We analyze the optical caustic produced by light refracted at the curved meniscus surrounding a cylindrical rod standing partially out of a liquid-filled container. When the rod is tilted from the vertical or when light is diagonally incident, the caustic is a four-cusped astroid with two of its cusps obscured by the rod’s shadow. If a portion of the flat end of the rod is raised above the water level, the caustic evolves into a pattern of five interlocking cusps. The five cusps result from symmetry breaking of a three-cusped surface perturbation caustic.
© 2003 Optical Society of America
James A. Lock, Charles L. Adler, Diana Ekelman, Jonathan Mulholland, and Brian Keating, "Analysis of the Shadow-Sausage Effect Caustic," Appl. Opt. 42, 418-428 (2003)