ABSTRACT
This chapter describes Mmanipulation of Light through a medium or obstruction. Many of the optical phenomena it discusses a direct cause of light encountering an object or a medium other than propagating in vacuum. The reason for including diffraction as part of the chapter on manipulation of light is because most of the diffraction it discusses a result of introducing an object into the light path. Diffracted light intensity can be calculated to use a finite element method to observe light behavior at any distance. Diffracted light amplitude in the far field can also be calculated by Fresnel equation, where the oscillating phase factor inside the equation is nearly constant. Interference of light is due to the wave nature of light. One of the phenomena that reduces light intensity as it transmits through a medium is absorption. When light is absorbed, its energy is converted into heat motion of the absorbing molecules.
