Modes and exceptional points in waveguides with impedance boundary conditions

TL;DR

This paper explores waveguides with impedance boundaries, demonstrating mode selectivity, amplification, and the existence of exceptional points, with potential for tunable control in non-conservative optical systems.

Contribution

It introduces the concept of exceptional points in impedance boundary waveguides and analyzes mode behavior and amplification in active and passive dielectric fillings.

Findings

Selective mode guiding and amplification with homogeneous pumping

Existence of exceptional points in non-conservative waveguides

Differences in TE and TM mode propagation analyzed

Abstract

A planar waveguide with impedance boundary, composed of non-perfect metallic plates, and with passive or active dielectric filling is considered. We show the possibility of selective mode guiding and amplification when homogeneous pump is added to the dielectric, and analyze differences in TE and TM mode propagation. Such a non-conservative system is also shown to feature exceptional points, for specific and experimentally tunable parameters, which are described for a particular case of transparent dielectric.