Probing strain and elastic properties of materials from wave-matter interactions

The resonant interaction of light or sound waves with matter either in the subwavelength scale or macroscopic scale modify the properties of the waves. The study of the linear or nonlinear properties of these interacting waves within the material can be used to study the mechanical properties of the materials. These non-invasive optical or ultrasonic techniques can be used to resolve the strain developed at the nanoscale or in the macroscopic scale depending on the dimension of the waves. In our group we study the strain variation in atomic layer materials such as layered two-dimensional materials with optical super-resolution using hyper-spectral second harmonic microscopy. We also use ultrasound spectroscopy for studying the elastic properties of materials. The spatial resolution and the effective depth of interaction can be controlled and modified using acoustic meta-lens. The various features of ultrasonic elastography and acoustic-metamaterials is being applied for next generation bio-imaging and non-destructive evaluation of additively manufactured materials.