokes parameters, in particular to a beam Stokes parameter measurement device.

背景技术 Background technique

193nm浸没式光刻是32nm节点主流光刻技术。在浸没式光刻技术中，采用某种液体填充在物镜最后一片镜片和硅片上的光刻胶之间，使得投影物镜和数据孔径得到了显著的提高，当投影物镜的数值孔径接近1或者更大时，照明光的偏振态对光刻成像的影响已无法忽略。采用合适的偏振光照明能在大数值孔径光刻系统中有效地提高成像对比度。随着浸没式光刻机投影物镜的数值孔径不断增大，采用偏振光照明结合分辨率增强技术成为提高光刻分辨率、提高光刻成像质量的有效途径。193nm immersion lithography is the mainstream lithography technology at 32nm node. In the immersion lithography technology, some kind of liquid is used to fill between the last lens of the objective lens and the photoresist on the silicon wafer, so that the projection objective lens and the data aperture have been significantly improved. When the numerical aperture of the projection objective lens is close to 1 or When it is larger, the influence of the polarization state of illumination light on lithography imaging can no longer be ignored. Appropriate polarized light illumination can effectively improve the imaging contrast in a large numerical aperture lithography system. As the numerical aperture of the projection objective lens of the immersion lithography machine continues to increase, the use of polarized light illumination combined with resolution enhancement technology has become an effective way to improve the resolution of lithography and improve the quality of lithography imaging.

在偏振光照明技术中，由于偏振控制的需要，应实时检测照明光的偏振信息。目前，最常用的光束偏振态检测技术是通过对光束斯托克斯参量测量来实现的，提高光束斯托克斯参量的测量精度至关重要。In polarized light illumination technology, due to the need of polarization control, the polarization information of illumination light should be detected in real time. At present, the most commonly used beam polarization state detection technology is realized by measuring the beam Stokes parameters, and it is very important to improve the measurement accuracy of the beam Stokes parameters.

在先技术1(参见D.Sabatke,M.R.Descour,E.I.Dereniak,W.C.Sweatt,S.A.Kemme,and G.S.Phipps,“Optimization of retardance for a complete Stokespolarimeter,”Opt.Lett.25(11),802–804(2000))对基于分立旋转波片法的光束斯托克斯参量测量装置进行了优化，采用四个优化的波片快轴角度，从而提高了检测系统的信噪比。该方法为了测量获得光束的全部四个斯托克斯参量，必须至少旋转四次波片，因此无法实现斯托克斯参量的实时测量。Prior art 1 (see D. Sabatke, M.R. Descour, E.I. Dereniak, W.C. Sweatt, S.A. Kemme, and G.S. Phipps, "Optimization of retardance for a complete Stokes polarimeter," Opt. Lett. 25(11), 802–804(2000 )) The beam Stokes parameter measurement device based on the discrete rotating wave plate method is optimized, and four optimized fast axis angles of the wave plate are used to improve the signal-to-noise ratio of the detection system. In order to measure all four Stokes parameters of the light beam in this method, the wave plate must be rotated at least four times, so real-time measurement of the Stokes parameters cannot be realized.

在先技术2（参见T.Hamamoto,H.Toyota,and H.Kikuta,“Microretarder array forimaging polarimetry in the visible wavelength region,”in Lithographic andMicromachining Techniques for Optical Component Fabrication,E.-B.Kley and H.P.Herzig,eds.,Proc.SPIE 4440,293-300(2001).）提出了基于相位延迟阵列的光束斯托克斯参量测量装置。其中相位延迟阵列中各相位延迟器的快轴方向采用了在先技术1中所优化的快轴角度，提高了检测系统的信噪比。由于采用了相位延迟器阵列，该装置实现了光束的斯托克斯参量实时测量。同时，由于该装置所需的相位延迟器阵列为亚波长光栅，采用电子束刻蚀；由于刻蚀工艺的原因，虽相位延迟器的快轴方向能精确刻蚀，但相位延迟却无法得到精确控制，从而该器件存在相位延迟误差，给斯托克斯参量测量系统带来一定误差。Prior Art 2 (see T.Hamamoto, H.Toyota, and H.Kikuta, "Microretarder array forimaging polarimetry in the visible wavelength region," in Lithographic and Micromachining Techniques for Optical Component Fabrication, E.-B.Kley and H.P. Herzig, eds.,Proc.SPIE 4440,293-300(2001).) A beam Stokes parameter measurement device based on a phase delay array was proposed. The fast axis direction of each phase retarder in the phase delay array adopts the optimized fast axis angle in the prior art 1, which improves the signal-to-noise ratio of the detection system. Due to the adoption of the phase retarder array, the device realizes the real-time measurement of the Stokes parameter of the light beam. At the same time, since the phase retarder array required by the device is a sub-wavelength grating, electron beam etching is used; due to the etching process, although the fast axis direction of the phase retarder can be etched accurately, the phase delay cannot be accurately etched. Control, so the device has a phase delay error, which brings a certain error to the Stokes parameter measurement system.

发明内容 Contents of the invention

本发明的目的是为了解决上述现有技术的不足，提供一种光束斯托克斯参量测量装置，以实现光束斯托克斯参量的实时测量，减小光束斯托克斯参量测量装置中相位延迟器件的相位延迟量误差、快轴方向误差和检偏器的透光轴方向误差、消光比误差对光束偏振态测量精度的影响。The purpose of the present invention is to solve the deficiencies in the prior art mentioned above, to provide a beam Stokes parameter measuring device, to realize the real-time measurement of the beam Stokes parameter, to reduce the phase in the beam Stokes parameter measuring device The influence of the phase delay error of the delay device, the fast axis direction error, the transmittance axis direction error of the analyzer, and the extinction ratio error on the measurement accuracy of the polarization state of the beam.

