Isotropic-Resolution Tomographic Diffractive Microscopy

International audienceMicroscopy techniques based on recording of the optical field diffracted by the specimen, in amplitude and phase, like Digital Holographic Microscopy (DHM) have been a growing research topic in recent years. Tomographic acquisitions are possible if one is able to record information, while controlling variations of the specimen illumination. Classical approaches consider either illumination variation, simple to implement, but suffering fro the classical "missing cone" problem, or sample rotation, delivering images with quasi-isotropic, but lower resolution. We have developed an original-, combined tomographic diffractive microscope setup, making use of specimen rotation as well as illumination rotation, which is able to deliver images with an almost isotropic resolution better than 200 nm

Tomographic diffractive microscopy with isotropic resolution

International audienceMicroscopy techniques allowing observation of unlabeled samples have recently experienced a regain of interest. In particular, approaches based on recording of the optical field diffracted by the specimen, in amplitude and phase, have proven their capacities for biological investigations. When combined with variations of specimen illumination, tomographic acquisitions are possible. One limitation of previously developed approaches is the anisotropic resolution, characteristic of all transmission microscopes. In this context, an instrument, characterized by isotropic high-resolution 3D imaging capabilities, is still awaited. For the first time, to the best of our knowledge, we have developed tomographic diffractive microscopy combining specimen rotation and illumination rotation, which delivers images with (almost) isotropic resolution below 200 nm. The method is illustrated by observations of nanoscopic fiber tips, microcrystals and pollens, and should be helpful for characterizing freestanding natural (diatoms, spores, red or white blood cells, etc.) or artificial samples. (C) 2017 Optical Society of Americ