Gate controlled resonant widths in double-bend waveguides: Bound states in the continuum

TL;DR

This paper investigates quantum transmission in double-bend waveguides, demonstrating how gate potentials can control resonant widths and induce bound states in the continuum, with differences observed between Z- and Pi-shaped structures.

Contribution

It introduces a method to control resonant widths and create bound states in the continuum in double-bend waveguides using gate potentials, highlighting structural chirality effects.

Findings

Gate potentials selectively affect resonant widths.

Bound states in the continuum can be realized in these waveguides.

Transmission differences are due to waveguide chirality.

Abstract

We consider quantum transmission through double-bend $\Pi$- and $Z$-shaped waveguides controlled by the finger gate potential. Using the effective non-Hermitian Hamiltonian approach we explain the resonances in transmission. We show a difference in transmission in the short waveguides that is the result of different chirality in $Z$ and $\Pi$ waveguides. We show that the potential selectively affects the resonant widths resulting in the occurrence of bound states in the continuum.