Eight-shot measurement of spatially non-stationary complex coherence function

Spatial coherence plays an important role in several real-world applications ranging from imaging to communication. As a result, its accurate characterization and measurement are extremely crucial for its optimal application. However, efficient measurement of an arbitrary complex spatial coherence function is still very challenging. In this letter, we propose an efficient, noise-insensitive interferometric technique that combines wavefront shearing and inversion for measuring the complex cross-spectral density function of the class of fields, in which the cross-spectral density function depends either on the difference of the spatial coordinates, or the squares of spatial coordinates, or both. This class of fields are most commonly encountered, and we experimentally demonstrate high-fidelity measurement of many stationary and non-stationary fields.