Measuring optical spatial coherence by using a programmable aperture

The modulus of optical spatial coherence established by an incoherent light source was measured with a revised experimental setup of the Thompson and Wolf experiment. We used a liquid crystal display as a programmable aperture, which replaced the mechanical aperture controls used previously and provided a robust way to address the position-dependent spatial coherence. As a demonstration, the angular diameter, 0. 982′, of an extended light source was estimated from a visibility analysis of the diffraction fringes.