Manifestation of the Roughness-Square-Gradient Scattering in Surface-Corrugated Waveguides

TL;DR

This paper introduces a new scattering mechanism in surface-corrugated waveguides caused by square-gradient terms in the Hamiltonian, which significantly affect wave attenuation, especially with small correlation lengths of surface roughness.

Contribution

It identifies and analyzes the impact of previously neglected square-gradient terms in the Hamiltonian on wave scattering in surface-corrugated waveguides.

Findings

Square-gradient terms significantly influence inverse attenuation length.

The effect is pronounced when the correlation length of surface roughness is small.

Numerical data support the analytical findings.

Abstract

We study a new mechanism of wave/electron scattering in multi-mode surface-corrugated waveguides/wires. This mechanism is due to specific square-gradient terms in an effective Hamiltonian describing the surface scattering, that were neglected in all previous studies. With a careful analysis of the role of roughness slopes in a surface profile, we show that these terms strongly contribute to the expression for the inverse attenuation length (mean free path), provided the correlation length of corrugations is relatively small. The analytical results are illustrated by numerical data.