Illustration of the phonon transmission/tunneling effect through a vacuum gap. Hot source radiates phonons towards cold sink and vice versa. Single phonon carries an electric field, illustrated by + or - signs of wavefront polarization. The polarization induces an electric field into the vacuum gap. The field enables finite transmission over the gap
M. Prunnila et. al.
nanoICT Strategic Research Agenda - Annex 1 - Nanophotonics and Nanophononics