
Interferometers are used in many fields of science and engineering. They are called interferometers because they work by merging two or more sources of light to create an interference pattern, which can be measured and analyzed.
Video Explanation of laser Interferometer

Laser Interferometers measure distance with extreme accuracy. It is possible to measure 1nm by laser Interferometer.

This resolution and accuracy make Laser Interferometers effectively the best way to measure distances accurately in most engineering applications.

Interferometers can also be used to measure other things apart from the distance like
- Straightness Measurement
- Combined straightness and displacement measurement
- Straightness measurement via Autocollimation.
- Flatness via autocollimation.
- Vibration.