HOW I DISCOVERED PHASE CONTRAST
HOW I DISCOVERED PHASE CONTRAST
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DOI：
10.1126/science.121.3141.345
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发表时间：
1955-01-01
期刊：
影响因子：
56.9
通讯作者：
ZERNIKE, F
中科院分区：
文献类型：
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作者：
ZERNIKE, F
在我使用显微镜工作时，并没有发现P HASE HASST，而是在我从事光学的另一部分工作时发现的。它起源于我对衍射光栅的兴趣，大约始于1920年。衍射光栅是由一个平面或凹面镜，在其表面上刻划了大量等距的凹槽组成。小的几乎不可避免的缺陷的位置的凹槽清楚地显示在光栅的光学行为。最明显的错误是一个周期性的，重复后，每一个旋转的螺丝的裁决引擎。凹槽的有规律的重复位移引起光路的相应变化，就好像镜面是波浪形的一样。因此，该仪器的行为就像一个常数约为2 mm的粗光栅叠加在其上，结果是每条强光谱线的右侧和左侧都伴随着一些弱的寄生线，即所谓的”罗兰鬼“。“如果人们向下看光栅的表面，把眼睛放在谱线的位置上，这些谱线会产生显著的效果。在这种情况下，完美的光栅将以光谱线的颜色显示均匀照明的表面。然而，实际上，人们看到的是一个强烈条纹状的表面。S.艾伦说，这些条纹不是真实的，只是主线和它的幻影之间干涉的结果。当鬼魂被掩盖时，条纹就消失了。我记得我强烈反对他关于不现实的结论。相反，我相信条纹表面比通过拍摄重影所获得的信息提供了更多关于周期性刻划误差的信息，因为在第一种情况下，重影的相对相位起作用，而在第二种情况下，这些相位丢失了。我把这个问题记在心里，打算一有机会就进一步研究。大约在1930年，我们的实验室获得了一个由伍德控制的大型凹面光栅，并将其安装在龙格-帕邢装置上。表面的条纹状外观很快就被发现了，但由于光栅距离眼睛有6米，我试着用一个小望远镜对准它，然后意想不到的事情发生了。这些条纹可以看得很清楚，但是当望远镜正好聚焦在光栅表面时，它们就消失了！通过一系列的实验和计算，我很快就成功地解释了这一点。回顾这一事件，我印象深刻的是
P HASE CONTRAST was not discovered while I was working with a microscope, but while I was working in a different part of optics. It originated in my interest in diffraction gratings, which began about 1920. A diffraction grating consists of a plane or concave mirror with a large number of equidistant grooves ruled on its surface. Small nearly unavoidable imperfections in the location of the grooves show clearly in the optical behavior of the grating. The most conspicuous error is a periodic one that repeats itself after each revolution of the screw of the ruling engine. The regularly recurring displacement of the grooves causes corresponding changes of the optical path, just as if the mirror sur-faee were wavy. Consequently the instrument behaves as if a coarse grating, with a constant of about 2 mm, were superimposed on it, with the result that each strong spectral line is accompanied to its right and left by a number of weak spurious lines, the so-called" Rowland ghosts." These lines havea remarkable effect if one looks down at thesurface of the grating, placing the eye at the position of a spectral line. A perfect grating would in this case show an evenly illuminated surface in the color of the spectral line. In reality, however, one sees a strongly striped sur-face.At the end of a 1902 paper H. S. Allen remarked that these stripes were nothing real but were simply the effect of the interference between the principal line and its ghosts. Indeed the stripes disappear when the ghosts are covered up. I remember strongly objecting to his conclusion of unreality. On the contrary, I was convinced that the striped surface gave more information about the periodic ruling errors than that obtainable by photographing the ghosts, because in the first case, the relative phases of the ghosts come into play, whereas these are lost in the second case. I kept the question in mind, planning to look further into it as soon as an opportunity arrived. About 1930 our laboratory obtained a large con-cave gratingruled by Wood and set it up in a Runge-Paschen mounting. The striped appearance of the sur-face was soon found, but because the gratingwas 6 m from the eye, I tried pointing a small telescope at it. Then the unexpected happened. The stripes could be seen very clearly, but they disappeared when the telescope was exactly focused on the surface of the grat-ing! By a succession of experiments and calculations I soon succeeded in explaining this. On looking back to this event, I am impressed by