Catastrophes in wavefront-coding spatial-domain design.

Spatial-domain design for wavefront-coding systems frequently simplifies the defining oscillatory integral of the point spread function (PSF) by means of the stationary phase approximation (SPA). Although the SPA applies over much of the support of the PSF, it tends to break down at or near the regions of highest intensity. A branch of mathematics known as catastrophe theory is shown to provide tools that can ferret out important design information precisely at the points where the SPA is unphysical.