可调谐位相型光瞳滤波器的横向光学超分辨和轴向扩展焦深

为克服传统光瞳滤波器的缺点，实现系统光学超分辨性能的可调谐性，设计了一种新型可调谐的位相型光瞳滤波器.该光瞳滤波器包括两个λ/4波片和置于其间的λ/2波片，其中λ/2波片分为两个可作相对旋转的区域.研究结果表明，通过旋转λ/2波片的任意一区域不仅可以实现系统横向光学超分辨能力的可调性，而且可以在横向分辨能力提高的同时实现光学系统轴向焦深的扩展以及轴向焦移.     

可调谐位相型光瞳滤波器的横向光学超分辨和轴向扩展焦深

为克服传统光瞳滤波器的缺点,实现系统光学超分辨性能的可调谐性,设计了一种新型可调谐的位相型光瞳滤波器.该光瞳滤波器包括两个λ/4波片和置于其间的λ/2波片,其中λ/2波片分为两个可作相对旋转的区域.研究结果表明,通过旋转λ/2波片的任意一区域不仅可以实现系统横向光学超分辨能力的可调性,而且可以在横向分辨能力提高的同时实现光学系统轴向焦深的扩展以及轴向焦移. 关键词： 光学超分辨 位相型光瞳滤波器 可调谐     

全场光学相干层析成像系统的研制

研制了一套采用旋转1/2波片无色散移相器进行移相操作的全场光学相干层析成像系统.该移相器能在宽光谱范围内无色散地获得8倍于1/2波片旋转角的移相量,能快速、方便地为各种移相算法提供所需的移相量.移相量实测结果表明：系统获得了8倍旋转角的移相量,提出的移相器结构正确.采用Hariharan移相算法对反射镜样品进行的成像实验表明系统具有较高的移相精度.最后进行的实物样品成像实验,检验了系统的有效性. 关键词： 全场光学相干层析成像 无色散移相器 旋转1/2波片     

Improved measurements of thermally induced birefringence effects in a laser material using a half-wave plate

The polarization dependence of a probe beam for use in measuring thermally induced birefringence effects in a laser-diode end-pumped Nd:YAG ceramic laser has been investigated. The variation in intensity of the probe beam was found to be 10.2% for a linearly polarized probe beam, 20.6% for a circularly polarized probe beam, and 31.4% for a circularly polarized probe beam using a half-wave plate with a pump power of 12 W. The angle between the analyzer and the inclination of the major axis of the elliptical polarization with respect to the x axis was controlled using a half-wave plate. By combining a half-wave plate with a circularly polarized probe beam, the variation in intensity increased compared with conventional methods.     

Measurement of optical rotation and phase retardance of optical samples with depolarization effects using linearly and circularly polarized probe lights

This paper presents an experimental technique for measuring the optical rotation, depolarization, and phase retardance of optical samples. In the proposed approach, the optical properties of the sample are derived using a Stokes–Mueller matrix formalism in conjunction with linearly and circularly polarized probe lights. For a compound sample comprising a half-wave plate positioned in front of glucose solutions with concentrations ranging from 0 to 1.2 g/dl, the average normalized error in the measured rotation angle is determined to be 3.11% when using a linearly polarized light. The average surviving linear and circular polarization fractions of the glucose solutions are determined to be 1.0252 and 0.9945. The average normalized error in the measured retardance of the half-wave plate is 3.45%. When measuring a compound sample comprising a half-wave plate positioned in front of the scattered glucose solutions with turbidities from 0% to 50% by the addition of milk, experimental results show that the induced rotation angle increased as the turbidity increased, whereas both surviving linear and circular polarization fractions decreased as the turbidity increased. The effect of the turbidity on rotation angle is more significant than that on both surviving linear and circular polarization fractions. The average normalized error in the measured retardance of the half-wave plate is 1.43%. Consequently, a simplified geometry of the polarimeter is proposed to independently estimate the rotation angle, surviving linear and circular polarization fractions, and retardance from the derived viable algorithm.     

