EM BEAMS AND SOME APPLICATIONS

This chapter introduces Gaussian beams (GBs) and complex source beams (CSBs). GBs and CSBs are closely related in that a CSB reduces to a GB in the paraxial region. GBs and CSBs are expressed in closed form and are very useful as independent wave objects for expanding and tracking arbitrary radiating fields. The chapter provides CSBs as the analytic continuation of an ideal point source into complex space. The GB as an analytic continuation of the geometrical optics (GO) ray‐tube can be justified by demonstrating that a GB is generated by a Gaussian aperture distribution. The analytic relationship of the astigmatic GB to a GO ray‐tube allows application of the laws of GO reflection to GBs simply by replacing the caustic locations with complex locations. GB edge diffraction was developed for GB scattering from a parabolic reflector using physical optics in, and diffraction of complex rays from a two‐dimensional wedge was presented.