Aluminum is currently emerging as a "hot topic" in plasmonics. Several reasons explain this fact. First, aluminium exhibits good plasmonic properties in the ultraviolet and deep ultraviolet – a spectral range where gold and silver no longer behave as metals. Second, aluminum is cheap and widely available, criteria of paramount importance when discussing industry-related applications. It is furthermore compatible with CMOS technology. Hoping to present an overview of this exciting topic, Stephen Gray (from Argonne National Laboratory, USA) and I have written a introductory review.
Paper abstract: We present an overview of 'aluminium plasmonics', i.e. the study of both fundamental and practical aspects of surface plasmon excitations in aluminium structures, in particular thin films and metal nanoparticles. After a brief introduction noting both some recent and historical contributions to aluminium plasmonics, we discuss the optical properties of aluminium and aluminium nanostructures and highlight a few selected studies in a host of areas ranging from fluorescence to data storage.
The paper is avalaible here: http://iopscience.iop.org/0022-3727/48/18/184001/article
You may also have a look at Journal of Physics D's Special Issue on Al Plasmonics. The issue is avalaible here: http://iopscience.iop.org/0022-3727/48/18
Julie's results on plasmonic enhancement of Si nanocrystals' luminescence have been published in Nature's Scientific Reports! Using an original fabrication technique (coupling e-beam lithography and reactive ion etching), we are able to precisely control the distance between a single layer of Si nanocrystals and a gold nanoparticle. The resulting hybrid emitter is 5-fold brighter than bare Si nanocrystals.
Paper abstract: Silicon nanocrystals offer huge advantages compared to other semi-conductor quantum dots as they are made from an abundant, non-toxic material and are compatible with silicon devices. Besides, among a wealth of extraordinary properties ranging from catalysis to nanomedicine, metal nanoparticles are known to increase the radiative emission rate of semiconductor quantum dots. Here, we use gold nanoparticles to accelerate the emission of silicon nanocrystals. The resulting integrated hybrid emitter is 5-fold brighter than bare silicon nanocrystals. We also propose an in-depth analysis highlighting the role of the different physical parameters in the photoluminescence enhancement phenomenon. This result has important implications for the practical use of silicon nanocrystals in optoelectronic devices, for instance for the design of efficient down-shifting devices that could be integrated within future silicon solar cells.
The paper is available, free of charge, here: http://www.nature.com/srep/2013/130916/srep02672/full/srep02672.html
In collaboration with Institut Jean Lamour (Nancy, France), I am involved in the study of the coupling between silicon nanocrystals and plasmonic nanostructures. The goal is to improve the quantum efficiency of silicon nanocrystals (aiming at applications such as energy down-shifting in silicon solar cells) and, from a more fundamental point of view, to understand the coupling between an emitter and a single plasmonic structure.
Collaboration: Julie Goffard (joint PhD student) ; Patrice Miska and Michel Vergnat (Univ. Lorraine)
The UV range is seldom studied in plasmonics, due to the difficulty to find proper materials. I am developping new platforms for UV plasmonics, using aluminum as a metal, aiming for new applications in sensing, fluorescence enhancement, or wide-band gap semiconductor optoelectronics.
Collaboration: Jérôme Martin, Jérôme Plain (UTT)
Last Paper: Localized surface plasmon resonances in the ultraviolet from large scale nanostructured aluminum films, Opt. Mat. Express 3, 954 (2013).
Abstract: We report on a straightforward preparation method to obtain a dense layer of quasi-spherical aluminum nanoparticles over a large area. The method is based on rapid thermal annealing of a thin aluminum film deposited on a super-repellent substrate. Diameters ranging from 2 to 15 nm are obtained by varying the film thickness. Aluminum nanoparticles exhibit well-defined localized surface plasmon resonances in the ultraviolet range as revealed by extinction measurements and confirmed by Mie theory.
I am involved in research in molecular plasmonics, that is, interaction between molecules (emitters or photo-sensitive materials) and plasmonic nanostructures. Topics include:
Jérôme Wenger's blog on nanophotonics: http://jw-photonics-inside.over-blog.org/
Nicolas Bonod's homepage (numerical modeling in nanophotonics): http://n.bonod.free.fr/
Research in biophotonics at Institut Fresnel: http://www.fresnel.fr/spip/spip.php?rubrique28