Tracking shear waves in turbid medium by light: theory, simulation, and experiment.

Shear wave propagation provides rich information for material mechanical characterization, including elasticity and viscosity. This Letter reports tracking of shear wave propagation in turbid media by laser-speckle-contrast analysis. The theory is described, and a Monte Carlo simulation of light shear wave interaction was developed. Simulation and experiments on tissue-mimicking phantoms agree well and show tracking of shear wave at the phantom surface and at depth as well as multiple shear waves interacting within the object. The relationship between speckle contrast value and shear wave amplitude is also investigated.