Tailoring Spontaneous Emission with Resonant Plasmonic Nanoantennas

Jean-Jacques Greffet Institut d'Optique, CNRS, Univ Paris-Sud, Laboratoire C Fabry, Palaiseau, France Benjamin Habert Institut d'Optique, CNRS, Univ Paris-Sud, Laboratoire C Fabry, Palaiseau, France Florian Bigourdan Institut d'Optique, CNRS, Univ Paris-Sud, Laboratoire C Fabry, Palaiseau, France Botao Ji Ecole Supérieure de Physique et Chimie Industrielles de Paris, Laboratoire de Physique et d'Etudes des Matériaux, Paris, France Emerson Giovanelli Ecole Supérieure de Physique et Chimie Industrielles de Paris, Laboratoire de Physique et d'Etudes des Matériaux, Paris, France Piernicola Spinicelli Ecole Supérieure de Physique et Chimie Industrielles de Paris, Laboratoire de Physique et d'Etudes des Matériaux, Paris, France Michel Nasilowski Ecole Supérieure de Physique et Chimie Industrielles de Paris, Laboratoire de Physique et d'Etudes des Matériaux, Paris, France Xiangzhen Xu Ecole Supérieure de Physique et Chimie Industrielles de Paris, Laboratoire de Physique et d'Etudes des Matériaux, Paris, France Nicolas Lequeux Ecole Supérieure de Physique et Chimie Industrielles de Paris, Laboratoire de Physique et d'Etudes des Matériaux, Paris, France Jean-Paul Hugonin Institut d'Optique, CNRS, Univ Paris-Sud, Laboratoire C Fabry, Palaiseau, France François Marquier Institut d'Optique, CNRS, Univ Paris-Sud, Laboratoire C Fabry, Palaiseau, France Benoit Dubertret Ecole Supérieure de Physique et Chimie Industrielles de Paris, Laboratoire de Physique et d'Etudes des Matériaux, Paris, France

In this talk, we introduce two nanoantennas. A gold nanoshell has been designed and fabricated in order to control the spontaneous emission of a single quantum dot. A gold nanocylinder has been designed as a nanoantenna in order to increase by more than an order of magnitude the power emitted by inelastic tunneling in a scanning tunneling microscope.

Colloidal semiconductor quantum dots (QDs) are fluorescent nanocrystals exhibiting exceptional optical properties¹, but their emission intensity strongly depends on their charging state² and their local environment³. This dependence leads to blinking at the single particle level⁴ or even complete fluorescence quenching, and limits the applications of QDs when used as fluorescent particles. In spite of many improvements using core/shell sQDs, colloidal non-blinking and environmentally robust nanoemitters have never been obtained. In this presentation, we show that single QD encapsulated in a silica shell that is coated with a continuous gold nanoshell provides a system with a stable and poissonian emission at room temperature that is preserved regardless of drastic changes in the local environment. This novel hybrid QD/silica/gold structure behaves as plasmonic resonator with strong (~ 6) Purcell factor, in very good agreement with the simulations. The gold nanoshell acts also as a shield that protects the QD fluorescence and enhances its resistance to high-power photoexcitation or high-energy electron beams. This plasmonic fluorescent resonator opens the way to a new family of plasmonic non-blinking nanoemitters with very robust optical properties that can be used from biosensing and targeting to nanophotonics engineering.

Light emission by inelastic tunneling has been known for decades. Yet, the conversion from electrons into photons is very low and the emission spectrum is very broad. Here, we introduce a nanocylinder that allows increasing the amplitude of the emitted plasmon by more than one order of magnitude and narrows the emitted spectrum providing an efficient way to control the emission frequency.

References:

[1] X. Michalet, et al. Science307, 538-544 (2005).

[2] P. Spinicelli et al. Phys Rev Lett102, 4, (2009).

[3] S. F Wuister,.C.D. Donega, & A. Meijerink. J Phys Chem B108, 17393-17397 (2004).

[4] M. Nirmal, et al. Nature383, 802-804 (1996).

jean-jacques.greffet@institutoptique.fr