Electromagnetic theory of gratings
Electromagnetic theory of gratings
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DOI：
10.1007/978-3-642-81500-3
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发表时间：
1980
期刊：
影响因子：
--
通讯作者：
R. Petit
中科院分区：
文献类型：
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作者：
R. Petit
当我还是一个学生的时候，在五十年代初，光栅的性质一般是根据光学的标量理论来解释的。光栅公式（预测给定入射角的衍射角）建立，实验验证，并广泛用作教科书问题的来源。事实上，这些光栅的性质，我们可以称之为光学性质，以令人满意的方式教授，学生们能够清楚地理解光栅对光的衍射和色散。另一方面，很少有人说的”能源性质”，即有关预测的效率。当然，火焰效应的存在是被指出的，但是关于效率曲线，经常没有其他的教导。最多一个好学生必须知道，对于一个echelette光栅，在给定的顺序的效率可以接近1，只要衍射波矢量可以推导出从入射的一个镜面反射的大面。实际上，这一经验法则通常足以充分利用大约30年前可用的光栅。由于第二次世界大战结束后光栅制造的惊人进步，获得每毫米线数越来越多的非常好的光栅成为可能。如今，在可见光区使用的光栅中，小于半微米的间距是常见的。
When I was a student, in the early fifties, the properties of gratings were generally explained according to the scalar theory of optics. The grating formula (which pre dicts the diffraction angles for a given angle of incidence) was established, exper imentally verified, and intensively used as a source for textbook problems. Indeed those grating properties, we can call optical properties, were taught'in a satisfac tory manner and the students were able to clearly understand the diffraction and dispersion of light by gratings. On the other hand, little was said about the" energy properties", ie, about the prediction of efficiencies. Of course, the existence of the blaze effect was pointed out, but very frequently nothing else was taught about the efficiency curves. At most a good student had to know that, for an eche lette grating, the efficiency in a given order can approach unity insofar as the diffracted wave vector can be deduced from the incident one by a specular reflexion on the large facet. Actually this rule of thumb was generally sufficient to make good use of the optical gratings available about thirty years ago. Thanks to the spectacular improvements in grating manufacture after the end of the second world war, it became possible to obtain very good gratings with more and more lines per mm. Nowadays, in gratings used in the visible region, a spacing small er than half a micron is common.