Abstract
A general theory is presented for the spatial correlations in the intensity of the radiation emitted by a random medium in thermal equilibrium. We find that a nonzero correlation persists over large distances, compared to the transverse coherence length of the thermal radiation. This long-range correlation vanishes in the limit of an ideal black body. We analyze two types of systems (a disordered waveguide and an optical cavity with chaotic scattering), in which it should be observable.
- Received 4 September 1998
DOI:https://doi.org/10.1103/PhysRevA.59.R43
©1999 American Physical Society