Mirror-effect based tomographic diffraction microscopy

摘要

Tomographic Diffraction Microscopy (TDM) is a technique that makes it possible to assess for 3D complex refractive index of the investigated sample without fluorescent labeling. Therefore, TDM is a method of choice for the characterization of biological samples or functionalized surfaces. TDM is a generalization of Digital Holographic Microscopy with a full control of the angle of illumination over the object. Angle can be modified either by sweeping the illumination on the object, or by rotating the object while maintaining the angle of illumination. Combining several hundreds of acquisition, it is possible to retrieve a full 3D information about both refraction and absorption of the object. Nevertheless, the time needed for data acquisition might become prohibitive for routine investigations, or dynamic sample imaging. Moreover, simultaneous reflection and transmission characterization of sample remains an experimental challenge. Recently a method called "Mirror-Assisted Tomographic Diffraction Microscopy" (MA-TDM) have been proposed [Opt. Lett. 35, 1857 (2010)], which theoretically allows to achieved isotropic 3D resolution by combining, in a simpler fashion, reflection and transmission modes. When transparent sample are considered, one can take benefits of this mirroring effect to limit the amount of acquired holograms, while maintaining the resolution of TDM. We propose to demonstrate this concept, using a specific preparation of the sample. It will be shown that, using an adequate data processing scheme, it is possible to reconstruct 3D objects using an annular illumination sweep, thus limiting the amount of acquisition. This study paves the way to a versatile TDM configuration allowing for both reflection and transmission acquisitions from a single image acquisition.