Berreman Embedded Eigenstates for Narrow-Band Absorption and Thermal Emission

Embedded eigenstates are nonradiative modes of an open structure with momentum compatible with radiation, yet characterized by unboundedly large Q factors. Traditionally, these states originate from total destructive interference of radiation from two or more nonorthogonal modes in periodic structures. In this work, we demonstrate a class of embedded eigenstates based on Berreman modes in epsilon-near-zero layered materials and propose realistic silicon carbide structures that support high-Q (-10(3)) resonances based on these principles. The proposed structures demonstrate strong absorption in a narrow spectral and angular range, giving rise to quasicoherent and highly directive thermal emission.