A point source in a disordered scattering medium generates a speckle pattern with nonuniversal features, giving rise to the so-called $C_0$ correlation. We analyze theoretically the relationship between the $C_0$ correlation and the statistical fluctuations of the local density of states, based on simple arguments of energy conservation. This derivation leads to a clear physical interpretation of the $C_0$ correlation. Using exact numerical simulations, we show that $C_0$ is essentially a correlation resulting from near-field interactions. These interactions are responsible for the nonuniversality of $C_0$ that confers to this correlation a huge potential for sensing and imaging at the subwavelength scale in complex media.

• Received 23 July 2010

DOI:https://doi.org/10.1103/PhysRevA.82.043823