Diffraction

Abstract

The diffraction phenomenon in which light sneaks around to the back of the shading screen is one of the typical properties inherent to light, and its physical explanation is described well in famous reference books on optics [1–3]. Diffraction is well known and we can easily observe this phenomenon by using a coherent beam from a laser. However, it is not easy to understand the theoretical description of diffraction completely. Here, we focus on diffraction in the Fraunhofer region, because it is much easier to understand fundamental properties of diffraction in this region rather than in the Fresnel region. In addition, most of the practical applications have been derived on the basis of the Fraunhofer diffraction. By using diffraction phenomena, a number of applications have been developed in optical metrology. However, topics such as structural analysis of a crystal using x-ray or neutron diffraction and another recently developed field like diffractive optics are not described here. The readers are referred to Refs. [4,5] to obtain useful knowledge in these fields.