Abstract

A generalization of intensity interferometry and imaging laser correlography (Hanbury Brown-Twiss effect) is described. The technique measures 〈l(x)A*(x + Δ + ϵ)A(x + Δ)〉, the correlation of the intensity at x with the field cross product at x + Δ over a distance ϵ. The result yields a term, μ*(Δ + ϵ)μ(Δ), analogous to the cross spectrum measured with the Knox-Thompson method for astronomical speckle imaging. The modulus and phase of the spatial coherence function can be recovered from this phase-difference-type term. The measurements involved do not require co-phasing over the large distance Δ. A light bucket measures l(x), and an interferometer with aperture ϵ (a lens is sufficient) measures A*(x + Δ + ϵ)A(x +Δ). The two measurements are numerically correlated. The results of a demonstration experiment that shows that the technique recovers modulus and phase information are presented.

© 1988 Optical Society of America