Interferometrisk

Interferometrisk is an adjective used in Swedish, Norwegian and Danish to describe something that relates to interferometry, a measurement method based on the superposition of waves to produce interference patterns. Interferometry uses coherent waves, typically light but also sound or radio waves, to determine small differences in optical path length, refractive index, or surface height with high precision.

The basic principle involves splitting an incoming wave into reference and measurement paths, then recombining them to create an interference pattern. The resulting intensity depends on the phase difference between the arms. By analyzing this phase, one can infer displacements, surface topography, or changes in refractive index with sub-wavelength sensitivity. Stability, coherence, and precise calibration are essential for accurate results.

Common interferometric instruments include the Michelson, Mach-Zehnder, Fabry-Pérot, and Sagnac interferometers. Techniques such as white-light interferometry, phase-shifting interferometry, and heterodyne detection expand the range of measurable quantities. Interferometric data are often processed with Fourier methods or phase-unwrapping algorithms to retrieve quantitative information.

Applications are widespread. In optics and engineering, interferometry enables precision surface testing, metrology, and lens or mirror characterization. In astronomy, large interferometers improve angular resolution; in gravitational-wave observatories, Michelson-type setups detect tiny spacetime perturbations. Radar interferometry (InSAR) is used in geodesy and remote sensing, while optical coherence tomography employs interferometric principles for high-resolution medical imaging.

Interferometrisk methods offer high sensitivity and non-contact measurement but require coherent sources, environmental stability, and complex data analysis. They provide a versatile framework for quantifying physical changes with exceptional precision.