  The physical aspects of partially coherent radiation interacting with
deterministic non-Hermitian periodic materials remain largely unexplored in the
statistical optics literature. Here, we consider the scattering of partially
coherent radiation by a deterministic periodic medium, symmetric under the
simultaneous transformations of parity inversion and time reversal, that is, a
parity-time (PT)-symmetric periodic medium. Taking into account light
fluctuations, one is able to describe the spectrum changes on propagation and
the influence of the coherence-driven angular divergence effect. The far-field
spectral density profile is found to depend crucially on the loss/gain
properties of the material, giving rise to unexpected and contrasting spectral
diffraction profiles when compared to the Hermitian ones.
