abstract Understanding the role of coherent electronic motion is expected to resolve general questions of importance in macromolecular energy transfer, in nature and in devices. Significant progress has been made using coherent optical four wave-mixing, however the interpretation of measurements is difficult in particular where multiple quantum transitions are strongly coupled, and new methods are required for an improved feedback to molecular simulation. We will look at a novel laser method, Angle-Resolved Coherent (ARC) imaging, that separates quantum coherences from energy transfers in to orthogonal dimensions, in an instantaneous two-dimensional mapping. The power of the new method is demonstrated with the light harvesting complex II (LH2) of purple bacteria. We reveal an evolving quantum coherence with a time-ordered matter-selection of transition energies at ambient temperature. We also reveal a coherent component to the energy transfer between macromolecular rings and a correlation between excitation and emission energies within a ring at ambient temperature. bio |