A NEW METHOD OF POLARIZATION MICROSCOPIC ANALYSIS. I. SCANNING WITH A BIREFRINGENCE DETECTION SYSTEM.
A NEW METHOD OF POLARIZATION MICROSCOPIC ANALYSIS. I. SCANNING WITH A BIREFRINGENCE DETECTION SYSTEM.
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DOI：
10.1083/jcb.18.2.223
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发表时间：
1963-08
期刊：
影响因子：
--
通讯作者：
MOORE RD
中科院分区：
文献类型：
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作者：
ALLEN RD;BRAULT J;MOORE RD
本文介绍了一种新的偏振光分析方法，即用一种高灵敏度的双折射电子探测器来确定物体的晶轴，然后测量由于双折射而引起的相位延迟。在该方法中采用的显微镜系统由一个电子双折射检测系统（BDS），一个无应变透镜的显微镜，和一个驱动阶段，用于通过试样在适当的速度跨越放置在现场停止和成像的光圈的图像在试样平面的聚光镜。该检测器在恒定偏转灵敏度约为0.001时直接将延迟记录为电压。1.1 V/埃单位，在120埃单位的范围内。对于由95 x，N形成的直径为36 µ的光斑，基础均方根噪声电平为0.002 A。A. 1.25物镜对，并与扫描光点直径的倒数成比例增加。高分辨率扫描的噪声增加可以通过增加仪器时间常数来抵消，仪器时间常数可以在0.004秒和0.4秒之间的数十倍内进行调节。采用调制光和快速电子检测器，避免了高消光偏振显微镜中的一些难题。举例来说：（a）测量的双折射分布不受通常的衍射异常的影响;因此不需要偏振整流器。(b)该检测器对双折射具有选择性，因此在分离对比度时不会因不同的光学特性（例如二向色性、光散射）而出现问题。(c)速度和灵敏度都比视觉或摄影方法提高了一到两个数量级，从而使大量的弱双折射，光散射和运动物体首次容易用偏振光进行分析。
A new method of polarized light analysis is described in which a highly sensitive electronic detector specific for birefringence is used to identify the crystalline axes of an object and then measure its phase retardation due to birefringence. The microscopic system employed in the method consists of an electronic birefringence detection system (BDS), a microscope with strain-free lenses, and a driven stage for passing the specimen at appropriate velocities across the image of an aperture placed at the field stop and imaged in the specimen plane by the condenser. The detector registers retardations directly as voltage at a constant deflection sensitivity of ca. 1.1 v per angstrom unit over a range of 120 angstrom units. The basal rms noise level is 0.002 A for a spot 36 µ in diameter formed by a 95 x, N. A. 1.25 objective pair, and increases in proportion to the reciprocal of the diameter of the scanning spot. The increase in noise with high resolution scanning can be offset by increasing the instrumental time constant, which is adjustable in decades between 0.004 and 0.4 seconds. A number of difficult problems in high extinction polarization microscopy are avoided by the use of modulated light and a rapid electronic detector. For example: (a) The measured distribution of birefringence is unaffected by the usual diffraction anomaly; therefore polarization rectifiers are not required. (b) The detector is selective for birefringence, so that there is no problem in separating contrast due to different optical properties (e.g. dichroism, light scattering). (c) The speed and sensitivity are both increased by between one and two orders of magnitude over that attainable by visual or photographic methods, thereby rendering a vast number of weakly birefringent, light-scattering, and motile objects readily analyzable for the first time with polarized light.