Novel method for measurement of retardance of a quarter-wave plate

A novel and simple method used for measurement of retardance of a quarter-wave plate employing two polaroids and a right-angle prism is reported. The theoretical analysis of the principle is given taking the Jones matrix as a mathematical tool. The uncertainty of the method is theoretically analyzed. An application example is also given. The measured result of the example is verified with a test. The main advantage of this method is that it can completely determine the retardance value, which overcomes the shortcomings of the existing methods reported before for determining only the multi-value function values, such as cosine or tangent value of the retardance. In addition, this method is also accurate, easy to operate and can also be used for the retardance measurement of other retardation plates.     

一种提高1/4波片相移量测量精度的方法

提出了一种新颖的，在已知四分之一波片快轴方向的情况下，利用两个偏振片和一个三棱镜来提高波片相位延迟角测量精度的简便方法，给出了对该方法的理论分析与不确定度公式，并给出了应用实例.此方法的主要优点是可以提高测量精度，并且操作简单，容易实现.     

Method for measuring retardation of a quarter-wave plate based on normalized secondary harmonic component

A method for measuring retardation of a quarter-wave plate based on normalized secondary harmonic component is proposed, and the measuring principle is analyzed. The optical measuring system is composed of a laser, a polarizer, a phase modulator, the quarter-wave plate to be measured, an analyzer and a detector. The azimuths of the transmission axes of the polarizer and the analyzer with respect to the modulating axis of the phase modulator are +45°, 0°, respectively. The retardation of the quarter-wave plate is calculated precisely using the normalized secondary harmonic components prior to and after 22.5° rotation of the quarter-wave plate. In this method, the major axis position of the quarter-wave plate is not required to be known in advance, and the measured retardation is independent of the intensity fluctuation of the light source. The feasibility of the method is verified by the experiments.     

Method to estimate the reflection-induced retardance of bulk glass optical current sensing head

A novel method used for the estimate of the reflection-induced retardance in a bulk glass current sensing head employing just a polarizer and an analyzer is proposed, the measuring optical set-up is given, the principle is theoretically analyzed, the uncertainty is calculated and the mathematical expression of it is given. Finally, an application example of the method is shown.     

Photoelastic stress pattern analysis using Fourier transform with carrier fringes: influence of quarter-wave plate error

The Fourier transform method, widely applied in photomechanics for the automated analysis of interferometric fringe patterns, has been recently extended to the photoelastic isochromatic fringe patterns analysis. Unfortunately, its use in photoelasticity involves some limitations that have not been completely highlighted in literature. This work deals with the influence of the quarter-wave plate tolerance on the evaluation of the retardation. Both theoretical and experimental analyses have shown that the quarter-wave plate error does not affect the retardation only if the principal stress directions in the model and in the carrier are aligned. In general, instead, the tolerance of the quarter-wave plates leads to an amplification of the retardation error due to the influence of the isoclinics with a subsequent restriction of the field in which the method can be applied. For instance, using common quarter-wave plates and tolerating a maximum retardation error of about 0.03 fringe order, than the Fourier transform method cannot be applied as a full-field technique but only in the model zones in which the misalignment between the principal stresses in the model and in the carrier is less than 15°.     

光学玻璃电流传感头线性双折射的一种测量方法

报告了一种测量光学玻璃电流传感头线性双折射的方法,以琼斯矩阵为数学工具给出了对该方法的理论分析、测量不确定度计算公式,并用实验方法给出了应用实例.此方法的主要优点是光路所用元件容易获得且测量结构简单实用.     

虚拟坐标激光动态跟踪测量系统中光路的琼斯矩阵分析

激光跟踪测量系统应用于工业领域 ,实现动态目标的实时跟踪和虚拟坐标的测量 ,是测控一体化的计算机集成系统。推导出该系统中光学系统的琼斯矩阵 ,采用矢量分析的方法 ,分析了光学系统 (包括分束器、平面跟踪镜和角锥棱镜 )对于任意方向入射光偏振态的影响以及光强变化的影响。在数值仿真的基础上 ,对光学系统进行优化设计 ,提高整个系统的跟踪测量性能。     

Structure of Deterministic Mueller Matrices and Their Reconstruction in the Method of Three Input Polarizations

The method of reconstruction of complete deterministic Mueller matrices for the structures of incomplete matrices, which are measured in the method of three input polarizations, has been developed. The method is based on reconstruction of the corresponding Jones matrices for the given structures of incomplete Mueller matrices.     

