Multiemulsion on-axis computer generated hologram.
Multiemulsion on-axis computer generated hologram.
复制标题
多乳液轴上计算机生成全息图。
作者：
D. Chu;J. Fienup;J. Goodman
致编辑的信件应寄至马萨诸塞州贝德福德AFCRL的应用光学编辑处。01730.如果作者将在他们的覆盖通信中说明他们是否希望他们的机构支付出版费用，出版时间应该缩短（对于那些这样做的人）。计算机全息术的一个关键问题是实现一种透明体，它雅阁计算的复变函数控制透射波在每一点的振幅和相位。同时进行振幅和相位控制的方法有很多，包括两个独立的透射结构的叠加，1-2正交全息图的使用，3载频全息图，4迂回相位全息图，5以及相关方法。6-8夹层全息图通常难以正确对准，并且正交全息图必须在精确的干涉布置中重建。载波频率全息图和迂回相位全息图再现孪生像;因此，它们都浪费分辨率，并且在计算机生成的形式中可实现的衍射效率低。Kino-forms 9更好地利用了可用的分辨率并且可以是高效的，但是由于丢弃幅度信息而遭受一定程度的背景噪声。我们希望报道一种新型的计算机生成全息图，它保留了相息图的优点，但提供了对振幅和相位透射率的有效控制。通过多重感光彩色胶片，一个夹层滤光片被记录下来，而不需要以后的校准。这种方法的另一个好处是可以通过任何药店购买和处理胶片;实验者不需要亲自进入任何胶片处理设施。我们使用的基本原理可以解释如下。彩色反转胶片包含几个乳剂层，每个乳剂层对可见光谱不同区域的光都非常敏感。我们的特殊实验使用了Kodachrome II，它有三层分别对蓝光、绿色和红光敏感。这些乳剂产生分别主要吸收蓝色（黄色）、吸收绿色（洋红）和吸收红色（青色）的染料图像。如果用单色光照射显影的透明片，这种光将主要被三种乳剂中的一种衰减。另外两种乳剂虽然不衰减光，但确实对透射光的相位产生影响，可能是通过浮雕和折射率变化（初步实验表明这两种效应都起作用）。因此，通过一对明智的曝光...
Letters to the Editors should be addressed to the Editor, APPLIED OPTICS, AFCRL, Bedford, Mass. 01730. If authors will state in their covering communication whether they expect their institutions to pay the publication charge, publication time should be shortened (for those who do). A key problem in computer holography is the realization of a transparency that controls both the amplitude and phase of a transmitted wave at each point in accord with a computed complex function. There are many approaches to simultaneous amplitude and phase control, including sandwiching of two independent transmitting structures, 1-2 the use of quadrature holograms, 3 carrier frequency holograms, 4 detour phase holograms, 5 and related methods. 6-8 Sandwich transparencies are generally difficult to align properly, and quadrature holograms must be reconstructed in a precision interferometric arrangement. Carrier frequency holograms and detour phase ho-lograms reconstruct twin images; as a consequence, they are both wasteful of resolution, and in computer-generated form are low in realizable diffraction efficiency. Kino-forms 9 make better use of available resolution and can be highly efficient, but suffer a degree of background noise due to the discarding of amplitude information. We wish to report on a new type of computer generated hologram that retains the advantages of a kinoform but provides effective control over both amplitude and phase transmittance. By means of multiemulsion color film, a sandwich filter is recorded with no need for later alignment. An added benefit of this approach is that the film can be purchased and processed through any drug store; the experimentor need not have personal access to any film processing facility. The basic principle we have used can be explained as follows. Color reversal films contain several emulsion layers, each ideally sensitive to light in a different region of the visible spectrum. Our particular experiments have used Kodachrome II, which has three layers sensitive individually to blue, green, and red light. These emulsions give rise to dye images that are predominantly blue absorbing (yellow), green absorbing (magenta), and red absorbing (cyan), respectively. If a developed transparency is illuminated by monochromatic light, such light will be attenuated predominantly by just one of the three emulsions. The other two emulsions, while not attenuating the light, do exert an influence on the phase of the transmitted light, presumably through both relief and index changes (preliminary experiments indicate that both effects play a role). Thus with a judicious pair of exposures …