Locked entropy in partially coherent fields
Abstract
We introduce a taxonomy for partially coherent optical fields spanning multiple degrees of freedom (DoFs) based on the rank of the associated coherence matrix (the number of non-zero eigenvalues). When DoFs comprise two spatial modes and polarization, a fourfold classification emerges, with rank-1 fields corresponding to fully coherent fields. We demonstrate theoretically and confirm experimentally that these classes have heretofore unrecognized different properties. Specifically, whereas rank-2 fields can always be rendered separable with respect to its DoFs via a unitary transformation, rank-3 fields are always non-separable. Consequently, the entropy for a rank-2 field can always be concentrated into a single DoF (thus ridding the other DoF of statistical fluctuations), whereas some entropy is always 'locked' in one DoF of a rank-3 field.
Cite
@article{arxiv.2310.14012,
title = {Locked entropy in partially coherent fields},
author = {Mitchell Harling and Varun A. Kelkar and Kimani C. Toussaint, and Ayman F. Abouraddy},
journal= {arXiv preprint arXiv:2310.14012},
year = {2023}
}