Jerome Wenger NanoBioPhotonics

Metal nanoapertures known as zero-mode waveguides (ZMWs) are receiving a large interest as they concentrate light into nanoscale volumes and enable single molecule fluorescence experiments at micromolar concentrations. Within the large single molecule fluorescence toolbox, FRET is certainly one of the most widely used. Therefore it is tempting to associate ZMWs with FRET. However, such experiments are challenged by the complex influence the metal may have on the FRET process.

In a recent Chem Phys Chem article, we quantify the FRET rates and efficiencies between individual donor-acceptor pairs in aluminum zero-mode waveguides. We also compare the FRET results between ZMWs milled in gold and aluminum, and discuss the influence of plasmon resonance effects.

Given the large interest raised by aluminum ZMWs and FRET separately, we believe that our detailed report will help to expand the application of ZMWs as new devices for enhanced single molecule FRET at physiological concentrations.

The technical program meeting for the CLEO Europe EQEC conference has just been held. For the EH Plasmonics and Metamaterials topic, we will have a total of seven sessions:
- Dielectric and hyperbolic metamaterials
- Chirality in plasmonics and metamaterials
- Plasmons in Low dimensionan materials
- Emission control with nanoantennas
- Nanoantennas: from sensing to thermoplasmonics
- Active plasmonics and metamaterials
- Coherent effects in nanophotonics
These sessions will provide an outstanding overview of current topics and future trends in metal nanophotonics from fundamentals towards applications and including all spectral regimes: plasmonic nanostructures, antennas, cavities and waveguides; metamaterials; hybrid materials; nonlinear structures and effects; active systems, systems with gain.

As we had a large number of submitted abstracts but a limited number of slots at the conference, the selection process was very fierce. About 50% of abstracts could be selected for talks, 25% for poster and unfortunately we had to reject about 25% of abstracts. This (relatively high) rejection rate is imposed by the CLEO/EQEC organization and does not necessarily reflect the will of the topical sub-committee (I would have liked to have more posters and less rejected papers). As the selection process is quite fierce, the abstract quality is a key factor. Here are a few hints to write better abstracts:
* state clearly your subject and the results you obtained
* explain how your work improves on the current knowledge or state-of-the-art
* if your abstract relates to a published article in a peer-reviewed journal, make it apparent.
* avoid parallel submission: do not multiply the abtracts on similar work

Metallic nanoparticles and more recently dielectric nanoparticles are receiving tremendous attention due to their ability to concentrate light energy into volumes at the nanometer scale. Optimizing the absorption of light by suitably designed nanoparticles is of crucial importance for a wide range of applications including optical antennas, light harvesting, thermoplasmonics and local surface plasmon resonance sensing.

In an article recently published in ACS Photonics, we develop a new conceptual framework to achieve ideal absorption of light by metallic and dielectric particles. Our main results:
- We provide analytical formulations Eq.(16) describing the conditions to reach ideal absorption up to nanoparticle sizes of several hundreds of nanometer.
- Being analytical, these formulas are of immediate use for other researchers to optimize absorption in nanoparticles.
- The approach covers the important experimental case of core-shell nanoparticles which can satisfy the ideal light absorption condition over the full visible spectrum.
- We also address the problem of light absorption by dielectric and lossy particles, like silicon, that can exhibit both electric and magnetic Mie resonances.
- Our method enables the calculation of non-fundamental ideal absorption modes.

Optical antennas for single molecule fluorescence detection at physiological concentration

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