基于半波片的偏振跟踪理论分析

分析了卫星量子密钥分配中采用半波片进行偏振跟踪的原理，通过旋转半波片实现对偏振“零”方向的跟踪.针对BB84协议和B92协议，给出了三组共轭基六个光子偏振态的变换关系式，分析了基于偏振跟踪的量子密钥编码原理. 关键词： 量子密钥分配 偏振跟踪 半波片     

初级能量平衡

针对“神光Ⅱ”精密化的要求，有用半波片和偏振片组合衰减装置精确控制光束能量，达到能量平衡。简要论述了半波片组合衰减器的工作原理。采用独特的方法，对高精度光电探头和半波片的特性进行了检测。在此基础上，运用自动控制技术进行智能调节，实现了闭环自动控制模拟实验，达到了均方根为２％的激光能量控制精度。     

具有准单级聚焦特性的梯形波带片（英）

为改进用于X射线聚焦的二值化Gabor波带片目前所存在的结构复杂、不利于加工制作的问题,在不改变梯形透过率函数的前提下,通过将传统的梯形孔基元变为平行四边形基元应用于波带片的设计之中,提出了一种聚焦效率更高的具有准单级聚焦特性的波带片。理论推导显示,该波带片除了像Fresnel波带片一样能够消除偶数级的焦点外,还可以消除3q级（q为整数）的焦点,1/m4（m为焦点级数）的效率衰减系数也使得高级衍射得到了很好的抑制。MATLAB数值模拟的结果证明,该波带片的特性不仅满足以上推论,还具有比Fresnel波带片和环带扇形基元阵列波带片更低的背景噪声,可以看作是一种准单级聚焦的新型波带片。此外,在同一波带内,这种基于平行四边形基元孔的波带片设计的透光区始终保持各处的径向宽度为该波带的一半,且扇区结构简单一致,能够降低不少加工难度,易于推广应用。     

Achromatic half-wave combination of birefringent plates

Half-wave retarders are primarily used in rotating the plane of polarization of polarized light. These retarders usually exhibit strong wavelength dependence. In this paper, the design and characteristics of an achromatic half-wave plate, formed by a cascaded system of birefringent plates, have been studied. Pancharatnam proposed a combination of three retarders in series and discussed the possibility of fabricating reasonably good achromatic quarter-wave plate with a suitable combination of their retardance. The system studied here is similar in construction to Pancharatnam configuration and behaves as an achromatic half-wave plate over a wide spectral range. The proposed configuration exhibits a maximum variation of only about ±1.4 degree over the entire wavelength range of 500–750 nm. In our analysis we have used Jones matrix formalism for the derivation of the general expression for the equivalent retardation and the azimuth of the combination.     

Simultaneous measurement of optical rotation angle and retardance

In this study, an optical scheme based on Stokes-Mueller Formalism and rotating wave-plate Stokes polarimeter is successfully developed to simultaneously measure optical rotation angle and retardance. The average relative errors in the measured rotation angle and retardance of a half-wave plate which are solved by nonlinear equations of detected Stokes parameters are determined to be just 0.74% (1.16% for a perfect half-wave plate with retardance of 180°) and 0.40% respectively. The average relative error in the measured rotation angles of glucose solutions with concentrations ranging from 0 to 1.2 g/dl is determined to be 4.53% (2.98% under calibration with sample cell). From the inspection of simultaneous measurement of rotation angle and retardance in a glucose solution followed by a half-wave plate, the average relative error in the measured rotation angles of glucose solutions is determined to be 4.23% (1.81% under calibration with sample cell). The correlation coefficient between the measured rotation angle and the glucose concentration is found to be 0.99966, while the standard deviation is just 0.00357°, and the average relative error in the measured retardance of a half-wave plate is determined to be just 0.47%. Consequently, the derived algorithm for simultaneously measuring rotation angle and retardance is feasible, and the developed system is evaluated with a precision of 10% approximately in rotation angle and a high precision of 0.0032% in retardance measurement.     

可调光瞳滤波器的轴向焦移及扩展焦深

光学超分辨、焦深扩展及焦移3种效应一直受到研究人员的关注,且在光学显微成像、光学校准、光学相干层析成像及光存储中有着重要的应用.提出一种可调谐光瞳滤波器来实现光学系统的轴向焦移及扩展焦深.该光瞳滤波器由两个完全相同且相互平行的λ/4波片和置于其间的λ/2波片组成,其中λ/2波片分为两个可作相对旋转的区域,并且通过推导得...     