本发明的技术解决方案如下：Technical solution of the present invention is as follows:

一种光束斯托克斯参量测量装置，其特点在于该装置的构成包括沿系统光轴依次设置的：分光棱镜组、相位延迟器阵列、检偏器和光电探测器阵列，所述的光电探测器阵列的输出端接信号处理系统，所述的光电探测器阵列各单元与所述的相位延迟器阵列各单元一一对应，并根据所述待测光的偏振方向，调整所述的检偏器的透光轴方向与所述待测光束的偏振方向平行及垂直后，分别再进行待测光束的偏振参量测量。A light beam Stokes parameter measurement device is characterized in that the composition of the device includes sequentially arranged along the optical axis of the system: a beam splitting prism group, a phase retarder array, a polarizer and a photodetector array, and the photodetector The output terminal of the detector array is connected to the signal processing system, and each unit of the photodetector array is in one-to-one correspondence with each unit of the phase retarder array, and the polarizer is adjusted according to the polarization direction of the light to be measured After the direction of the light transmission axis of the device is parallel to and perpendicular to the polarization direction of the light beam to be measured, the polarization parameters of the light beam to be measured are measured respectively.

所述的分光棱镜组为分光比已知的分光棱镜的组合，将一束入射光形成多个出射子光束。The beam-splitting prism group is a combination of beam-splitting prisms with a known beam-splitting ratio, and forms a beam of incident light into multiple outgoing sub-beams.

所述相位延迟器阵列是由四个相同的相位延迟器在同一平面内按四象限排列组成，分别为第一相位延迟器、第二相位延迟器、第三相位延迟器、第四相位延迟器；所述的第一相位延迟器、第二相位延迟器、第三相位延迟器、第四相位延迟器的快轴方向与所述的检偏器的透光轴方向夹角θ_i(i＝1,2,3,4)分别为-45°、0°、30°和60°，所述相位延迟器产生90°相位延迟量。The phase retarder array is composed of four identical phase retarders arranged in four quadrants in the same plane, which are respectively the first phase retarder, the second phase retarder, the third phase retarder, and the fourth phase retarder ; The angle θ _i (i= 1, 2, 3, 4) are -45°, 0°, 30° and 60° respectively, and the phase retarder produces a 90° phase delay.

所述的光电探测器阵列为多个光电探测器形成的组合体，或为二维面阵探测器，所述的光电探测器阵列各单元与所述的相位延迟器阵列各单元一一对应，是由相同的在同一平面内按四象限排列的第一光电探测器、第二光电探测器、第三光电探测器、第四光电探测器组成。The photodetector array is a combination of multiple photodetectors, or a two-dimensional area array detector, and each unit of the photodetector array corresponds to each unit of the phase retarder array, It is composed of the same first photodetector, second photodetector, third photodetector and fourth photodetector arranged in four quadrants in the same plane.

利用所述的光束斯托克斯参量测量装置进行光束斯托克斯参量测量的方法，其特征在于：当已知待测光束的偏振方位角为

时，该方法包括下列步骤：The method for measuring the beam Stokes parameter by using the described beam Stokes parameter measuring device is characterized in that: when the polarization azimuth angle of the beam to be measured is known to be

, the method includes the following steps:

①调整所述的检偏器的透光轴方向与所述的待测光束的偏振方向垂直，调整所述的相位延迟器阵列使其第一相位延迟器、第二相位延迟器、第三相位延迟器、第四相位延迟器的快轴方向与所述的检偏器的透光轴方向夹角θ_i(i＝1,2,3,4)分别为-45°、0°、30°和60°，并按下述公式计算系统矩阵A的逆矩阵A^-1的值：① Adjust the direction of the transmission axis of the analyzer to be perpendicular to the polarization direction of the beam to be measured, and adjust the array of phase retarders to make the first phase retarder, the second phase retarder, and the third phase retarder The included angles θ _i (i=1, 2, 3, 4) between the fast axis direction of the retarder and the fourth phase retarder and the light transmission axis direction of the analyzer are -45°, 0°, and 30° respectively and 60°, and calculate the value of the inverse matrix A ^-1 of the system matrix A according to the following formula:

${A A}^{- - 11} = = {[\begin{matrix} {a a}_{1111} & {a a}_{1212} & {a a}_{1313} & {a a}_{1414} \\ {a a}_{21 twenty one} & {a a}_{22 twenty two} & {a a}_{23 twenty three} & {a a}_{24 twenty four} \\ {a a}_{3131} & {a a}_{3232} & {a a}_{3333} & {a a}_{3434} \\ {a a}_{4141} & {a a}_{4242} & {a a}_{4343} & {a a}_{4444} \end{matrix}]}^{- - 11}$

其中矩阵各元素分别为：The elements of the matrix are:

a_i1＝1a _i1 =1

i＝1,2,3,4;i=1,2,3,4;

②利用光束斯托克斯参量测量装置对待测光束进行测量，所述的第一光电探测器、第二光电探测器、第三光电探测器、第四光电探测器分别得到待测光束的光强信息为并按下列公式计算得到第一次斯托克斯参量:

②Measure the light beam to be measured by using the beam Stokes parameter measuring device, and the first photodetector, the second photodetector, the third photodetector, and the fourth photodetector respectively obtain the light intensity of the light beam to be measured information for And calculate the first Stokes parameter according to the following formula:

$[\begin{matrix} {S S}_{00}^{9090} \\ {S S}_{11}^{9090} \\ {S S}_{22}^{9090} \\ {S S}_{33}^{9090} \end{matrix}] = = {A A}^{- - 11} [\begin{matrix} {I I}_{11}^{9090} \\ {I I}_{22}^{9090} \\ {I I}_{33}^{9090} \\ {I I}_{44}^{9090} \end{matrix}];;$

③调整所述的检偏器的透光轴方向与所述的待测光束的偏振方向平行，调整所述的相位延迟器阵列使第一相位延迟器、第二相位延迟器、第三相位延迟器、第四相位延迟器的快轴方向与检偏器透光轴方向的夹角θ_i(i＝1,2,3,4)分别为-45°、0°、30°和60°，按下述公式计算得到系统矩阵A的逆矩阵A^-1的值：③ Adjust the direction of the transmission axis of the analyzer to be parallel to the polarization direction of the beam to be measured, and adjust the array of phase retarders so that the first phase retarder, the second phase retarder, and the third phase retarder The included angles θ _i (i=1, 2, 3, 4) between the fast axis direction of the fourth phase retarder and the light transmission axis direction of the analyzer are -45°, 0°, 30° and 60° respectively, Calculate the value of the inverse matrix A ^-1 of the system matrix A according to the following formula:

