Gilles LERONDEL

LNIO

Marc LAMY DE LA CHAPELLE

LNIO

Rodolphe JAFFIOL

LNIO

Christian PRINS / Nacima LABADI

ISTIT, equipe OSI

Gilles LERONDEL

LNIO

Photonic crystals present remarkable properties such as the full control of light propagation and material emission. These properties are introduced via a periodic refractive index modulation. This modulation leads to specific electromagnetic field distributions at the light wavelength scale. A sub-wavelength field mapping using near field optical microscopy should lead to the full characterization of the structure. We already validate the method for structures presenting a weak refractive index modulation (weak coupling regime). The subject of this work is to extend the method to structures presenting a strong refractive index modulation (strong coupling regime) like silicon based structures. The originality of this work lies both in the structures and the heterodyne type of scanning near optical microscope used.

Raman spectroscopy, Surface Enhanced Raman Scattering, Near-Field optic, carbon nanotubes, nanostructures

Marc LAMY DE LA CHAPELLE

LNIO

The aim of this research is to study the vibrational properties of individual nanostructure such as nanotubes, nanowires or nanparticles. This implies the development of specific techniques. First, to observe a few number of nanostructures, the Raman signal as to be enhanced. Indeed, The investigation of nano-objects implies a momentous reduction of the analysed area and therefore of the Raman signal. Such studies require techniques exploiting local enhancements of the electromagnetic field. One of these is the so-called Surface Enhanced Raman Scattering or SERS. The enhancement is achieved when the illumination wavelength is tuned to one of the localized surface plasmon excitations of the SERS active substrate. This SERS technique is currently developed in the laboratory, and in particular through the fabrication of substrates where the shape, size and the distribution of the silver or gold nanoparticles are controlled. Consequently, the plasmon resonances can be monitored to match the desired wavelength and optimize the local field enhancement.
Second, to reach spatial resolutions in the nanometer range (nano Raman), we propose to couple a Raman spectroscope to a Near-Field optical microsocpe. We thus believe we will reach a spatial resolution of 50 nm and as well observe several or a single nanostructure.

Development of a scanning near-field optical microscope for the study of biological environment at molecular scale

Rodolphe JAFFIOL

LNIO

The objective of this PhD thesis is to develope a local probe optical microsocope dedicated to biophysics studies. The best appropriate way combine a scanning optical microscope with an optical spectroscopy unit. We choose to perform fluorescence correlation spectroscopy (FCS). At room temprature, FCS was implemented in many in vitro and in vivo setup to investigate biomolecular interaction and biomolecular diffusion process. About the optical microscopy we propose two complementary methods : confocal microscopy and apertureless near-field microscopy. The main point in these two schemes is to reduce the detection volume for probing just few molecules. This project will involve close collaboration with several biophysics group in Grenoble and in Reims.

Arc routing problems with split services and time windows

Christian PRINS
Nacima LABADI

ISTIT, Equipe OSI

In arc routing problems, the purpose is to process at minimal cost with vehicles a set of tasks located on the arcs (roads or streets) of a network. The goal of the thesis is to study this kind of problems when additional constraints are considered such as time windows and split deliveries. These extensions allow modelling real world applications such as urban waste collection, winter gritting, meter reading etc. Mathematical models, lower bounds and efficient solution algorithms must be developped and appraised on pertinent benchmarks.