Scattering and radiation singularities in epsilon-near-zero structures

We study the extreme and singular electromagnetic response of epsilon-near-zero (ENZ) structures. In particular, we show that ENZ-dielectric-ENZ multilayers can be designed to support: (a) singularities in their scattering spectrum, known as embedded eigenstates, which can be exploited for extreme light trapping in open systems, as well as for enhanced sensing; (b) peaks in their photonic density of states, or Van-Hove singularities, which determine strong enhancement of emission/radiation from small sources. Our findings shed light on the physics of these extreme electromagnetic effects, and represent an important step toward their application in various practical scenarios.