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

TL;DR

This paper investigates how placing a single molecule near nanostructures affects its fluorescence, including emission rates and patterns, using combined experimental and theoretical approaches to achieve significant emission modifications.

Contribution

It combines scanning probe microscopy with spectroscopy to analyze fluorescence modification near nanostructures, emphasizing plasmon effects and proposing arrangements for large emission enhancements.

Findings

Emission rates can be modified by over 1000 times.

Spectral and angular emission characteristics are significantly altered.

Experimental results agree with theoretical models.

Abstract

The coupling of nanostructures with emitters opens ways for the realization of man-made subwavelength light emitting elements. In this article, we investigate 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. Our experimental findings are in excellent semi-quantitative agreement with the outcome of theoretical calculations. We express our results in the framework of optical nanoantennae and propose arrangements that could lead to the modification of spontaneous emission by more than 1000 times.