The tunneling of a well-defined propagating state from one wire to another,
leaving all other neighbor states unaffected, is of great importance for p
hotons, electrons and phonons. We present a simple coupling structure enabl
ing such a transfer to be realized, for any given state energy and state wi
dth. We illustrate the analytic study of this structure by an application t
o the transmission of a telecommunication signal. We discuss then how such
a structure could be realized with the help of current surface technologies
. (C) 2001 Elsevier Science Ltd. All rights reserved.