Interferometriaan

Interferometriaan, or interferometry, is a family of techniques that use the interference of waves to measure differences in optical path length, wavelength, or the spatial structure of light, sound, or matter waves. By combining two or more coherent wavefronts, interferometry can translate phase information into observable intensity variations, enabling precision metrology and high-resolution imaging.

The core idea is to split a wave, let the parts travel along different routes, and then recombine them. The resulting intensity pattern depends on the phase difference Δφ between the paths. For light, Δφ = (2π/λ)ΔL, where ΔL is the path difference. Coherence length determines whether fringes are visible; fringe visibility encodes contrast and is influenced by noise and dispersion.

Historically, Young demonstrated light interference in 1801, and Albert A. Michelson refined interferometry for precision measurements and astronomy. Today, interferometry underpins gravitational-wave detectors (LIGO/Virgo), high-resolution imaging, metrology, and precision spectroscopy. Variants include optical interferometry, radio interferometry, and atom interferometry.

Optical interferometers include the Michelson, Mach–Zehnder, and Fabry–Pérot configurations, used for surface profiling, spectroscopy, and phase measurements. Astronomical interferometry combines light from multiple telescopes to achieve higher angular resolution, with facilities such as the Very Large Telescope Interferometer (VLTI) and CHARA. Radio interferometry employs arrays like the Very Large Array or ALMA, and very-long-baseline interferometry links widely separated antennas to image distant objects. Atom interferometry uses interference of atomic wavefunctions for precision gravimetry and inertial sensing.

Practical use requires stable optical paths, coherent sources, and careful calibration. Environmental vibrations, atmospheric turbulence, and dispersion limit fringe contrast and phase accuracy, necessitating careful data processing and control of experimental conditions.