${A A}^{- - 11} {= = [\begin{matrix} {a a}_{1111} & {a a}_{1212} & {a a}_{1313} & {a a}_{1414} \\ {a a}_{21 twenty one} & {a a}_{22 twenty two} & {a a}_{23 twenty three} & {a a}_{24 twenty four} \\ {a a}_{3131} & {a a}_{3232} & {a a}_{3333} & {a a}_{3434} \\ {a a}_{4141} & {a a}_{4242} & {a a}_{4343} & {a a}_{4444} \end{matrix}]}^{- - 11}$

其中矩阵各元素分别为：The elements of the matrix are:

a_i1＝1a _i1 =1

i＝1,2,3,4;i=1,2,3,4;

④再利用光束斯托克斯参量测量装置对待测光束进行测量，所述的第一光电探测器（501）、第二光电探测器（502）、第三光电探测器（503）、第四光电探测器（504）分别得到待测光束的光强信息为

并按下列公式计算得到第二次斯托克斯参量:

④ Use the beam Stokes parameter measuring device to measure the beam to be measured, the first photodetector (501), the second photodetector (502), the third photodetector (503), the fourth photodetector The detector (504) respectively obtains the light intensity information of the beam to be measured as

And calculate the second Stokes parameter according to the following formula:

$[\begin{matrix} {S S}_{00}^{00} \\ {S S}_{11}^{00} \\ {S S}_{22}^{00} \\ {S S}_{33}^{00} \end{matrix}] = = {A A}^{- - 11} [\begin{matrix} {I I}_{11}^{00} \\ {I I}_{22}^{00} \\ {I I}_{33}^{00} \\ {I I}_{44}^{00} \end{matrix}];;$

⑤对所述的

和

按下列公式进行计算，得到所述的待测光束的最终斯托克斯参量：⑤ For the mentioned

and

Calculate according to the following formula to obtain the final Stokes parameter of the beam to be measured:

${S S}_{00} = = \frac{11}{22} (({S S}_{00}^{00} + + {S S}_{00}^{9090}))$ ${S S}_{11} = = \frac{{S S}_{11}^{9090}}{{S S}_{00}^{9090}} {S S}_{00}$ ${S S}_{22} = = \frac{{S S}_{22}^{9090}}{{S S}_{00}^{9090}} {S S}_{00}$ ${S S}_{33} = = \frac{{S S}_{33}^{99 00} + + {S S}_{33}^{00}}{{22 S S}_{00}^{9090}} {S S}_{00} . .$

利用所述的光束斯托克斯参量测量装置进行光束斯托克斯参量测量的方法，其特征在于：当未知待测光束的偏振方向时，其具体的测量步骤如下：The method for measuring the beam Stokes parameter by using the beam Stokes parameter measuring device is characterized in that: when the polarization direction of the beam to be measured is unknown, the specific measurement steps are as follows:

①利用所述的光束斯托克斯参量测量装置测量待测光束的大致偏振方位角

① Measuring the approximate polarization azimuth angle of the beam to be measured using the beam Stokes parameter measuring device

②调整所述的检偏器的透光轴方向与所述的待测光束的偏振方向垂直，调整所述的相位延迟器阵列，使第一相位延迟器、第二相位延迟器、第三相位延迟器、第四相位延迟器的快轴方向与所述的检偏器的透光轴方向夹角θ_i(i＝1,2,3,4)分别为-45°、0°、30°和60°，按下述公式计算得到系统矩阵A的逆矩阵A^-1的值：② Adjust the direction of the transmission axis of the analyzer to be perpendicular to the polarization direction of the beam to be measured, and adjust the array of phase retarders so that the first phase retarder, the second phase retarder, and the third phase retarder The included angles θ _i (i=1, 2, 3, 4) between the fast axis direction of the retarder and the fourth phase retarder and the light transmission axis direction of the analyzer are -45°, 0°, and 30° respectively and 60°, the value of the inverse matrix A ^-1 of the system matrix A is calculated according to the following formula:

其中矩阵各元素分别为：The elements of the matrix are:

a_i1＝1a _i1 =1

i＝1,2,3,4;i=1,2,3,4;

③再利用光束斯托克斯参量测量装置对待测光束进行测量，所述的第一光电探测器（501）、第二光电探测器（502）、第三光电探测器（503）、第四光电探测器（504）分别得到待测光束的光强信息为

并按下列公式计算得到第一次斯托克斯参量:

③Use the light beam Stokes parameter measuring device to measure the light beam to be measured, the first photodetector (501), the second photodetector (502), the third photodetector (503), the fourth photodetector The detector (504) respectively obtains the light intensity information of the beam to be measured as

And calculate the first Stokes parameter according to the following formula:

④调整所述的检偏器的透光轴方向与所述的待测光束的偏振方向平行，调整所述的相位延迟器阵列使第一相位延迟器、第二相位延迟器、第三相位延迟器、第四相位延迟器的快轴方向与检偏器透光轴方向的夹角θ_i(i＝1,2,3,4)分别为-45°、0°、30°和60°，按下述公式计算得到系统矩阵A的逆矩阵A^-1的值：④ Adjust the direction of the transmission axis of the analyzer to be parallel to the polarization direction of the beam to be measured, and adjust the array of phase retarders so that the first phase retarder, the second phase retarder, and the third phase retarder The included angles θ _i (i=1, 2, 3, 4) between the fast axis direction of the fourth phase retarder and the light transmission axis direction of the analyzer are -45°, 0°, 30° and 60° respectively, Calculate the value of the inverse matrix A ^-1 of the system matrix A according to the following formula:

其中矩阵各元素分别为：The elements of the matrix are:

a_i1＝1a _i1 =1

i＝1,2,3,4;i=1,2,3,4;

⑤再利用光束斯托克斯参量测量装置对待测光束进行测量，所述的第一光电探测器、第二光电探测器、第三光电探测器、第四光电探测器分别得到待测光束的光强信息

并按下列公式计算得到第二次斯托克斯参量:

