采用偏振分不棱镜的光桥式补偿技术

介绍了一种使用偏振分光棱镜的新型光桥式补偿技术，研究了棱镜消光比变化引起的误差。使用该补偿结构的光纤压力传感器实际应用于石油化工门油罐储量计量，其现场运行长期稳定性优于０．２％。     

偏振分光镜旋转角度误差的确定

偏振分光镜存在旋转角度误差是引起激光外差干涉非线性误差的来源之一.提出了一种确定激光外差干涉偏振分光镜旋转角度误差的方法.通过分析偏振分光镜旋转角度误差在其它条件下对激光外差干涉非线性误差的影响,得出偏振分光镜存在的旋转角度误差将极大地增加非线性误差的一次谐波,但改变二次谐波很小.对光电接收器输出信号进行频谱分析,分离出激光外差干涉非线性误差的一次谐波和二次谐波,通过测量非线性误差二次谐波相对测量信号的大小,通过应用非线性误差二次谐波幅度比值与偏振分光镜旋转角度误差之间的模型,确定偏振分光镜旋转角度误差.实验结果表明,应用该方法能够得到偏振分光镜的旋转角度误差,从而为调整偏振分光镜提供了实验依据.     

采用偏振分光棱镜的光桥式补偿技术

介绍了一种使用偏振分光棱镜的新型光桥式补偿技术。研究了棱镜消光比变化引起的误差。使用该补偿结构的光纤压力传感器已实际应用于石油化工部门油罐储量计量，其现场运行长期稳定性优于０．２％。     

用偏振干涉仪检定0.01μm位移传感器的初步试验

一、偏振干涉仪法的测量原理传感器的检定是将传感器的测杆与干涉仪的可动镜接触,将由干涉仪测得的可动镜实际移动的距离与由传感器测得的移动距离比较,就得到传感器的示值误差。因此,检定装置的关键是其精度和分辨率高于传感器的干涉仪。干涉仪的光路图见图1,从激光器发出的线偏振光与偏振分光镜的水平轴成45°角的方向入射,经偏振分光镜分成S光和P光,分别经参考镜和可动镜反射后,再次在偏振分光镜处会     

单频激光干涉仪四通道信号接收系统

在单频激光干涉仪四通道信号接收系统原理基础上，提出一种采用Wollaston棱镜的四通道信号接收系统。当使用偏振分光镜的四通道信号接收系统时，由于偏振混合现象，在信号接收的过程中会增加额外的误差。而Wollaston棱镜的自然物理特性提供了更好的分光性能，从而能降低偏振混合所带来的影响，提高了信号输出质量，并能简化接收系统中的光学元件。     

光纤传感器中偏振开关法消偏振衰落技术

针对低双折射光纤双光束干涉型传感器两臂偏振态随机变化引起的信号衰落,提出的一种新型消偏振方式可以在可见度略有下降的情况下,较好地消除偏振态变化引起的干涉信号可见度的随机变化。该方案是通过相互正交的两个偏振态,补偿由于其中一个偏振态变化导致的干涉信号衰落。通过自动增益控制电路（AGC）可以使传感信号稳定,能够在信噪比有所下降的情况下消除偏振衰落的影响,实现干涉型光纤传感器的消偏振衰落。     

基于穆勒系数测量的目标识别技术研究

目标对入射偏振光的退偏振特性与目标的材料有着密切的联系,并且对激光入射角的变化特别敏感,而目标的穆勒矩阵完全描述了其对入射偏振光的退偏振特性。因此可以利用测量目标的穆勒系数实现识别目标的目的。利用这一思想提出一种基于穆勒系数测量的目标识别技术。实验采用He-Ne激光作为照明光源,获取不同入射角时铝制飞机模型机翼和涂漆木板的穆勒系数。结果显示:两者的穆勒系数具有明显差异,随着激光入射角增加,两者的穆勒系数先减小后增大。对实验结果进行详细分析,并给出处于杂乱背景中飞机模型的强度图像和偏振图像。     

光纤陀螺掺铒光纤光源消偏技术

针对泵浦偏振态对高精度光纤陀螺掺铒光纤光源平均波长稳定性产生影响的问题,设计了掺铒光纤光源泵浦消偏的结构,该结构采用Lyot光纤消偏器来对泵浦光进行消偏,理论分析了该结构中Lyot消偏器结构参数的选取.实验验证了掺铒光纤光源的波分复用器具有偏振特性,会影响掺铒光纤光源平均波长稳定性,采用设计的泵浦消偏结构可有效消除波分...     

