Light’s Orbital Angular Momentum （光的轨道角动量）.pdfVIP

Light’s Orbital Angular Momentum ular transitions. What’s new and ex- The realization that light beams can have quantized orbital citing is that it is now possible to pro- angular momentum in addition to spin angular momentum duce, rather easily, laboratory light has led, in recent years, to novel experiments in quantum beams with quantized orbital angular mechanics and new methods for manipulating microparticles. momentum. These beams can be used to investigate all the analogues of po- larized light. For example, one can Miles Padgett, Johannes Courtial, and Les Allen look for a photon analogue of the spin–orbit coupling of electrons and, ike all wave phenomena, light has mechanical proper- quite generally, to search for new optical interactions. L ties. Johannes Kepler suggested that comet tails al- ways point away from the Sun because light carries linear Optical angular momentum momentum. In 1905, John Poynting developed the theory To a considerable extent, one can understand light’s mo- of electromagnetic radiation pressure and momentum den- mentum properties without reference to photons. A care- sity and, in 1921, Albert Einstein showed that Planck’s ful analytic treatment of the elec