3D images, video of crystal structure possible using laser scattering tomography
3D images, video of crystal structure possible using laser scattering tomography lead image
A Stanford research team has explored using laser scattering tomography (LST) to scan successive planes in a crystal and provide data which allows visualization of the defect structures in 2 or 3 dimensions. Their technique even provides videos of changes happening under various forces, and along any axis of the crystal. This made it possible, for the first time, to observe the dynamics of poling, which uses an electric field to align ferroelectric domains in the same directions, in a ferroelectric single crystal. The group reports on this work in Journal of Applied Physics.
For this experiment, the research team selected strontium barium niobate (Sr1-xBaxNb2O6, SBN), a ferroelectric crystal used in a number of optical applications. The team leveraged an existing apparatus developed to study defects in protein crystals for a NASA program that consisted of a 4 mW He-Ne laser focused to a narrow beam, a motorized three-axis translation stage, a microscope and a CCD camera. The Stanford team first collected laser scatter data from within horizontal slices scanned along the crystal’s x-axis and then by scanning the crystal slice by slice in the z direction, the researchers were able to produce a three-dimensional map highlighting various features of its structure.
The authors write that this ability to study morphological features in 3D, which reveals the shape of the defects by looking at them in different directions, demonstrates this technique’s potential as a powerful new nondestructive imaging tool with applications such as periodically poled structures for quasi-phase-matching, holographic data storage, and characterizing optical materials defect structures in semiconductors and protein crystals.
Source: “Tracking ferroelectric domain growth using laser scattering tomography,” by Howard S. Lee, Robert C. De Mattei, and Robert S. Feigelson, Journal of Applied Physics (2017). The article can be accessed at https://doi.org/10.1063/1.4986375 .
