title: Anomalous behavior of spectra near phase singularities of focused waves.
abstract: It is shown that remarkable spectral changes take place in the neighborhood of phase singularities near the focus of a converging, spatially fully coherent polychromatic wave diffracted at an aperture. In particular, when the spectrum of the wave in the aperture consists of a single line with a narrow Gaussian profile, the spectrum near a phase singularity (i.e., near points of zero intensity of some particular spectral component) changes drastically along a closed loop around the singularity. The spectrum is redshifted at some points, blueshifted at others, and is split into two lines elsewhere.
authors.affiliation: Department of Physics and Astronomy, University of Rochester, River Campus Station, Rochester, NY 14627-0171, USA.
authors.forename: G
authors.initials: G
authors.lastname: Gbur
authors.forename: T D
authors.initials: TD
authors.lastname: Visser
authors.forename: E
authors.initials: E
authors.lastname: Wolf