Exceptional points are singularities in the parameter space of a physical system where two or more eigenvalues, and their associated eigenvectors, simultaneously coalesce. Here, it is shown that non-local acoustic metagratings that enable precise control over their multiple orders of diffraction, can serve as a robust platform for investigating higher-order exceptional points in free space.
- Xinsheng Fang
- Nikhil J R K Gerard
- Yong Li
