Right-angle prisms are often preferable to
an inclined mirror in applications involving
severe acoustic or inertial loads. This is
because a right-angle prism is easier to mount
and deforms much less than a mirror in response
to external mechanical stress. Very high transmission
can be achieved by using the hypotenuse face in total
internal reflection, and by antireflective coating
on the entrance and exit faces. Alternatively,
the hypotenuse face can be used in external reflection,
and coating with a metallic reflective coating.
