Editing Confocal

In [[geometry]], '''confocal''' means having the same [[Focus (geometry)|foci]]: [[confocal conic sections]].

* For an optical cavity consisting of two mirrors, confocal means that they share their foci. If they are identical mirrors, their [[Radius of curvature (optics)|radius of curvature]], ''R''<sub>mirror</sub>, equals ''L'', where ''L'' is the distance between the mirrors.
* In [[conic section]]s, it is said of two [[ellipse]]s, two [[hyperbola]]s, or an ellipse and a hyperbola which share both foci with each other. If an ellipse and a hyperbola are confocal, they are [[perpendicular]] to each other.
* In [[optics]], it means that one [[Focus (optics)|focus]] or image point of one lens is the same as one focus of the next [[lens (optics)|lens]].

==See also==
*[[Confocal laser scanning microscopy]]
*[[Confocal microscopy]]
*{{section link|List of orbits|Eccentricity classifications}}
{{set index article|mathematics}}

[[Category:Elementary geometry]]
[[Category:Optics]]