optic axis

American  

noun

Crystallography.

1. (in a crystal exhibiting double refraction) the direction or directions, uniaxial or biaxial, respectively, along which this phenomenon does not occur.

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optic axis British  

noun

1. the direction in a uniaxial crystal or one of the two directions in a biaxial crystal along which a ray of unpolarized light may pass without undergoing double refraction

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Etymology

Origin of optic axis

First recorded in 1655–65

Example Sentences

In the oceanic Decapoda the cornea does not completely close, but leaves a central aperture traversed by the optic axis.

From Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 6 "Celtes, Konrad" to "Ceramics" by Various

A surface expressing the optical relations of such crystals is thus an ellipsoid of revolution about the optic axis.

From Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 7 "Crocoite" to "Cuba" by Various

Bouty 5.97 Elsas Quartz—     along optic axis 4.55 P.J.

From Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 3 "Electrostatics" to "Engis" by Various

This direction of no double refraction is called the optic axis of the crystal.

From Six Lectures on Light Delivered In The United States In 1872-1873 by Tyndall, John

The source of light—the filament of a Nernst lamp—was moved about in a plane 120 cm. distant from the eye and perpendicular to the optic axis.

From Clever Hans (The horse of Mr. Von Osten): A contribution to experimental animal and human psychology by Pfungst, Oskar