Coherent properties of focused wide partially coherent beams in inhomogeneous media

The quasioptics approximation is used to analyze the propagation of a partially coherent radiation beam in a statistically inhomogeneous medium with a regular refractive index profile. This involves solving the parabolic equation for the complex field amplitude which in particular makes it possible to generalize the van Cittert–Zernike theorem (propagation of radiation in inhomogeneous media). The coherence radius is calculated and its ratio to the transverse size of the beam is analyzed.