Instrumentation
Quadrature phase interferometers
We have developed differential interferometers featuring a pm resolution in a mm range: thanks to a quadrature phase detection scheme, we access 9 orders of magnitude with a single sensor ! The intrinsic spectral noise can be as low as 1fm/√Hz in a 1Hz-1MHz bandwidth, with an excellent long term stability.
enhanced force resolution AFM
Ludovic Bellon, Audrey Steinberger
Several home made Atomic Force Microscopes (AFM) are powered by our quadrature phase differential interferometers for the detection of the deflexion of the AFM cantilever. We can thus measure the deflexion of the force sensor with a fm/√Hz resolution in a several μm input range, a 10 to 100 fold improvement of both sensitivity and range with respect to commercial systems. Moreover, the system is perfectly calibrated, offering world leading precision down to 10aN/√Hz.
optical tweezers
Artyom Petrosyan, Sergio Ciliberto, Thomas Gibaud
Optical tweezers is a tool which allows to manipulate micro and nano particles without mechanical contact, using the radiation force of a focused laser beam. Optical tweezers can be used to manipulate small dielectric spheres, bacteria, metal particles, strand of DNA, etc. We are using our home made optical tweezers for small force ~fN and displacement measurements with high precision and accuracy.
high resolution surface plasmon microscopy
Françoise Argoul
Physics of the violin
Antoine Naert, Jean-Pierre Zaygel
To characterize a musical instrument of the family of the violin (viola, cello, etc.), it must be submitted to a perturbation that does not affect bridge and strings. The important point is that these last elements have a strong but not relevant response. A system has been developed that measures the response to a broad-band perturbation. The response function is very sensitive to slight differences between instruments and is insensitive to surrounding noise. This might become very helpful for the violin maker, in repair as well as construction. It can also be used to artificially play the instrument, and improve its quality this way. Patent: FR20120060891.
Ultra low-noise electronic amplifiers
The laboratory is equipped to perform low noise measurements particularly at low frequencies. A Faraday screen is available. Low noise electronics, which has been developed in our laboratory and in our electronic shop, has performances, in terms of voltage and current noises, that are better than those of commercial instrumentation. Other electronic systems, also developed in our laboratory, allows the simultaneous and accurate measurement on a wide frequency range of the response function of electronic components.
velocimetry in liquid metals
Nicolas Plihon, Jean-François Pinton
We have developed an electrodeless technique for localized measurements of velocity in electrically conducting fluids. The spatial resolution ranges from the mm to a few cm size for velocity amplitudes ranging from cm/s to tens of m/s, especially suited for liquid metal. The time dynamics probed DC components to kHz turbulent fluctuations. We have developed prototypes in liquid gallium and liquid sodium pipe flows and highly turbulent flows which demonstrated the proof of concept both for mean flows and turbulence measurements. Our technique is simple to implement, does not require electrical contact with the fluid (easing chemical compatibility issues, maintenance, conception) nor hazardous radiations. Patent: FR20100054250.
mems sensors for macroscopic flows
Julien Salort, Francesca Chilla
In turbulent thermally-driven flows, heat is transported by coherent structures called “thermal plumes”. Our main objective is to design an innovative sensor that will allow direct access to statistical features of these objects. The sensor will probe locally velocity and temperature fluctuations at the same point, giving access to the advected turbulent heat flux. It consists in a modified SiO2 cantilever anemometer (1.2 µm thick, 50x375 µm in size). The measurement combines a strain gauge to measure the cantilever elongation and a temperature-sensitive thin layer to measure the temperature. Joint work with FEMTO-ST Besançon and Institut Néel Grenoble.
Smart Particles
Francesca Chilla, Jean-François Pinton
Following the idea of atmospheric balloons we have developed a small size smart particle to measure lagrangian temperature in turbulent thermal convection. The particle motion is followed with a camera and allows us to reconstruct also lagrangian velocity as well as local heat flux. Other kind of measurements (such as concentration or pressure) have been developed in collaboration with smartINST company.
Shadow-Particle Tracking Velocimetry
We have developed a Shadow-Particle Tracking Velocimetry (S-PTV) setup which allows for the precise measurement of size and position of particles in turbulent flows. This setup has been used to study the melting of ice particles in fully turbulent water flows. In such configuration, the evolution of the particle size allows for the measurement of the turbulent heat flux at the surface of the moving particle, found to be proportionnal to the Reynolds number in the utlimate regime of forced convection! The setup is currently used to measure the rotation and translation of small anisotropic objects in non homogeneous flows.