Characteristic properties of the spatial correlations and visibility in mixed light ghost imaging

Recently, we developed a new ghost imaging (GI) detection concept based on the superposition of object and reference beams with subsequent photon statistics evaluation by using one single photon counting detector (PS-GI). Here, we derive analytical expressions for the spatial correlations of this mixed light GI concept considering the mode properties of the speckles of an illuminating classical pseudothermal source. This model supports the first experimental results of PS-GI in [Opt. Lett.41, 2863-2866 (2016)OPLEDP0146-959210.1364/OL.41.002863] and explains deviating characteristic features in comparison to state-of-the-art GI detection, such as maximum and minimum ghost image signals as well as the visibility performance. Furthermore, the model also explains the higher order correlations, which have been experimentally obtained by using a single detector. The overall good agreement between theory and experiment provides physical insight into the functional principle of mixed light GI, thus fostering PS-GI as a real alternative to established GI technologies.