Phase singularities in beams

Abstract

Beams of electromagnetic radiation with phase singularities can transport angular momentum and exert torques on objects. In this paper we discuss the generation of such beams and present a simple analysis of the phenomenon. These beams and their effects have been studied at optical and at millimeter wavelengths. We describe a particularly efficient way of generating these beams at millimeter wavelengths employing a specially configured blazed grating.