  Experimental efforts to measure neutrinos by radio-frequency (RF) signals
resulting from neutrino interactions in-ice have intensified over the last
decade. Recent calculations indicate that one may dramatically improve the
sensitivity of ultra-high energy ("UHE"; >EeV) neutrino experiments via
detection of radio waves trapped along the air-ice surface. Detectors designed
to observe the "Askaryan effect" currently search for RF electromagnetic pulses
propagating through bulk ice, and could therefore gain sensitivity if signals
are confined to the ice-air boundary. To test the feasibilty of this scenario,
measurements of the complex radio-frequency properties of several
air-dielectric interfaces were performed for a variety of materials.
Two-dimensional surfaces of granulated fused silica (sand), both in the lab as
well as occurring naturally, water doped with varying concentrations of salt,
natural rock salt formations, granulated salt and ice itself were studied, both
in North America and also Antarctica. In no experiment do we observe
unambiguous surface wave propagation, as would be evidenced by signals
travelling with reduced signal loss and/or superluminal velocities, compared to
conventional EM wave propagation.
