Singular Optics

Abstract At positions where the intensity of a wavefield vanishes, the phase is undefined and hence “singular.” Traditionally thought of as mere mathematical curiosities, thesephase singularitieshave been shown to have a well‐defined and non‐trivial mathematical structure and their existence has implications for a number of optical applications. This article summarizes the field ofsingular optics. It begins with examples of singularities that appear in optical wavefields, looks at analogies between the typical structures of singularities (optical vortices) and dislocations in crystal structures, and then considers general properties of optical vortices. The generation and detection of vortex‐carrying beams is discussed, and the angular momentum properties of such beams are analyzed. Finally, other types of singularities in wavefields are considered, and possible applications of singularities are surveyed.