title: Argand-plane vorticity singularities in complex scalar optical fields: an experimental study using optical speckle.
abstract: The Cornu spiral is, in essence, the image resulting from an Argand-plane map associated with monochromatic complex scalar plane waves diffracting from an infinite edge. Argand-plane maps can be useful in the analysis of more general optical fields. We experimentally study particular features of Argand-plane mappings known as "vorticity singularities" that are associated with mapping continuous single-valued complex scalar speckle fields to the Argand plane. Vorticity singularities possess a hierarchy of Argand-plane catastrophes including the fold, cusp and elliptic umbilic. We also confirm their connection to vortices in two-dimensional complex scalar waves. The study of vorticity singularities may also have implications for higher-dimensional fields such as coherence functions and multi-component fields such as vector and spinor fields.
authors.forename: Freda
authors.initials: F
authors.lastname: Rothschild
authors.forename: Alexis I
authors.initials: AI
authors.lastname: Bishop
authors.forename: Marcus J
authors.initials: MJ
authors.lastname: Kitchen
authors.forename: David M
authors.initials: DM
authors.lastname: Paganin