* Astronomy

Astronomy, medicine, detection of dangerous gas, monitoring of the quality of water, from fundamental research to day to day life, the applications of spectrometry can be applied.
The principle consists of measuring precisely the wavelengths emitted or absorptive by an object in order to analyse its exact composition of it.  The only problem, with dimensions of about 10 X 10 X 5 cm, the object is sometimes too cumbersome. But while conceiving SWIFTS, a team of researchers francais carried out by Etienne Coarer, engineer-astronomer at the Laboratory of Astrophysics of Grenoble (UMR CNRS, University Joseph Fourier), has brought about a revolutionary solution to this problem of obstruction. It acts of the smallest spectrometer never conceived, 750 X 22 X 500 µm!
The principle rests on a new combination of a technique of interferometry worked out by the Nobel Prize of physique Gabriel Lippmann at the end of the 19th century, and micro-electronics. SWIFTS is made up of an optical fibre in which a wave comes to interfere with itself according to two possible configurations: either by laying out a mirror in end of fibre, it acts then of the Lippmann effect, or by separating the incidental light in two waves which are then injected into fibre in the two directions of propagation. The interferogram thus obtained must be measured by nanodetectors for then being treated in order to deduce from it the intensity according to the wavelengths which make the incidental radiation. To simulate these nanodetectors which do not exist yet, the team of Etienne Coarer laid out a series of gold nanofoils of 50 Nm thickness and 4 µm length with  dimensions of fibre.  The first results obtained with SWIFTS are more than encouraging: a spectral resolution of 4 Nm to a wavelength of 1,5 µm.

Read more   (French)