波片对偏振激光干涉仪非线性误差的影响

利用琼斯矩阵理论,研究了基于偏振移相技术的激光干涉仪中1/4波片和1/2波片的非理想因素导致非线性误差的产生机理和变化规律.理论研究表明:在导致波片处于非理想状态的各个因素中,干涉仪中两个1/4波片的差模延迟角误差Δεq所产生的恒定偏置误差和接收装置中1/4波片的延迟角误差εq3所引起的一次谐波非线性误差,是组成干涉仪非线性误差的最主要的两个部分;波片各种误差源非理想因素导致的非线性误差在小误差情况下经线性叠加后由干涉仪最终输出.     

Non-destructive thickness measurement of dichromated gelatin films deposited on glass plates

A quick estimation of the thickness of thin films deposited on glass plates is described in this paper. The principle of the method is based on the measurement of the Haidinger fringes generated by the film. For ease of observation and measurement, a commercial Fizeau-type interferometer such as a Zygo interferometer using a large angle of illumination has been used. The simple modification to observe the Haidinger fringes with the Fizeau-type interferometer is also described. The thickness of the film is related to the diameters of the Haidinger fringes. It is possible to estimate the thickness quickly by counting the number of fringes. A more accurate estimate can be obtained by the measurement of the diameters of the fringes and using these data in a formula that relates these two to the thickness of the film. The method is found to be useful for measuring the thickness of dichromated gelatin films (DCG) coated on a substrate to make holographic optical elements. The accuracy in estimating the thickness of the film is of the order . The method is entirely non-destructive and works well in the thickness range of 5–.     

大口径连续相位板面形检测与评价

基于全局最小二乘拼接算法和图像融合算法建立了连续相位板（CPP）子孔径拼接检测算法,并根据全局相关匹配原理提出采用面形残差来评价CPP的加工面形。采用高精度动态干涉仪等设备建立了相应的检测系统,并针对430 mm430 mm口径CPP开展了数值模拟和检测实验。理论计算结果表明：系统计算误差为0.005 nm。实验结果表明,整个检测系统软硬件RMS误差小于5 nm,基本满足CPP面形检测要求。从而验证了CPP检测和评价的正确性和可行性。     

Analysis of Birefringence Compensation Using a Quarter-Wave Plate in Solid-State Lasers

Using Jones matrix formulation, the theoretical calculations of birefringence compensation technique for a quarter-wave plate scheme are presented. This scheme was proposed and experimentally demonstrated by W. A. Clarkson et al. (Opt. Lett. 24 (1999) 820). In the present paper we have theoretically confirmed that using this method, even in principle, complete compensation is not possible. However, it is shown quantitatively that this scheme does makes possible effective compensation for the birefringence in as few as several tens of watts of pumping power region, which is an attractive feature for laser-diode (LD) pumped solid-state laser systems. We also found good agreement between our theoretical calculations and experimental results obtained by W. A. Clarkson et al. For example, from the analysis we show that only < 0.1% loss will be generated by about 10 W of heat deposited in the rod. This corresponds to about 30 W of LD pump power, which may generate from 6 to 10 W output power depending upon the conversion efficiency of type lasers     

非理想1/4波片对泵浦光偏振态的影响

为了研究调整架角度误差以及波片与光源波长不匹配对线偏振光经过1/4波片之后偏振态的影响,本文利用坐标变换法得到1/4波片的琼斯矩阵,并用琼斯矩阵表示各偏振态。推导出波片与光源不匹配时对偏振态的影响理论模型。当考虑到调整架的角度误差时,对入射光偏振态以及波片的琼斯矩阵表达式做引入角度误差的泰勒展开,最后得到和实验结果匹配的仿真曲线。仿真结果表明,当采用808 nm 1/4波片对795 nm波长的线偏振光作用时,在不考虑调整误差的理想情况下出射光椭圆度最高为0.9746,考虑调整误差时,对应理想情况下椭圆度最高为0.96,椭圆度最高点偏移1.72°。仿真和实验结果为进一步分析泵浦光椭圆度对原子参数的影响提供了依据。     

