Diffraction of complex molecules by structures made of light

We study the loss of spatial coherence in the extended wave function of fullerenes due to collisions with background gases. From the gradual suppression of quantum interference with increasing gas pressure we are able to support quantitatively both the predictions of decoherence theory and our picture of the interaction process. We thus explore the practical limits of matter wave interferometry at finite gas pressures and estimate the required experimental vacuum conditions for interferometry with even larger objects.

We have demonstrated that structures made of light can be used to coherently control the motion of complex molecules. In particular, we showed diffraction of the fullerenes C60 and C70 by a thin grating made of green laser light. We have shown that the principles of this effect, well known from atom optics, can be successfully extended to massive and large molecules which are internally in a thermodynamic mixed state and which do not exhibit narrow optical resonances.

Klaus Hornberger, Stefan Uttenthaler, Bjoern Brezger, Lucia Hackermueller, Markus Arndt, Anton Zeilinger

Phys. Rev. Lett. 90, 160401 (2003)
arxiv.org/abs/quant-ph/0303093