5. Utilize the light beam Stokes parameter measuring device again to measure the light beam to be measured, and the first photodetector, the second photodetector, the third photodetector, and the fourth photodetector obtain the light of the light beam to be measured respectively. strong information

And calculate the second Stokes parameter according to the following formula:

⑥对所述的

和

按下列公式进行计算，得到所述的待测光束的最终斯托克斯参量：⑥ For the above

and

本发明与在先技术相比，具有以下优点及积极效果：Compared with the prior art, the present invention has the following advantages and positive effects:

1、本发明光束斯托克斯参量测量装置采用了相位延迟器阵列代替传统旋的转相位延迟器，光电探测器阵列代替了传统的单个光电探测器，光电探测器阵列各单元与相位延迟器阵列各单元一一对应，采用该装置可实时测量光束的全部四个斯托克斯参量。1. The beam Stokes parameter measuring device of the present invention adopts the phase retarder array to replace the traditional rotary phase retarder, the photodetector array replaces the traditional single photodetector, each unit of the photodetector array and the phase retarder Each unit of the array corresponds one by one, and all four Stokes parameters of the beam can be measured in real time by using the device.

2、由于制造工艺原因，相位延迟器阵列的延迟量较难得到精确的控制。而偏振测量装置中，相位延迟器阵列的延迟量、快轴方向和检偏器的透光轴方向、消光比等参量的误差将会影响斯托克斯参量的测量精度。利用本发明的检测方法，通过将检偏器的透光轴方向调整至与待测光束的偏振方向垂直或平行时，再分别进行测量，通过对数据的处理得到光束的斯托克斯参量，该法可有效减小上述制造误差对斯托克斯参量测量精度的影响，实现高精度斯托克斯参量测量。2. Due to the manufacturing process, it is difficult to accurately control the delay amount of the phase retarder array. In the polarization measurement device, errors in parameters such as the retardation of the phase retarder array, the direction of the fast axis, the direction of the transmittance axis of the analyzer, and the extinction ratio will affect the measurement accuracy of the Stokes parameters. Utilize the detection method of the present invention, by adjusting the direction of the transmission axis of the polarizer to be perpendicular or parallel to the polarization direction of the beam to be measured, and then measure respectively, and obtain the Stokes parameter of the beam by processing the data, The method can effectively reduce the influence of the above-mentioned manufacturing error on the Stokes parameter measurement accuracy, and realize high-precision Stokes parameter measurement.

附图说明 Description of drawings

图1为本发明光束斯托克斯参量测量装置示意图；Fig. 1 is the schematic diagram of beam Stokes parameter measuring device of the present invention;

图2为本发明实施例中相位延迟阵列的结构图；2 is a structural diagram of a phase delay array in an embodiment of the present invention;

图3为本发明实施例中光电探测器阵列的结构图；3 is a structural diagram of a photodetector array in an embodiment of the present invention;

图4为当存在相位延迟器的相位延迟量误差Δδ=2°，快轴方向误差Δθ=0.1°，检偏器透光轴方向误差Δα=0.1°时，归一化斯托克斯参量S₁₀误差随入射光偏振方向的变化。Figure 4 shows the normalized Stokes parameter S when there is a phase delay error of the phase retarder Δδ=2°, a fast axis direction error Δθ=0.1°, and an analyzer light transmission axis direction error Δα=0.1° ₁₀ The error varies with the polarization direction of the incident light.

图5为当存在相位延迟器的相位延迟量误差Δδ=2°，快轴方向误差Δθ=0.1°，检偏器透光轴方向误差Δα=0.1°时，归一化斯托克斯参量S₂₀误差随入射光偏振方向的变化。Figure 5 shows the normalized Stokes parameter S when there is a phase delay error of the phase retarder Δδ=2°, a fast axis direction error Δθ=0.1°, and an analyzer light transmission axis direction error Δα=0.1° ₂₀ The error varies with the polarization direction of the incident light.

图6为当存在相位延迟器的相位延迟量误差Δδ=2°，快轴方向误差Δθ=0.1°，检偏器透光轴方向误差Δα=0.1°时，归一化斯托克斯参量S₃₀误差随入射光偏振方向的变化。Figure 6 shows the normalized Stokes parameter S when there is a phase delay error of the phase retarder Δδ=2°, a fast axis direction error Δθ=0.1°, and an analyzer light transmission axis direction error Δα=0.1° ₃₀ The error varies with the polarization direction of the incident light.

具体实施方式 Detailed ways

下面结合实施例和附图对本发明作进一步说明，但不应以此限制本发明的包含范围。The present invention will be further described below in conjunction with the embodiments and accompanying drawings, but the scope of the present invention should not be limited thereto.

本发明光束斯托克斯参量测量装置实施例的示意图如图1所示，沿装置系统光轴依次为：分光棱镜组2、相位延迟器阵列3、检偏器4、光电探测器阵列5，该光电探测器阵列的输出信号接信号处理系统6；光电探测器阵列各单元与相位延迟器阵列各单元一一对应；待测光束1沿系统光轴入射至所述的分光棱镜组2、相位延迟器阵列3和检偏器4，由所述的光电探测器阵列5探测光强，该光电探测器阵列5输出的电信号送入所述的信号处理系统6进行数据处理。The schematic diagram of the embodiment of the beam Stokes parameter measuring device of the present invention is shown in Fig. 1, along the optical axis of the device system, there are: beam splitting prism group 2, phase retarder array 3, analyzer 4, photodetector array 5, The output signal of the photodetector array is connected to the signal processing system 6; each unit of the photodetector array corresponds to each unit of the phase retarder array; The retarder array 3 and the polarizer 4 detect the light intensity by the photodetector array 5, and the electrical signal output by the photodetector array 5 is sent to the signal processing system 6 for data processing.

