Coherent control of light scattering

Abstract

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.