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Modification of single molecule fluorescence close to a nanostructure: radiation pattern, spontaneous emission and quenching

2008; Taylor & Francis; Volume: 106; Issue: 7 Linguagem: Inglês

10.1080/00268970802002510

1362-3028

S. Kühn, G. Mori, Mario Agio, Vahid Sandoghdar,

Near-Field Optical Microscopy

Abstract The coupling of nanostructures with emitters opens up ways for the realization of man-made subwavelength light emitting elements. In this article we present an overview of our recent progress in the modification of fluorescence when an emitter is placed close to a nanostructure. In order to control the wealth of parameters that contribute to this process, we have combined scanning probe technology with single molecule microscopy and spectroscopy. We discuss the enhancement and reduction of molecular excitation and emission rates in the presence of a dielectric or metallic nanoparticle and emphasize the role of plasmon resonances in the latter. Furthermore, we examine the spectral and angular emission characteristics of the molecule–particle system. The experimental findings are in excellent semi-quantitative agreement with the outcome of theoretical calculations. We show that the interaction of an emitter with a nanoparticle can be expressed in the framework of an optical nanoantennae and propose arrangements that could lead to the modification of spontaneous emission by more than 1000 times. Keywords: fluorescence enhancementplasmon resonancenanoantennaspontaneous emissionquenching Acknowledgements We thank F. Robin for fabricating gold nanoantennae at FIRST, the Center for Micro- and Nanoscale Science, ETH Zurich. We thank U. Håkanson, L. Rogobete and F. Kaminski for fruitful discussions. This work was supported by the Swiss Ministry of Education and Science (EU IP-Molecular Imaging), the ETH Zurich initiative on Composite Doped Metamaterials (CDM) and the Swiss National Foundation (SNF).