High-power femtosecond chirped pulse excitation of molecules in solution

The effects of varying the chirp and intensity of an ultrashort pulse exciting the molecules LD690 and LDS750 in room temperature liquid solutions are investigated experimentally and theoretically. For low-power excitation, we find that the absorption and amount of excited state population are independent of chirp, while for high-power excitation we observe a strong chirp dependence. The high-power data results from an intra-pulse pump-dump process which is enhanced by negatively chirped pulses and prevented by positively chirped pulses.