所述相位延迟器阵列是由四个相同的第一相位延迟器301、第二相位延迟器302、第三相位延迟器303、第四相位延迟器304在同一平面内按四象限排列组成，相位延迟器产生90°相位延迟量，为四分之一波片或液晶调制器；所述的第一相位延迟器、第二相位延迟器、第三相位延迟器、第四相位延迟器的快轴方向与所述的检偏器4的透光轴方向所成的角度分别为-45°、0°、30°和60°。The phase retarder array is composed of four identical first phase retarders 301, second phase retarders 302, third phase retarders 303, and fourth phase retarders 304 arranged in four quadrants in the same plane, and the phase The retarder produces a 90° phase delay, which is a quarter-wave plate or a liquid crystal modulator; the fast axis of the first phase retarder, the second phase retarder, the third phase retarder, and the fourth phase retarder The angles formed by the direction and the direction of the light transmission axis of the analyzer 4 are respectively -45°, 0°, 30° and 60°.

所述的光电探测器阵列为多个光电探测器形成的组合体，或为二维面阵探测器，所述的光电探测器为光电二极管、光电三极管、光电倍增管或光电池。所述的光电探测器阵列结构与所述的相位延迟器阵列的结构相对应，是由相同的在同一平面内按四象限排列的第一光电探测器、第二光电探测器、第三光电探测器、第四光电探测器组成。The photodetector array is a combination of multiple photodetectors, or a two-dimensional area array detector, and the photodetectors are photodiodes, phototransistors, photomultiplier tubes or photocells. The structure of the photodetector array corresponds to the structure of the phase retarder array, and is composed of the same first photodetector, second photodetector, and third photodetector arranged in four quadrants in the same plane. device and a fourth photodetector.

利用本发明光束斯托克斯参量测量装置对待测光束的斯托克斯参量的测量方法（本实施例为未知待测光束1的偏振方向）的具体测量步骤如下：The specific measurement steps of the method for measuring the Stokes parameter of the beam to be measured by using the beam Stokes parameter measuring device of the present invention (in this embodiment, the polarization direction of the beam to be measured 1 is unknown) are as follows:

①利用本发明光束斯托克斯参量测量装置测量待测光束1的大致偏振方位角

① Measuring the approximate polarization azimuth angle of the beam 1 to be measured by using the beam Stokes parameter measuring device of the present invention

②调整所述的检偏器4的透光轴方向与所述的待测光束1的偏振方向垂直，调整所述的相位延迟器阵列3，使第一相位延迟器301、第二相位延迟器302、第三相位延迟器303、第四相位延迟器304的快轴方向与所述的检偏器4的透光轴方向夹角θ_i(i＝1,2,3,4)分别为-45°、0°、30°和60°，按下述公式计算得到系统矩阵A的逆矩阵A^-1的值：② adjust the direction of the transmission axis of the analyzer 4 to be perpendicular to the polarization direction of the light beam 1 to be measured, and adjust the phase retarder array 3 so that the first phase retarder 301 and the second phase retarder 301 302, the angles θ _i (i=1, 2, 3, 4) between the fast axis direction of the third phase retarder 303 and the fourth phase retarder 304 and the light transmission axis direction of the analyzer 4 are respectively - 45°, 0°, 30° and 60°, the value of the inverse matrix A ^-1 of the system matrix A is calculated according to the following formula:

其中矩阵各元素分别为：The elements of the matrix are:

a_i1＝1a _i1 =1

i＝1,2,3,4;i=1,2,3,4;

③再利用光束斯托克斯参量测量装置对待测光束进行测量得，所述的第一光电探测器501、第二光电探测器502、第三光电探测器503、第四光电探测器504分别得到待测光束的光强信息为

并按下列公式计算得到第一次斯托克斯参量:

③Use the light beam Stokes parameter measuring device to measure the light beam to be measured, and the first photodetector 501, the second photodetector 502, the third photodetector 503, and the fourth photodetector 504 respectively obtain The light intensity information of the beam to be measured is

And calculate the first Stokes parameter according to the following formula:

④调整所述的检偏器4的透光轴方向与所述的待测光束1的偏振方向平行，调整所述的相位延迟器阵列3，使所述的第一相位延迟器301、第二相位延迟器302、第三相位延迟器303、第四相位延迟器304的快轴方向与检偏器透光轴方向的夹角θ_i(i＝1,2,3,4)分别为-45°、0°、30°和60°，按下述公式计算得到系统矩阵A的逆矩阵A^-1的值：④ adjust the direction of the transmission axis of the analyzer 4 to be parallel to the polarization direction of the beam to be measured 1, adjust the phase retarder array 3 so that the first phase retarder 301, the second The angles θ _i (i=1, 2, 3, 4) between the fast axis direction of the phase retarder 302, the third phase retarder 303, and the fourth phase retarder 304 and the light transmission axis direction of the analyzer are respectively -45 °, 0°, 30° and 60°, the value of the inverse matrix A ^-1 of the system matrix A is calculated according to the following formula:

其中矩阵各元素分别为：The elements of the matrix are:

a_i1＝1a _i1 =1

i＝1,2,3,4;i=1,2,3,4;

⑤再利用光束斯托克斯参量测量装置对待测光束进行测量，所述的第一光电探测器501、第二光电探测器502、第三光电探测器503、第四光电探测器504分别得到待测光束的光强信息为

并按下列公式计算得到第二次斯托克斯参量:

5. Utilize the light beam Stokes parameter measuring device again to measure the light beam to be measured, and the first photodetector 501, the second photodetector 502, the third photodetector 503, and the fourth photodetector 504 are respectively obtained The light intensity information of the measuring beam is

And calculate the second Stokes parameter according to the following formula:

⑥对所述的

和

and

本发明的基本原理如下：Basic principle of the present invention is as follows:

定义xyz坐标系，其中z轴为所述光束斯托克斯参量测量装置的光轴方向，xy平面为与光轴垂直的平面。设待测光束1的Stokes矢量为S=[S₀,S₁,S₂,S₃]^T（右上角“T”表示矩阵转置）。定义线偏振光的偏振方向与x轴正方向之间的角度为偏振方位角其范围为

