Domain structure investigation of triglycine sulfate by digital in-line holographic microscopy

The domain structure is an important characteristic of ferroelectrics. One of the most intensively studied ferroelectrics is triglycine sulfate (TGS). The domains in TGS cannot be observed directly by usual optical methods. Many methods have been developed for the observation of the domain structure in TGS like: the etching method, the powder deposition method, the decoration method, the nematic liquid crystal method, the pyroelectric probe technique, the cleavage method, the scanning electron microscopy method, and others. Despite of all these efforts, the domain structure in TGS still cannot be visualized routinely. We suggest a new method for observation of the domains in TGS, in particular digital in-line holographic microscopy (DILHM). DILHM allows direct visualization of the domain structure, without any preliminary preparation of the samples. A big advantage of the new method is its ability to extract information about the change of the domain structure in depth from one digital hologram only.