The Coherence Theory program investigates the properties of optical fields and effects produced by partially coherent sources and fields. In particular, the group has made important contributions towards clarifying the relationship between the coherence properties of optical fields and the use of radiometry to describe the energy propagated by such fields. Professor John Foley was recently elected a Fellow of the Optical Society of America in recognition of his work in this area.

A second area of investigation is the propagation of partially coherent fields through optical systems. In a series of papers, the group has shown that the key parameter in determining whether spatial coherence effects alter the spectrum of the light in the receiving plane of an optical system is the ratio of the system to the ratio of the correlation length of light in the entrance pupil of the system to the radius of the entrance pupil.

Other topics under investigation include the scattering of partially coherent light from fluctuations in media and frequency shifts due to source correlations.