Flat Mirror
Optical cross section of a flat mirror with a given reflectivity at a particular wavelength can be express by this formula.
Where is the cross sectional diameter of the beam. Note that the direction of the light has to be perpendicular to the mirror surface for this formula to be valid, else the return from the mirror would no longer go back to it source.
In order to maximize the return a corner reflector is used. The alignment of a corner reflector with respect to the source is not as critical as the alignment of a flat mirror.
Read more about this topic: Optical Cross Section
Famous quotes containing the words flat and/or mirror:
“They all see you when you least suspect.
Out flat in your p.j.’s glowering at T.V.
or at the oven gassing the cat
or at the Hotel 69 head to knee.”
—Anne Sexton (1928–1974)
“Some moralist or mythological poet
Compares the solitary soul to a swan;
I am satisfied with that,
Satisfied if a troubled mirror show it,
Before that brief gleam of its life be gone....”
—William Butler Yeats (1865–1939)