Time evolution of universal optical fluctuations

Abstract
We show that in a dynamic multiply scattering system, the intensity-intensity correlation function of universal optical fluctuations does not decay exponentially, but rather drops rapidly to half its initial value and then tails off very slowly to zero. We illustrate this dramatic behavior, and the approach to the ensemble average, with high-speed video images. We also present quantitative results for the correlation function, and provide a theory which is in excellent agreement with the data.