Chemical Physics Letters, Vol.366, No.3-4, 398-405, 2002
Stimulated emission depletion of two-photon excited states
Stimulated emission depletion of fluorescence (STED) from a two-photon excited molecular population is demonstrated for fluorescein in ethylene glycol and methanol. Time resolved fluorescence intensity and anisotropy measurements were made using picosecond time-correlated single photon counting (TCSPC). Pump-dump time delayed total fluorescence intensity measurements were used to characterise the response of the system and to provide additional data on the dump transition dynamics. Cross-sections for the stimulated transition in methanol and ethylene glycol were 1.4 and (3.6 +/- 1.0) x 10(-16) cm(2), respectively, the corresponding ground state vibrational lifetimes were 636 and 717 +/- 99 fs. (C) 2002 Elsevier Science B.V. All rights reserved.