Circular polarization after reflection from a perpendicular mirror

[Grand]

Homework Statement

If a light beam is circularly polarized and then bounced off a mirror perpendicular to the optical axis, what is the new polarization.

My thought is, because circularly polarized light has basically 2 components behaving like waves, each of them is going to experience a phase shift by pi, so then the light will have the same polarization as it had before.

 

[chrisbaird]

Sounds right to me. Generally, we use http://en.wikipedia.org/wiki/Wave_plate" to alter the polarization of a wave, and not mirrors.