Abstract The synergy between topology and non-Hermiticity in photonics holds immense potential for next-generation optical devices that are robust against defects. However, most demonstrations of non-Hermitian and topological photonics have been limited to super-wavelength scales due to increased radiative losses at the deep-subwavelength scale. By carefully designing radiative losses at the nanoscale, we demonstrate a non-Hermitian plasmonic–dielectric metasurface in the visible with non-trivial topology. The metasurface is based on a fourth order passive parity-time symmetric system. The designed device exhibits an exceptional concentric ring in its momentum space and is described by a Hamiltonian with a non-Hermitian Z 3 ${\mathbb{Z}}_{3}$ topological invariant of V = −1. Fabricated devices are characterized using Fourier-space imaging for single-shot k -space measurements. Our results demonstrate a way to combine topology and non-Hermitian nanophotonics for designing robust devices with novel functionalities.
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Non-Hermitian topological photonics
Recent years have witnessed a flurry of research activities in topological photonics, predominantly driven by the prospect for topological protection–a property that endows such systems with robustness against local defects, disorder, and perturbations. This field emerged in fermionic environments and primarily evolved within the framework of quantum mechanics which is by nature a Hermitian theory. However, in light of the ubiquitous presence of non-Hermiticity in a host of natural and artificial settings, one of the most pressing questions today is how non-Hermiticity may affect some of the predominant features of topological arrangements and whether or not novel topological phases may arise in non-conservative and out of equilibrium systems that are open to the environment. Here, we provide a brief overview of recent developments and ongoing efforts in this field and present our perspective on future directions and potential challenges. Special attention will be given to the interplay of topology and non-Hermiticity–an aspect that could open up new frontiers in physical sciences and could lead to promising opportunities in terms of applications in various disciplines of photonics.
more » « less- PAR ID:
- 10400503
- Publisher / Repository:
- Optical Society of America
- Date Published:
- Journal Name:
- Optical Materials Express
- Volume:
- 13
- Issue:
- 4
- ISSN:
- 2159-3930
- Format(s):
- Medium: X Size: Article No. 870
- Size(s):
- Article No. 870
- Sponsoring Org:
- National Science Foundation
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