  Research on matter waves is a thriving field of quantum physics and has
recently stimulated many investigations with electrons, neutrons, atoms,
Bose-condensed ensembles, cold clusters and hot molecules. Coherence
experiments with complex objects are of interest for exploring the transition
to classical physics, for measuring molecular properties and they have even
been proposed for testing new models of space-time. For matter-wave experiments
with complex molecules, the strongly dispersive effect of the interaction
between the diffracted molecule and the grating wall is a major challenge
because it imposes enormous constraints on the velocity selection of the
molecular beam. We here describe the first experimental realization of a new
interferometer that solves this problem by combining the advantages of a
Talbot-Lau setup with the benefits of an optical phase grating and we show
quantum interference with new large molecules.