定义所述的相位延迟器阵列中第一相位延迟器、第二相位延迟器、第三相位延迟器和第四相位延迟器的快轴方向与x轴正方向之间的角度为快轴角度，依次为θ_i，其范围为-90°≤θ_i≤90°，i＝1,2,3,4；定义与检偏器的透光轴方向与x轴正方向之间的角度为透光轴角度α，其范围为-90°≤α≤90°。Define an xyz coordinate system, wherein the z-axis is the direction of the optical axis of the beam Stokes parameter measuring device, and the xy plane is a plane perpendicular to the optical axis. Let the Stokes vector of beam 1 to be measured be S=[S ₀ , S ₁ , S ₂ , S ₃ ] ^T ("T" in the upper right corner indicates matrix transposition). Define the angle between the polarization direction of linearly polarized light and the positive direction of the x-axis as the polarization azimuth angle its range is

Define the angle between the fast axis direction of the first phase retarder, the second phase retarder, the third phase retarder and the fourth phase retarder in the phase retarder array and the positive direction of the x-axis as the fast axis angle, It is θ _i in turn, and its range is -90°≤θ _i ≤90°, i=1,2,3,4; the angle between the light transmission axis direction of the analyzer and the positive direction of the x-axis is defined as light transmission Shaft angle α, which ranges from -90°≤α≤90°.

所述的相位延迟器阵列中第i相位延迟器的Mueller矩阵为：The Mueller matrix of the i-th phase retarder in the phase retarder array is:

$M m (({θ θ}_{i i})) = = [\begin{matrix} 11,, & 00,, & 00,, & 00,, \\ 00,, & {cos cos}^{22} {22 θ θ}_{i i} + + {sin sin}^{22} {22 θ θ}_{i i} cos cos δ δ,, & {sin sin 22 θ θ}_{i i} {cos cos 22 θ θ}_{i i} - - {sin sin 22 θ θ}_{i i} {cos cos 22 θ θ}_{i i} cos cos δ δ,, & - - {sin sin 22 θ θ}_{i i} sin sin δ δ \\ 00,, & {sin sin 22 θ θ}_{i i} {cos cos 22 θ θ}_{i i} - - {sin sin 22 θ θ}_{i i} {cos cos 22 θ θ}_{i i} cos cos δ δ,, & {sin sin}^{22} {22 θ θ}_{i i} + + {cos cos}^{22} {22 θ θ}_{i i} cos cos δ δ,, & {cos cos 22 θ θ}_{i i} sin sin δ δ \\ 00,, & {sin sin 22 θ θ}_{i i} sin sin δ δ,, & - - {cos cos 22 θ θ}_{i i} sin sin δ δ,, & cos cos δ δ \end{matrix}]$

(1)(1)

其中，δ为相位延迟器的相位延迟量，θ_i为第i个相位延迟器的快轴角度。Among them, δ is the phase delay amount of the phase retarder, and θ _i is the fast axis angle of the i-th phase retarder.

所述的检偏器的Mueller矩阵为：The Mueller matrix of the described polarizer is:

$P P ((α α)) = = [\begin{matrix} 11,, & \frac{p p - - 11}{p p + + 11} cos cos 22 α α,, & \frac{p p - - 11}{p p + + 11} sin sin 22 α α,, & 00 \\ \frac{p p - - 11}{p p + + 11} cos cos 22 α α,, & {cos cos}^{22} 22 α α + + \frac{22 \sqrt{p p}}{p p + + 11} {sin sin}^{22} 22 α α,, & sin sin 22 α α cos cos 22 α α - - \frac{22 \sqrt{p p}}{p p + + 11} sin sin 22 α α cos cos 22 α α,, & 00 \\ \frac{p p - - 11}{p p + + 11} sin sin 22 α α,, & sin sin 22 α α cos cos 22 α α - - \frac{22 \sqrt{p p}}{p p + + 11} sin sin 22 α α cos cos 22 α α,, & {sin sin}^{22} 22 α α + + \frac{22 \sqrt{p p}}{p p + + 11} {cos cos}^{22} 22 α α,, & 00 \\ 00,, & 00,, & 00,, & \frac{22 \sqrt{p p}}{p p + + 11} \end{matrix}] - - - - - - ((22))$

其中，p为检偏器的消光比、α为检偏器透光轴角度。Among them, p is the extinction ratio of the analyzer, and α is the angle of the transmission axis of the analyzer.

待测光束1经过分光棱镜组后形成四束出射子光束，分别通过相位延迟器阵列中第一相位延迟器、第二相位延迟器、第三相位延迟器和第四相位延迟器和检偏器后，第i束光的Stokes矢量为S′＝P(α)M(θ_i)S。由于Stokes矢量的第一行表示光波的总强度，光电探测器能够探测到的光强即为此强度值，所以此处只关心Stokes矢量的第一行数值。为了便于理解，以第i束光为例进行说明。The beam 1 to be measured passes through the beam splitting prism group to form four outgoing sub-beams, which respectively pass through the first phase retarder, the second phase retarder, the third phase retarder and the fourth phase retarder and the analyzer in the phase retarder array Afterwards, the Stokes vector of the i-th beam is S'=P(α)M(θ _i )S. Since the first line of the Stokes vector represents the total intensity of the light wave, the light intensity that the photodetector can detect is this intensity value, so only the value of the first line of the Stokes vector is concerned here. For ease of understanding, the i-th light beam is taken as an example for illustration.

在理想情况下，可以测量得到的关于S₀、S₁、S₂、S₃的四元一次方程为：Ideally, the four-dimensional linear equations about S ₀ , S ₁ , S ₂ , and S ₃ that can be measured are:

${S S}_{00}^{' '} (({θ θ}_{i i})) = =$

${S S}_{00} + + {S S}_{11} \frac{p p - - 11}{p p + + 11} {{cos cos 22 α α [[{cos cos}^{22} 22 (({θ θ}_{i i})) + + {sin sin}^{22} 22 (({θ θ}_{i i})) cos cos δ δ]] + + sin sin 22 α α sin sin 22 (({θ θ}_{i i})) cos cos 22 (({θ θ}_{i i})) ((11 - - cos cos δ δ))}}$

$+ + {S S}_{22} \frac{p p - - 11}{p p + + 11} {{cos cos 22 α α sin sin 22 (({θ θ}_{i i})) cos cos 22 (({θ θ}_{i i})) ((11 - - cos cos δ δ)) + + sin sin 22 α α [[{sin sin}^{22} 22 (({θ θ}_{i i})) {+ + cos cos}^{22} 22 (({θ θ}_{i i})) cos cos δ δ]]}}$