自适应光强变化的动态边缘位置提取方法

目的研究LED背光源光照强度变化对视觉测量系统二维尺寸测量精度的影响。方法通过对图像灰度与光源强度的关系进行理论推导和实验探究,得出背光源强度对图像边缘位置的影响规律。结果随着光源强度的增强,边缘位置附近像素灰度值逐渐增大,边缘位置发生内缩,可达4.7个像素(20.03μm)。通过自适应光强变化的动态边缘位置提取方法进行补偿,各标准轴直径测量误差减小到1个像素(4.26μm)以内。结论光照强度变化对影像测量系统测量精度有很大的影响,自适应光强变化的动态边缘位置提取方法能够有效补偿测量误差,提高测量精度。     

独立通道偏振罗盘信息检测方法及传感器设计

目前偏振光导航传感器大多以POL-神经元模型为基础,误差主要来源于通道间信号增益差异,以及检偏器阵列的相对角度误差。为了提高偏振罗盘信息的检测精度,提出了一种独立通道偏振罗盘信息检测方法。利用三个相互独立的偏振光检测通道测量大气偏振信息,获取航向角信息。并且,结合分时复用技术,设计了独立通道偏振光导航传感器,提出了相应的标定方法和误差补偿算法。实验结果表明,独立通道偏振光导航传感器能够显著降低偏振罗盘信息检测误差,补偿后传感器误差在±0.05°以内。     

Polarization holographic high-density optical data storage in bacteriorhodopsin film

Optical films containing the genetic variant bacteriorhodopsin BR-D96N were experimentally studied in view of their properties as media for holographic storage. Different polarization recording schemes were tested and compared. The influence of the polarization states of the recording and readout waves on the retrieved diffractive image's intensity and its signal-to-noise ratio were analyzed. The experimental results showed that, compared with the other tested polarization relations during holographic recording, the discrimination between the polarization states of diffracted and scattered light is optimized with orthogonal circular polarization of the recording beams, and thus a high signal-to-noise ratio and a high diffraction efficiency are obtained. Using a He-Ne laser (633 nm, 3 mW) for recording and readout, a spatial light modulator as a data input element, and a 2D-CCD sensor for data capture in a Fourier transform holographic setup, a storage density of 2 x 10(8) bits/cm2 was obtained on a 60 x 42 microm2 area in the BR-D96N film. The readout of encoded binary data was possible with a zero-error rate at the tested storage density.     

Ocular aberrations with ray tracing and Shack-Hartmann wave-front sensors: does polarization play a role?

Ocular aberrations were measured in 71 eyes by using two reflectometric aberrometers, employing laser ray tracing (LRT) (60 eyes) and a Shack-Hartmann wave-front sensor (S-H) (11 eyes). In both techniques a point source is imaged on the retina (through different pupil positions in the LRT or a single position in the S-H). The aberrations are estimated by measuring the deviations of the retinal spot from the reference as the pupil is sampled (in LRT) or the deviations of a wave front as it emerges from the eye by means of a lenslet array (in the S-H). In this paper we studied the effect of different polarization configurations in the aberration measurements, including linearly polarized light and circularly polarized light in the illuminating channel and sampling light in the crossed or parallel orientations. In addition, completely depolarized light in the imaging channel was obtained from retinal lipofuscin autofluorescence. The intensity distribution of the retinal spots as a function of entry (for LRT) or exit pupil (for S-H) depends on the polarization configuration. These intensity patterns show bright corners and a dark area at the pupil center for crossed polarization, an approximately Gaussian distribution for parallel polarization and a homogeneous distribution for the autofluorescence case. However, the measured aberrations are independent of the polarization states. These results indicate that the differences in retardation across the pupil imposed by corneal birefringence do not produce significant phase delays compared with those produced by aberrations, at least within the accuracy of these techniques. In addition, differences in the recorded aerial images due to changes in polarization do not affect the aberration measurements in these reflectometric aberrometers.     

偏振器对比较式光学电流互感器性能的影响

使用偏振态分析工具,分析了偏振器性能--偏振度、消光比的不完善以及偏置角误差等因素对比较式光学电流互感器性能的影响.结果表明,由于双输入双输出的特殊传感头结构的采用,使得比较式OCT可以有效克服偏振度和消光比的不完善带来的不利影响,但是传感头的起偏器与检偏器之间的偏置角误差会对比较式OCT的性能产生较大的影响.可以采用改进工艺精确调整偏置角、增大参考直流磁场和软件修正等措施加以改进.对改进后的比较式OCT进行了实验,实验结果表明在50℃的温度变化范围内,互感器的误差变化量仅为0.7%,较之采用比较式补偿之前的误差变化量16%,温度性能得到了显著的提高.     

