Articles récents

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.

Mental Flow, Focus and the Zone for Scientists

17 Février 2016 , Rédigé par JW

Whenever you are writing a paper, preparing a presentation or performing a delicate experiment, you are facing a performance challenge: how to get the best output with limited resources of time, energy or grant money. This is when you need to get into the Zone. The Zone is the state of mind where you actively do your stuff with best performance, master every detail, and fly above the difficulties. And it’s enjoyable. While well acknowledged in athletics or car racing, the Zone is a concept largely underrated in academia.

Tips how to get into the Zone:

1- It comes only with experience. The first time you do something, you will not get into it: too many things to control, too many fears/issues… The Zone requires experience and training in the activity.

2- Don’t force. The Zone is essentially sub-conscious. Recognize when you’re out of it and don’t feel guilt. That happens, you will recover. Forgive yourself.

3- Get motivation on a single specific task. Select a challenge you really wish to achieve. Not too easy, not too difficult. You need a genuine sincere will. Don’t worry about success chances while setting your goal. If there is a chance, that’s enough to give a honest try. Obviously select only one task at a time. The Zone is all about mental focus.

4- Set the right conditions. Timing is an issue, some people just don’t perform well before 10am or without a dose of caffeine. The Zone is a connection between body, mind and the rest of the world. So get your body mechanics in working order. Same for inner emotions. Same for external disturbances like excess noise, light or heat.

5- Turn off disturbances. Turn off all non-necessary items for socializing: phone, internet… People will call you later, you’re in the Zone now. Doing your job more efficiently leaves more free time later for other activities.

6- Reject negative feelings. Fear, anger or unrelated irrelevant thoughts are the paths to the dark side. Throw them away as soon as these thoughts appear. Because they always appear. Focus on breathe and on your current activity is a proven method. Also don’t pay attention to your mistakes. Mistakes are normal, you notice them, correct them, you have to move on.

7- Visualize success. You must be convinced of your success chances. Even if they are very weak, there must always be hope. See yourself performing ideally well. Get the energy from the positive feelings.

8- Focus your attention to positive feedback. Every little step is bringing closer to success. Focusing on positive feedback will improve your self confidence. Enjoying what you are doing is key.

9- Get lost. Your sense of self should disappear as the notion of time. This is where you connect all pieces and get the best performance.

10- Rehearse and try again. Probably the first time it will last 5 or 10 minutes. It disappears if you become too much aware of it and want to control it. Focus on the activity and on rejecting immediately negative feelings.

Further reading: list of websites, How to Find Your State of Flow, How to Achieve the Creative State of Flow

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