interferometreja

Interferometreja is a measurement technique that uses the interference of waves to extract precise information about differences in optical path length, refractive index, or surface topography. While most widely used with light, interferometric methods can also employ radio waves, microwaves, or matter waves in specialized experiments.

The central idea is the superposition of coherent waves. When two or more waves share a common origin and maintain a fixed phase relationship, their amplitudes add, producing constructive or destructive interference. The resulting intensity depends on the phase difference, which is proportional to the optical path difference ΔOPL = nΔL. A typical metric is φ = (2π/λ) ΔOPL, where λ is the wavelength in the medium. Achieving high sensitivity requires high coherence and stable environments to prevent phase noise.

Common interferometers include the Michelson, which splits and recombines a beam to measure small path changes; the Mach–Zehnder, used for sensing and modulation; the Fabry–Pérot cavity, which enhances sensitivity through multiple reflections; and the Sagnac interferometer, suitable for rotation sensing. In astronomy, interferometry combines light from separate telescopes to achieve higher angular resolution (radio and optical VLBI are notable examples).

Applications are broad: metrology (length standards and calibration), surface profilometry and flatness measurements, spectroscopy, and optical coherence tomography in medicine. In fundamental physics, interferometry tested gravitational waves, studied quantum coherence, and explored matter-wave interference.

Limitations include vibration and thermal fluctuations, air or vacuum stability, and the need for stable phase reference and coherence. Careful calibration and environmental control are essential for accurate results.