birefringence

noun

bi·​re·​frin·​gence ˌbī-ri-ˈfrin-jən(t)s 

plural birefringences

1

: the refraction of light in an anisotropic material (such as calcite) in two slightly different directions to form two rays

According to G. Blom of Philips, video disc acrylics must be optically clear and free of striations and birefringence. Clear vinyl often is highly birefringent.

—Technical Survey

called also double refraction

2

: the visual effect produced by birefringence

The diagnosis was made before scanning in 22 patients by the detection of deposits with apple-green birefringence …

—Philip N. Hawkins et al.

3

: the difference between the angles of refraction of light rays exhibiting birefringence

birefringent

ˌbī-ri-ˈfrin-jənt 

adjective

Examples of birefringence in a Sentence

Recent Examples on the Web

The femto-second lasers used for recording record nanostructures that can encode data in their width, height, depth, polarization and birefringence, hence the 5D name. —Thomas Coughlin, Forbes.com, 18 Aug. 2025

This produces something called a birefringence in the vacuum itself. —Paul Sutter, Ars Technica, 17 June 2022

One of them is known as vacuum birefringence: the notion that a strong, external field can cause this type of polarization — the creation of an internal field — to empty space itself. —Ethan Siegel, Forbes, 7 May 2021

Icelandic spars are crystals of calcium carbonate which have a special property called birefringence: light hitting the mineral is split and follows two parallel paths through it, which explains how calcite makes objects look doubled. —Douglas Main, Discover Magazine, 4 Nov. 2011

Word History

Etymology

International Scientific Vocabulary bi- entry 1 + refringent refracting, from Latin refringent-, refringens, present participle of refringere to break up — more at refract

First Known Use

1879, in the meaning defined at sense 1

Medical Definition

birefringence

noun

bi·​re·​frin·​gence ˌbī-ri-ˈfrin-jən(t)s 

: the refraction of light in an anisotropic material in two slightly different directions to form two rays

also : the visual effect produced by birefringence

The diagnosis was made before scanning in 22 patients by the detection of deposits with apple-green birefringence …

—Philip N. Hawkins et al., The New England Journal of Medicine

birefringent

-jənt 

adjective