SU(2) structure of the Poincaré sphere for light beams with orbital angular momentum

An SU(2) basis for the recently proposed analog of the Poincaré sphere for light beams with orbital angular momentum is presented. The work of Padgett Courtial [Opt. Lett.24, 430 (1999)] is generalized in several directions, including quantized as well as partially coherent beams with orbital angular momentum. The SU(N) version of the present theory can be used for higher-order Laguerre–Gauss beams.