Institut Fresnel

The SEMO team (ElectroMagnetic and Optical Probing) is directed by Guillaume Maire since 2022.

It started under the name of TEM (Remote Sensing and Experimentation in Microwaves), created and directed by Marc Saillard from 1997 to 2003, then under the name SEMO directed by Hugues Giovannini and Anne Sentenac from 2004 to 2006, Anne Sentenac from 2006 to 2012, Patrick Chaumet from 2012 to 2017, Kamal Belkebir from 2017 to 2022, and Guillaume Maire since 2022.

The research themes of the SEMO team concern the use of electromagnetic waves, in particular in the optical and microwave domains, to detect, locate and characterize objects at a distance.
The waves are used as probes that interact with the objects and media studied.

The properties (intensity distribution, phase, polarization, frequency) of the waves returned by the objects are then analyzed, thanks to various models, to find the characteristic parameters describing the objects or media studied. This work uses electromagnetic theories of diffraction / scattering.

They are both theoretical and experimental. The applications of this work concern among others space oceanography, the detection of buried objects (pipes, anti-personnel mines), radar imaging, the characterization of scattering media (paints, waste water, rough surfaces) and optical microscopy.

All these works lead us to study more fundamental aspects such as the resolution limit in imaging, the role of multiple scattering in effective media theories or the influence of the finite size of the medium on the mean fields.

In parallel with these main research topics we also study optical forces and torques as well as the lifetime of fluorescent molecules in complex environments.

Organization of special sessions:

A. Sentenac, O. Haeberle and K. Belkebir, Special Issue: Digital Optical Microscopy, J. Modern Optics 57, 685 (2010).
K. Belkebir and M. Saillard, Special section on testing inversion algorithms against experimental data: inhomogeneous targets, Inverse Problems, 21, S1-S3 (2005).
K. Belkebir and M. Saillard, Special section on testing inversion algorithms against experimental data, Inverse Problems, 17, 1565-1571, (2001).

Resources

Computational code for electromagnetic wave diffraction by objects with arbitrary two- and three-dimensional geometry (method of moments) in homogeneous space or in a multilayer free slicing: IFDDA

Two and three dimensional inverse diffraction code.
One- and two-dimensional rough surface scattering code.
Diffraction code by gratings (modal method or method of moments).
Inversion using the time reversal operator.
Electromagnetic pulse diffraction code in two and three dimensions.
Code for the calculation of optical forces for any object in three dimensions (anisotropy, permeability, permittivity, shape) in the harmonic and pulse regime.