改善液晶光阀投影光学系统偏振特性的理论设计方法

定量分析了液晶光阀投影光学系统中影响系统对比度的主要因素，利用矢量方法建立三维空间数学模型对光线进行追迹，并利用琼斯矩阵和矢量光学的原理分析了偏振器件--主要是波片--和各种光学薄膜对光学系统性能的影响。给出了在一定假设条件下的对没有波片的光学系统和插入波征后的光学系统的仿真计算结果。两组数据比较表明在光路中插入合适相位差的波片可以显著提高系统对比度等性能。     

新型静态偏振风成像干涉仪理论探测误差的分析与计算

简述了新型静态偏振风成像干涉仪的原理,推导出一般情况下系统的Jones矩阵.在此基础上计算了系统中各偏振器件重要参数在非理想情况下对风速和温度探测结果的影响.利用计算机模拟对探测误差进行了分析,并按照系统精度要求从理论上提出了各重要参数的误差容限.该研究为新型静态偏振风成像干涉仪的研制、定标及后期数据处理提供了理论依据. 关键词： 静态偏振风成像干涉仪 Jones矩阵 方位角误差 相位延迟量误差     

Using transient and steady-state SEA to assess potential errors in the measurement of structure-borne sound power input from machinery on coupled reception plates

Isolated reception plates provide an engineering approach to quantify the structure-borne sound power input from machinery through the measurement of the spatial-average velocity level and structural reverberation times. For applications in building acoustics there are practical and economic reasons to consider using coupled reception plates formed by solid heavyweight walls or floors that are structurally coupled to other building elements. This paper uses transient and steady-state statistical energy analysis to investigate how the errors depend upon the building structure to which the coupled reception plate is connected. It is shown that the problem is twofold. Firstly, in the low- and mid-frequency ranges, the steady-state velocity level on the coupled reception plate is increased by energy returning from other coupled plates. Secondly, the structural decays on the coupled reception plate have significant curvature due to returning energy; hence short evaluation ranges are needed to minimise the error when determining the total loss factor. This leads to a problematic situation where the coupled reception plate appears to give the correct answer due to the error in the energy cancelling out the error in the total loss factor. The latter error can be minimised using short evaluation ranges for the structural reverberation time.     

基于共光路干涉原理的精细表面粗糙度测量方法

提出了一种利用光的干涉原理测量光滑物体表面粗糙度的方法.该方法采用两光束共光路、同心聚焦扫描可实现表面粗糙度的绝对测量.使用一个半波片改变一路光束的偏振态,避免了传统测量系统中光路具有可逆性的问题,保证了系统的稳定性.使用一个l/4波片使接收端的光束偏振态方向一致,使干涉信号可见度最大.该系统光路结构简单,容易实现.对一标准量块进行了测量,并对光功率计分辨率对测量结果的影响进行了分析,结果表明本系统在实验室现有条件下可以测量轮廓算术平均偏差Ra为0.012μm的粗糙度量块.     

多方向偏振片及1/4波片对全偏振检测的影响研究

理论上推导了光线通过任意方向偏振片和任意方向1/4波片的出射光强与全Stokes参量关系的表达式,利用自然背景下的人造目标为对象开展全偏振检测实验,并以目标与背景偏振度对比为主要指标,研究了多方向情况下上述两种偏振器件影响全偏振检测的因素。研究表明下述三种情况方程组秩小于4导致全偏振检测无效:固定1/4波片方向而改变偏振片方向;固定偏振片方向改变1/4波片方向,且四组角度中两器件平行及垂直的关系同时出现;偏振片与1/4波片有三组角度相同,第四组角度关系为平行或垂直。实验表明,固定偏振片方向改变1/4波片方向,探测结果与固定偏振片方向的取值有关;采用偏振片与1/4波片三组方向相同,第四组夹角45°的全偏振检测方式,偏振度对比较高。     

测量光学玻璃电流传感头线性双折射的新方法

线性双折射是光学(含光纤)电流传感头的重要光学参量之一,会明显影响光学电流传感器的性能,因此测量光学传感头内线性双折射的大小对于提高光学电流传感器的性能有重要意义.本文报道了一种测量光学玻璃电流传感头线性双折射的新方法,以琼斯矩阵为数学工具给出了对该方法的理论分析及测量不确定度分析,并用实验方法给出了应用实例.此方法的主要优点是弥补了以前报道过的两种测量方法暴露出的无法唯一地确定光学玻璃电流传感头线性双折射的大小,或虽然能测定双折射大小,但测量不确定度较大的不足.实验结果表明:本方法可明显地提高测量准确度.