径向偏振调制对聚焦光斑匀滑及偏振特性的影响

基于标量衍射理论建立了光谱色散平滑(SSD)、随机相位板(RPP)和偏振匀滑(PS)联用的光束匀滑方案数值仿真模型。以斑纹对比度和偏振度为主要评价参量,利用该模型研究了径向偏振调制的匀滑及消偏振特性。研究表明,径向偏振调制可以有效降低聚焦光斑斑纹对比度和偏振度。使用半波片拼接方式产生近似径向偏振光时,拼接单元数对匀滑及偏振特性影响较小,8片拼接的匀滑效果已与理想径向偏振光几乎一致。对比分析了径向偏振调制、正交偏振调制和双折射楔三种PS方式,结果表明,由于三种PS方式本质上的一致性,光束的匀滑及偏振特性差别较小。     

An instrument for measuring low optical rotation angle

This paper develops a linear heterodyne interferometer based on phase-locked extraction for measuring low optical rotation angle. The validity of the proposed design is demonstrated by measuring a half-wave plate. The average relative error in the measured rotation angle of the half-wave plate is determined as just 0.74%. When applied to the measurement of glucose solutions with concentrations ranging from 0 to 1.2 g/dl, the average relative error in the measured rotation angle of glucose solutions is determined to be 1.46%. The correlation coefficient between the measured rotation angle and the glucose concentration is determined to be 0.999991, while the standard deviation is just 0.00051°. The current system is capable of measuring glucose concentration as low as 0.01 g/dl with an error of 6.67% in the rotation angle measurement. Overall, the experimental results demonstrate the ability of the proposed system to obtain highly accurate measurement of the optical rotation angle.     

Influence of the magnetic structure parity on conditions of the electromagnetic transparency of an antiferromagnetic plate

Bulletin of the Russian Academy of Sciences: Physics - Using the example of a transparent half-wave plate of a compensated antiferromagnetic with anti-symmetric magnetoelectric interaction, the...     

Optical properties of a QHQ ferroelectric liquid crystal phase modulator

A half-wave plate sandwiched between two-quarter-wave plates (a QHQ) may be used as a variable linear retarder. We describe some new features of the optical properties of such a device and present results of an experimental demonstration of a ferroelectric liquid crystal phase-only modulator based on the above principle.     

稳态大视场偏振干涉成像光谱仪中视场补偿型Savart偏光镜透射率研究

论述了基于视场补偿型Savart偏光镜的稳态大视场偏振干涉成像光谱仪的分光机理.依据电磁场边值条件,分析了光在视场补偿型Savart偏光镜中各晶体分界面上的透射情况,得出了透射率的理论计算公式.采用计算机模拟,分析了在半波片为不同材料时,透射率随入射波长、视场角及半波片厚度的变化关系.研究表明,视场补偿型Savart偏光镜具有大视场、高通量、高探测灵敏度的显著特点.此研究可为新型干涉成像光谱技术的研究和新型偏振干涉成像光谱仪的设计、研制提供重要的理论指导. 关键词： 偏振干涉成像光谱仪 视场补偿型Savart偏光镜 透射率 电磁场边值条件     

高阶邦加球上柱矢量光束的变换

本文从理论和实验上系统研究了利用半波片实现高阶邦加球上柱矢量光束变换的方法.通过琼斯矩阵的方法理论分析得出变换前后柱矢量光束在高阶邦加球上两个对应点的纬度相反,经度随半波片的光轴方向角的不同而改变.最后,基于空间光调制器搭建了一套柱矢量光束产生及其变换系统,实验结果证明了这种方法的可行性.     

Crosstalk elimination in multi-view autostereoscopic display based on polarized lenticular lens array

An autostereoscopic display composed of a directional backlight,an image display panel,a striped half-wave plate,and a polarized lenticular lens array is proposed.The directional backlight emitting the parallel light can redirect the cones of light to lenticular lens array and reduce the chromatic spatial-interference effect.The striped half-wave plate,located in front of the image display panel,transformed the polarization direction of the lights from the directional backlight into two mutually perpendicular directions.The polarized lenticular lens array not only can divide the light from the left and right view images to send to left and right eyes but also can reduce the crosstalk of the stereoscopic images.The proposed autostereoscopic display can produce high quality stereoscopic images without crosstalk at the optimal viewing distance.     

Generation of arbitrary four-atom entangled decoherence-free states

This paper proposes a scheme to generate arbitrary four-atom entangled decoherence-free states by using simple linear optical elements, four one-sided cavities in which four atoms are confined respectively. By conveniently tuning the titled angle of one half-wave plate, it can obtain arbitrary four-atom entangled decoherence-free states with a successful probability of 1 as long as there is no photon loss.