| Project Detail |
Scattering in turbid media strongly limits the use of optical methods: atmospheric scattering can prevent remote sensing and optical imaging of tissues or scattering materials is usually only limited to a thin surface layer. Being able to see through strongly diffusive media in a non-invasive way is therefore a goal pursed by many researchers in various fields. It involves the development of many new experimental optical methods and the physical understanding of the scattering processes. The problem can be cast into an indirect measurement problem: how to get information about a sample from a set of different probes and measurements? Classical tomography is a specific case of this class of problem. From the informational point of view, the question is how to obtain the highest amount of information for given measurements, or conversely how to design the optimal measurements to maximize our knowledge on the sample?Quantum information theory, by formalizing the link between information and measurements, provides the theoretical tools to answer those questions. Starting from the equivalence between 2-level quantum systems (qubits) and classical polarization states, we will develop, in this project, a general framework inspired by quantum information processing to describe polarimetric time of flight experiments, and to process the data. From the experimental side, we will develop a new state-of-the-art time-resolved backscattering microscope, that will allow to illuminate samples with various parameters of light: laser pulses of varying wavelength and of well-defined polarization. The detection will make use of novel cameras with high temporal resolution, combined with the polarimetric setup. In parallel to the experiments, Monte-Carlo simulations will be realized, that will provide data for the implementation of new algorithms. Those ones will aim at reconstructing the structure of anisotropic scatterers embedded in highly diffusive media. Adaptive algorithms will be implemented that steer actively the measurement setup during the data acquisition in order to minimize the acquisition time. The potential application of the developed experimental setup and algorithms for medical purposes will be investigate by performing measurements on phantoms and biological samples. |
