science: a quick tangent

Oct 22, 2008 10:44

In the comments, someone mentioned the LCD. As it turns out, they got the explanation for how it works somewhat right. Somewhat ( Read more... )

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mrotakki October 22 2008, 21:49:13 UTC
Unfortunately, not really. The big assumption in this entire set-up is that (here comes the huge physics word of the day) the nematic material is uniaxial. In other words, the index of the material along the long axis is different from the orthogonal axis. There is an index for the parallel and perpendicular axis (to the long axis of the molecule). The perpendicular index is what allows polarized light to move "unmolested" and the index parallel to the long axis interacts with the polarized to allow for wave guiding.

In order for the molecule to take unpolarized light and create linearly plane polarized light, you would first have to design a material that is multiaxial so that it can essentially "stop" all but one linearly polarized wave - which is pretty much impossible as far as I know. There may be a way to do this theoretically, but off the top of my head, the best you can do is to take unpolarized light and selectively reflect one handedness of circularly polarized light. You certainly could imagine a device built in this fashion - transmission and blocking of one handedness of circularly polarized light, but the switching speed and the engineering of the physical device is vastly unfavorable compared to just shoving on a polarizer.

Sorry!

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