Abstract: Optical analogs of multi-dimensional NMR techniques allow for the study of the ultrafast dynamics of complex condensed-phase chemical and biological systems. Here,we describe advances in multi-dimensional optical spectroscopy using light sources that span the visible and near-infrared regions of the electromagnetic spectrum and allow access to the entire vibronic manifold of states. Specifically, we demonstrate acquisition of high quality spectra of cyanine dyes and the photosynthetic protein, LH2, in 1 ms with sub-6 fs temporal resolution. Unlike the majority of 2D techniques that rely on spectral
interferometry to measure the signal phase, we show here that spatial, or more generally, spatial-spectral interferometry (SSI) allows for inherently higher spectral resolution along the rephasing frequency axis, while simultaneously providing significantly higher sensitivity. We discuss how this technological advance may enable two-dimensional optical spectroscopy to transform from a highly specialized technique to a general analytical tool for examining the electronic and vibrational structure of a wide range of molecular systems in real-time. In particular, we show results on the coherent dynamics of a cyanine dye in which the solvent takes the places of strongly coupled intramolecular vibrations during the first 200 fs. This measurement was enabled by the simultaneously high temporal and spectral resolution and large bandwidth from WHITE GRAPES by SSI. Finally, we discuss technical advances to enable 2D spectroscopy in the far-infrared and THz regimes, where sensitive detection is challenging. The methods described here are ideal for studying exciton transport in highly coupled molecular system at the extremes of time and energy.