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Image from page 347 of “The Bell System technical journal” (1922)
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Image by Internet Archive Book Images
Identifier: systembelltechni2122amerrich
Title: The Bell System technical journal
Year: 1922 (1920s)
Authors: American Telephone and Telegraph Company
Subjects: Telecommunication Electric engineering Communication Electronics Science Technology
Publisher: [Short Hills, N.J., etc., American Telephone and Telegraph Co.]
Contributing Library: Prelinger Library
Digitizing Sponsor: Internet Archive

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Text Appearing Before Image:
e.Also since the vibration is perpendicular to the plane of z and p2 the rayP2 does not break up inside the crystal but passes through and out un- 248 BELL SYSTEM TECHNICAL JOURNAL changed. All rays from 5 in the horizontal plane emerge plane polarizedand can be extinguished by an analyzer set for vertical extinction. Theray po is in both these planes so it can be similarly extinguished. With the ray ps the situation is different. Here the vibration is not in thez p3 plane so the ray breaks up inside the crystal into two components whichtravel with different velocities and recombine in or out of phase to give thevarious degrees of elliptical polarization (including plane and circular).Hence, an eye looking back along ps, through an analyzer set for verticalextinction, will see light or dark depending on the phase shift N. Now thisphase shift for a given thickness of plate is zero along po but increases as6 increases (without changing <^; see Fig. 2.28), passing through one integral

Text Appearing After Image:
<1) = I 80° Fig. 2.29—A plot of phase as a function of and d value after another. Therefore, as we allow 6 to increase, the eye shouldsee alternate dark and bright regions. Moreover, since the crystal is op-tically symmetric about z, if is changed without changing d, the apparentbrightness will not change (except that if = 0, 90°, 180° or 270° the fieldis dark as we previously explained). Consequently, if we could see alongall directions at once we would see a pattern of concentric dark rings on adark cross as shown in Fig. 2.29. But we can see along all these directions at once if we employ a properlyplaced lens for a lens can converge all these rays to one point where an eyecan be placed for viewing. Thus an eye at e, Fig. 2.30, will see, in the direction e po, the ray that SPECIFYING QUART/. CRYSTAL ORIENTATION 249 started along s po. It will see along e pi the ray that started along 5 pi.Every point on the lens will have associated with it a

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Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability – coloration and appearance of these illustrations may not perfectly resemble the original work.

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