Digital holography

Digital holographic microscopy for biological imaging

Health care domain is always on the lookout for new simple and effective devices, for biological research and screening/identification/diagnostic of diseases. High resolution 3D quantitative imaging of cell structures and of their dynamics is a powerful approach in various biomedical applications. Digital holography is a state of the art technique providing quantitative images of biological samples with added functionalities over conventional microscopes: label-free, high contrast, quantitative. It is based on the principle of interferences between a coherent illumination beam and the beam diffracted through the sample. The resulting interference patterns (holograms) are recorded by a digital sensor and reconstructed (refocused) numerically to estimate the objects size, phase profile, refractive index, absorption coefficient. All these data lead to identification and classification of phenotypes of biological objects (e.g. cells, bacteria).

To better optimize reconstruction and improve the classification results, we co-design both holographic setups and reconstruction algorithms based on inverse problems approach.

Video of holograms of cells (recorded at CEA Leti, Cédric Allier).

O. Flasseur, C. Fournier, N. Verrier, L. Denis, F. Jolivet, A. Cazier, and T. Lépine. Self-calibration for lensless color microscopy. Applied Optics, 56(13), 2017.

 C. Fournier, F. Jolivet, L. Denis, N. Verrier, E. Thiebaut, C .Allier, and T. Fournel, Pixel super-resolution in digital holography by regularized reconstruction. Applied Optics, 56(1):69#77, 2017.

N. Verrier, C. Fournier, A. Cazier, and T. Fournel. Co-design of an in-line holographic microscope with enhanced axial resolution: selective filtering digital holography. JOSA A, 33(1), 2016.

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