Check out in the August issue of ACS Nano, a paper in collaboration with the Weizmann Institute of Science on the use of colloidal quantum dots to probe the local field enhancement on photonic antennas.
Plasmonic nanoantennas constitute a very active area of nanosciences, and have turned into essential devices to manipulate light at the nanoscale. Various spectroscopic methods are commonly used to quantify the overall amplification brought by an optical antenna on the emitted signal. However, experimentally characterizing the antenna’s response at the excitation frequency solely remains a scientific and technical challenge. Such characterization is highly needed to fully understand and optimize the antenna’s design.
Our paper describes a novel experimental method to directly characterize the antenna amplification on the excitation field independently on the emission process. We take advantage of the complex transient photoluminescence dynamics of colloidal quantum dots to probe photonic nanoantennas made of dielectric microspheres and gold nanoapertures.
This work has four major aspects of general interest:
1) we describe a novel and direct approach to quantify the electromagnetic amplification on an optical antenna for the excitation process only.
2) we demonstrate a new form of enhanced (nonlinear) light-matter interaction at the nanoscale via the increased doubly excited state formation on nanoantennas
3) we introduce a novel use of multiple excited states in colloidal quantum dots for nanophotonic applications. This effect is impossible to obtain with (organic) molecular systems.
4) we show excellent agreement between experimental results and numerical simulations.
From tonight, and ongoing every Friday night in June, a 10W green laser beam will be sent over Marseille historical center. This will redo Fizeau's experiment and measure the speed of light.
See the blog: un laser sur Marseile
Different animations will be distributed along the laser beam path. Posters to illustrate the concepts and applications of lasers, and demonstrations with lasers :
* mini laser show
* laser balloon burning
* schweppes fluorescence
* invisible ink seen with laser
* CD rom physics