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

Kasimir Blomstedt*, Tero Setälä, Jani Tervo, Jari Turunen, Ari T. Friberg

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

13 Citations (Scopus)


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


  • spatial coherence
  • polarization of electromagnetic fields
  • blackbody radiation

Fingerprint Dive into the research topics of 'Partial polarization and electromagnetic spatial coherence of blackbody radiation emanating from an aperture'. Together they form a unique fingerprint.

Cite this