The existence of caustics and cusps in a rigorous ray tracing representation

Abstract

With rigorous ray tracing, caustics and their associated cusps in addition to those of classical ray tracing are encountered. These additional caustics are associated with classical (WKB) vertex points. Rigorous ray tracing also confirms those caustics that exist under a classical ray tracing representation, albeit both displaced from the classical locations into the classical shadow zone and perhaps deformed with additional cusps.