Chapter 3 - Propagation and Diffraction of Optical Waves

Abstract

This chapter introduces wave optics by starting from Maxwell's equations and derives the wave equation. It also discusses the solutions of the wave equation and reviews power flow and polarization. Thereafter, it explains diffraction through the use of the Fresnel diffraction formula, which is derived in a unique manner using Fourier transforms. The chapter takes a look at the spatial transfer function and the impulse response of propagation. It also describes the distinguishing features of Fresnel and Fraunhofer diffraction and provides several illustrative examples. It analyzes diffraction from rectangular and circular apertures and analyzes the diffraction of a Gaussian beam. Furthermore, it describes wavefront transformation by a lens and illustrates the Fourier transforming properties of a lens. Gaussian beam lensing is also discussed in the chapter. The chapter then provides an understanding of linear wave propagation. It derives the wave equation and reviews some of the traveling-wave type solutions of the equation in different coordinate systems, defines the concept of intrinsic impedance, Poynting vector, and intensity, and introduces the subject of polarization.