Fig. 1: S0- and A0-waves in the artery.

a Schematic of a flattened artery tissue on a water bath to avoid dehydration. The elastic waves are excited by the contact probe and are measured by an OCT beam. b Photograph of the setup. c Typical OCT image of a sample. M: Media. A: Adventitia. d Representative wave motion profile measured in the artery for two different wave frequencies of 8 and 16 kHz. The displacement map (real part) is overlaid on the gray scale optical coherence tomography image. e Displacement extracted along the sample surface at 8 kHz. Solid and dashed lines denote the real and imagery parts of the displacement, respectively. f The displacement is Fourier transformed to wavenumber space, in which the primary A0 and S0 can be resolved. g Representative experimental data (circles) for phase velocities measured at different frequencies. Two modes are identified between 5 and 10 kHz, corresponding to the A0 and S0 modes. At high frequencies above 10 kHz, only a single mode is reliably detected, which is interpreted as the S0 mode in the limit of Rayleigh surface wave regime. The error bars represent the standard deviation of three replicate measurements on a single sample. h Schematics of a pure dilatational wave profile and a pure flexural wave displacement. i Finite element simulation results for the modal shapes of the A0 wave, S0 wave, and a combination of the two modes with equal amplitudes.