Know All About The Optical Prisms

The great Isaac Newton was the man who discovered prism and how it helps in breaking the light into component wavelengths, or colors. Prisms are made with any clear compound and are generally cut with specially angled facets. What makes prism such a talked about topic is that it can bend light. There are various factors which influences light like the material that the optical prisms are made of, the number and angle of the facets affect the light coming through the prism is reflected, refracted and dispersed.

Shapes & Materials Of Prism

Triangular shape is the most common shape for experimental prisms with flat sides though prisms can be rectangular, hexagonal, trapezoidal or multifaceted. For instance, raindrops which have no facets can have the prism like properties. Optical Prisms are usually made of glass, plastics or fluorite and these are divided into three categories.

Dispersive prisms are the one which spread light into separate wavelengths, Reflective prisms reverse or flip images through internal reflection and Polarizing prisms separate light by polarization. The Polarizing prisms and dispersive prisms use the same principles but the dispersive prisms are made with a specialized substance that can separate light by the orientation of the light waves.

Light Refraction

Refraction simply describes how light bends as moves from air to another clear medium. Refraction is the reason on why a straight rod appears to have a kink when you put it in a glass of water. When a beam of light encounters the surface of a prism, it slows a bit. The slowing down changes the angle at which the light moves. The light bends again as it exits the prism. This angle between the two surfaces is called the refracting angle and how much the medium bends the light is the refractive index.

The Rainbow Colors

The triangular prism and the sun catcher in your window both project rainbow colors onto the wall, it is called dispersion and a byproduct of refraction. The light which sun provides us is made up of a spectrum of different wavelengths. When different wavelengths hit the prism’s surface, they bend slightly in different angles. The shortest wavelengths, which appear violet to the human eye, are bent the most. On the other hand, the longest wavelengths, which appear red to the human eye, are bent the least. Next, you can see the entire spectrum of visible light.

Internal Reflection

He internal reflection flips, skews and rotates image. For instance, when two prisms are kept opposite to each other and are used to flip images in binoculars, though it is called reflection but the internal reflection is caused by the refractive angles of the prisms. Now what happens when the angle of refraction for the prism is larger than the critical angle for that prism?

Optical Prisms are also often used to re-direct light by using internal reflection. The beam of light will reflect back into the prism until it hits a surface at less than the critical angle and leaves the prism. Internal reflection is the process of how signals travel through fiber optic cable.

Miki Barzig is an author/writer, a Marine Corps veteran and a perpetual student of art, journaling and life. She has written for several national and trade publications and continues to build her library with her own publications.