The three-dimensional boundary where light rays bunch together after interacting with a curved optical element. It forms a surface of infinite ray density in classical geometrical optics, typically manifesting as the bright, curved shapes seen at the bottom of a coffee cup.
Heard on the job
We need to map the caustic surface to understand the intensity distribution near focus.
Related terms
Caustic
The bright envelope of light rays formed when a beam is reflected or refracted by a curved surface.
Caustic curve
A two-dimensional cross-section of the envelope formed by reflected or refracted rays.
Spherical aberration
An optical defect where light rays passing through the edge of a lens focus at a different point than central rays.