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a prism is supposed to scatter light rays and separate it into rainbow,then why in a prism periscope the prism send light rays to a particular direction instead of scattering?
Welcome to the PF.a prism is supposed to scatter light rays and separate it into rainbow,then why in a prism periscope the prism send light rays to a particular direction instead of scattering?
a prism is supposed to scatter light rays and separate it into rainbow,then why in a prism periscope the prism send light rays to a particular direction instead of scattering?
Prisms can be used in more than one way and their angles can be accordingly different.a prism is supposed to scatter light rays and separate it into rainbow,then why in a prism periscope the prism send light rays to a particular direction instead of scattering?
When used in imaging applications, prisms are generally oriented so that total internal reflection occurs- see, for example:
https://www.edmundoptics.com/resources/application-notes/optics/optical-prism-application-examples/
Prisms can be used in more than one way and their angles can be accordingly different.
You will have seen a diagram of this use of a prism. You will notice that light enters and leaves the prism along a Normal. So there is no dispersion there.
I agree with that 'second level' of prism knowledge. CA is always a problem in optics but the symmetry of the way prisms tend to be used must help a lot.For most prisms in optical systems, the majority of the light doesn't enter at the normal angle. However, the fact that the angle to the normal is generally small and that you're not trying to focus the light with the prism keeps the chromatic aberration low. I believe the dispersion generated by the first surface is counteracted by the exiting surface, perhaps with a small lateral (side-to-side/up-and-down) offset of the image in the different colors. But I admit I haven't worked with prisms in well over a year, and even then I don't think we investigated the chromatic aberration of a prism, so don't take my word as the law on this.