Setälä Tero, Kaivola Matti, Friberg Ari T
Department of Engineering Physics and Mathematics, Helsinki University of Technology, PO. Box 2200, FIN-02015 HUT, Finland.
Opt Lett. 2003 Jul 1;28(13):1069-71. doi: 10.1364/ol.28.001069.
We consider stationary electromagnetic fields modeled as superpositions of unpolarized and angularly uncorrelated plane waves and show that in anisotropic case the electric cross-spectral tensor is proportional to the imaginary part of the Green tensor. This is as for blackbody radiation, but here the field need not be in thermal equilibrium. We also evaluate the degree of polarization for a homogeneous but nonisotropic field for which the plane waves propagate within a cone of angles. The results are compared with the known polarization properties of blackbody radiation.
我们考虑将平稳电磁场建模为非极化且角度不相关的平面波的叠加，并表明在各向异性情况下，电交叉谱张量与格林张量的虚部成正比。这与黑体辐射的情况相同，但这里的场不必处于热平衡状态。我们还评估了平面波在一个角度锥内传播的均匀但非各向同性场的极化程度。将结果与黑体辐射的已知极化特性进行了比较。
