Fizeau interferometer

The term Fizeau interferometer also refers to an interferometric arrangement used by Hippolyte Fizeau in a famous 1851 experiment that seemingly supported the partial ether-drag hypothesis of Augustin Jean Fresnel, but which ultimately played an instrumental role in bringing about a crisis in physics that led to Einstein's development of the theory of special relativity.

[2][3] The reference piece is sometimes realized by a diffractive optical element (computer-generated hologram or CGH), as this can be manufactured by high accuracy lithographic methods.

In 1851, Fizeau used an entirely different form of interferometer to measure the effect of movement of a medium upon the speed of light, as seen in Fig. 3.

Over half a century passed before a satisfactory explanation of Fizeau's unexpected measurement was developed with the advent of Einstein's theory of special relativity.

The two beams are recombined at the detector, forming an interference pattern that depends upon any difference in time traveling the two paths.

Figure 1. Fizeau interferometer
Figure 2. Optical testing with a Fizeau interferometer and a computer generated hologram
Figure 3. Fizeau interferometer for measuring the effect of water movement upon the speed of light .