Unidirectional guided resonances in anisotropic waveguides

TL;DR

This paper demonstrates the existence of unidirectional guided resonances in anisotropic waveguides, enabling control over radiation direction and wavelength, with potential applications in integrated photonics.

Contribution

It introduces a novel mechanism for unidirectional guided resonances in anisotropic waveguides by breaking polar anisotropy-symmetry, allowing selective radiation control.

Findings

UGRs occur at specific wavelengths and directions.

Radiation can be canceled in one channel and redirected into another.

The mechanism allows tuning of resonance properties.

Abstract

We show that anisotropic planar anti-guiding waveguide structures with two radiation channels towards the surrounding cladding materials can support unidirectional guided resonances (UGRs), where radiation is cancelled in one of the radiation channels and redirected into the other. Their formation is subtle as it requires breaking the so-called polar anisotropy-symmetry of the structures. Then, UGRs appear at specific wavelengths and light propagation directions, are robust, and are characterised by phase singularities in the channel in which radiation is cancelled. The mechanism we describe allows for ready selection of the radiation direction, as well as tuning of the wavelength and the propagation angle at which UGRs occur.