Cross-spectral densities with helical-Cartesian phases

We introduce a class of planar, stationary sources whose cross-spectral densities carry a combination of helical and Cartesian phases. The helical phase is linear, separable in polar coordinates, resulting in a vortex-like average intensity with a dark area centered on the optical axis; the Cartesian counterpart is separable in the x- and y-coordinates and is responsible for asymmetric average intensity redistribution along the x- and y-axes. While endless possibilities exist for modeling of the Cartesian phase factor, in this paper we employ a superposition of linear phases with arbitrarily assigned weighing factors. Such construction is analytically and experimentally useful in general and, in particular, as we show, for generation of asymmetric vortex lattices.