Coherently and Fluorescence-Detected Four- and Six-Wave-Mixing Two-Dimensional Electronic Spectroscopy: Measuring Multi-Exciton Dynamics and Delocalization

We directly compare nonlinear coherently and fluorescence-detected two-dimensional electronic spectra of electronically coupled squaraine heterodimers. By identifying signatures of multi-exciton nonequilibrium dynamics and delocalization, we establish grounds for interpretation of these nonlinear spectroscopy implementations.