  Within a new paradigm for communications on the nanoscale, high-frequency
surface acoustic waves are becoming effective data carrier and encoder. On-chip
communications require acoustic wave propagation along nano-corrugated surfaces
which strongly scatter traditional Rayleigh waves. Here we propose the delivery
of information using subsurface acoustic waves with hypersound frequencies ~20
GHz, which is a nanoscale analogue of subsurface sound waves in the ocean. A
bunch of subsurface hypersound modes is generated by pulsed optical excitation
in a multilayer semiconductor structure with a metallic nanograting on top. The
guided hypersound modes propagate coherently beneath the nanograting, retaining
the surface imprinted information, on a distance of more than 50 {\mu}m which
essentially exceeds the propagation length of Rayleigh waves. The concept is
suitable for interfacing single photon emitters, such as buried quantum dots,
carrying coherent spin excitations in magnonic devices, and encoding the
signals for optical communications at the nanoscale.
