Imaging of fullerenes
High-harmonic generation is studied as a tool to image molecular
structure on an ultrafast time scale. Harmonic signals generated in
highly symmetric fullerenes (C20 to C180)
using an extension of the so-called Lewenstein
model exhibit modulations in the plateaus of the spectra at
mid-infrared wavelengths (upper panel). Theoretical
analysis of the results has shown that the minima are due to
multislit interference effects arising from the contributions of the
different atomic centers to the dipole moment. The modulations
disappear if the atomic contributions are added incoherently (middle panel).
The position of the minima are found to be in good agreement with
those in the recombination matrix element (lower panel),
which can be used to retrieve the
radius of the fullerenes from the spectra.
M.F. Ciappina et al., Phys. Rev. A 76 (2007) 063406; ibid. 78 (2008) 063405
