Marsh, RJ;
Armoogum, DA;
Bain, AJ;
(2002)
Stimulated emission depletion following two photon excitation.
In: Andrews, DL, (ed.)
Nonlinear Spectroscopy.
Society of Photo-Optical Instrumentation Engineers (SPIE): Seattle, WA, USA.
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Abstract
The technique of stimulated emission depletion of fluorescence (STED) from a two photon excited molecular population is demonstrated in the S, excited state of fluorescein in ethylene glycol and methanol. Two photon excitation (pump) is achieved using the partial output of a regeneratively amplified Ti:Sapphire laser in conjunction with an optical parametric amplifier whose tuneable output provides a synchronous depletion (dump) pulse. Time resolved fluorescence intensity and anisotropy measurements of the fluorescein emission are made using picosecond time-correlated single photon counting. Pump-dump time delayed fluorescence intensity measurements are used to characterise the response of the system and to provide additional data on saturation dynamics of the dump transition. Two photon STED is modelled using both approximate analytical techniques in the weak dump limit and by numerical solutions to the appropriate rate equations. The latter are used to fit experimental data from which it is possible to determine the cross-section for the stimulated transition and lifetime of the upper vibrational levels of the ground state.
| Type: | Proceedings paper |
|---|---|
| Title: | Stimulated emission depletion following two photon excitation |
| Event: | Nonlinear Spectroscopy |
| Location: | SEATTLE, WA |
| Dates: | 08 July 2002 - 09 July 2002 |
| ISBN: | 0819445800 |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1117/12.451385 |
| Publisher version: | http://dx.doi.org/10.1117/12.451385 |
| Language: | English |
| Additional information: | Copyright © 2002 Society of Photo Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited. |
| Keywords: | two photon, stimulated emission, fluorescence lifetime, anisotropy, vibrational relaxation, fluorescein, picosecond polarized fluorescence, anisotropic fluid media, spectroscopy, microscopy |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/27788 |
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