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There are some one-way transparent glasses.

Light can pass the glass in this way, but cannot in the other way around.

It is quite contrary to the experience that the path of light is reversible.

So what is the reason behind?

John
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  • Can you please explain the question or provide a photograph? – Aaryan Dewan Dec 29 '15 at 15:36
  • One-way glass can't exist because of the reciprocity theorem for electromagnetic waves. The way one way mirrors work is, as James said, by using differences in contrast. Today cameras and monitors can replace these systems, anyway. – CuriousOne Dec 29 '15 at 19:21

2 Answers2

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I don't think such a thing exists. Rather, the lighting on the two sides of the glass determine which side may be seen through.

If your eye is on the bright side, then you see the reflected light from your side.

If your eye is on the dark side, you see the other side because your view is not contaminated by reflections.

https://en.wikipedia.org/wiki/One-way_mirror

http://science.howstuffworks.com/question421.htm

James
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To complement the existing answer and comments, it is possible to "brake" the reciprocity of the light path using the polarization and a magnetic field. A Faraday isolator uses this principle to allow only one direction of propagation. However it is not a simple transparent glass, but it requires different components (polarizers + Faraday rotator).

scrx2
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