  A combination of spatial interference patterns and spectral interferometry
are used to find the global phase for non-collinear two-dimensional
Fourier-transform (2DFT) spectra. Results are compared with those using the
spectrally resolved transient absorption (STRA) method to find the global phase
when excitation is with co-linear polarization. Additionally cross-linear
polarized 2DFT spectra are correctly phased using the all-optical technique,
where the SRTA is not applicable.
