Caustic (optics)

Caustics produced by a glass of water, visible as patches of light

Nephroid caustic at the bottom of a teacup

Caustics in shallow water

In optics, a caustic or caustic network^[1] is the envelope of light rays which have been reflected or refracted by a curved surface or object, or the projection of that envelope of rays on another surface.^[2] The caustic is a curve or surface to which each of the light rays is tangent, defining a boundary of an envelope of rays as a curve of concentrated light.^[2] In some cases caustics can be seen as patches of light or their bright edges, shapes which often have cusp singularities.

^ Lynch, DK; Livingston, W (2001). "The caustic network". Color and Light in Nature. Cambridge University Press. ISBN 978-0-521-77504-5.
^ ^a ^b Weinstein, Lev Albertovich (1969). Open Resonators and Open Waveguides. Boulder, Colorado: The Golem Press.

[1] Lynch, DK; Livingston, W (2001). "The caustic network". Color and Light in Nature. Cambridge University Press. ISBN 978-0-521-77504-5.

[WEI69-2] Weinstein, Lev Albertovich (1969). Open Resonators and Open Waveguides. Boulder, Colorado: The Golem Press.

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