ABSTRACT
The three physical processes for controlling light are reflection, refraction, and diffraction. For many years, the two primary methods were reflection and refraction, and therefore, lenses and mirrors were the principal tools for bending or dispersing light to achieve a given purpose. Diffraction has had limited application. While elements such as gratings and Fresnel zone plates have been manufactured, their use was limited due to low diffraction efficiencies and the complexity of fabrication. This entry introduces the modeling building blocks for the design and analysis of diffractive optical elements.
