  The Fano lineshape arises from the interference of two excitation pathways to
reach a continuum. Its generality has resulted in a tremendous success in
explaining the lineshapes of many one-dimensional spectroscopies - absorption,
emission, scattering, conductance, photofragmentation - applied to very varied
systems - atoms, molecules, semiconductors and metals. Unravelling a
spectroscopy into a second dimension reveals the relationship between states in
addition to decongesting the spectra. Femtosecond-resolved two-dimensional
electronic spectroscopy (2DES) is a four-wave mixing technique that measures
the time-evolution of the populations, and coherences of excited states. It has
been applied extensively to the dynamics of photosynthetic units, and more
recently to materials with extended band-structures. In this letter, we solve
the full time-dependent third-order response, measured in 2DES, of a Fano model
and give the new system parameters that become accessible.
