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Bound states in the continuum

Abstract

Bound states in the continuum (BICs) are waves that remain localized even though they coexist with a continuous spectrum of radiating waves that can carry energy away. Their very existence defies conventional wisdom. Although BICs were first proposed in quantum mechanics, they are a general wave phenomenon and have since been identified in electromagnetic waves, acoustic waves in air, water waves and elastic waves in solids. These states have been studied in a wide range of material systems, such as piezoelectric materials, dielectric photonic crystals, optical waveguides and fibres, quantum dots, graphene and topological insulators. In this Review, we describe recent developments in this field with an emphasis on the physical mechanisms that lead to BICs across seemingly very different materials and types of waves. We also discuss experimental realizations, existing applications and directions for future work.

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Figure 1: Illustration of a BIC.
Figure 2: Symmetry-protected bound states.
Figure 3: Fabry–Pérot BICs.
Figure 4: Single-resonance parametric BICs.
Figure 5: A BIC through inverse construction.
Figure 6: Applications of BICs and quasi-BICs.

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Acknowledgements

The authors thank A. Maznev, N. Rivera, F. Wang, H. Zhou, M. Segev, N. Moiseyev, S. Longhi, P. McIver, M. McIver, F. Benabid, and S. G. Johnson for discussions. This work was partially supported by the National Science Foundation through grant no. DMR-1307632 and by the Army Research Office through the Institute for Soldier Nanotechnologies under contract no. W911NF-13-D-0001. B.Z., J.D.J. and M.S. were partially supported by S3TEC (analysis and reading of the manuscript), an Energy Frontier Research Center funded by the US Department of Energy under grant no. DE-SC0001299. B.Z. was partially supported by the United States–Israel Binational Science Foundation (BSF) under award no. 2013508.

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Hsu, C., Zhen, B., Stone, A. et al. Bound states in the continuum. Nat Rev Mater 1, 16048 (2016). https://doi.org/10.1038/natrevmats.2016.48

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