A study on the multiplication technique of nano-moire fringe

A nano-moire fringe multiplication method is proposed and used to measure nano-deformation of single crystal materials. The lattice structure of single crystal materials is captured by TEM (Transmission Electron Microscope) and acted as a specimen grating. An unidirectional grating fabricated on glass or film is selected as a reference grating. The formation principles of TEM nano-moire fringe, the relationship between TEM magnification and grating frequency, as well as displacement and strain measurement method are discussed. A nano-moire fringe pattern can be reproduced in a 4f optical filter system with a specimen grating and a prepared reference grating. By selecting the reference grating with specific frequency and utilizing different diffraction order, a multiplying moire fringe pattern can be obtained. The results illustrate that this technique can be used to measure deformation in nano-scale. This method is especially useful in the measurement of inhomogeneous displacement field, and can be utilized to reveal nano-mechanical behavior such as dislocation and atomic bond failure.