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SYBP: Biophotonik

SYBP 2: Einzelmolekülmethoden II

SYBP 2.4: Hauptvortrag

Donnerstag, 7. März 2002, 15:30–16:00, HS 11/215

Radiative Decay Engineering: Fluorescence In Metallic Nanocavities — •Jörg Enderlein — Institut für Biologische Informationsverarbeitung 1, Forschungszentrum Jülich

When considering fluorescence near metals, three effects have to be taken into account: (i) the changed intensity of the exciting electric field, due to the interaction of the incident light with the metal; (ii) the altered lifetime of the excited state of the molecule due to its electromagnetic interaction with the metal; (iii) the partial absorption of emitted energy by the metal.

This paper presents the results of theoretical studies concerning the fluorescence of single or few molecules within metallic nanocavities. Quantitative treatment of the fluorescence emission is done within the framework of classical electrodynamics, which has proven to be extremely successful in treating similar problems in the past. It is found that under special conditions, the fluorescence properties of the molecules can enhance dramatically, increasing their detectable fluorescence brightness and photostability by one to two orders of magnitude. These effects become even more pronounced when considering multi-photon excitation of fluorescence. Furthermore, significant changes in absorption and emission spectra are predicted. Besides the pure fundamental interest in the interaction between molecular dipole emitters and metallic nanocavities, the found results have far reaching consequences for many practical applications, such as devising new lasing materials, or fluorescent labels with unusual properties.