Articles récents

Competition between Förster Resonance Energy Transfer and Donor Photodynamics in Plasmonic Dimer Nanoantennas

22 Avril 2016 , Rédigé par JW

Competition between Förster Resonance Energy Transfer and Donor Photodynamics in Plasmonic Dimer Nanoantennas

Plasmonic nanoantennas provide powerful means to concentrate light into nanoscale dimensions and enhance the fluorescence from single quantum emitters. However, the effects of a resonant plasmonic antenna on Förster resonance energy transfer (FRET) between single molecules remained elusive so far. We address this challengein a recent ACS Photonics publication, and report FRET between single donor and acceptor fluorescent molecules deterministically located inside the nanogap of a resonant gold dimer antenna.

Significance:

- While previous works were limited to moderate nanophotonic effects and lacked position control of the dyes, our gold antennas provide 10x stronger photonic effects on accurately positioned donor and acceptor molecules. This sets unprecedented conditions to explore the limits of nanophotonics to control energy transfer at the nanoscale.

- We conclusively demonstrate enhanced energy transfer rate constants in resonant plasmonic nanoantennas, in good agreement with numerical simulations.

- Our results exemplify the competition between radiative and non-radiative processes in complex nanophotonic systems and highlight geometrical parameters and design rules to optimize nanoantennas for non-radiative energy harvesting.

Coupling Emitters and Silver Nanowires for Long-Range Plasmon-Mediated FRET

31 Mars 2016 , Rédigé par JW

Coupling Emitters and Silver Nanowires for Long-Range Plasmon-Mediated FRET

Quantum plasmonics and the interaction of quantum emitters with metal nanostructures are receiving a large interest. However, coupling two quantum emitters via a surface plasmon waveguide has remained a major technical challenge.

In a recent ACS Nano publication, we take a significant step towards achieving this goal and demonstrate for the first time the plasmon-mediated fluorescence energy transfer between two nanoparticles separated by micron distance. The key technical innovation is brought by a dedicated dual-beam optical microscope, allowing us to find the best configurations that maximize the nanoparticle-nanowire coupling.

Significance:

- We describe the experimental conditions to achieve high figures of merit for coupling nanoemitters with plasmonic waveguides, in excellent agreement with numerical simulations.

- We provide the first demonstration of long-range fluorescence energy transfer between two nanoparticles mediated by nanowire surface plasmons.

Picosecond lifetimes and high quantum yields in plasmonic dimer antennas

24 Mars 2016 , Rédigé par JW

Picosecond lifetimes and high quantum yields in plasmonic dimer antennas

Coupling single fluorescent emitters to plasmonic resonators is essential in optimizing solid-state light sources. However, the non-scalability of the current approaches remains still a major challenge. In a recent ACS Nano publication, we overcome the scalability issue and demonstrate the self-assembly of colloidal nanostructures associating a single molecule to optimized gold nanoparticle dimers.

Significance:

- We achieve the large scale bottom-up production of millions of reproducible samples deterministically coupling a single emitter to plasmonic optical antennas.

- The nanoemitters achieve luminescence lifetimes down to a few picoseconds (some of the shortest ever reported) and importantly maintain a high quantum yields of 70 %.

- Our data uniquely quantifies the statistical dispersions of the fluorescence intensity and decay rate enhancements in plasmonic dimer antennas.

Carnival in the lab

29 Février 2016 , Rédigé par JW

Carnival in the lab

A freshly shaved CNRS researcher in shirt, a nano space pirate and doughnuts... mmm... lots of doughnuts!!

[Edit] Wenger on defeat, discipline, Barcelona

25 Février 2016 , Rédigé par JW

Arsene Wenger speaks about Barcelona: "They are better than us, everybody knows that, but I think we could’ve won the game tonight if we kept the discipline until the end."

Obviously thinking about ICFO, wasn't he? Let's follow coach Wenger's advice. Discipline and we'll get'em.

[EditJW1] Material deleted. Heretic content. Defeat is just another step to success.

[EditPW2] We are not in competition with ICFO. Nor anybody else. Just to improve ourselves.

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