Laser action on one side mirrors (half silvered) and prisms

I know that half silvered mirrors are used in the production of laser emission. Can half silvered mirrors be used outside the instrument so the rays get reflected back on one side of the mirror and pass through the other side?

What will be the result if a half silvered mirror is kept rotating and laser is made to pass through it?

Similarly what will be the result if a prism is kept rotating and laser is made to pass through it?

Series of prisms and mirrors are used in the instrument to produce laser but can we obtain more patterns (movement of laser in entertainment lasers) when we keep a rotating half silvered mirror and prism (different cases) and laser is made to pass through it?

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1 Answer

Asking for laser applications of mirrors, you should know that a mirror also may transmit light. This phenomenon is not known to us from our daily experience. According to Fresnel equations the silvered mirror doesn't have a reflection of 100%. It's transmitted power is attenuated in a silver layer or the following varnish.

The half silvered mirror you are thinking of lacks this absorption layers and a small amount of light passes through. This type of mirror, without defects, is independant of rotation.

Highschool physics simplifies its application in a laser resonator to the fact, that transmission $T=0.01$ and reflection is $R=0.99$. Light hitting the the mirror will be reflected several times inside the two mirrors of a laser resonator. Inside the laser resonator is the the active medium which clones the photons and thereby amplifies the light power. However a small amount of will be transmitted through the mirror as a laser beam.

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By this, do you mean that though the mirror is kept rotating the laser just pass through it and we won't get movement of the Ray due to constantly changing angles in which they strike the mirror as the mirror is rotating....? –  Vishwas.P Jun 24 '13 at 10:36
Yes, if the ray is perpendicular to the mirror. –  Stefan Bischof Jun 24 '13 at 10:53