The radiation of electromagnetic and mechanical waves depends not only on the intrinsic
properties of the emitter but also on the surrounding environment. This principle has laid the …

Non-Hermitian physical systems have attracted considerable attention lately for their
unconventional behaviour around exceptional points (EPs)—spectral singularities at which …

We identify a new kind of physically realizable exceptional point (EP) corresponding to
degenerate coherent perfect absorption, in which two purely incoming solutions of the wave …

Many novel properties of non-Hermitian systems are found at or near the exceptional points—
branch points of complex energy surfaces at which eigenvalues and eigenvectors coalesce …

Topological edge modes are excitations that are localized at the materials' edges and yet
are characterized by a topological invariant defined in the bulk. Such bulk–edge …

Recently, exceptional points, a degeneracy of open wave systems, have been observed in
photonics, acoustics, and electronics. They have mainly been realized as a degeneracy of …

BACKGROUND Singularities are critical points for which the behavior of a mathematical
model governing a physical system is of a fundamentally different nature compared to the …

We study the Mie-like scattering from an open subwavelength resonator made of a high-
index dielectric material, when its parameters are tuned to the regime of interfering …

A system is non-Hermitian when it exchanges energy with its environment and
nonreciprocal when it behaves differently upon the interchange of input and response …

I review the four mechanisms of bound states in the continuum (BICs) in the application of
microwave and acoustic cavities open to directional waveguides. The most simple are …