A new design of resonant coupling transducer that can connect a magneto-inductive waveguide to real impedance is demonstrated. The transducer can provide exact impedance matching at two separate frequencies and approximate matching between, allowing low reflectivity to be achieved over a broad band. The theory is confirmed experimentally using thin-film magneto-inductive cable operating near 10...

a composite mechanism so that in the yellowred part of the spectrum its sensitivity is determined by long(and/or medium-) wave sensitive cones. It also obviates the contradiction between the single q(r) directional sensitivity result of Stiles (1939) and the suggestion (Enoch and Stiles, 1961) that short-wave sensitive cones are more sensitive to light entering through the edge than through the...

When recorded on an horizontal array, the acoustic intensity of a broadband source presents a striation pattern due to interferences between modes. This pattern is a robust feature of waveguide propagation and is described by a scalar parameter called waveguide invariant. In classical shallow water configurations, this invariant is close to 1 and has been used to perform source localization or ...

Contradirectional propagation through active, first-order, almost-periodic, corrugated waveguide gratings is analyzed by using both coupled-mode theory and a combined effective-index/impedance-matching matrix technique. For TE-mode operation, which is near the first-order Bragg wavelength, the equivalence of the two techniques is analytically demonstrated for shallow surface corrugations.

A slab-waveguide-based configuration for efficient frequency conversion is proposed. In the proposed structure, frequency conversion is induced through cascaded multistep nonreciprocal interband photonic transitions activated by external refractive-index modulations. The advantages of interband photonic transition over intraband photonic transition for frequency conversion are analyzed with the...