fourbeam

Fourbeam may refer to multiple things in science and technology. In optics, four-beam configurations involve four coherent light paths that are combined or interrogated to produce interference. Common geometries include square, cross, or tetrahedral layouts, realized with beam splitters, mirrors, and phase controls. Compared with two-beam interferometry, four-beam setups offer potential gains in phase sensitivity and noise rejection through differential measurements, at the cost of increased alignment complexity. Achieving stable operation requires precise path-length matching, polarization control, and high-quality optics. Applications include precision metrology, surface topography mapping, holographic data storage, and variants of optical coherence tomography. In some research contexts, four-beam interferometry is used to reconstruct phase information from multiple fringe patterns, enabling improved surface reconstruction and measurement accuracy.

In imaging and signal processing, four-beam approaches can be employed to capture directional information or to implement four-way beam steering in photonic circuits, contributing to advances in LIDAR and 3D imaging.

Fourbeam is also used as a brand name or product line for optical components or consumer lighting products, and may appear in marketing materials to denote multiple beams in a device. The term is not tied to a single standardized specification, and its exact meaning is defined by the context in which it is used.

See also: multi-beam interferometry, optical coherence tomography, holography, photonics, LIDAR.