title: Communication modes applied to axicons.
abstract: The communication modes, which constitute a convenient method for the propagation and information analysis of optical fields, are formulated in the generalized axicon geometry. The transmitting region is the axicon's annular aperture, and the observation domain is the optical axis containing the focal line segment. We show that in rotational symmetry one may employ the prolate spheroidal wave functions to represent the communication modes. Further, in usual circumstances the modes can be approximated by quadratic waves in the aperture domain and by sinc functions in the image domain. Both the exact communication modes and the approximate technique are confirmed numerically, with linear axicons as examples.
authors.forename: Anna
authors.initials: A
authors.lastname: Burvall
authors.forename: Per
authors.initials: P
authors.lastname: Martinsson
authors.forename: Ari
authors.initials: A
authors.lastname: Friberg