Topological scattering singularities and embedded eigenstates for polarization control and sensing applications
Abstract
Epsilon-near-zero and epsilon near-pole materials enable reflective systems supporting a class of symmetry-protected and accidental embedded eigenstates (EE) characterized by a diverging phase-resonance. Here we show that pairs of topologically protected scattering singularities necessarily emerge from EEs when a non-Hermitian parameter is introduced, lifting the degeneracy between oppositely charged singularities. The underlying topological charges are characterized by an integer winding number and appear as phase vortices of the complex reflection coefficient. By creating and annihilating them, we show that these singularities obey charge conservation, and provide versatile control of amplitude, phase and polarization in reflection, with potential applications for polarization control and sensing.
Cite
@article{arxiv.2102.06958,
title = {Topological scattering singularities and embedded eigenstates for polarization control and sensing applications},
author = {Zarko Sakotic and Alex Krasnok and Andrea Alú and Nikolina Jankovic},
journal= {arXiv preprint arXiv:2102.06958},
year = {2021}
}