Mueller polarimetry can be integrated into almost any active imaging or spectroscopic system, and thus can provide polarimetric information at any spatial scale
Basically, to convert an active imaging system or a spectrophotometer into a polarimeter, one has to add a Polarization State Generator (PSG) in the illumination arm, and a Polarization State Analyzer, or PSA, in the detection arm.
All our polarimeters but one make use of liquid crystals (LCs) in their PSGs and PSAs, as these devices fast, easy to use and are very well suited for imaging applications, with wide angular acceptances and minimal aberrations.
These instruments can image either the sample itself (real space imaging), or the back focal plane of the objective (conoscopic imaging), In this latter mode the instrument is
equivalent to a 2D goniometric polarimeter, with azimuthal angle spanning the full 0°-360° range, and polar angle 0°- 60°.
This development was an essential part of Sami Ben Hatit’s thesis, defended in 2009.
Schematic representation of the polarimetric Microscope mounted in reflection configuration.
Macroscopic Imager Polarimeter
The new version, compatible with in vivo examination of uterine cervix (polarimetric colposcope), acquires the 16 raw images in 80 ms, without degrading the measurement accuracy.
Polarimeter based on Liquid Crystal Devices
Optical outline of the LCE based spectroscopic polarimeter in reflection configuration. The polarization state generator (PSG) includes a fixed linear polarizer and two LCE variable retarders. The same elements can be found in the polarisation state analyzer (PSA), located after the sample, but in reverse order.
Broadband Polarimeter based on Achoromatic Optical Elements
The broadband polarimeter can be used to study for instance: doping levels of transparent conducting oxydes, to characterize the optical properties of low-E coatings, or to characterize the chemical composition of thin fimms made of organic molecules.
An advanced version of this instrument, working inside of a vacuum chamber, is going to be integrated in a characterization platform at LTM (Grenoble) within the Equipex IMPACT.
|Polarimètre de Mueller||LCE Polarimeter in detail|