The surface defined by the locus of points that have the same
phase,
i.e., have the same
path length from the source. [After
2196]
Note 1: The wavefront is perpendicular to the
ray that represents an
electromagnetic wave.
Note 2: The plane in which the electric and magnetic
field vectors lie is tangential to the wavefront at every point.
Note 3: The vector that represents the wavefront indicates the direction of
propagation.
Note 4: For parallel,
i.e., collimated, rays, the wavefront is plane. For rays diverging from a point, or converging toward a point, the wavefront is spherical. For rays with varying divergence or convergence, the wavefront has other shapes, such as ellipsoidal and paraboloidal, depending on the nature of the source.
