Interferometer
Interferometers are for measuring the interference properties of light waves. One of their purposes is to measure things precisely, for example in the Michelson interferometer.
Interferometer Media
Figure 3. Colored and monochromatic fringes in a Michelson interferometer: (a) White light fringes where the two beams differ in the number of phase inversions; (b) White light fringes where the two beams have experienced the same number of phase inversions; (c) Fringe pattern using monochromatic light (sodium D lines)
Figure 6. Three amplitude-splitting interferometers: Fizeau, Mach–Zehnder, and Fabry Pérot.
Figure 11. The VLA interferometer