  Standard rheometers assess mechanical properties of viscoelastic samples up
to 100~Hz, which often hinders the assessment of the local-scale dynamics. We
demonstrate that high-frequency analysis can be achieved by inducing broadband
Rayleigh waves and monitoring their media-dependent propagation using Optical
Coherence Tomography. Here, we present a new broadband wave analysis based on
two-dimensional Fourier Transformation. We validated this method by comparing
the mechanical parameters to monochromatic excitation data and a standard
oscillatory test. Our method allows for high-frequency mechanical spectroscopy,
which could be used to investigate the local-scale dynamics of different
biological tissues and the influence of diseases on their microstructure.
