Subpicosecond relaxation study of malachite green using a three-laser frequency-domain technique

We report measurements of the ground-state-recovery dynamics of malachite green in water, made using a new three-laser tunable-induced-grating technique. We observe a recovery consistent with either the sum of two decaying exponentials (0.78±0.10 and 7.4±3.0 ps) or with a uniform range of exponentials (0.34±0.04 to 7.2±3.0 ps). Our three-frequency induced-grating method provides a new and useful approach for studying picosecond and femtosecond atomic and molecular processes, working in the frequency rather than the time domain.