Coherent-mode representation of propagation-invariant fields

Abstract

The general coherent-mode structure of a propagation-invariant field is found as the solution of the differential equation for propagation of the coherent modes of said field. It is shown that three kinds of the propagation-invariant fields exist. Examples of propagation-invariant fields of the three kinds are discussed. © 2001 Elsevier Science B.V. All rights reserved.