Optics is the science that studies light and our interaction with it. There are two branches of optics: physical optics and geometrical optics.

Physical optics studies the nature and propagation of light. While the ancient Greeks and Arabs have some notions about light, it was not until the 17th century that science began to understand what light is. In 1690 Christiaan Huygens published his book Treatise on Light, describing light as a wave motion. Fourteen years later in 1704, Isaac Newton published his Opticks, describing light as consisting of moving particles.

Though both points of view were useful in the description of phenomena involving light, Newton’s views were dominant until the 1800s. Then, scientists like Thomas Young and Augustin-Jean Fresnel described the phenomena of interference and diffraction by assuming that light was composed of waves. Waves traveling independently could combine with other waves to enhance one another, or cancel...