Light in a Twist: Optical Angular Momentum

摘要

In 1992 Allen et al. recognized that light beams could carry an angular momentum in addition to that arising from the photon spin. This orbital angular momentum can be created using lenses or diffractive optics, the later often formed using liquid crystal displays. Both whole beams and single photons can carry this twist, and transfer it to particles causing them to spin. This paper introduces the underlying principles of orbital angular momentum and reviews a number of its manifestations and applications. These effects highlight how optics still contains surprises and opportunities for manipulation, imaging and communication in both the classical and quantum worlds.