Nanomagnetic behavior of fullerene thin films in Earth magnetic field in dark and under polarization light influences

In this paper magnetic fields intensity of C60 thin films of 60 nm and 100 nm thickness under the influence of polarization lights are presented. Two proton magnetometers were used for measurements. Significant change of magnetic field intensity in range from 2.5 nT to 12.3 nT is identified as a difference of dark and polarization lights of 60 nm and 100 nm thin films thickness, respectively. Specific power density of polarization light was 40 mW/cm2. Based on 200 measurement data average value of difference between magnetic intensity of C60 thin films, with 60 nm and 100 nm thickness, after influence of polarization light, were 3.9 nT and 9.9 nT respectively.     

白光干涉法偏振耦合测试及数据采样分析

基于白光干涉原理,通过麦克尔逊干涉仪的光程补偿作用,检测保偏光纤空间分布寄生偏振耦 合强度和耦合点位置。经数据采样时域理论分析知:扫描步长增大时,耦合强度检测误差和耦合点位置判断误差呈线性增大。扫描步长小于500nm时,强度误差小于5%,位置误差在11mm之内。     

多束相干光叠加的计算机模拟

研究了具有空间不对称分布的多束相干光的叠加问题。对参考平面上相干光产生的干涉光强分布进行理论推导和数值计算,从理论上定量地分析了多束相干光的波矢量、偏振态对干涉光强分布的影响。模拟结果表明波矢量的改变主要影响干涉光强的空间分布,激光束偏振态的改变主要影响干涉场的对比度。     

用火花塞光纤传感器测量发动机的爆震

应用所研制的火花塞光纤传感测量系统对ＢＪ４９２Ｑ汽油机进行爆震燃烧测量和研究。分析了爆震燃烧对火焰光辐射变化的影响。正常燃烧理论空燃比工况时，ＣＨ（４３１．５ｎｍ），Ｃ２（５１６．５ｎｍ）及Ｈ２Ｏ（５８８ｎｍ）自由基的光强曲线出现双峰值，着火延迟期内光辐射为自由基的光辐射。爆震燃烧较强工况，只出现一个较大光强峰值，主要是碳粒子的热辐射，峰值处出现剧烈波动，相位提前，无自由基光辐射。爆震燃烧较强峰值     

A New Method for Spectral Performance Evaluation of a Chromatic and Achromatic Quarter-Wave Retarder

When a polarized polychromatic beam passes through a quarter-wave retarder, the constituent spectral components suffer different changes in the state of polarization. As a result, when the beam passes through an analyzer, the intensity of the resultant beam changes, depending on the orientation of the analyzer, state of polarization of the input beam, spectral and spatial intensity distribution of the source and the wavelength-dependent retardance of the quarter-wave retarder. The intensity variation of the resulting beam is theoretically and experimentally observed, with the variation of the azimuthal angle of the analyzer for film-type chromatic and prism-type achromatic quarter-wave retarders. The spectral performances of achromatic retarders are generally evaluated by measuring retardances at discrete wavelengths by using a monochromatic beam of light over the wavelength range of interest. In this study, a simple method is used for computing the fractional nonlinear polarization (FNLP) from theoretically and experimentally obtained intensity variations for evaluating the spectral performance of both achromatic and chromatic quarter-wave retarders operating over a broad spectral range in the visible region using a polychromatic beam of light. FNLP variation is also shown for a film-type chromatic quarter-wave retarder using a monochromatic source of light. The experimentally obtained values are compared with theoretical values and a good agreement is observed. The applications of the method for the performance evaluation of quarter-wave retarders are discussed.     

Polarization sensing with visual detection

We describe a new approach to fluorescence sensing which relies on visual determination the polarization. The sensing device consists of a fluorescent probe, which changes intensity in responses to the analyte, and an oriented fluorescent film, which is not affected by the analyte. An emission filter is selected to observe the emission from both the film and the sensing fluorophore. Changes in the probe intensity result in changes in the polarization of the combined emission from the sensor and reference. The degree of polarization can be detected visually using a dual polarizer with adjacent sections oriented orthogonally to each other. The emission passing through the dual polarizer is viewed with a second analyzing polarizer. This analyzer is rotated manually to yield equal intensities from both sides of the dual polarizer. This approach was used to measure the concentration of RhB in intralipid and to measure pH using 6-carboxyfluorescein. The analyzer angle is typically accurate to 1 degree, providing pH values accurate to +/- 0.1 pH unit at the midpoint of the titration curve. We also describe a method of visual polarization sensing that does not require an oriented film and that can use the same fluorophore for the sample and reference. These approaches to visual sensing are generic and can be applied to a wide variety of analytes for which fluorescent probes are available. Importantly, the devices are simple, with the only electronic component being the light source.