Thermal excitation of broadband and long-range surface waves on SiO2 submicron films

We detect thermally excited surfaces waves on a submicron SiO₂ layer, including Zenneck and guided modes in addition to Surface Phonon Polaritons. The measurements show the existence of these hybrid thermal-electromagnetic waves from near- (2.7 μm) to far- (11.2 μm) infrared. Their propagation distances reach values on the order of the millimeter, several orders of magnitude larger than on semi-infinite systems. These two features, spectral broadness and long range propagation, make these waves good candidates for near-field applications both in optics and in thermics due to their dual nature.