We aim to model the near-field raman spectroscopy experiments developed
in our laboratory, as well as optimize the structures and substrate
used for these experiments.
Development of simulation tools based on the Finite Element Method, the
Finite-Difference Time-Domain method and the Coupled-Wave Method.
Results and prospects
Near-field Raman spectroscopy is a technique to study the structure of
matter at the nano-metric scale.
This kind of spectroscopy allows us to find informations about the composition
of the studied samples.
Nevertheless, this is only possible if the signal over noise ratio is great
For this reason, the electric field seen by the sample has to be enhanced
by mean of surface plasmons generated through the excitation
of resonant substrates.
Two approaches were developed in order to model this kind of resonant
The first one is based on the Finite Element Method (currently 2D),
the second one on the Finite-Difference Time-Domain method (2D and 3D).
The FEM allows the fine description of geometries with a high level of
complexity, and can solve harmonic or stationary problems
(i.e. independent of time).
The FDTD method is currently applied to the study of plasmon resonance in
nano-structures, and numerical results in good agreement with those
obtained experimentally were observed.
Comparisons between both methods are performed, and the choice of the
method is directed by the time requirement, the memory requirement,
and the precision of the mesh needed.
A collaboration with Brahim Guizal (Laboratoire P.M. Duffieux, Besançon)
will enable us to perform further comparisons with spectral
method (mainly the Coupled-Wave Method).
© Copyright 2007-2012 Thomas Grosges.