7. Conclusion

3D phase imaging is a label-free alternative to fluorescence microscopy. Unlike DIC or phase-contrast microscopy, digital holography provides quantitative phase information, but suffers from limited 3D resolution. Diffractive tomography is based on holography, but provides higher-resolution 3D imaging, by merging the different projections obtained on the object by varying a parameter (angle of illumination, angle of rotation of the object, wavelength). This technique makes it possible to measure refractive index and absorption in 3D. The availability of commercial systems makes this technique an interesting complement to fluorescence imaging, for scientists unable to mark their samples or looking for an alternative or complementary imaging mode.