Transmission through surface-corrugated unidirectional waveguides

We study wave transmission G through quasi-one-dimensional waveguides with constant cross section. Constant cross section means that an infinite set of lines of the same length (that do not intersect each other) which are perpendicular to one boundary of the waveguide are also perpendicular to the other boundary. This makes the sign of the tangential velocity for all collision points of an arbitrary particle trajectory to stay constant, so that the classical or ray dynamics in the waveguide is unidirectional. In particular, we report the systematic enhancement of transmission in unidirectional corrugated waveguides when contrasting their transmission properties with those for equivalent constant-width waveguides (for which the classical dynamics is not unidirectional since particles moving in one direction along the waveguide can change its direction of motion). Also, we verify the universality of the distribution of transmissions P(G) in the diffusive ( ⟨G⟩>1) and localized ( ⟨G⟩≪1) regimes of transport. Moreover, we show that in the transition regime, ⟨G⟩∼1, P(G) is well described by the DMPK approach (the Fokker-Planck approach of Dorokhov, Mello, Pereyra, and Kumar) to bulk-disordered wires.