Open AccessOptical orbital angular momentum of evanescent Bessel waves
Author(s) -
Zhenshan Yang
Publication year - 2015
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.23.012700
Subject(s) - physics , bessel function , angular momentum , optics , evanescent wave , paraxial approximation , light beam , orbital angular momentum of light , optical vortex , total angular momentum quantum number , classical mechanics , beam (structure)
We show that the orbital angular momentum (OAM) of evanescent light is drastically different from that of traveling light. Specifically, the paraxial contribution (typically the most significant part in a traveling wave) to the OAM vanishes in an evanescent Bessel wave when averaged over the azimuthal angle. Moreover, the OAM per unit energy for the evanescent Bessel field is reduced by a factor of (1+κ2/k2) from the standard result for the corresponding traveling field, where k and κ are the wave number and the evanescent decay rate, respectively.