Stimulated emission three-pulse photo-echo peakshift: a mixed pump-probe and photon-echo technique for studying excited-state dynamics

A novel four-pulse photon-echo technique for exploring condensed phase dynamics at different parts of the excited-state potential energy surface is presented. In contrast to traditional three-pulse photon-echo signals, the introduction of a fourth pump pulse allows the use of photon-echo techniques to probe excited-state phenomena. Here, a "proof of principle" experiment is presented where the excited-state solvent dynamics of the coumarin 153 chromophore dissolved in methanol is explored. The fluctuations of the stimulated emission transition is probed, in contrast to the ground-state absorption transition explored in traditional echo measurements. Distinctly different excited-state dynamics, in contrast to ground-state signals, is observed and discussed.