title: Quasi-intrinsic angular momentum and the measurement of its spectrum.
abstract: We introduce the concept of quasi-intrinsic angular momentum to denote fields for which the mean value of the angular momentum is unaltered by a lateral shift of the rotation axis but the spectrum changes. This property is exemplified by the orbital angular momentum of a beam of light about its propagation direction. We propose an interferometric experiment to measure efficiently the exact angular momentum spectrum and variance for light beams with any arbitrary spatial distribution.
authors.affiliation: SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG, United Kingdom.
authors.forename: Roberta
authors.initials: R
authors.lastname: Zambrini
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Barnett