A103 - Single-shot polarimetric and quantitative phase imaging

Baptiste Blochet (baptiste.blochet@parisdescartes.fr)
Anis Aggoun (anis.aggoun@inserm.fr)

The polarization and the phase of a beam can carry information about objects the light encountered. Quantitative phase imaging typically allows high-contrast imaging of transparent object such as cultured cells and can extract important biophysical parameters. Polarimetric imaging provides complementary information about nanoscopic molecular ordering both through birefringence or fluorescence polarization. Wavefront sensors (WFS) are simple and compact optical devices providing both the intensity and the wavefront (or spatial phase) of a light beam, from a single image acquisition. The phase information is encoded at a camera plane by placing a so-called Hartman mask upstream. Contrary to phase imaging, polarimetric imaging still typically requires several (≥4) sequential measurements involving several dynamic polarization optics. Relying on the principle of WFS, we have developed a system allowing to provide all at once: high-resolution intensity, phase, and polarization images, in a single acquisition step, and in real time. Our system is based on the use of an optimized polarization-modulating Hartmann mask. In this workshop, we will introduce the principle and illustrate the performances of a single-shot high-resolution polarimetric wavefront sensor prototype that we developed in our laboratories. We will discuss the information that these two contrast modalities (phase and polarization) can bring to bioimaging: label free imaging, sensitivity to the nanoscopic molecular orientation, application to fluorescence imaging. Proof-of-principle samples (ranging from soft matter to biomimetic and fixed fluorescent cells) will be available to illustrate the principle and potentialities of the system. Our real-time monitoring and acquisition software will allow participants to bring their own samples and to experiment themselves. The participants will then learn both basic knowledge about phase and polarization imaging as well as about potential bio-applications.