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Post-doctoral position in Orsay, France

Nanometer-scale optical spectroscopies with electrons

Contact :

The position will be granted through the European STREP SPANS project :

Description of the work :

The aim of the project is to develop new types of optical excitation spectroscopies with nanometer resolution, and to apply them to metallic nanoparticles. It is well known that the optical absorption and scattering properties of metallic nanoparticles that are smaller than typical optical wavelengths strongly depend on their sizes and shapes. It is now possible to control these structural parameters. However, the combined characterisation of the structural and optical properties of single nanoparticles at the nanometre scale is not possible by conventional methods like near-field optical microscopy. Such a characterisation would be of enormous benefit for the emerging fields of nanotechnology in general and plasmonics in particular, the numerous applications of which (from telecoms to cancer therapy) rely on a good knowledge of the nanometric variations of optical excitations in metallic structures. In the host team, we have recently demonstrated the use of low-loss EELS for the nanometre-scale measurement of the optical properties of individual metallic nanoparticles in relation with their shapes. In particular, we have been able to map the optical eignemode variations within individual metallic nanoparticles (J. Nelayah et al. Nature Physics, 3, 348 (2007)). We would like to go a step further and detect the the light emitted by surface plasmons simultaneously with the EELS signal. Such an experiment should unveil previously incaccessible features of plasmon physics. The host team is currently developing a new technique, Electron Induced Radiation Emission (EIRE), with which surface plasmon de-excitation processes can be investigated. The work of the post-doctoral researcher will be : 1. To characterise the optical properties of metallic nanoparticles by EELS and EIRE 2. To participate in the development of the EIRE instrumentation. The chosen candidate will be integrated in a STREP project made up of three teams. He/she will benefit from the expertise of the host team (a world leader in TEM, with particular emphasis on EELS) and from cutting-edge laboratory-built EELS detection systems and the arrival of a next generation NION Ultra-STEM Scanning Transmission Electron Microscope. The Southampton team will prepare samples and provide expertise in optical techniques. The San Sebastian team is a world leader in the development of theory and modelling of optical properties of nano-objects, and in particular in the interpretation of low-energy-loss EELS. It is also at the root of the theoretical treatment leading to EIRE.

Requirements : Good (S)TEM operation, and EELS knowledge would be strongly recommended, but not mandatory if the motivation of the candidate and her/his interest in the subject are sufficiently strong. Also, good technical skills would be appreciated.

Duration and availability : The position is open at any time from September 2006. Duration is 1.5 years Location : Laboratoire de Physique des Solides, Bâtiment 510, Université Paris Sud, 91405 Orsay.

The LPS is located in a leafy campus, close to several French laboratories of international renown. The Lab is 30 mn from the centre of Paris by train.