Decoherence in a Talbot–Lau interferometer: the influence of molecular scattering

This work describes the interference of C70 fullerenes in a Talbot–Lau interferometer with a large separation between the diffraction gratings. This permits the observation of recurrences of the interference contrast both as a function of the de Broglie wavelength and in dependence of the interaction of background gases. An exponential decrease of the fringe visibility with increasing background pressure was observed and good quantitative agreement with the predictions of decoherence theory was found. From extrapolation of the limits of matter wave interferometry it can be concluded that the influence of collisional decoherence may be well under control in future experiments with proteins and even larger objects.