# Brillouin zone folding driven bound states in the continuum

Article · Wenhao Wang, Yogesh Kumar Srivastava, Thomas Caiwei Tan, Zhiming M. Wang, Ranjan Singh

- Archive id: doi:10.1038/s41467-023-38367-y
- Published: 2023-05-17
- Venue: Nature Communications
- DOI: https://doi.org/10.1038/s41467-023-38367-y
- PMID: 37198151
- Citations: 273
- Source URL: https://doi.org/10.1038/s41467-023-38367-y
- PDF: https://www.nature.com/articles/s41467-023-38367-y.pdf
- Provenance: openalex

## Abstract

Non-radiative bound states in the continuum (BICs) allow construction of resonant cavities with confined electromagnetic energy and high-quality (Q) factors. However, the sharp decay of the Q factor in the momentum space limits their usefulness for device applications. Here we demonstrate an approach to achieve sustainable ultrahigh Q factors by engineering Brillouin zone folding-induced BICs (BZF-BICs). All the guided modes are folded into the light cone through periodic perturbation that leads to the emergence of BZF-BICs possessing ultrahigh Q factors throughout the large, tunable momentum space. Unlike conventional BICs, BZF-BICs show perturbation-dependent dramatic enhancement of the Q factor in the entire momentum space and are robust against structural disorders. Our work provides a unique design path for BZF-BIC-based silicon metasurface cavities with extreme robustness against disorder while sustaining ultrahigh Q factors, offering potential applications in terahertz devices, nonlinear optics, quantum computing, and photonic integrated circuits.

_Abstract reproduced under CC-BY (publisher license, via OpenAlex)._

Topics: [Photonic, Spin & Topological Qubits](https://space-kitty.com/topics/photonic-topological-qubits)

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