$+ + {S S}_{33} \frac{p p - - 11}{p p + + 11} [[sin sin 22 α α cos cos 22 (({θ θ}_{i i})) - - cos cos 22 α α sin sin 22 (({θ θ}_{i i}))]] sin sin δ δ - - - - - - ((33))$

其中我们令where we make

${a a}_{i i 11} = = 11$

${a a}_{i i 22} = = \frac{p p - - 11}{p p + + 11} {{cos cos 22 α α [[{cos cos}^{22} 22 (({θ θ}_{i i})) + + {sin sin}^{22} 22 (({θ θ}_{i i})) cos cos δ δ]] + + sin sin 22 α α sin sin 22 (({θ θ}_{i i})) cos cos 22 (({θ θ}_{i i})) ((11 - - cos cos δ δ))}}$

${a a}_{i i 33} = = \frac{p p - - 11}{p p + + 11} {{cos cos 22 α α sin sin 22 (({θ θ}_{i i})) cos cos 22 (({θ θ}_{i i})) ((11 - - cos cos δ δ)) + + sin sin 22 α α [[{sin sin}^{22} 22 (({θ θ}_{i i})) {+ + cos cos}^{22} 22 (({θ θ}_{i i})) cos cos δ δ]]}}$

${a a}_{i i 44} = = \frac{p p - - 11}{p p + + 11} [[sin sin 22 α α cos cos 22 (({θ θ}_{i i})) - - cos cos 22 α α sin sin 22 (({θ θ}_{i i}))]] sin sin δ δ$

则（3）式可以写为Then (3) can be written as

${I I}_{i i} = = {S S}_{00}^{' '} = = [\begin{matrix} {a a}_{i i 11} & {a a}_{i i 22} & {a a}_{i i 33} & {a a}_{i i 44} \end{matrix}] [\begin{matrix} {S S}_{00} \\ {S S}_{11} \\ {S S}_{22} \\ {S S}_{33} \end{matrix}] - - - - - - ((44))$

这样采用所述的探测器阵列对所述的分光棱镜组产生的四束出射子光束同时测量，In this way, the four outgoing sub-beams produced by the beam splitting prism group are measured simultaneously by using the detector array,

我们可以得到方程：We can get the equation:

$[\begin{matrix} {I I}_{11} \\ {I I}_{22} \\ {I I}_{33} \\ {I I}_{44} \end{matrix}] = = [\begin{matrix} {a a}_{1111} & {a a}_{1212} & {a a}_{1313} & {a a}_{1414} \\ {a a}_{21 twenty one} & {a a}_{22 twenty two} & {a a}_{23 twenty three} & {a a}_{24 twenty four} \\ {a a}_{3131} & {a a}_{3232} & {a a}_{3333} & {a a}_{3434} \\ {a a}_{4141} & {a a}_{4242} & {a a}_{4343} & {a a}_{4444} \end{matrix}] [\begin{matrix} {S S}_{00} \\ {S S}_{11} \\ {S S}_{22} \\ {S S}_{33} \end{matrix}] - - - - - - ((55))$

上式即为I＝AS （6）The above formula is I=AS (6)

其中 $A = [\begin{matrix} a_{11} & a_{12} & a_{13} & a_{14} \\ a_{21} & a_{22} & a_{23} & a_{24} \\ a_{31} & a_{32} & a_{33} & a_{34} \\ a_{41} & a_{42} & a_{43} & a_{44} \end{matrix}] - - - (7)$ in $A = [\begin{matrix} a_{11} & a_{12} & a_{13} & a_{14} \\ a_{twenty one} & a_{twenty two} & a_{twenty three} & a_{twenty four} \\ a_{31} & a_{32} & a_{33} & a_{34} \\ a_{41} & a_{42} & a_{43} & a_{44} \end{matrix}] - - - (7)$

这里我们称A为系统矩阵。Here we call A the system matrix.

当系统矩阵A存在逆矩阵A^-1时，由（6）式我们可以得到待测光斯托克斯参量：When the system matrix A has an inverse matrix A ^-1 , we can get the Stokes parameters of the light to be measured from formula (6):

S＝A^-1I （8）S＝A ^-1 I (8)

但在实际测量时，由于在器件制造和测量过程中可能存在各种误差，如四分之一波片的快轴角度误差、相位延迟量误差和偏振棱镜透光轴角度误差、消光比误差等，此时我们得到的关于S₀、S₁、S₂、S₃的四元一次方程为：However, in the actual measurement, various errors may exist in the process of device manufacturing and measurement, such as the fast axis angle error of the quarter-wave plate, the phase delay error, the polarizing prism transmission axis angle error, and the extinction ratio error. , at this time we get the quaternary linear equations about S ₀ , S ₁ , S ₂ , S ₃ as:

${S S}_{00}^{' '} ((θ θ)) = =$

${S S}_{00} + + {S S}_{11} \frac{p p - - 11}{p p + + 11} {{cos cos 22 ((α α + + Δα Δα)) [[{cos cos}^{22} 22 (({θ θ}_{i i} + + Δθ Δθ)) + + {sin sin}^{22} 22 (({θ θ}_{i i} + + Δθ Δθ)) cos cos ((δ δ + + Δδ Δδ))]]$

$+ + sin sin 22 ((α α + + Δα Δα)) sin sin 22 (({θ θ}_{i i} + + Δθ Δθ)) cos cos 22 (({θ θ}_{i i} + + Δθ Δθ)) ((11 - - cos cos ((δ δ + + Δδ Δδ))))}}$

$+ + {S S}_{22} \frac{p p - - 11}{p p + + 11} {{cos cos 22 ((α α + + Δα Δα)) sin sin 22 (({θ θ}_{i i} + + Δθ Δθ)) cos cos 22 (({θ θ}_{i i} + + Δθ Δθ)) ((11 - - cos cos ((δ δ + + Δδ Δδ))))$

