Partial polarization and electromagnetic spatial coherence of blackbody radiation emanating from an aperture

Research output: Contribution to journalArticle


Research units

  • University of Eastern Finland


We consider, within the classical theory of electromagnetic coherence, the spectral coherence properties of a field emanating from an aperture in a blackbody cavity. Spatial coherence and polarization are assessed both in the aperture and in its far zone. We derive an expression for the full 3×3 cross-spectral density matrix of the field in the opening and discuss the validity of some related results given in the literature. The aperture field serves as a finite, planar secondary source whose transverse coherence length is found to be of the order of the wavelength and which is unpolarized in the three-dimensional sense. The far field is obtained by propagating each of the three source-field components separately, resulting in the evaluation of the far-field spatial coherence in any pair of directions, paraxial or nonparaxial. We show that in the paraxial case, the coherence properties coincide with those obtained for a planar, secondary source which is spatially δ-correlated and unpolarized. The results can find applications in the modeling of thermal sources and in the propagation of natural light fields.


Original languageEnglish
Article number013824
JournalPhysical Review A
Issue number1
Publication statusPublished - 16 Jul 2013
MoE publication typeA1 Journal article-refereed

    Research areas

  • spatial coherence, polarization of electromagnetic fields, blackbody radiation

ID: 6898729