The Michelson Interferometer
Light from a mono-chromatic source is split into two beams of equal amplitude by a partially-silvered diagonal mirror.
Beams are recombined and interfere at the retina.
Path-length difference is twice the distance a mirror moves.
One “fringe” each time mirror moves by l/2.
Notes:
One of the plane mirrors is fixed and the other movable. The Michelson interferometer is a very precise instrument for comparing distance with light wavelength. It was also a crucial instrument in inspiring Einstein’s Theory of Relativity, as we will see in the next lecture.