Optical axis 41456 224216305 2008-07-07T21:06:20Z Thijs!bot 1392310 robot Removing: [[it:Asse ottico]] Modifying: [[de:Optische Achse (Film)]] [[Image:Optical axis en.png|thumb|300px|Optical axis (coincides with red ray) and rays symmetrical to optical axis (pair of blue and pair of green rays) propagating through different lenses.]] In [[optics]], the term '''optical axis''' is used to define a direction along which there is some degree of [[rotational symmetry]]. It can be used in several contexts: * In an [[optics|optical]] system, the optical axis is an imaginary line that defines the path along which light propagates through the system. For a system composed of simple [[lens (optics)|lenses]] and [[mirror]]s, the axis passes through the center of curvature of each surface, and coincides with the axis of [[rotational symmetry]]. The optical axis is often coincident with the system's mechanical axis, but not always, as in the case of [[off-axis optical system]]s. *In an [[Index_ellipsoid#Uniaxial_indicatrix|uniaxial]] [[birefringence|birefringent]] material, the optical axis is the axis of optical anisotropy. *For an [[optical fiber]], the optical axis is along the center of the fiber core, and is also known as the ''fiber axis''. ==See also== *[[Ray (optics)]] *[[Cardinal point (optics)]] ==References== *[[Federal Standard 1037C]] *[[Department of Defense Dictionary of Military and Associated Terms]] [[Category:Geometrical optics]] [[Category:Fiber optics]] [[de:Optische Achse (Film)]] [[eo:Optika akso]] [[ko:광축]] [[nl:Optische as]] [[ja:光学軸]] [[pl:Oś optyczna]] [[ru:Оптическая ось]] [[sk:Optická os]] [[uk:Оптична вісь]] [[zh:光轴]]