$+ + sin sin 22 ((α α + + Δα Δα)) [[{sin sin}^{22} 22 (({θ θ}_{i i} + + Δθ Δθ)) + + {cos cos}^{22} 22 (({θ θ}_{i i} + + Δθ Δθ)) cos cos ((δ δ + + Δδ Δδ))]]}}$

$+ + {S S}_{33} \frac{p p - - 11}{p p + + 11} [[sin sin 22 ((α α + + Δα Δα)) cos cos 22 (({θ θ}_{i i} + + Δθ Δθ)) - - cos cos 22 ((α α + + Δα Δα)) sin sin 22 (({θ θ}_{i i} + + Δθ Δθ))]] sin sin ((δ δ + + Δδ Δδ))$

（9）(9)

其中：Δδ为相位延迟器的相位延迟误差，Δθ为相位延迟器的快轴角度误差，Δα为检偏器的透光轴角度误差。Among them: Δδ is the phase delay error of the phase retarder, Δθ is the fast axis angle error of the phase retarder, and Δα is the light transmission axis angle error of the analyzer.

由于在实际测量中，存在上述的误差，由光电探测器探测到的光强应采用（9）式表示，而在计算斯托克斯参量S₀、S₁、S₂、S₃时我们使用的是（3）式，从而导计算所得到的斯托克斯参量存在误差。Due to the above-mentioned errors in actual measurement, the light intensity detected by the photodetector should be expressed by formula (9), and when calculating the Stokes parameters S ₀ , S ₁ , S ₂ , and S ₃ we use (3), so there is an error in the calculated Stokes parameters.

我们模拟了不同偏振方向的线偏振度为95%入射光在相应误差情况下所得斯托克斯参量的误差，其中相应误差为：相位延迟量误差Δδ=2°，快轴方向误差Δθ=0.1°，检偏器透光轴方向误差Δα=0.1°。We simulated the errors of the Stokes parameters obtained under the corresponding error conditions of the incident light with a degree of linear polarization of 95% in different polarization directions, where the corresponding errors are: phase delay error Δδ=2°, fast axis direction error Δθ=0.1 °, the direction error of the transmittance axis of the analyzer is Δα=0.1°.

归一化的斯托克斯参量误差ΔS₁₀、ΔS₂₀、ΔS₃₀随线偏振光的偏振方向变化如图4、图5、图6所示，传统方法如细线所示，本发明方法如粗线所示。传统方法将检偏器透光轴方向置于0°，本发明方法将检偏器透光轴方向分别调整至与待测光束的偏振方向成0°与90°后再进行测量，并进行数据处理。从图4、5、6我们可以看出，传统方法中，归一化斯托克斯参量误差随待测光束的偏振方向变化较大，如归一化斯托克斯参量S10误差，对于偏振方向为0°待测光束远大于偏振方向为90°待测光束，其误差值相差0.07。而采用本发明的方法，归一化斯托克斯参量误差随待测光束的偏振方向变化较小，有效地在Δδ=2°、Δθ=0.1°、Δα=0.1°的情况下，将归一化斯托克斯参量S₁₀，S₂₀，S₃₀误差减小到0.005以内，从而实现了待测光束斯托克斯参量的高精度测量。The normalized Stokes parameter errors ΔS ₁₀ , ΔS ₂₀ , and ΔS ₃₀ vary with the polarization direction of linearly polarized light as shown in Figure 4, Figure 5, and Figure 6. The traditional method is shown as a thin line, and the method of the present invention is shown as shown in bold. In the traditional method, the direction of the transmittance axis of the analyzer is set at 0°. In the method of the present invention, the direction of the transmittance axis of the analyzer is adjusted to 0° and 90° with the polarization direction of the beam to be measured, and then the measurement is performed, and the data deal with. From Figures 4, 5, and 6, we can see that in the traditional method, the normalized Stokes parameter error varies greatly with the polarization direction of the beam to be measured, such as the normalized Stokes parameter S10 error, for the polarization The beam to be measured with a direction of 0° is much larger than the beam to be measured with a polarization direction of 90°, and the difference between the error values is 0.07. However, with the method of the present invention, the normalized Stokes parameter error changes less with the polarization direction of the beam to be measured, effectively under the conditions of Δδ=2°, Δθ=0.1°, Δα=0.1°, the normalized Stokes parameter error will be normalized The errors of the Stokes parameters S ₁₀ , S ₂₀ , and S ₃₀ are reduced to within 0.005, thereby realizing high-precision measurement of the Stokes parameters of the beam to be measured.

Claims

1. A light beam Stokes parameter measuring device, characterized in that the composition of the device includes sequentially arranged along the optical axis of the system: beam splitting prism group (2), phase retarder array (3), polarizer (4) and the photodetector array (5), the output terminal of the photodetector array (5) is connected to the signal processing system (6), and each unit of the photodetector array (5) is connected with the phase retarder array (3) Each unit corresponds one by one, and according to the polarization direction of the light to be measured, after adjusting the direction of the transmission axis of the analyzer (4) to be parallel and perpendicular to the polarization direction of the light beam to be measured, respectively Then measure the polarization parameter of the beam to be measured.

2. The light beam Stokes parameter measuring device according to claim 1, characterized in that: the beam splitting prism group (2) is a combination of beam splitting prisms with a known splitting ratio, and forms a beam of incident light into multiple emit sub-beams.

3. The beam Stokes parameter measuring device according to claim 1, characterized in that: the phase retarder array (3) is composed of four identical phase retarders arranged in four quadrants in the same plane, They are the first phase delayer (301), the second phase delayer (302), the third phase delayer (303), and the fourth phase delayer (304); the first phase delayer (301), The included angle θ _i ( i=1, 2, 3, 4) are -45°, 0°, 30° and 60° respectively, and the phase retarder generates a 90° phase delay.

4. The beam Stokes parameter measuring device according to claim 1, characterized in that: the photodetector array (5) is a combination of multiple photodetectors, or a two-dimensional area array detection The device is composed of the same first photodetector (501), second photodetector (502), third photodetector (503) and fourth photodetector (504) arranged in four quadrants in the same plane , and together with the first phase retarder (301), the second phase retarder (302), the third phase retarder (303), and the fourth phase retarder (304) of the phase retarder array (3) One to one correspondence.