Spectral overlap in direct measurements of displaced single‐photon states

Many sophisticated quantum states of light display non‐classical, characteristic oscillations in their photon statistics altering with respect to the applied displacement. In order to detect these oscillations the mode matching between the studied state and the displacement field plays a crucial role. Only recently the developments in the photon counting techniques have allowed the direct measurements of the photon‐number distributions of quantum states. We investigate the properties of displaced single photons by applying time‐multiplexed detection of photon statistics and quantify the value of the mode overlap.