birefringence(redirected from Extraordinary ray)
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Related to Extraordinary ray: double refraction
the quality of transmitting light unequally in different directions.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
the property of having more than one refractive index according to the direction of the transmitted light.
Farlex Partner Medical Dictionary © Farlex 2012
birefringenceAn optical property of materials in which the refractive index differs for light polarised in 1 plane compared to the normal (orthogonal) plane. Crossed Nicoll prisms cause birefringent material to appear bright against a dark background.
Form birefringence—due to differences in molecular organisation of a material.
Stress birefringence—due to tension-related differences in molecular alignment.
Flow birefringence—due to differences in alignment of rod-like particles in fluids.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.
dou·ble re·frac·tion(dŭb'ĕl rĕ-frak'shŭn)
The property of having more than one refractive index according to the direction of the transmitted light.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
birefringenceSplitting of light into two separate beams.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
Property of anisotropic media such as crystals, whereby an incident light beam is split up into two beams, each plane polarized at right angles to the other. One beam, called ordinary, obeys Snell's law, while the other, called extraordinary, does not. Syn. double refraction. See anisotropic; law of refraction; Nicol prism; Wollaston prism.
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann