a. Pertaining to, or possessing the properties of, a
species of caustic curves formed by refraction. See Caustic surface,
under Caustic.
n. That which burns by refraction, as a double convex
lens, or the sun's rays concentrated by such a lens, sometimes used as
a cautery.
n. A curved formed by the consecutive intersections of
rays of light refracted through a lens.
散焦面, 散焦曲线