Scientists use many methods in order to render the phase of a wave visible.
One of the most popular methods of phase visualisation is interferometry. In order for interferometry to be possible, the radiation must be sufficiently coherent. In practice, this usually requires the source to be monochromated before useful interferograms can be taken. The act of monochromating a source will typically reduce its intensity by orders of magnitude, thus greatly reducing exposure times. On the left is shown a wrapped phase map, such as may be obtained from interferometry.