Optical angular momentum in atomic transitions: a paradox

Stated simply the paradox is as follows: it is clear that the orbital angular momentum of a light beam in its direction of propagation is an intrinsic quantity, and therefore has the same value everywhere in the beam. How then can a Gaussian beam, with precisely zero orbital angular momentum, drive...

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Bibliographic Details
Published in:arXiv.org 2022-03
Main Authors: Barnett, Stephen M, Speirits, Fiona C, Babiker, Mohamed
Format: Article
Language:English
Subjects:
Angular momentum
Gaussian beams (optics)
Light beams
Paradoxes
Quadrupoles
Online Access:Get full text
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Summary:Stated simply the paradox is as follows: it is clear that the orbital angular momentum of a light beam in its direction of propagation is an intrinsic quantity, and therefore has the same value everywhere in the beam. How then can a Gaussian beam, with precisely zero orbital angular momentum, drive a (single-photon) quadrupole transition which requires the transfer of angular momentum 2\(\hbar\) to an absorbing atom?
ISSN:2331-8422
DOI:10.48550/arxiv.2203.03742