Based on ultrahigh-order modes in symmetric metal-cladding waveguide with millimeter
scale, a new oscillating wave sensor is investigated to measure minute changes in various
parameters of aqueous solution. In the proposed geometry, the sample acts as the guiding layer
where oscillating waves propagate. Owing to the concentrated power in the sensing region and the
use of the very sensitive ultrahigh-order modes and the unusual large Goos-Hänchen shift, it is
demonstrated both theoretically and experimentally that its sensitivity is enhanced by one order of
magnitude than that of evanescent wave sensor.