A HYBRID GO-GAUSSIAN RAY BEAM

In modem geometrical optics (GO) the field solutions are described as bundles of rays in which the field associated with each ray is indepen dent of the fields of the other rays. Bill this description is not val id in caustic regions where neighboring rays intersect. The Gaussian b eam provides an approximate global description of a modal-type field s olution, which is valid even in caustic regions where GO is invalid. I n this article a hybrid GO-Gaussian ray beam is presented. It behaves as a GO my bundle in one cross section along the propagation direction and as a Gaussian beam in the other. We also present the equations fo r the reflection of such a beam from an arbitrary curved reflector. (C ) 1997 John Wiley & Sons, Inc.