This is a review on theoretical and experimental studies on dielectric microcavities, which
play a significant role in fundamental and applied research. The basic concepts and theories …

Optical whispering‐gallery mode (WGM) microcavities featuring ultrahigh Q factors and
small mode volumes enhance significantly the interaction between light and matter …

Controlling the emission and the flow of light in micro-and nanostructures is crucial for on-
chip information processing. Here we show how to impose a strong chirality and a …

Several types of sensors used in physics are based on the detection of splittings of resonant
frequencies or energy levels. We propose here to operate such sensors at so-called …

A general theory of sensors based on the detection of splittings of resonant frequencies or
energy levels operating at so-called exceptional points is presented. Exploiting the complex …

Parameter-dependent non-Hermitian quantum systems typically not only possess
eigenvalue degeneracies, but also degeneracies of the corresponding eigenfunctions at …

A Brillouin-Wigner perturbation theory is developed for open electromagnetic systems which
are characterised by discrete resonant states with complex eigenenergies. Since these …

Optical microcavities can be designed to take advantage of total internal reflection, which
results in resonators supporting whispering-gallery modes (WGMs) with a high-quality factor …

We study the photon blockade at exceptional points for a non-Hermitian optomechanical
system coupled to the driven whispering-gallery-mode microresonator with two …

There are numerous physical situations in which a hole or leak is introduced in an otherwise
closed chaotic system. The leak can have a natural origin, it can mimic measurement …