Volumephase

Volumephase is a term encountered in wave physics and imaging to denote the spatially varying phase of a coherent wave field within a volumetric medium. Unlike a two-dimensional phase map defined on a surface, volumephase refers to a phase function φ(r) where r = (x, y, z) specifies position inside the volume. The phase encodes the accumulated optical path length through the medium and depends on the refractive-index distribution n(r).

In a monochromatic setting with vacuum wavelength λ, the phase at a point along a propagation path can be expressed as φ(r) = φ0 + (2π/λ) ∫ n(r(s)) ds, where the integral is taken along the ray path from a reference point to r. In heterogeneous media, the phase variation reflects both the geometry of the path and local variations of refractive index. In discrete or computational models, φ is represented on a 3D grid and updated through numerical integration or reconstruction algorithms.

Volumephase plays a role in several areas, including volumetric phase imaging, three-dimensional holography, optical tomography, and adaptive optics. In these contexts, the goal is often to reconstruct the three-dimensional phase distribution from intensity or interferometric measurements, which can require phase retrieval, phase unwrapping, or tomographic reconstruction methods. Measurement approaches include digital holography, interferometry, and wavefront sensing, often coupled with computational techniques to obtain a consistent 3D phase map.

The term volumephase is not universally standardized and may be used variably in the literature to describe volumetric phase structures or three-dimensional phase analyses. Related concepts include optical path length, phase map, phase front, and volumetric imaging.