  Recently, a broad spectrum of exceptional scattering effects, including bound
states in the continuum, exceptional points in PT-symmetrical non-Hermitian
systems, and many others attainable in wisely suitably engineered structures
have been predicted and demonstrated. Among these scattering effects, those
that rely on coherence properties of light are of a particular interest today.
Here, we have discussed coherent scattering effects in photonics. Coherent
perfect absorption (CPA) generalizes the concept of perfect absorption to
systems with several excitation channels. This effect allows all-optical light
manipulation by tuning of parameters of coherent excitation. In its turn, the
virtual perfect absorption (VPA) effect generalizes the concept of CPA to
complex frequencies and Hermitian systems. In contrast to real energy
dissipation in PA and CPA, in VPA the energy is trapped in a resonator till
excitation continuous exponentially growth and gets released when it breaks.
Additionally, VPA provides a way to perfectly couple to any even lossless
high-Q resonators. Finally, employing principles of coherent excitation can
boost the performance of traditional WPT systems via coherently enhanced
wireless power transfer (CWPT) effect.
