Stellar interferometry in photon-counting regime: experiment on a laboratory prototype

We report on the experimental validation of the photon noise correction applied on interferometric data, in the frame of an imaging laboratory test using the end-to-end demonstrator "Optical Aperture Synthesis Technologies 2". The light flux is scaled to astronomy level to achieve a quantitative comparison between the contrasts and phase closure measurements simultaneously measured in photon counting regime and in high flux level regime. This experiment uses a three-telescope array linked by optical fiber to the mixing station. We show that it is possible to correct properly the interferometric data with light power levels reaching 1 femto-Watt at a 680 nm mean wavelength. This corresponds to a photon flux close to 2.5 photons per millisecond and to 25 photons for each snap shot.