Epsilon-near-zero modes in transdimensional planar plasmonic nanostructures

Transdimensional (TD) materials are ultrathin planar nanostructures composed of a precisely controlled finite number of monolayers[1]. Plasmonic TD materials offer advances such as controlled light confinement and thickness-controlled light-matter coupling that can further develop the fields of nanophotonics and metamaterials. We use quantum electrodynamics and the confinement-induced nonlocal dielectric response model based on the Keldysh-Rytova electron interaction potential to study the epsilon-near-zero modes (ENZ) of plasmonic films in the TD regime[2]. New remarkable effects are revealed. They are the plasmon mode degeneracy lifting and the dipole emitter coupling to the ENZ modes split. The latter leads to the thickness-controlled spontaneous decay with up to three-orders-of-magnitude increased rates. Knowledge of these features is advantageous both for the fundamental understanding of the electromagnetic properties and for the development of the new design principles of efficient photonic nanodevices with desired characteristics that are built on ultrathin metallic TD films. -- [1]A.Boltasseva & V.M.Shalaev, ACS Photonics 6, 1 (2019); [2]I.V.Bondarev, H.Mousavi, & V.M.Shalaev, arXiv1908.00640.