Abstract
The properties of speckle produced near the focal plane of a lens with a linearly translating diffuser in the pupil are investigated. Expressions for the space—time amplitude and intensity correlations are derived in the Gaussian-field limit. The intensity correlations obtained are not cross-spectrally pure but rather imply some degree of speckle translation in directions both parallel and antiparallel to the diffuser velocity. Lens aberrations are found to have a significant effect on the intensity correlations, and theoretical results are presented for defocus and some of the primary aberrations. Experimental measurements with a two-detector instrument and photon-correlation equipment are found to be in good agreement with the theory.