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Exceptional points and non-Hermitian photonics at the nanoscale

Nature Nanotechnology volume 18, pages 706–720 (2023)Cite this article

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Abstract

Exceptional points (EPs) arising in non-Hermitian systems have led to a variety of intriguing wave phenomena, and have been attracting increased interest in various physical platforms. In this Review, we highlight the latest fundamental advances in the context of EPs in various nanoscale systems, and overview the theoretical progress related to EPs, including higher-order EPs, bulk Fermi arcs and Weyl exceptional rings. We peek into EP-associated emerging technologies, in particular focusing on the influence of noise for sensing near EPs, improving the efficiency in asymmetric transmission based on EPs, optical isolators in nonlinear EP systems and novel concepts to implement EPs in topological photonics. We also discuss the constraints and limitations of the applications relying on EPs, and offer parting thoughts about promising ways to tackle them for advanced nanophotonic applications.

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Fig. 1: EPs and their applications.
Fig. 2: PT-symmetry and EPs in nanophotonic systems.
Fig. 3: Schematics of several EP sensors and performance degradation caused by fabrication variations.
Fig. 4: EP encircling and its applications.
Fig. 5: Non-reciprocal wave propagation with nonlinearity.
Fig. 6: Non-Hermiticity in applications of topological photonics and metasurfaces.

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Acknowledgements

This work has been supported by the National Natural Science Foundation of China (grant numbers 11674118 and 12074137), the State Key Laboratory of Artificial Microstructure and Mesoscopic Physics (Peking University), the State Key Laboratory of Advanced Technology for Materials Synthesis and Processing (Wuhan University of Technology), the Air Force Office of Scientific Research MURI programme and the Simons Foundation.

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Author notes

  1. These authors contributed equally: Aodong Li, Heng Wei, Michele Cotrufo.

Authors and Affiliations

  1. Wuhan National Laboratory for Optoelectronics and School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, China

    Aodong Li, Bingcong Xu, Jian Wang & Lin Chen

  2. Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore

    Heng Wei, Weijin Chen, Jianfeng Chen & Cheng-Wei Qiu

  3. Photonics Initiative, Advanced Science Research Center, City University of New York, New York, NY, USA

    Michele Cotrufo, Sander Mann, Xiang Ni & Andrea Alù

  4. Department of Electrical Engineering, Ginzton Laboratory, Stanford University, Stanford, CA, USA

    Shanhui Fan

  5. Department of Applied Physics, Stanford University, Stanford, CA, USA

    Shanhui Fan

  6. Physics Program, Graduate Center, City University of New York, New York, NY, USA

    Andrea Alù

  7. State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing, China

    Lin Chen

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Li, A., Wei, H., Cotrufo, M. et al. Exceptional points and non-Hermitian photonics at the nanoscale. Nat. Nanotechnol. 18, 706–720 (2023). https://doi.org/10.1038/s41565-023-01408-0

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