Huygens’ Theory of Double Refraction

Huygens’ theory of double refraction defines how a single light wave can split into two separate waves when it passes through certain materials. This phenomenon is particularly noticeable in crystals such as calcite. When light enters calcite, it splits into two rays, each traveling at a different speed and in slightly different directions. This splitting is due to the crystal’s unique internal structure.

Christiaan Huygens developed a theory, which distinguishes between two types of rays:

Type of Ray	Description
Ordinary Ray	This ray follows the standard laws of refraction, traveling through the crystal at a constant speed regardless of its direction.
Extraordinary Ray	Unlike the ordinary ray, this ray does not follow the usual laws of refraction. Its speed varies depending on the direction in which it travels relative to the crystal’s internal structure.

The unique behavior of these rays is due to the anisotropic nature of the crystal, meaning the crystal has different properties in different directions.

Wave Theory of Light

Wave theory of light postulates that a light source emits light waves that spread in all directions. A light wave on striking a mirror gets reflected according to the angles but with each wave turned back to front, it produces a reversed image. In this article, we will explore wave theory of light along with the history of wave theory of light. Also, we will discuss Huygen’s wave theory of light and its construction. Let’s start our learning on the topic “Wave Theory of Light.”

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