We observe light and color, yet the theories used to explain the nature of light are not always clear; different theories are used to explain different optical phenomenon. Light photons have both wave and particle properties peacefully co-existing. Some experiments reveal the particle behavior of photons, others the wave behavior. The peaceful co-existence is often referred to as "wave-particle duality".

Particle (photon) Theory--light consists of "particles" of energy of zero rest mass, traveling at the speed of light. A photon is a dimensionless and massless "particle".

Wave Theory--the propagation of light is associated with electromagnetic energy moving in wave. The crest and trough of waves (vibration direction) are randomly perpendicular to propagation direction (direction of light movement).

In the interaction of light with crystalline materials, we are concerned with refraction, interference, and ploarizaiton, phenomenon explained by wave theory. Thus, we shall consider light to consist of tranverse waves transmitted by atomic vibration.

This page (http://www.ces.ncsu.edu/plymouth/programs/drees2.html) created by
Vera MacConnell, Research Technician, I on October 26, 1997.
Last Updated on November 11, 1997.