Interactions between materials, their surfaces, and applied stresses are involved in every man-made construction in the world. Therefore, finding ways to interact without altering inherent properties of materials is of great interest. Surface spectroscopies, including second harmonic generation (SHG) and sum frequency generation (SFG), are inherently noninvasive testing methods. Both SHG and SFG are well-developed techniques that can be used in various applications including the characterization of material state. Both of these techniques allow for a noninvasive analysis of various materials, such as metals and polymers. We have used SHG as a method to characterize the change in signal strength before and after mechanical, chemical, and thermal stress. The results have allowed for comparisons to established methods such as electron backscatter diffraction (EBSD) and indenter testing. SHG shows great potential for a new nondestructive evaluation (NDE) technique to provide more information alongside current destructive and nondestructive methods. SFG has long been used to excite vibrations in the bulk and at interfaces. This allows for a deeper understanding of any molecular change induced by stress such as preferred orientation and new chemical interactions. Overall developments in surface specific methods deepens our understanding of how we interface with the universe.
College and Department
Physical and Mathematical Sciences; Chemistry and Biochemistry
BYU ScholarsArchive Citation
Rellaford, Kaylee N., "Non-Linear Optical Characterization of Stressed Materials" (2021). Theses and Dissertations. 9324.
spectroscopy, nondestructive evaluation, interface, deformation, polymer characterization