Inverse source problem for discrete Helmholtz equation

We consider multi-frequency inverse source problem for the discrete Helmholtz operator on the square lattice ${\mathbb{Z}}^d$, $d\ge 1$. We consider this problem for the cases with and without phase information. We prove uniqueness results and present examples of non-uniqueness for this problem for the case of compactly supported source function, and a Lipshitz stability estimate for the phased case is established. Relations with inverse scattering problem for the discrete Schrödinger operators in the Born approximation are also provided.