Noun
a line that passes through the center of curvature of a lens so that light is neither reflected nor refracted
in a doubly refracting crystal, the line in the direction of which no double refraction occurs
Source: WordNetin a normal eye the optic axis is the direction in which objects are seen most distinctly Source: Internet
a crystal may have either one or two optic axes Source: Internet
An optic axis can be the fast or the slow axis for the crystal depending on the crystal at hand. Source: Internet
Recall that a half-wave plate rotates polarization as twice the angle between incident polarization and optic axis (principal plane). Source: Internet
Axially rotated elements Assume an optical element has its optic axis perpendicular to the surface vector for the plane of incidence and is rotated about this surface vector by angle θ/2 (i. Source: Internet
The crystal is cut into a plate, with the orientation of the cut chosen so that the optic axis of the crystal is parallel to the surfaces of the plate. Source: Internet