Stuttgart 2012 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 17: Femtosecond Spectroscopy IV
MO 17.1: Hauptvortrag
Donnerstag, 15. März 2012, 10:30–11:00, V38.03
Ultrafast Processes in Single Molecules: from Small Chromophores to Photosynthetic Antenna Complexes — •Richard Hildner1, Daan Brinks1, Richard J. Cogdell2, and Niek F. van Hulst1,3 — 1ICFO - Institut de Ciencies Fotoniques, 08860 Castelldefels — 2University of Glasgow, Glasgow G12 8TA — 3ICREA - Institucio Catalana de Recerca i Estudis Avancats, 08015 Barcelona
Ultrafast excitation-energy transfer is at the heart of both natural and artificial light-harvesting, and plays a key role in the initial steps of photosynthesis as well as in photovoltaic applications of organic functional materials. However, a detailed nanoscale understanding of energy-transfer processes is hampered to date, because molecular systems are often highly heterogeneous with disordered environments and current ultrafast techniques intrinsically average over large ensembles.
Here, we present our recent advances in combining femtosecond pulse-shaping techniques with single-molecule detection schemes at room temperature. Employing phase-controlled double-pulse excitation, we resolved ultrafast electronic coherences and their femtosecond decay in a model system, individual terrylene molecules embedded in a polymer matrix. We also observed and manipulated vibrational wave packet interference in single molecules by adapting the time and phase distribution of the laser field to the ultrafast molecular dynamics. Finally, we discuss how these techniques can be extended to multichromophoric molecular systems. Preliminary results on the ultrafast dynamics of electronic excitations within individual light-harvesting complexes of purple bacteria are presented.