extraordinary ray

optics

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June 26, 2026

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The extraordinary ray is a concept in optics related to double refraction. When unpolarized light enters certain anisotropic materials, it splits into two rays: the ordinary ray and the extraordinary ray. The ordinary ray follows the standard laws of refraction, with a constant speed in all directions within the medium. In contrast, the extraordinary ray does not adhere to these ordinary laws because its speed varies depending on its direction within the material. This phenomenon is observed in crystals like calcite, ice, and quartz.123

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$double refraction$
double refraction
One ray (called the extraordinary ray) is bent, or refracted, at an angle as it travels through the medium; the other ray (called the ordinary ray) passes through the medium unchanged.
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One ray (called the extraordinary ray) is bent, or refracted, at an angle as it travels through the medium; the other ray (called the ordinary ray) passes through the medium unchanged.
Read More