What are the working principles of laser interferometer?

A laser interferometer operates on the principle of interference, where it splits a coherent laser beam into two paths that travel different distances before being recombined. When the beams merge, they create an interference pattern due to phase differences caused by variations in path length, which can result from changes in distance or the presence of external factors. By analyzing this interference pattern, precise measurements can be obtained, making laser interferometers highly effective for applications such as distance measurement, surface profiling, and gravitational wave detection. The sensitivity to minute changes in distance allows for the detection of variations as small as fractions of a wavelength of the laser light used.