Interferometry is a technique used to measure small distances or changes in physical properties by analyzing the interference patterns created when two or more waves overlap. This method is commonly applied in fields like astronomy, optics, and metrology to achieve high precision in measurements. In practice, interferometers split a light beam into two paths, which are then recombined. The resulting interference pattern reveals information about the differences in the paths, such as changes in distance or refractive index. This technique is essential for advancements in technologies like laser systems and fiber optics.