An optical axis is a line along which there is some degree of rotational symmetry in an optical system such as a camera lens or microscope.
The optical axis is an imaginary line that defines the path along which light propagates through the system. For a system composed of simple lenses and mirrors, 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 systems.
For an optical fiber, the optical axis is along the center of the fiber core, and is also known as the fiber axis.
Famous quotes containing the words optical and/or axis:
“It is said that a carpenter building a summer hotel here ... declared that one very clear day he picked out a ship coming into Portland Harbor and could distinctly see that its cargo was West Indian rum. A county historian avers that it was probably an optical delusion, the result of looking so often through a glass in common use in those days.”
—For the State of New Hampshire, U.S. public relief program (1935-1943)
“A book is not an autonomous entity: it is a relation, an axis of innumerable relations. One literature differs from another, be it earlier or later, not because of the texts but because of the way they are read: if I could read any page from the present time—this one, for instance—as it will be read in the year 2000, I would know what the literature of the year 2000 would be like.”
—Jorge Luis Borges (1899–1986)