title: Phase measurement of waves that obey nonlinear equations.
abstract: We consider the problem of phase retrieval for classical and quantum wave fields that obey a wide class of nonlinear wave equations. This problem is tackled by means of a suitable generalization of existing methods based on the linear transport-of-intensity equation. The extension of these ideas to systems of coupled nonlinear wave equations is also given.
authors.forename: D
authors.initials: D
authors.lastname: Paganin
authors.forename: K A
authors.initials: KA
authors.lastname: Nugent