ABSTRACT
This chapter discusses the Gerchberg–Saxton algorithm because it is a relatively simple iterative algorithm that illustrates the application of algorithms to the beam shaping problem. It describes the application of popular optimization algorithms to the beam shaping problem. The chapter examines the basic system considerations for beam shaping. It provides a simplified approach that exploits the global optimization capabilities found in several commercial lens design programs. Beam shaping is the process of redistributing the irradiance and phase of a beam of optical radiation. The irradiance distribution defines the profile of the beam, such as Gaussian, circular, rectangular, annular, or multimode. Beam integrators are especially suited to multimode lasers with a relatively low degree of spatial coherence. Beam shaping design can be approached using either physical or geometrical optics. Lossless beam shaping is related to the phase retrieval problem of image recovery or reconstruction, in that both problems are involved with determining the phase associated with a Fourier transform magnitude.
